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Sample records for central memory cd4

  1. Human CD4+ central and effector memory T cells produce IL-21: effect on cytokine-driven proliferation of CD4+ T cell subsets.

    PubMed

    Onoda, Tadashi; Rahman, Mizanur; Nara, Hidetoshi; Araki, Akemi; Makabe, Koki; Tsumoto, Kouhei; Kumagai, Izumi; Kudo, Toshio; Ishii, Naoto; Tanaka, Nobuyuki; Sugamura, Kazuo; Hayasaka, Kiyoshi; Asao, Hironobu

    2007-10-01

    IL-21 regulates certain functions of T cells, B cells, NK cells and dendritic cells. Although activated CD4(+) T cells produce IL-21, data identifying the specific CD4(+) T cell subsets that produce IL-21 are conflicting. In a previous study, mouse IL-21 message was detected in T(H)2, whereas human IL-21 (hIL-21) message was found in both T(H)1 and follicular helper T cells. To identify the IL-21-secreting cell populations in human, we established a hybridoma cell line producing an anti-hIL-21 mAb. Intracellular hIL-21-staining experiments showed that hIL-21 was mainly expressed in activated CD4(+) central memory T cells and in activated CD4(+) effector memory T cells, but not in activated CD4(+) naive T cells. Moreover, IL-21 was produced upon activation by some IFN-gamma-producing T(H)1-polarized cells and some IL-17-producing T(H)17-polarized cells, but not by IL-4-producing T(H)2-polarized cells. These results suggest that specific CD4(+) T cell populations produce IL-21. In the functional analysis, we found that IL-21 significantly enhanced the cytokine-driven proliferation of CD4(+) helper T cells synergistically with IL-7 and IL-15 without T cell activation stimuli. Taken together, IL-21 produced from CD4(+) memory T cells may have a supportive role in the maintenance of CD4(+) T cell subsets.

  2. Hoxb4 Overexpression in CD4 Memory Phenotype T Cells Increases the Central Memory Population upon Homeostatic Proliferation

    PubMed Central

    Fournier, Marilaine; Labrecque, Nathalie; Bijl, Janet J.

    2013-01-01

    Memory T cell populations allow a rapid immune response to pathogens that have been previously encountered and thus form the basis of success in vaccinations. However, the molecular pathways underlying the development and maintenance of these cells are only starting to be unveiled. Memory T cells have the capacity to self renew as do hematopoietic stem cells, and overlapping gene expression profiles suggested that these cells might use the same self-renewal pathways. The transcription factor Hoxb4 has been shown to promote self-renewal divisions of hematopoietic stem cells resulting in an expansion of these cells. In this study we investigated whether overexpression of Hoxb4 could provide an advantage to CD4 memory phenotype T cells in engrafting the niche of T cell deficient mice following adoptive transfer. Competitive transplantation experiments demonstrated that CD4 memory phenotype T cells derived from mice transgenic for Hoxb4 contributed overall less to the repopulation of the lymphoid organs than wild type CD4 memory phenotype T cells after two months. These proportions were relatively maintained following serial transplantation in secondary and tertiary mice. Interestingly, a significantly higher percentage of the Hoxb4 CD4 memory phenotype T cell population expressed the CD62L and Ly6C surface markers, characteristic for central memory T cells, after homeostatic proliferation. Thus Hoxb4 favours the maintenance and increase of the CD4 central memory phenotype T cell population. These cells are more stem cell like and might eventually lead to an advantage of Hoxb4 T cells after subjecting the cells to additional rounds of proliferation. PMID:24324706

  3. Establishment and Reversal of HIV-1 Latency in Naive and Central Memory CD4+ T Cells In Vitro

    PubMed Central

    Zerbato, Jennifer M.; Serrao, Erik; Lenzi, Gina; Kim, Baek; Ambrose, Zandrea; Watkins, Simon C.; Engelman, Alan N.

    2016-01-01

    ABSTRACT The latent HIV-1 reservoir primarily resides in resting CD4+ T cells which are a heterogeneous population composed of both naive (TN) and memory cells. In HIV-1-infected individuals, viral DNA has been detected in both naive and memory CD4+ T cell subsets although the frequency of HIV-1 DNA is typically higher in memory cells, particularly in the central memory (TCM) cell subset. TN and TCM cells are distinct cell populations distinguished by many phenotypic and physiological differences. In this study, we used a primary cell model of HIV-1 latency that utilizes direct infection of highly purified TN and TCM cells to address differences in the establishment and reversal of HIV-1 latency. Consistent with what is seen in vivo, we found that HIV-1 infected TN cells less efficiently than TCM cells. However, when the infected TN cells were treated with latency-reversing agents, including anti-CD3/CD28 antibodies, phorbol myristate acetate/phytohemagglutinin, and prostratin, as much (if not more) extracellular virion-associated HIV-1 RNA was produced per infected TN cell as per infected TCM cell. There were no major differences in the genomic distribution of HIV-1 integration sites between TN and TCM cells that accounted for these observed differences. We observed decay of the latent HIV-1 cells in both T cell subsets after exposure to each of the latency-reversing agents. Collectively, these data highlight significant differences in the establishment and reversal of HIV-1 latency in TN and TCM CD4+ T cells and suggest that each subset should be independently studied in preclinical and clinical studies. IMPORTANCE The latent HIV-1 reservoir is frequently described as residing within resting memory CD4+ T cells. This is largely due to the consistent finding that memory CD4+ T cells, specifically the central (TCM) and transitional memory compartments, harbor the highest levels of HIV-1 DNA in individuals on suppressive therapy. This has yielded little research

  4. Polyfunctional cytokine responses by central memory CD4+T cells in response to bovine tuberculosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    CD4 T cells are crucial in immunity to tuberculosis (TB). Polyfunctional CD4 T cells simultaneously produce interferon-gamma (IFN-gamma), interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha) and play relevant roles in several chronic infections, including human TB and HIV. Mycobacterium ...

  5. Polyfunctional cytokine responses by central memory CD4*T cells in response to bovine tuberculosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    CD4 T cells are crucial in immunity to tuberculosis (TB). Polyfunctional CD4 T cells simultaneously produce interferon-gamma (IFN-gamma), interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha) and play relevant roles in several chronic infections, including human TB. Mycobacterium bovis in...

  6. CXCR5 expressing human central memory CD4 T cells and their relevance for humoral immune responses.

    PubMed

    Chevalier, Nina; Jarrossay, David; Ho, Edwin; Avery, Danielle T; Ma, Cindy S; Yu, Di; Sallusto, Federica; Tangye, Stuart G; Mackay, Charles R

    2011-05-15

    High expression of CXCR5 is one of the defining hallmarks of T follicular helper cells (T(FH)), a CD4 Th cell subset that promotes germinal center reactions and the selection and affinity maturation of B cells. CXCR5 is also expressed on 20-25% of peripheral blood human central memory CD4 T cells (T(CM)), although the definitive function of these cells is not fully understood. The constitutive expression of CXCR5 on T(FH) cells and a fraction of circulating T(CM) suggests that CXCR5(+) T(CM) may represent a specialized subset of memory-type T(FH) cells programmed for homing to follicles and providing B cell help. To verify this assumption, we analyzed this cell population and show its specialized function in supporting humoral immune responses. Compared with their CXCR5(-) T(CM) counterparts, CXCR5(+) T(CM) expressed high levels of the chemokine CXCL13 and efficiently induced plasma cell differentiation and Ig secretion. We found that the distinct B cell helper qualities of CXCR5(+) T(CM) were mainly due to high ICOS expression and pronounced responsiveness to ICOS ligand costimulation together with large IL-10 secretion. Furthermore, B cell helper attributes of CXCR5(+) T(CM) were almost exclusively acquired on cognate interaction with B cells, but not with dendritic cells. This implies that a preferential recruitment of circulating CXCR5(+) T(CM) to CXCL13-rich B cell follicles is required for the promotion of a quick and efficient protective secondary humoral immune response. Taken together, we propose that CXCR5(+) T(CM) represent a distinct memory cell subset specialized in supporting Ab-mediated immune responses.

  7. ICOS is required for the generation of both central and effector CD4(+) memory T-cell populations following acute bacterial infection.

    PubMed

    Marriott, Clare L; Carlesso, Gianluca; Herbst, Ronald; Withers, David R

    2015-06-01

    Interactions between ICOS and ICOS ligand (ICOSL) are essential for the development of T follicular helper (Tfh) cells and thus the formation and maintenance of GC reactions. Given the conflicting reports on the requirement of other CD4(+) T-cell populations for ICOS signals, we have employed a range of in vivo approaches to dissect requirements for ICOS signals in mice during an endogenous CD4(+) T-cell response and contrasted this with CD28 signals. Genetic absence of ICOSL only modestly reduced the total number of antigen-specific CD4(+) T cells at the peak of the primary response, but resulted in a severely diminished number of both T central memory and T effector memory cells. Treatment with blocking anti-ICOS mAb during the primary response recapitulated these effects and caused a more substantial reduction than blocking CD28 signals with CTLA4Ig. During the memory phase of the response further signals through ICOS or CD28 were not required for survival. However, upon secondary challenge only Tfh cell expansion remained heavily ICOS-dependent, while CD28 signals were required for optimal expansion of all subsets. These data demonstrate the importance of ICOS signals specifically for memory CD4(+) T-cell formation, while highlighting the potential of therapeutically targeting this pathway.

  8. Protective Immunity Induced with the RTS,S/AS Vaccine Is Associated with IL-2 and TNF-α Producing Effector and Central Memory CD4+ T Cells

    PubMed Central

    Rein, Lisa E.; Moris, Philippe; Janssens, Michel; Ofori-Anyinam, Opokua; Cohen, Joe; Kester, Kent E.; Heppner, D. Gray; Krzych, Urszula

    2011-01-01

    A phase 2a RTS,S/AS malaria vaccine trial, conducted previously at the Walter Reed Army Institute of Research, conferred sterile immunity against a primary challenge with infectious sporozoites in 40% of the 80 subjects enrolled in the study. The frequency of Plasmodium falciparum circumsporozoite protein (CSP)-specific CD4+ T cells was significantly higher in protected subjects as compared to non-protected subjects. Intrigued by these unique vaccine-related correlates of protection, in the present study we asked whether RTS,S also induced effector/effector memory (TE/EM) and/or central memory (TCM) CD4+ T cells and whether one or both of these sub-populations is the primary source of cytokine production. We showed for the first time that PBMC from malaria-non-exposed RTS,S-immunized subjects contain both TE/EM and TCM cells that generate strong IL-2 responses following re-stimulation in vitro with CSP peptides. Moreover, both the frequencies and the total numbers of IL-2-producing CD4+ TE/EM cells and of CD4+ TCM cells from protected subjects were significantly higher than those from non-protected subjects. We also demonstrated for the first time that there is a strong association between the frequency of CSP peptide-reactive CD4+ T cells producing IL-2 and the titers of CSP-specific antibodies in the same individual, suggesting that IL-2 may be acting as a growth factor for follicular Th cells and/or B cells. The frequencies of CSP peptide-reactive, TNF-α-producing CD4+ TE/EM cells and of CD4+ TE/EM cells secreting both IL-2 and TNF-α were also shown to be higher in protected vs. non-protected individuals. We have, therefore, demonstrated that in addition to TNF-α, IL-2 is also a significant contributing factor to RTS,S/AS vaccine induced immunity and that both TE/EM and TCM cells are major producers of IL-2. PMID:21779319

  9. Divergent CD4+ T memory stem cell dynamics in pathogenic and nonpathogenic simian immunodeficiency virus infections.

    PubMed

    Cartwright, Emily K; McGary, Colleen S; Cervasi, Barbara; Micci, Luca; Lawson, Benton; Elliott, Sarah T C; Collman, Ronald G; Bosinger, Steven E; Paiardini, Mirko; Vanderford, Thomas H; Chahroudi, Ann; Silvestri, Guido

    2014-05-15

    Recent studies have identified a subset of memory T cells with stem cell-like properties (T(SCM)) that include increased longevity and proliferative potential. In this study, we examined the dynamics of CD4(+) T(SCM) during pathogenic SIV infection of rhesus macaques (RM) and nonpathogenic SIV infection of sooty mangabeys (SM). Whereas SIV-infected RM show selective numeric preservation of CD4(+) T(SCM), SIV infection induced a complex perturbation of these cells defined by depletion of CD4(+)CCR5(+) T(SCM), increased rates of CD4(+) T(SCM) proliferation, and high levels of direct virus infection. The increased rates of CD4(+) T(SCM) proliferation in SIV-infected RM correlated inversely with the levels of central memory CD4(+) T cells. In contrast, nonpathogenic SIV infection of SM evidenced preservation of both CD4(+) T(SCM) and CD4(+) central memory T cells, with normal levels of CD4(+) T(SCM) proliferation, and lack of selective depletion of CD4(+)CCR5(+) T(SCM). Importantly, SIV DNA was below the detectable limit in CD4(+) T(SCM) from 8 of 10 SIV-infected SM. We propose that increased proliferation and infection of CD4(+) T(SCM) may contribute to the pathogenesis of SIV infection in RM.

  10. Immune memory in CD4+ CD45RA+ T cells.

    PubMed Central

    Richards, D; Chapman, M D; Sasama, J; Lee, T H; Kemeny, D M

    1997-01-01

    This study addresses the question of whether human peripheral CD4+ CD45RA+ T cells possess antigen-specific immune memory. CD4+ CD45RA+ T cells were isolated by a combination of positive and negative selection. Putative CD4+ CD45RA+ cells expressed CD45RA (98.9%) and contained < 0.1% CD4+ CD45RO+ and < 0.5% CD4+ CD45RA+ CD45RO+ cells. Putative CD45RO+ cells expressed CD45RO (90%) and contained 9% CD45RA+ CD45RO+ and < 0.1% CD4+ CD45RA+ cells. The responder frequency of Dermatophagoides pteronyssinus-stimulated CD4+ CD45RA+ and CD4+ CD45RO+ T cells was determined in two atopic donors and found to be 1:11,314 and 1:8031 for CD4+ CD45RA+ and 1:1463 and 1:1408 for CD4+ CD45RO+ T cells. The responder frequencies of CD4+ CD45RA+ and CD4+ CD45RO+ T cells from two non-atopic, but exposed, donors were 1:78031 and 1:176,903 for CD4+ CD45RA+ and 1:9136 and 1:13,136 for CD4+ CD45RO+ T cells. T cells specific for D. pteronyssinus were cloned at limiting dilution following 10 days of bulk culture with D. pteronyssinus antigen. Sixty-eight clones were obtained from CD4+ CD45RO+ and 24 from CD4+ CD45RA+ T cells. All clones were CD3+ CD4+ CD45RO+ and proliferated in response to D. pteronyssinus antigens. Of 40 clones tested, none responded to Tubercule bacillus purified protein derivative (PPD). No difference was seen in the pattern of interleukin-4 (IL-4) or interferon-gamma (IFN-gamma) producing clones derived from CD4+ CD45RA+ and CD4+ CD45RO+ precursors, although freshly isolated and polyclonally activated CD4+ CD45RA+ T cells produced 20-30-fold lower levels of IL-4 and IFN-gamma than their CD4+ CD45RO+ counterparts. Sixty per cent of the clones used the same pool of V beta genes. These data support the hypothesis that immune memory resides in CD4+ CD45RA+ as well as CD4+ CD45RO+ T cells during the chronic immune response to inhaled antigen. PMID:9301520

  11. Transcriptomic Analysis Implicates the p53 Signaling Pathway in the Establishment of HIV-1 Latency in Central Memory CD4 T Cells in an In Vitro Model.

    PubMed

    White, Cory H; Moesker, Bastiaan; Beliakova-Bethell, Nadejda; Martins, Laura J; Spina, Celsa A; Margolis, David M; Richman, Douglas D; Planelles, Vicente; Bosque, Alberto; Woelk, Christopher H

    2016-11-01

    The search for an HIV-1 cure has been greatly hindered by the presence of a viral reservoir that persists despite antiretroviral therapy (ART). Studies of HIV-1 latency in vivo are also complicated by the low proportion of latently infected cells in HIV-1 infected individuals. A number of models of HIV-1 latency have been developed to examine the signaling pathways and viral determinants of latency and reactivation. A primary cell model of HIV-1 latency, which incorporates the generation of primary central memory CD4 T cells (TCM), full-length virus infection (HIVNL4-3) and ART to suppress virus replication, was used to investigate the establishment of HIV latency using RNA-Seq. Initially, an investigation of host and viral gene expression in the resting and activated states of this model indicated that the resting condition was reflective of a latent state. Then, a comparison of the host transcriptome between the uninfected and latently infected conditions of this model identified 826 differentially expressed genes, many of which were related to p53 signaling. Inhibition of the transcriptional activity of p53 by pifithrin-α during HIV-1 infection reduced the ability of HIV-1 to be reactivated from its latent state by an unknown mechanism. In conclusion, this model may be used to screen latency reversing agents utilized in shock and kill approaches to cure HIV, to search for cellular markers of latency, and to understand the mechanisms by which HIV-1 establishes latency.

  12. Transcriptomic Analysis Implicates the p53 Signaling Pathway in the Establishment of HIV-1 Latency in Central Memory CD4 T Cells in an In Vitro Model

    PubMed Central

    White, Cory H.; Moesker, Bastiaan; Beliakova-Bethell, Nadejda; Martins, Laura J.; Richman, Douglas D.; Planelles, Vicente; Woelk, Christopher H.

    2016-01-01

    The search for an HIV-1 cure has been greatly hindered by the presence of a viral reservoir that persists despite antiretroviral therapy (ART). Studies of HIV-1 latency in vivo are also complicated by the low proportion of latently infected cells in HIV-1 infected individuals. A number of models of HIV-1 latency have been developed to examine the signaling pathways and viral determinants of latency and reactivation. A primary cell model of HIV-1 latency, which incorporates the generation of primary central memory CD4 T cells (TCM), full-length virus infection (HIVNL4-3) and ART to suppress virus replication, was used to investigate the establishment of HIV latency using RNA-Seq. Initially, an investigation of host and viral gene expression in the resting and activated states of this model indicated that the resting condition was reflective of a latent state. Then, a comparison of the host transcriptome between the uninfected and latently infected conditions of this model identified 826 differentially expressed genes, many of which were related to p53 signaling. Inhibition of the transcriptional activity of p53 by pifithrin-α during HIV-1 infection reduced the ability of HIV-1 to be reactivated from its latent state by an unknown mechanism. In conclusion, this model may be used to screen latency reversing agents utilized in shock and kill approaches to cure HIV, to search for cellular markers of latency, and to understand the mechanisms by which HIV-1 establishes latency. PMID:27898737

  13. Preferential expansion of human virus-specific multifunctional central memory T cells by partial targeting of the IL-2 receptor signaling pathway: the key role of CD4+ T cells.

    PubMed

    Schmueck, Michael; Fischer, Annika M; Hammoud, Ben; Brestrich, Gordon; Fuehrer, Henrike; Luu, Si-Hong; Mueller, Karin; Babel, Nina; Volk, Hans-Dieter; Reinke, Petra

    2012-05-15

    Effector memory T cells are effective in controlling acute infections, but central memory T cells play a key role in long-lasting protection against viruses and tumors. In vivo/in vitro challenge by Ag commonly supports the generation of effector memory T cells with limited longevity. To our knowledge, this study demonstrates for the first time in the human system and under rechallenge conditions that targeting IL-2R by partial mammalian target of rapamycin inhibition or blocking IL-2Rα enriches human CD4(+)/CD8(+) central memory T cells within the virus-specific T cell product associated with enhanced functionality (i.e., multicytokine secretors, including IL-2; enhanced CD137 and CD107a expression on CD8(+) and CD4(+) T cells, respectively; and killing infected target cells). Remarkably, the effects on CD8(+) T cells are mainly mediated via the enhancement of CD4(+) T cell function. The data reveal new insights into the role of CD4(+) T cell support for the quality of CD8(+) T cell memory, even under rechallenge conditions. Moreover, our method offers a new approach to improve the long-lasting efficacy of adoptive T cell therapy in patients.

  14. CD4 T-cell memory generation and maintenance.

    PubMed

    Gasper, David J; Tejera, Melba Marie; Suresh, M

    2014-01-01

    Immunologic memory is the adaptive immune system's powerful ability to remember a previous antigen encounter and react with accelerated vigor upon antigen re-exposure. It provides durable protection against reinfection with pathogens and is the foundation for vaccine-induced immunity. Unlike the relatively restricted immunologic purview of memory B cells and CD8 T cells, the field of CD4 T-cell memory must account for multiple distinct lineages with diverse effector functions, the issue of lineage commitment and plasticity, and the variable distribution of memory cells within each lineage. Here, we discuss the evidence for lineage-specific CD4 T-cell memory and summarize the known factors contributing to memory-cell generation, plasticity, and long-term maintenance.

  15. Persistent expansion of CD4+ effector memory T cells in Wegener's granulomatosis.

    PubMed

    Abdulahad, W H; van der Geld, Y M; Stegeman, C A; Kallenberg, C G M

    2006-09-01

    In order to test the hypothesis that Wegener's granulomatosis (WG) is associated with an ongoing immune effector response, even in remission, we examined the distribution of peripheral naive and memory T-lymphocytes in this disease, and analyzed the function-related phenotypes of the memory T-cell population. Peripheral blood mononuclear cells (PBMCs) were freshly isolated from WG-patients in remission (R-WG, n=40), active WG-patients (A-WG, n=17), and age-matched healthy controls (HCs, n=21). Expression of CD4, CD8, CD45RO, CCR7, interleukin (IL)-18Ralpha, ST2L, and FoxP3 were determined by four-color flow cytometric analysis. CD45RO and CCR7 were used for distinction between naive and memory T cells, IL-18Ralpha, ST2L, and FoxP3 for the assessment of Type1, Type2, and regulatory T-cells, respectively. In R-WG, the CD4+CD45RO+CCR7- effector memory T-cell subpopulation (TEM) was relatively increased, whereas the CD4+CD45RO-CCR7+ naive T-cell population (TNaive) was decreased as compared to HC. The distribution of naive and memory CD8+T cells did not differ between R-WG, A-WG, and HC, nor did CD4+CD45RO+CCR7+ central memory T cells (TCM). In contrast to HC, the percentage of CD4+TNaive cells in R-WG correlated negatively with age, whereas CD4+TEM cells showed a positive correlation. In R-WG, a skewing towards Type2 T cells was observed in CD4+TEM cells. No differences were detected in FoxP3+CD4+TEM cells between R-WG and A-WG, whereas the FoxP3-CD4+TEM cells were increased in R-WG and decreased in A-WG as compared to HC. Collectively, peripheral blood homeostasis of CD4+T cells is disturbed in R-WG with the persistent expansion of non-regulatory CD4+TEM cells. These cells might be involved in relapse and may constitute a target for therapy.

  16. A colitogenic memory CD4+ T cell population mediates gastrointestinal graft-versus-host disease

    PubMed Central

    Zhou, Vivian; Agle, Kimberle; Chen, Xiao; Beres, Amy; Komorowski, Richard; Belle, Ludovic; Taylor, Carolyn; Zhu, Fenlu; Haribhai, Dipica; Williams, Calvin B.; Verbsky, James; Blumenschein, Wendy; Sadekova, Svetlana; Bowman, Eddie; Ballantyne, Christie; Weaver, Casey; Serody, David A.; Vincent, Benjamin; Serody, Jonathan; Cua, Daniel J.; Drobyski, William R.

    2016-01-01

    Damage to the gastrointestinal tract is a major cause of morbidity and mortality in graft-versus-host disease (GVHD) and is attributable to T cell–mediated inflammation. In this work, we identified a unique CD4+ T cell population that constitutively expresses the β2 integrin CD11c and displays a biased central memory phenotype and memory T cell transcriptional profile, innate-like properties, and increased expression of the gut-homing molecules α4β7 and CCR9. Using several complementary murine GVHD models, we determined that adoptive transfer and early accumulation of β2 integrin–expressing CD4+ T cells in the gastrointestinal tract initiated Th1-mediated proinflammatory cytokine production, augmented pathological damage in the colon, and increased mortality. The pathogenic effect of this CD4+ T cell population critically depended on coexpression of the IL-23 receptor, which was required for maximal inflammatory effects. Non–Foxp3-expressing CD4+ T cells produced IL-10, which regulated colonic inflammation and attenuated lethality in the absence of functional CD4+Foxp3+ T cells. Thus, the coordinate expression of CD11c and the IL-23 receptor defines an IL-10–regulated, colitogenic memory CD4+ T cell subset that is poised to initiate inflammation when there is loss of tolerance and breakdown of mucosal barriers. PMID:27500496

  17. Peripheral T Follicular Helper Cells Are the Major HIV Reservoir within Central Memory CD4 T Cells in Peripheral Blood from Chronically HIV-Infected Individuals on Combination Antiretroviral Therapy

    PubMed Central

    Pallikkuth, Suresh; Sharkey, Mark; Babic, Dunja Z.; Gupta, Sachin; Stone, Geoffrey W.; Fischl, Margaret A.; Stevenson, Mario

    2015-01-01

    ABSTRACT In this study, we examined the peripheral blood (PB) central memory (TCM) CD4+ T cell subsets designated peripheral T follicular helper cells (pTfh cells) and non-pTfh cells to assess HIV permissiveness and persistence. Purified pTfh and non-pTfh cells from healthy HIV-negative donors were tested for HIV permissiveness using green fluorescent protein (GFP)-expressing HIV-1NL4-3/Ba-L, followed by viral reactivation using beads coated with anti-CD3/anti-CD28 monoclonal antibodies. The role of pTfh cells in HIV persistence was analyzed in 12 chronically HIV-1 infected patients before and 48 weeks after initiation of raltegravir-containing combination antiretroviral therapy (cART). Total cellular HIV-1 DNA and episomes containing two copies of the viral long terminal repeat (2LTR circles) were analyzed in using droplet digital PCR in the purified pTfh and non-pTfh cells. Activation-inducible HIV p24 expression was determined by flow cytometry. Results indicate that pTfh cells, in particular PD1+ pTfh cells, showed greater permissiveness for HIV infection than non-pTfh cells. At week 48 on cART, HIV DNA levels were unchanged from pre-cART levels, although a significant decrease in 2LTR circles was observed in both cell subsets. Inducible HIV p24 expression was higher in pTfh cells than in non-pTfh cells, with the highest frequencies in the PD1+ CXCR3− pTfh cell subset. Frequencies of HLADR+ CD38+ activated CD4 T cells correlated with 2LTR circles in pTfh and non-pTfh cells at both time points and with p24+ cells at entry. In conclusion, among CD4 TCM cells in PB of aviremic patients on cART, pTfh cells, in particular the PD1+ CXCR3− subset, constitute a major HIV reservoir that is sustained by ongoing residual immune activation. The inducible HIV p24 assay is useful for monitoring HIV reservoirs in defined CD4 T cell subsets. IMPORTANCE Identification of the type and nature of the cellular compartments of circulating HIV reservoirs is important for

  18. Quantifying susceptibility of CD4+ stem memory T-cells to infection by laboratory adapted and clinical HIV-1 strains.

    PubMed

    Flynn, Jacqueline K; Paukovics, Geza; Cashin, Kieran; Borm, Katharina; Ellett, Anne; Roche, Michael; Jakobsen, Martin R; Churchill, Melissa J; Gorry, Paul R

    2014-02-10

    CD4+ T cells are principal targets for human immunodeficiency virus type 1 (HIV-1) infection. CD4+ T cell subsets are heterogeneous cell populations, divided by functional and phenotypic differences into naïve and memory T cells. The memory CD4+ T cells are further segregated into central, effector and transitional memory cell subsets by functional, phenotypic and homeostatic characteristics. Defining the distribution of HIV-1 infection in different T cell subsets is important, as this can play a role in determining the size and composition of the viral reservoir. Both central memory and transitional memory CD4+ T cells have been described as long-lived viral reservoirs for HIV. Recently, the newly described stem memory T cell subset has also been implicated as a long-lived HIV reservoir. Using green fluorescent protein (GFP) reporter strains of HIV-1 and multi parameter flow cytometry, we developed an assay to simultaneously quantify the susceptibility of stem memory (TSCM), central memory, effector memory, transitional memory and naïve CD4+ T cell subsets, to HIV-1 infection in vitro. We show that TSCM are susceptible to infection with laboratory adapted and clinical HIV-1 strains. Our system facilitates the quantitation of HIV-1 infection in alternative T cell subsets by CCR5- and CXCR4-using viruses across different HIV-1 subtypes, and will be useful for studies of HIV-1 pathogenesis and viral reservoirs.

  19. Quantifying Susceptibility of CD4+ Stem Memory T-Cells to Infection by Laboratory Adapted and Clinical HIV-1 Strains

    PubMed Central

    Flynn, Jacqueline K.; Paukovics, Geza; Cashin, Kieran; Borm, Katharina; Ellett, Anne; Roche, Michael; Jakobsen, Martin R.; Churchill, Melissa J.; Gorry, Paul R.

    2014-01-01

    CD4+ T cells are principal targets for human immunodeficiency virus type 1 (HIV-1) infection. CD4+ T cell subsets are heterogeneous cell populations, divided by functional and phenotypic differences into naïve and memory T cells. The memory CD4+ T cells are further segregated into central, effector and transitional memory cell subsets by functional, phenotypic and homeostatic characteristics. Defining the distribution of HIV-1 infection in different T cell subsets is important, as this can play a role in determining the size and composition of the viral reservoir. Both central memory and transitional memory CD4+ T cells have been described as long-lived viral reservoirs for HIV. Recently, the newly described stem memory T cell subset has also been implicated as a long-lived HIV reservoir. Using green fluorescent protein (GFP) reporter strains of HIV-1 and multi parameter flow cytometry, we developed an assay to simultaneously quantify the susceptibility of stem memory (TSCM), central memory, effector memory, transitional memory and naïve CD4+ T cell subsets, to HIV-1 infection in vitro. We show that TSCM are susceptible to infection with laboratory adapted and clinical HIV-1 strains. Our system facilitates the quantitation of HIV-1 infection in alternative T cell subsets by CCR5- and CXCR4-using viruses across different HIV-1 subtypes, and will be useful for studies of HIV-1 pathogenesis and viral reservoirs. PMID:24517971

  20. IL-15 induces CD4+ effector memory T cell production and tissue emigration in nonhuman primates

    PubMed Central

    Picker, Louis J.; Reed-Inderbitzin, Edward F.; Hagen, Shoko I.; Edgar, John B.; Hansen, Scott G.; Legasse, Alfred; Planer, Shannon; Piatak, Michael; Lifson, Jeffrey D.; Maino, Vernon C.; Axthelm, Michael K.; Villinger, Francois

    2006-01-01

    HIV infection selectively targets CD4+ effector memory T (TEM) cells, resulting in dramatic depletion of CD4+ T cells in mucosal effector sites in early infection. Regeneration of the TEM cell compartment is slow and incomplete, even when viral replication is controlled by antiretroviral therapy (ART). Here, we demonstrate that IL-15 dramatically increases in vivo proliferation of rhesus macaque (RM) CD4+ and CD8+ TEM cells with little effect on the naive or central memory T (TCM) cell subsets, a response pattern that is quite distinct from that of either IL-2 or IL-7. TEM cells produced in response to IL-15 did not accumulate in blood. Rather, 5-bromo-2′-deoxyuridine (BrdU) labeling studies suggest that many of these cells rapidly disperse to extralymphoid effector sites, where they manifest (slow) decay kinetics indistinguishable from that of untreated controls. In RMs with uncontrolled SIV infection and highly activated immune systems, IL-15 did not significantly increase CD4+ TEM cell proliferation, but with virologic control and concomitant reduction in immune activation by ART, IL-15 responsiveness was again observed. These data suggest that therapeutic use of IL-15 in the setting of ART might facilitate specific restoration of the CD4+ T cell compartment that is the primary target of HIV with less risk of exhausting precursor T cell compartments or generating potentially deleterious regulatory subsets. PMID:16691294

  1. Oct1 and OCA-B are selectively required for CD4 memory T cell function.

    PubMed

    Shakya, Arvind; Goren, Alon; Shalek, Alex; German, Cody N; Snook, Jeremy; Kuchroo, Vijay K; Yosef, Nir; Chan, Raymond C; Regev, Aviv; Williams, Matthew A; Tantin, Dean

    2015-11-16

    Epigenetic changes are crucial for the generation of immunological memory. Failure to generate or maintain these changes will result in poor memory responses. Similarly, augmenting or stabilizing the correct epigenetic states offers a potential method of enhancing memory. Yet the transcription factors that regulate these processes are poorly defined. We find that the transcription factor Oct1 and its cofactor OCA-B are selectively required for the in vivo generation of CD4(+) memory T cells. More importantly, the memory cells that are formed do not respond properly to antigen reencounter. In vitro, both proteins are required to maintain a poised state at the Il2 target locus in resting but previously stimulated CD4(+) T cells. OCA-B is also required for the robust reexpression of multiple other genes including Ifng. ChIPseq identifies ∼50 differentially expressed direct Oct1 and OCA-B targets. We identify an underlying mechanism involving OCA-B recruitment of the histone lysine demethylase Jmjd1a to targets such as Il2, Ifng, and Zbtb32. The findings pinpoint Oct1 and OCA-B as central mediators of CD4(+) T cell memory.

  2. Differential T cell receptor-mediated signaling in naive and memory CD4 T cells.

    PubMed

    Farber, D L; Acuto, O; Bottomly, K

    1997-08-01

    Naive and memory CD4 T cells differ in cell surface phenotype, function, activation requirements, and modes of regulation. To investigate the molecular bases for the dichotomies between naive and memory CD4 T cells and to understand how the T cell receptor (TCR) directs diverse functional outcomes, we investigated proximal signaling events triggered through the TCR/CD3 complex in naive and memory CD4 T cell subsets isolated on the basis of CD45 isoform expression. Naive CD4 T cells signal through TCR/CD3 similar to unseparated CD4 T cells, producing multiple tyrosine-phosphorylated protein species overall and phosphorylating the T cell-specific ZAP-70 tyrosine kinase which is recruited to the CD3zeta subunit of the TCR. Memory CD4 T cells, however, exhibit a unique pattern of signaling through TCR/CD3. Following stimulation through TCR/CD3, memory CD4 T cells produce fewer species of tyrosine-phosphorylated substrates and fail to phosphorylate ZAP-70, yet unphosphorylated ZAP-70 can associate with the TCR/CD3 complex. Moreover, a 26/28-kDa phosphorylated doublet is associated with CD3zeta in resting and activated memory but not in naive CD4 T cells. Despite these differences in the phosphorylation of ZAP-70 and CD3-associated proteins, the ZAP-70-related kinase, p72syk, exhibits similar phosphorylation in naive and memory T cell subsets, suggesting that this kinase could function in place of ZAP-70 in memory CD4 T cells. These results indicate that proximal signals are differentially coupled to the TCR in naive versus memory CD4 T cells, potentially leading to distinct downstream signaling events and ultimately to the diverse functions elicited by these two CD4 T cell subsets.

  3. IL-10 is excluded from the functional cytokine memory of human CD4+ memory T lymphocytes.

    PubMed

    Dong, Jun; Ivascu, Claudia; Chang, Hyun-Dong; Wu, Peihua; Angeli, Roberta; Maggi, Laura; Eckhardt, Florian; Tykocinski, Lars; Haefliger, Carolina; Möwes, Beate; Sieper, Jochen; Radbruch, Andreas; Annunziato, Francesco; Thiel, Andreas

    2007-08-15

    Epigenetic modifications, including DNA methylation, profoundly influence gene expression of CD4(+) Th-specific cells thereby shaping memory Th cell function. We demonstrate here a correlation between a lacking fixed potential of human memory Th cells to re-express the immunoregulatory cytokine gene IL10 and its DNA methylation status. Memory Th cells secreting IL-10 or IFN-gamma were directly isolated ex vivo from peripheral blood of healthy volunteers, and the DNA methylation status of IL10 and IFNG was assessed. Limited difference in methylation was found for the IL10 gene locus in IL-10-secreting Th cells, as compared with Th cells not secreting IL-10 isolated directly ex vivo or from in vitro-established human Th1 and Th2 clones. In contrast, in IFN-gamma(+) memory Th cells the promoter of the IFNG gene was hypomethylated, as compared with IFN-gamma-nonsecreting memory Th cells. In accordance with the lack of epigenetic memory, almost 90% of ex vivo-isolated IL-10-secreting Th cells lacked a functional memory for IL-10 re-expression after restimulation. Our data indicate that IL10 does not become epigenetically marked in human memory Th cells unlike effector cytokine genes such as IFNG. The exclusion of IL-10, but not effector cytokines, from the functional memory of human CD4(+) T lymphocytes ex vivo may reflect the need for appropriate regulation of IL-10 secretion, due to its potent immunoregulatory potential.

  4. Expression of CD8alpha identifies a distinct subset of effector memory CD4+ T lymphocytes.

    PubMed

    Macchia, Iole; Gauduin, Marie-Claire; Kaur, Amitinder; Johnson, R Paul

    2006-10-01

    Circulating CD4+ CD8+ T lymphocytes have been described in the peripheral blood of humans and several animal species. However, the origin and functional properties of these cells remain poorly understood. In the present study, we evaluated the frequency, phenotype and function of peripheral CD4+ CD8+ T cells in rhesus macaques. Two distinct populations of CD4+ CD8+ T cells were identified: the dominant one was CD4hi CD8lo and expressed the CD8alphaalpha homodimer, while the minor population was CD4lo CD8hi and expressed the CD8alphabeta heterodimer. The majority of CD4hi CD8alphalo T cells exhibited an activated effector/memory phenotype (CCR5lo CD7- CD28- HLA-DR+) and expressed relatively high levels of granzyme B. Intracellular cytokine staining assays demonstrated that the frequency of cytomegalovirus-specific T cells was enriched five-fold in CD4hi CD8alphalo T cells compared to single-positive CD4+ T cells, whereas no consistent enrichment was observed for simian immunodeficiency virus (SIV)-specific T cells. Cross-sectional studies of SIV-infected animals demonstrated that the frequency of CD4hi CD8alphalo T cells was lower in wild-type SIV-infected animals compared to uninfected controls, although prospective studies of SIV-infected animals demonstrated depletion of CD4hi CD8alphalo lymphocytes only in a subset of animals. Taken together, these data suggest that CD4+ T cells expressing CD8alpha represent an effector/memory subset of CD4+ T cells and that this cell population can be depleted during the course of SIV infection.

  5. New Insights into the Generation of CD4 Memory May Shape Future Vaccine Strategies for Influenza.

    PubMed

    Devarajan, Priyadharshini; Bautista, Bianca; Vong, Allen M; McKinstry, Karl Kai; Strutt, Tara M; Swain, Susan L

    2016-01-01

    Influenza viral evolution presents a formidable challenge to vaccination due to the virus' ability to rapidly mutate to evade immune responses. Live influenza infections generate large and diverse CD4 effector T cell responses that yield highly protective, long-lasting CD4 T cell memory that can target conserved viral epitopes. We review advances in our understanding of mechanisms involved in generating CD4 T cell responses against the influenza A virus (IAV), focusing on specialized follicular helper (TFH) and CD4 cytotoxic (ThCTL) effector subsets and on CD4 T cell memory. We also discuss two recent findings in context of enhancing vaccine responses. First, helper T cells require priming with APC secreting high levels of IL-6. Second, the transition of IAV-generated effectors to memory depends on IL-2, costimulation and antigen signals, just before effectors reach peak numbers, defined as the "memory checkpoint." The need for these signals during the checkpoint could explain why many current influenza vaccines are poorly effective and elicit poor cellular immunity. We suggest that CD4 memory generation can be enhanced by re-vaccinating at this time. Our best hope lies in a universal vaccine that will not need to be formulated yearly against seasonal antigenically novel influenza strains and will also be protective against a pandemic strain. We suggest a vaccine approach that elicits a powerful T cell response, by initially inducing high levels of APC activation and later providing antigen at the memory checkpoint, may take us a step closer to such a universal influenza vaccine.

  6. IL-21 is required for CD4 memory formation in response to viral infection

    PubMed Central

    Yuan, Yuqing; Huang, Xiaopei

    2017-01-01

    IL-21 has been shown to play an important role in the CD8 T cell response during acute and chronic viral infections. However, the role of IL-21 signaling in the CD4 T cell response to viral infection remains incompletely defined. In a model of infection with vaccinia virus, we show that intrinsic IL-21 signaling on CD4 T cells was critical for the formation of memory CD4 T cells in vivo. We further reveal that IL-21 promoted CD4 T cell survival in a mechanism dependent on activation of the STAT1 and STAT3 signaling pathways. In addition, the activation of Akt is also required for IL-21–dependent survival of CD4 T cells in vivo. These results identify a critical role for intrinsic IL-21 signaling in CD4 T cell survival and memory formation in response to viral infection in vivo and may provide insights into the design of effective vaccine strategies.

  7. Human memory, but not naive, CD4+ T cells expressing transcription factor T-bet might drive rapid cytokine production.

    PubMed

    Yu, Si-fei; Zhang, Yan-nan; Yang, Bin-yan; Wu, Chang-you

    2014-12-19

    We found that after stimulation for a few hours, memory but not naive CD4(+) T cells produced a large amount of IFN-γ; however, the mechanism of rapid response of memory CD4(+) T cells remains undefined. We compared the expression of transcription factors in resting or activated naive and memory CD4(+) T cells and found that T-bet, but not pSTAT-1 or pSTAT-4, was highly expressed in resting memory CD4(+) T cells and that phenotypic characteristics of T-bet(+)CD4(+) T cells were CD45RA(low)CD62L(low) CCR7(low). After short-term stimulation, purified memory CD4(+) T cells rapidly produced effector cytokines that were closely associated with the pre-existence of T-bet. By contrast, resting naive CD4(+) T cells did not express T-bet, and they produced cytokines only after sustained stimulation. Our further studies indicated that T-bet was expressed in the nuclei of resting memory CD4(+) T cells, which might have important implications for rapid IFN-γ production. Our results indicate that the pre-existence and nuclear mobilization of T-bet in resting memory CD4(+) T cells might be a possible transcriptional mechanism for rapid production of cytokines by human memory CD4(+) T cells.

  8. Memory CD4+ T cells are suppressed by CD8+ regulatory T cells in vitro and in vivo

    PubMed Central

    Long, Xin; Cheng, Qi; Liang, Huifang; Zhao, Jianping; Wang, Jian; Wang, Wei; Tomlinson, Stephen; Chen, Lin; Atkinson, Carl; Zhang, Bixiang; Chen, Xiaoping; Zhu, Peng

    2017-01-01

    Background: Acute graft rejection mediated by alloreactive memory CD4+ T cells is a major obstacle to transplantation tolerance. It has been reported that CD8+ T regulatory cells (Tregs) have the ability to induce graft tolerance by restraining the function of activated CD4+ T cells, but not including memory T cells. The aim of this study is to elucidate the effect of CD8+ Tregs on alloreactive memory CD4+ T cells. Methods: We detected Qa-1 expression and performed proliferative assay on memory CD4+ T cells. All memory CD4+ T cells were purified from mice receiving skin allografts. We performed inhibitory and cytotoxic assays on CD8+ Tregs, which were isolated from a T cell vaccination mouse model, and IL-2, IL-4, IL-10 and IFN-γ levels were measured in co-culture supernatants by ELISA. To confirm CD8+ Tregs inhibition of memory CD4+ T cells in-vivo, we utilized a murine model of cardiac allograft transplantation. Results: Memory CD4+ T cells mediated acute allograft rejection, and CD8+ Tregs suppressed the proliferation of memory CD4+ T cells. In vitro, memory CD4+ T cells were inhibited and lysed by CD8+ Tregs. There was a positive correlation between IFN-γ levels, and cell lysis rate induced by CD8+ Tregs. In-vivo studies demonstrated CD8+ Tregs prolonged graft survival times, by inhibiting CD4+ memory T cells, through a Qa-1-peptide-TCR pathway. Conclusions: CD8+ Tregs inhibit CD4+ memory T cell-mediated acute murine cardiac allograft rejection, and further prolong graft survival times. These results provide new insights into immune regulation of organ rejection. PMID:28123634

  9. A subset of memory CD4+ helper T lymphocytes identified by expression of Pgp-1

    PubMed Central

    1989-01-01

    The Pgp-1 glycoprotein (Ly-24 antigen) is acquired by mature murine T lymphocytes at the time of primary antigen stimulation Pgp-1 was previously shown to be a useful cell surface marker for distinguishing antigen-specific memory CD8+ T lymphocytes after immunization. Here we demonstrate that this observation extends to CD4+ T lymphocytes. Antigen-specific CD4+ T cells in mice immunized with sperm whale myoglobin or keyhole limpet hemocyanin were contained nearly exclusively in the minor Pgp-1+ subset. PMID:2564418

  10. Defining CD4 T cell memory by the epigenetic landscape of CpG DNA methylation.

    PubMed

    Komori, H Kiyomi; Hart, Traver; LaMere, Sarah A; Chew, Pamela V; Salomon, Daniel R

    2015-02-15

    Memory T cells are primed for rapid responses to Ag; however, the molecular mechanisms responsible for priming remain incompletely defined. CpG methylation in promoters is an epigenetic modification, which regulates gene transcription. Using targeted bisulfite sequencing, we examined methylation of 2100 genes (56,000 CpGs) mapped by deep sequencing of T cell activation in human naive and memory CD4 T cells. Four hundred sixty-six CpGs (132 genes) displayed differential methylation between naive and memory cells. Twenty-one genes exhibited both differential methylation and gene expression before activation, linking promoter DNA methylation states to gene regulation; 6 of 21 genes encode proteins closely studied in T cells, whereas 15 genes represent novel targets for further study. Eighty-four genes demonstrated differential methylation between memory and naive cells that correlated to differential gene expression following activation, of which 39 exhibited reduced methylation in memory cells coupled with increased gene expression upon activation compared with naive cells. These reveal a class of primed genes more rapidly expressed in memory compared with naive cells and putatively regulated by DNA methylation. These findings define a DNA methylation signature unique to memory CD4 T cells that correlates with activation-induced gene expression.

  11. Defining CD4 T Cell Memory by the Epigenetic Landscape of CpG DNA Methylation

    PubMed Central

    Komori, H. Kiyomi; Hart, Traver; LaMere, Sarah A.; Chew, Pamela V.; Salomon, Daniel R.

    2015-01-01

    Memory T cells are primed for rapid responses to antigen; however, the molecular mechanisms responsible for priming remain incompletely defined. CpG methylation in promoters is an epigenetic modification, which regulates gene transcription. Using targeted bisulfite sequencing, we examined methylation of 2100 genes (56,000 CpG) mapped by deep sequencing of T cell activation in human naïve and memory CD4 T cells. 466 CpGs (132 genes) displayed differential methylation between naïve and memory cells. 21 genes exhibited both differential methylation and gene expression before activation, linking promoter DNA methylation states to gene regulation; 6 of 21 genes encode proteins closely studied in T cells, while 15 genes represent novel targets for further study. 84 genes demonstrated differential methylation between memory and naïve cells that correlated to differential gene expression following activation, of which 39 exhibited reduced methylation in memory cells coupled with increased gene expression upon activation compared to naïve cells. These reveal a class of primed genes more rapidly expressed in memory compared to naïve cells and putatively regulated by DNA methylation. These findings define a DNA methylation signature unique to memory CD4 T cells that correlates with activation-induced gene expression. PMID:25576597

  12. Differentiation of distinct long-lived memory CD4 T cells in intestinal tissues after oral Listeria monocytogenes infection.

    PubMed

    Romagnoli, P A; Fu, H H; Qiu, Z; Khairallah, C; Pham, Q M; Puddington, L; Khanna, K M; Lefrançois, L; Sheridan, B S

    2017-03-01

    Mucosal antigen-specific CD4 T-cell responses to intestinal pathogens remain incompletely understood. Here we examined the CD4 T-cell response after oral infection with an internalin A 'murinized' Listeria monocytogenes (Lm). Oral Lm infection induced a robust endogenous listeriolysin O (LLO)-specific CD4 T-cell response with distinct phenotypic and functional characteristics in the intestine. Circulating LLO-specific CD4 T cells transiently expressed the 'gut-homing' integrin α4β7 and accumulated in the intestinal lamina propria and epithelium where they were maintained independent of interleukin (IL)-15. The majority of intestinal LLO-specific CD4 T cells were CD27(-) Ly6C(-) and CD69(+) CD103(-) while the lymphoid LLO-specific CD4 T cells were heterogeneous based on CD27 and Ly6C expression and predominately CD69(-). LLO-specific effector CD4 T cells transitioned into a long-lived memory population that phenotypically resembled their parent effectors and displayed hallmarks of residency. In addition, intestinal effector and memory CD4 T cells showed a predominant polyfunctional Th1 profile producing IFNγ, TNFα, and IL-2 at high levels with minimal but detectable levels of IL-17A. Depletion of CD4 T cells in immunized mice led to elevated bacterial burden after challenge infection highlighting a critical role for memory CD4 T cells in controlling intestinal intracellular pathogens.

  13. Differentiation of distinct long-lived memory CD4 T cells in intestinal tissues after oral Listeria monocytogenes infection

    PubMed Central

    Romagnoli, PA; Fu, HH; Qiu, Z; Khairallah, C; Pham, QM; Puddington, L; Khanna, KM; Lefrançois, L; Sheridan, BS

    2016-01-01

    Mucosal antigen-specific CD4 T cell responses to intestinal pathogens remain incompletely understood. Here we examined the CD4 T cell response after oral infection with an internalin A ‘murinized’ Listeria monocytogenes (Lm). Oral Lm infection induced a robust endogenous listeriolysin O (LLO)-specific CD4 T cell response with distinct phenotypic and functional characteristics in the intestine. Circulating LLO-specific CD4 T cells transiently expressed the ‘gut-homing’ integrin α4β7 and accumulated in the intestinal lamina propria and epithelium where they were maintained independent of IL-15. The majority of intestinal LLO-specific CD4 T cells were CD27− Ly6C− and CD69+ CD103− while the lymphoid LLO-specific CD4 T cells were heterogeneous based on CD27 and Ly6C expression and predominately CD69−. LLO-specific effector CD4 T cells transitioned into a long-lived memory population that phenotypically resembled their parent effectors and displayed hallmarks of residency. In addition, intestinal effector and memory CD4 T cells showed a predominant polyfunctional Th1 profile producing IFNγ, TNFα and IL-2 at high levels with minimal but detectable levels of IL-17A. Depletion of CD4 T cells in immunized mice led to elevated bacterial burden after challenge infection highlighting a critical role for memory CD4 T cells in controlling intestinal intracellular pathogens. PMID:27461178

  14. Human Memory CD4+ T Cell Immune Responses against Giardia lamblia.

    PubMed

    Saghaug, Christina Skår; Sørnes, Steinar; Peirasmaki, Dimitra; Svärd, Staffan; Langeland, Nina; Hanevik, Kurt

    2015-09-16

    The intestinal protozoan parasite Giardia lamblia may cause severe prolonged diarrheal disease or pass unnoticed as an asymptomatic infection. T cells seem to play an important role in the immune response to Giardia infection, and memory responses may last years. Recently, TH17 responses have been found in three animal studies of Giardia infection. The aim of this study was to characterize the human CD4(+) T cell responses to Giardia. Peripheral blood mononuclear cells (PBMCs) were obtained from 21 returning travelers with recent or ongoing giardiasis and 12 low-risk healthy controls and stimulated in vitro with Giardia lamblia proteins. Production of tumor necrosis factor alpha (TNF-α), gamma interferon, interleukin-17A (IL-17A), IL-10, and IL-4 was measured in CD4(+) effector memory (EM) T cells after 24 h by flow cytometry. After 6 days of culture, activation and proliferation were measured by flow cytometry, while an array of inflammatory cytokine levels in supernatants were measured with multiplex assays. We found the number of IL-17A-producing CD4(+) EM T cells, as well as that of cells simultaneously producing both IL-17A and TNF-α, to be significantly elevated in the Giardia-exposed individuals after 24 h of antigen stimulation. In supernatants of PBMCs stimulated with Giardia antigens for 6 days, we found inflammation-associated cytokines, including 1L-17A, as well as CD4(+) T cell activation and proliferation, to be significantly elevated in the Giardia-exposed individuals. We conclude that symptomatic Giardia infection in humans induces a CD4(+) EM T cell response of which IL-17A production seems to be an important component.

  15. Human Memory CD4+ T Cell Immune Responses against Giardia lamblia

    PubMed Central

    Sørnes, Steinar; Peirasmaki, Dimitra; Svärd, Staffan; Langeland, Nina

    2015-01-01

    The intestinal protozoan parasite Giardia lamblia may cause severe prolonged diarrheal disease or pass unnoticed as an asymptomatic infection. T cells seem to play an important role in the immune response to Giardia infection, and memory responses may last years. Recently, TH17 responses have been found in three animal studies of Giardia infection. The aim of this study was to characterize the human CD4+ T cell responses to Giardia. Peripheral blood mononuclear cells (PBMCs) were obtained from 21 returning travelers with recent or ongoing giardiasis and 12 low-risk healthy controls and stimulated in vitro with Giardia lamblia proteins. Production of tumor necrosis factor alpha (TNF-α), gamma interferon, interleukin-17A (IL-17A), IL-10, and IL-4 was measured in CD4+ effector memory (EM) T cells after 24 h by flow cytometry. After 6 days of culture, activation and proliferation were measured by flow cytometry, while an array of inflammatory cytokine levels in supernatants were measured with multiplex assays. We found the number of IL-17A-producing CD4+ EM T cells, as well as that of cells simultaneously producing both IL-17A and TNF-α, to be significantly elevated in the Giardia-exposed individuals after 24 h of antigen stimulation. In supernatants of PBMCs stimulated with Giardia antigens for 6 days, we found inflammation-associated cytokines, including 1L-17A, as well as CD4+ T cell activation and proliferation, to be significantly elevated in the Giardia-exposed individuals. We conclude that symptomatic Giardia infection in humans induces a CD4+ EM T cell response of which IL-17A production seems to be an important component. PMID:26376930

  16. Filarial infection modulates the immune response to Mycobacterium tuberculosis through expansion of CD4+ IL-4 memory T cells

    PubMed Central

    Chatterjee, Soumya; Clark, Carolyn E.; Lugli, Enrico; Roederer, Mario; Nutman, Thomas B.

    2015-01-01

    Exaggerated CD4+T helper 2-specific cytokine producing memory T cell responses developing concomitantly with a T helper1 response might have a detrimental role in immunity to infection caused by Mycobacterium tuberculosis (Mtb). To assess the dynamics of antigen (Ag)-specific memory T cell compartments in the context of filarial infection we used multiparameter flow cytometry on PBMCs from 25 microfilaremic filarial -infected (Inf) and 14 filarial-uninfected (Uninf) subjects following stimulation with filarial (BmA) or with the Mycobacterium tuberculosis (Mtb)-specific Ag CFP10. Our data demonstrated that the Inf group not only had a marked increase in BmA-specific CD4+IL-4+ cells (Median net frequency compared to baseline (Fo)=0.09% vs. 0.01%, p=0.038) but also to CFP10 (Fo =0.16% vs. 0.007%, p=0.04) and Staphylococcal Enterotoxin B (SEB) (Fo =0.49% vs. 0.26%, p=0.04). The Inf subjects showed a BmA-specific expansion of CD4+CD45RO+IL-4+ producing central memory (TCM, CD45RO+CCR7+CD27+) (Fo =1.1% vs. 0.5%, p=0.04) as well as effector memory (TEM CD45RO+CCR7-CD27-) (Fo =1.5% vs. 0.2%, p=0.03) with a similar but non-significant response to CFP10. In addition, there was expansion of CD4+ IL-4+ CD45RA+ CCR7+CD27+ (naïve-like) in Inf individuals compared to Uninf subjects. Among Inf subjects with definitive latent tuberculosis , there were no differences in frequencies of IL-4 producing cells within any of the memory compartments compared to the Uninf group. Our data suggest that filarial infection induces antigen-specific, exaggerated IL-4 responses in distinct T cell memory compartments to Mtb-specific antigens, which are attenuated in subjects who are able to mount a delayed type hypersensitivity reaction to Mtb. PMID:25667413

  17. Kynurenine Reduces Memory CD4 T-Cell Survival by Interfering with Interleukin-2 Signaling Early during HIV-1 Infection

    PubMed Central

    Dagenais-Lussier, Xavier; Aounallah, Mouna; Mehraj, Vikram; El-Far, Mohamed; Tremblay, Cecile; Sekaly, Rafick-Pierre; Routy, Jean-Pierre

    2016-01-01

    ABSTRACT Early HIV-1 infection is characterized by enhanced tryptophan catabolism, which contributes to immune suppression and disease progression. However, the mechanism by which kynurenine, a tryptophan-related metabolite, induces immune suppression remains poorly understood. Herein, we show that the increased production of kynurenine correlates with defective interleukin-2 (IL-2) signaling in memory CD4 T cells from HIV-infected subjects. Defective IL-2 signaling in these subjects, which drives reduced protection from Fas-mediated apoptosis, was also associated with memory CD4 T-cell loss. Treatment of memory CD4 T cells with the concentration of kynurenine found in plasma inhibited IL-2 signaling through the production of reactive oxygen species. We further show that IL-2 signaling in memory CD4 T cells is improved by the antioxidant N-acetylcysteine. Early initiation of antiretroviral therapy restored the IL-2 response in memory CD4 T cells by reducing reactive oxygen species and kynurenine production. The study findings provide a kynurenine-dependent mechanism through IL-2 signaling for reduced CD4 T-cell survival, which can be reversed by early treatment initiation in HIV-1 infection. IMPORTANCE The persistence of functional memory CD4 T cells represents the basis for long-lasting immune protection in individuals after exposure to HIV-1. Unfortunately, primary HIV-1 infection results in the massive loss of these cells within weeks of infection, which is mainly driven by inflammation and massive infection by the virus. These new findings show that the enhanced production of kynurenine, a metabolite related to tryptophan catabolism, also impairs memory CD4 T-cell survival and interferes with IL-2 signaling early during HIV-1 infection. PMID:27356894

  18. Gut memories do not fade: epigenetic regulation of lasting gut homing receptor expression in CD4(+) memory T cells.

    PubMed

    Szilagyi, B A; Triebus, J; Kressler, C; de Almeida, M; Tierling, S; Durek, P; Mardahl, M; Szilagyi, A; Floess, S; Huehn, J; Syrbe, U; Walter, J; Polansky, J K; Hamann, A

    2017-02-15

    The concept of a "topographical memory" in lymphocytes implies a stable expression of homing receptors mediating trafficking of lymphocytes back to the tissue of initial activation. However, a significant plasticity of the gut-homing receptor α4β7 was found in CD8(+) T cells, questioning the concept. We now demonstrate that α4β7 expression in murine CD4(+) memory T cells is, in contrast, imprinted and remains stable in the absence of the inducing factor retinoic acid (RA) or other stimuli from mucosal environments. Repetitive rounds of RA treatment enhanced the stability of de novo induced α4β7. A novel enhancer element in the murine Itga4 locus was identified that showed, correlating to stability, selective DNA demethylation in mucosa-seeking memory cells and methylation-dependent transcriptional activity in a reporter gene assay. This implies that epigenetic mechanisms contribute to the stabilization of α4β7 expression. Analogous DNA methylation patterns could be observed in the human ITGA4 locus, suggesting that its epigenetic regulation is conserved between mice and men. These data prove that mucosa-specific homing mediated by α4β7 is imprinted in CD4(+) memory T cells, reinstating the validity of the concept of "topographical memory" for mucosal tissues, and imply a critical role of epigenetic mechanisms.Mucosal Immunology advance online publication 15 February 2017. doi:10.1038/mi.2017.7.

  19. Virus-specific CD4+ memory phenotype T cells are abundant in unexposed adults

    PubMed Central

    Su, Laura F.; Kidd, Brian A.; Han, Arnold; Kotzin, Jonathan J.; Davis, Mark M.

    2013-01-01

    While T cell memory is generally thought to require direct antigen exposure, we find an abundance of memory phenotype cells (20–90%, averaging over 50%) of CD4+ T cells specific for viral antigens in adults that have never been infected. These cells express the appropriate memory markers and genes, rapidly produce cytokines, and have clonally expanded. This contrasts with newborns where the same T cell receptor (TCR) specificities are almost entirely naïve, which may explain the vulnerability of young children to infections. One mechanism for this phenomenon is TCR cross-reactivity to environmental antigens and in support of this we find extensive cross-recognition by HIV-1 and influenza-reactive T lymphocytes to other microbial peptides and the expansion of one of these following influenza vaccination. Thus the presence of these memory phenotype T cells has significant implications for immunity to novel pathogens, child and adult health, and the influence of pathogen-rich versus hygienic environments. PMID:23395677

  20. ICOS and Bcl6-dependent pathways maintain a CD4 T cell population with memory-like properties during tuberculosis

    PubMed Central

    Moguche, Albanus O.; Shafiani, Shahin; Clemons, Corey; Larson, Ryan P.; Dinh, Crystal; Higdon, Lauren E.; Cambier, C.J.; Sissons, James R.; Gallegos, Alena M.; Fink, Pamela J.

    2015-01-01

    Immune control of persistent infection with Mycobacterium tuberculosis (Mtb) requires a sustained pathogen-specific CD4 T cell response; however, the molecular pathways governing the generation and maintenance of Mtb protective CD4 T cells are poorly understood. Using MHCII tetramers, we show that Mtb-specific CD4 T cells are subject to ongoing antigenic stimulation. Despite this chronic stimulation, a subset of PD-1+ cells is maintained within the lung parenchyma during tuberculosis (TB). When transferred into uninfected animals, these cells persist, mount a robust recall response, and provide superior protection to Mtb rechallenge when compared to terminally differentiated Th1 cells that reside preferentially in the lung-associated vasculature. The PD-1+ cells share features with memory CD4 T cells in that their generation and maintenance requires intrinsic Bcl6 and intrinsic ICOS expression. Thus, the molecular pathways required to maintain Mtb-specific CD4 T cells during ongoing infection are similar to those that maintain memory CD4 T cells in scenarios of antigen deprivation. These results suggest that vaccination strategies targeting the ICOS and Bcl6 pathways in CD4 T cells may provide new avenues to prevent TB. PMID:25918344

  1. Telomerase Is Involved in IL-7-Mediated Differential Survival of Naive and Memory CD4+ T Cells1

    PubMed Central

    Yang, Yinhua; An, Jie; Weng, Nan-ping

    2008-01-01

    IL-7 plays an essential role in T cell maintenance and survival. The survival effect of IL-7 is thought to be mediated through regulation of Bcl2 family proteins. After a comparative analysis of IL-7-induced growth and cell death of human naive and memory CD4+ T cells, we observed that more memory CD4+ T cells underwent cell division and proceeded to apoptosis than naive cells in response to IL-7. However, IL-7-induced expressions of Bcl2 family members (Bcl2, Bcl-xL, Bax, and Bad) were similar between naive and memory cells. Instead, we found that IL-7 induced higher levels of telomerase activity in naive cells than in memory cells, and the levels of IL-7-induced telomerase activity had a significant inverse correlation with cell death in CD4+ T cells. Furthermore, we showed that reducing expression of telomerase reverse transcriptase and telomerase activity significantly increased cell death of IL-7-cultured CD4+ T cells. Together, these findings demonstrate that telomerase is involved in IL-7-mediated differential survival of naive and memory CD4+ T cells. PMID:18322183

  2. Plasmodium falciparum apical membrane antigen 1 vaccine elicits multifunctional CD4 cytokine-producing and memory T cells.

    PubMed

    Huaman, Maria Cecilia; Mullen, Gregory E D; Long, Carole A; Mahanty, Siddhartha

    2009-08-20

    The Plasmodium falciparum apical membrane antigen 1 (AMA1) is a leading vaccine candidate and was tested for safety and immunogenicity in human Phase I Clinical Trials. PBMC from vaccine recipients were analyzed by flow cytometric methods to determine the nature of T-cell responses and AMA1-reactive memory T cells. Both CD4 and CD8 T cells produced a number of cytokines following AMA1 re-stimulation, with IL-5-producing cells at the highest frequency, consistent with a Th2 bias. The relative frequency of multifunctional cells synthesizing Th1 cytokines IFN-gamma, IL-2 and TNF-alpha changed after each vaccination. Interestingly, median fluorescence intensity measurements revealed that cells producing more than one cytokine contributed greater quantities of each cytokine than cell populations that produced each of the cytokines alone. AMA1 vaccination also elicited the development of memory cell populations, and both central and effector memory T cells were identified concurrently after the AMA1 vaccination. The detailed profile of multifunctional T-cell responses to AMA1 presented here will advance our ability to assess the immunogenicity of human malarial vaccines.

  3. Skin CD4+ memory T cells exhibit combined cluster-mediated retention and equilibration with the circulation

    PubMed Central

    Collins, Nicholas; Jiang, Xiaodong; Zaid, Ali; Macleod, Bethany L.; Li, Jane; Park, Chang Ook; Haque, Ashraful; Bedoui, Sammy; Heath, William R.; Mueller, Scott N.; Kupper, Thomas S.; Gebhardt, Thomas; Carbone, Francis R.

    2016-01-01

    Although memory T cells within barrier tissues can persist as permanent residents, at least some exchange with blood. The extent to which this occurs is unclear. Here we show that memory CD4+ T cells in mouse skin are in equilibrium with the circulation at steady state. These cells are dispersed throughout the inter-follicular regions of the dermis and form clusters with antigen presenting cells around hair follicles. After infection or administration of a contact sensitizing agent, there is a sustained increase in skin CD4+ T-cell content, which is confined to the clusters, with a concomitant CCL5-dependent increase in CD4+ T-cell recruitment. Skin CCL5 is derived from CD11b+ cells and CD8+ T cells, with the elimination of the latter decreasing CD4+ T-cell numbers. These results reveal a complex pattern of tissue-retention and equilibration for CD4+ memory T cells in skin, which is altered by infection and inflammation history. PMID:27160938

  4. Treatment with targeted Vesicular Stomatitis Virus generates therapeutic multifunctional anti-tumor memory CD4 T-cells

    PubMed Central

    Gao, Yanhua; Whitaker-Dowling, Patricia; Griffin, Judith A.; Bergman, Ira

    2011-01-01

    A generally applicable, easy-to-use method of focusing a patient's immune system to eradicate or prevent cancer has been elusive. We are attempting to develop a targeted virus to accomplish these aims. We previously created a recombinant replicating Vesicular Stomatitis Virus that preferentially infected Her2/neu expressing breast cancer cells and showed therapeutic efficacy in an implanted Balb/c mouse tumor model. The current work shows that this therapy generated therapeutic anti-tumor CD4 T-cells against multiple tumor antigens. CD4 T-cells transferred directly from cured donor mice could eradicate established tumors in host mice. T-cells were transferred directly from donor mice and were not stimulated ex vivo. Both tumors that expressed Her2/neu and those that did not were cured by transferred T-cells. Analysis of cytokines secreted by anti-tumor memory CD4 T-cells displayed a multifunctional pattern with high levels of IFNγ, IL-4 and IL-17. Anti-tumor memory CD4 T-cells traveled to the mesenteric lymph nodes and were activated there. Treatment with targeted rrVSV is a potent immune adjuvant that generates therapeutic, multifunctional anti-tumor memory CD4 T-cells that recognize multiple tumor antigens. Immunity elicited by viral therapy is independent of host major histocompatibility complex (MHC) or knowledge of tumor antigens. Virus-induced tumor immunity could have great benefit in the prevention and treatment of tumor metastases. PMID:22240921

  5. Epigenomic Profiling of Human CD4(+) T Cells Supports a Linear Differentiation Model and Highlights Molecular Regulators of Memory Development.

    PubMed

    Durek, Pawel; Nordström, Karl; Gasparoni, Gilles; Salhab, Abdulrahman; Kressler, Christopher; de Almeida, Melanie; Bassler, Kevin; Ulas, Thomas; Schmidt, Florian; Xiong, Jieyi; Glažar, Petar; Klironomos, Filippos; Sinha, Anupam; Kinkley, Sarah; Yang, Xinyi; Arrigoni, Laura; Amirabad, Azim Dehghani; Ardakani, Fatemeh Behjati; Feuerbach, Lars; Gorka, Oliver; Ebert, Peter; Müller, Fabian; Li, Na; Frischbutter, Stefan; Schlickeiser, Stephan; Cendon, Carla; Fröhler, Sebastian; Felder, Bärbel; Gasparoni, Nina; Imbusch, Charles D; Hutter, Barbara; Zipprich, Gideon; Tauchmann, Yvonne; Reinke, Simon; Wassilew, Georgi; Hoffmann, Ute; Richter, Andreas S; Sieverling, Lina; Chang, Hyun-Dong; Syrbe, Uta; Kalus, Ulrich; Eils, Jürgen; Brors, Benedikt; Manke, Thomas; Ruland, Jürgen; Lengauer, Thomas; Rajewsky, Nikolaus; Chen, Wei; Dong, Jun; Sawitzki, Birgit; Chung, Ho-Ryun; Rosenstiel, Philip; Schulz, Marcel H; Schultze, Joachim L; Radbruch, Andreas; Walter, Jörn; Hamann, Alf; Polansky, Julia K

    2016-11-15

    The impact of epigenetics on the differentiation of memory T (Tmem) cells is poorly defined. We generated deep epigenomes comprising genome-wide profiles of DNA methylation, histone modifications, DNA accessibility, and coding and non-coding RNA expression in naive, central-, effector-, and terminally differentiated CD45RA(+) CD4(+) Tmem cells from blood and CD69(+) Tmem cells from bone marrow (BM-Tmem). We observed a progressive and proliferation-associated global loss of DNA methylation in heterochromatic parts of the genome during Tmem cell differentiation. Furthermore, distinct gradually changing signatures in the epigenome and the transcriptome supported a linear model of memory development in circulating T cells, while tissue-resident BM-Tmem branched off with a unique epigenetic profile. Integrative analyses identified candidate master regulators of Tmem cell differentiation, including the transcription factor FOXP1. This study highlights the importance of epigenomic changes for Tmem cell biology and demonstrates the value of epigenetic data for the identification of lineage regulators.

  6. Memory-like CD8+ and CD4+ T cells cooperate to break peripheral tolerance under lymphopenic conditions.

    PubMed

    Le Saout, Cecile; Mennechet, Sandie; Taylor, Naomi; Hernandez, Javier

    2008-12-09

    The onset of autoimmunity in experimental rodent models and patients frequently correlates with a lymphopenic state. In this condition, the immune system has evolved compensatory homeostatic mechanisms that induce quiescent naive T cells to proliferate and differentiate into memory-like lymphocytes even in the apparent absence of antigenic stimulation. Because memory T cells have less stringent requirements for activation than naive cells, we hypothesized that autoreactive T cells that arrive to secondary lymphoid organs in a lymphopenic environment could differentiate and bypass the mechanisms of peripheral tolerance such as those mediated by self-antigen cross-presentation. Here, we show that lymphopenia-driven proliferation and differentiation of potentially autoreactive CD8(+) T cells into memory-like cells is not sufficient to induce self-reactivity against a pancreatic antigen. Induction of an organ-specific autoimmunity required antigen-specific CD4(+) T cell help. Notably, we found that this function could be accomplished by memory-like CD4(+) T cells generated in vivo through lymphopenia-induced proliferation. These helper cells promoted the further differentiation of memory-like CD8(+) T cells into effectors in response to antigen cross-presentation, resulting in their migration to the tissue of antigen expression where autoimmunity ensued. Thus, the cooperation of self-reactive memory-like CD4(+) and CD8(+) T cells under lymphopenic conditions overcomes cross-tolerance resulting in autoimmunity.

  7. Memory CD4+ T cells are required for optimal NK cell effector functions against the opportunistic fungal pathogen Pneumocystis murina.

    PubMed

    Kelly, Michelle N; Zheng, Mingquan; Ruan, Sanbao; Kolls, Jay; D'Souza, Alain; Shellito, Judd E

    2013-01-01

    Little is known about the role of NK cells or their interplay with other immune cells during opportunistic infections. Using our murine model of Pneumocystis pneumonia, we found that loss of NK cells during immunosuppression results in substantial Pneumocystis lung burden. During early infection of C57B/6 CD4(+) T cell-depleted mice, there were significantly fewer NK cells in the lung tissue compared with CD4(+) T cell-intact animals, and the NK cells present demonstrated decreased upregulation of the activation marker NKp46 and production of the effector cytokine, IFN-γ. Furthermore, coincubation studies revealed a significant increase in fungal killing when NK cells were combined with CD4(+) T cells compared with either cell alone, which was coincident with a significant increase in perforin production by NK cells. Finally, however, we found through adoptive transfer that memory CD4(+) T cells are required for significant NK cell upregulation of the activation marker NK group 2D and production of IFN-γ, granzyme B, and perforin during Pneumocystis infection. To the best of our knowledge, this study is the first to demonstrate a role for NK cells in immunity to Pneumocystis pneumonia, as well as to establish a functional relationship between CD4(+) T cells and NK cells in the host response to an opportunistic fungal pathogen.

  8. Antiviral Innate Immune Activation in HIV-Infected Adults Negatively Affects H1/IC31-Induced Vaccine-Specific Memory CD4+ T Cells

    PubMed Central

    Schindler, Tobias; Kagina, Benjamin M.; Zhang, Jitao David; Lukindo, Tedson; Mpina, Maxmillian; Bang, Peter; Kromann, Ingrid; Hoff, Søren T.; Andersen, Peter; Reither, Klaus; Churchyard, Gavin J.; Certa, Ulrich

    2015-01-01

    Tuberculosis (TB) remains a global health problem, with vaccination being a necessary strategy for disease containment and elimination. A TB vaccine should be safe and immunogenic as well as efficacious in all affected populations, including HIV-infected individuals. We investigated the induction and maintenance of vaccine-induced memory CD4+ T cells following vaccination with the subunit vaccine H1/IC31. H1/IC31 was inoculated twice on study days 0 and 56 among HIV-infected adults with CD4+ lymphocyte counts of >350 cells/mm3. Whole venous blood stimulation was conducted with the H1 protein, and memory CD4+ T cells were analyzed using intracellular cytokine staining and polychromatic flow cytometry. We identified high responders, intermediate responders, and nonresponders based on detection of interleukin-2 (IL-2), tumor necrosis factor alpha (TNF-α), and gamma interferon (IFN-γ) expressing central (TCM) and effector memory CD4+ T cells (TEM) 182 days after the first immunization. Amplicon-based transcript quantification using next-generation sequencing was performed to identify differentially expressed genes that correlated with vaccine-induced immune responses. Genes implicated in resolution of inflammation discriminated the responders from the nonresponders 3 days after the first inoculation. The volunteers with higher expression levels of genes involved in antiviral innate immunity at baseline showed impaired H1-specific TCM and TEM maintenance 6 months after vaccination. Our study showed that in HIV-infected volunteers, expression levels of genes involved in the antiviral innate immune response affected long-term maintenance of H1/IC31 vaccine-induced cellular immunity. (The clinical trial was registered in the Pan African Clinical Trials Registry [PACTR] with the identifier PACTR201105000289276.) PMID:25924764

  9. Distinct Effector Memory CD4+ T Cell Signatures in Latent Mycobacterium tuberculosis Infection, BCG Vaccination and Clinically Resolved Tuberculosis

    PubMed Central

    Adekambi, Toidi; Ibegbu, Chris C.; Kalokhe, Ameeta S.; Yu, Tianwei; Ray, Susan M.; Rengarajan, Jyothi

    2012-01-01

    Two billion people worldwide are estimated to be latently infected with Mycobacterium tuberculosis (Mtb) and are at risk for developing active tuberculosis since Mtb can reactivate to cause TB disease in immune-compromised hosts. Individuals with latent Mtb infection (LTBI) and BCG-vaccinated individuals who are uninfected with Mtb, harbor antigen-specific memory CD4+ T cells. However, the differences between long-lived memory CD4+ T cells induced by latent Mtb infection (LTBI) versus BCG vaccination are unclear. In this study, we characterized the immune phenotype and functionality of antigen-specific memory CD4+ T cells in healthy BCG-vaccinated individuals who were either infected (LTBI) or uninfected (BCG) with Mtb. Individuals were classified into LTBI and BCG groups based on IFN-γ ELISPOT using cell wall antigens and ESAT-6/CFP-10 peptides. We show that LTBI individuals harbored high frequencies of late-stage differentiated (CD45RA−CD27−) antigen-specific effector memory CD4+ T cells that expressed PD-1. In contrast, BCG individuals had primarily early-stage (CD45RA−CD27+) cells with low PD-1 expression. CD27+ and CD27− as well as PD-1+ and PD-1− antigen-specific subsets were polyfunctional, suggesting that loss of CD27 expression and up-regulation of PD-1 did not compromise their capacity to produce IFN-γ, TNF-α and IL-2. PD-1 was preferentially expressed on CD27− antigen-specific CD4+ T cells, indicating that PD-1 is associated with the stage of differentiation. Using statistical models, we determined that CD27 and PD-1 predicted LTBI versus BCG status in healthy individuals and distinguished LTBI individuals from those who had clinically resolved Mtb infection after anti-tuberculosis treatment. This study shows that CD4+ memory responses induced by latent Mtb infection, BCG vaccination and clinically resolved Mtb infection are immunologically distinct. Our data suggest that differentiation into CD27−PD-1+ subsets in LTBI is driven by Mtb

  10. Direct ex vivo analysis of human CD4(+) memory T cell activation requirements at the single clonotype level.

    PubMed

    Bitmansour, Arlene D; Douek, Daniel C; Maino, Vernon C; Picker, Louis J

    2002-08-01

    CD4(+) memory T cells continuously integrate signals transmitted through the TCR and costimulatory molecules, only responding when the intensity of such signals exceeds an intrinsic activation threshold. Recent data suggest that these activation thresholds can be regulated independently of TCR specificity, and that threshold tuning may constitute a major mechanism for controlling T cell effector activity. In this work we take advantage of the profound clonotypic hierarchies of the large human CD4(+) T cell response to CMV to study activation thresholds of fresh (unexpanded) memory T cells at the clonotypic level. We identified dominant responses to CMV matrix determinants mediated by single TCRB sequences within particular TCR-Vbeta families. The specific response characteristics of these single, Ag-specific, TCRB-defined clonotypes could be unequivocally determined in fresh PBMC preparations by cytokine flow cytometry with gating on the appropriate Vbeta family. These analyses revealed 1) optimal peptides capable of eliciting specific responses by themselves at doses as low as 2 pg/ml, with each log increase in dose eliciting ever-increasing frequencies of responding cells over a 4- to 5-log range; 2) significant augmentation of response frequencies at all submaximal peptide doses by CD28- and CD49d-mediated costimulation; 3) differential dose response and costimulatory characteristics for IFN-gamma and IL-2 responses; and 4) no association of activation requirements with the CD27-defined CD4(+) T cell memory differentiation pathway. Taken together these data confirm that triggering heterogeneity exists within individual CD4(+) memory T cell clonotypes in vivo and demonstrate that such single clonotypes can manifest qualitatively different functional responses depending on epitope dose and relative levels of costimulation.

  11. Retention of Ag-specific memory CD4(+) T cells in the draining lymph node indicates lymphoid tissue resident memory populations.

    PubMed

    Marriott, Clare L; Dutton, Emma E; Tomura, Michio; Withers, David R

    2017-03-15

    Several different memory T-cell populations have now been described based upon surface receptor expression and migratory capabilities. Here we have assessed murine endogenous memory CD4(+) T cells generated within a draining lymph node and their subsequent migration to other secondary lymphoid tissues. Having established a model response targeting a specific peripheral lymph node, we temporally labelled all the cells within draining lymph node using photoconversion. Tracking of photoconverted and non-photoconverted Ag-specific CD4(+) T cells revealed the rapid establishment of a circulating memory population in all lymph nodes within days of immunisation. Strikingly, a resident memory CD4(+) T cell population became established in the draining lymph node and persisted for several months in the absence of detectable migration to other lymphoid tissue. These cells most closely resembled effector memory T cells, usually associated with circulation through non-lymphoid tissue, but here, these cells were retained in the draining lymph node. These data indicate that lymphoid tissue resident memory CD4(+) T-cell populations are generated in peripheral lymph nodes following immunisation.

  12. Differing requirements for CCR4, E-selectin, and α4β1 for the migration of memory CD4 and activated T cells to dermal inflammation.

    PubMed

    Gehad, Ahmed; Al-Banna, Nadia A; Vaci, Maria; Issekutz, Andrew C; Mohan, Karkada; Latta, Markus; Issekutz, Thomas B

    2012-07-01

    CCR4 on T cells is suggested to mediate skin homing in mice. Our objective was to determine the interaction of CCR4, E-selectin ligand (ESL), and α(4)β(1) on memory and activated T cells in recruitment to dermal inflammation. mAbs to rat CCR4 were developed. CCR4 was on 5-21% of memory CD4 cells, and 20% were also ESL(+). Anti-TCR-activated CD4 and CD8 cells were 40-55% CCR4(+), and ∼75% of both CCR4(+) and CCR4(-) cells were ESL(+). CCR4(+) memory CD4 cells migrated 4- to 7-fold more to dermal inflammation induced by IFN-γ, TNF, TLR agonists, and delayed-type hypersensitivity than CCR4(-) cells. CCR4(+) activated CD4 cells migrated only 5-50% more than CCR4(-) cells to these sites. E-selectin blockade inhibited ∼60% of CCR4(+) activated CD4 cell migration but was less effective on memory cells where α(4)β(1) was more important. Anti-α(4)β(1) also inhibited CCR4(-) activated CD4 cells more than CCR4(+) cells. Anti-E-selectin reduced activated CD8 more than CD4 cell migration. These findings modify our understanding of CCR4, ESL, α(4)β(1), and dermal tropism. There is no strict relationship between CCR4 and ESL for skin homing of CD4 cells, because the activation state and inflammatory stimulus are critical determinants. Dermal homing memory CD4 cells express CCR4 and depend more on α(4)β(1) than ESL. Activated CD4 cells do not require CCR4, but CCR4(+) cells are more dependent on ESL than on α(4)β(1), and CCR4(-) cells preferentially use α(4)β(1). The differentiation from activated to memory CD4 cells increases the dependence on CCR4 for skin homing and decreases the requirement for ESL.

  13. The Acquisition of a Memory Phenotype by Murine CD4+ T Cells Is Accompanied by a Loss in Their Capacity to Increase Intracellular Calcium

    PubMed Central

    Hertogh-Huijbregts, Anita

    1992-01-01

    During the process of aging, the fraction of CD4+ T Cells with a naive phenotype, that is, Pgp-1- CD45RBHighMEL-14+, decreases in favor of CD4+ T memory cells. Total CD4+ T cells from aged mice displayed a diminished calcium response to anti-CD3 and even ionomycin as compared to the cells from young mice, and this was related to the changed composition of the CD4+ T-cell population. Regardless the age of the donor mice, naive CD4+ T cells effectively increased intracellular calcium, whereas memory CD4+ T cells were impaired in this regard. In addition, a heterogeneity in the differentiation stage of the naive CD4+ T cells was shown by the observation that calcium mobilization in naive CD4+ T cells from young mice was more profound than that in their aged counterparts. These data thus indicate that during the acquisition of a memory phenotype, murine CD4+ T cells lose the capacity to increase intracellular calcium, which in turn may be responsible for the decreased level of IL-2 production by these cells. PMID:1364177

  14. Neutrophils acquire the capacity for antigen presentation to memory CD4(+) T cells in vitro and ex vivo.

    PubMed

    Vono, Maria; Lin, Ang; Norrby-Teglund, Anna; Koup, Richard A; Liang, Frank; Loré, Karin

    2017-04-06

    Neutrophils are critical cells of the innate immune system and rapidly respond to tissue injury and infection. Increasing evidence also indicates that neutrophils have versatile functions in contributing to adaptive immunity by internalizing and transporting antigen and influencing antigen-specific responses. Here, we demonstrate that freshly isolated human neutrophils can function as antigen-presenting cells (APCs) to memory CD4(+) T cells. Neutrophils pulsed with the cognate antigens cytomegalovirus pp65 or influenza hemagglutinin were able to present the antigens to autologous antigen-specific CD4(+) T cells in a major histocompatibility complex class II (MHC-II; HLA-DR)-dependent manner. Although myeloid dendritic cells and monocytes showed superior presenting ability, neutrophils consistently displayed antigen presentation capability. Upregulation of HLA-DR on neutrophils required the presence of the antigen-specific or activated T cells whereas exposure to innate stimuli such as Toll-like receptor ligands was not sufficient. Neutrophils sorted from vaccine-draining lymph nodes from rhesus macaques also showed expression of HLA-DR and were capable of presenting vaccine antigen to autologous antigen-specific memory CD4(+) T cells ex vivo. Altogether, the data demonstrate that neutrophils can adapt a function as APCs and, in combination with their abundance in the immune system, may have a significant role in regulating antigen-specific T-cell responses.

  15. Restoration of CD4+ Responses to Copathogens in HIV-Infected Individuals on Antiretroviral Therapy Is Dependent on T Cell Memory Phenotype.

    PubMed

    Riou, Catherine; Tanko, Ramla F; Soares, Andreia P; Masson, Lindi; Werner, Lise; Garrett, Nigel J; Samsunder, Natasha; Abdool Karim, Quarraisha; Abdool Karim, Salim S; Burgers, Wendy A

    2015-09-01

    Antiretroviral therapy (ART) induces rapid suppression of viral replication and a progressive replenishment of CD4(+) T cells in HIV-infected individuals. However, the effect of ART on restoring pre-existing memory CD4(+) T cells specific for common copathogens is still unclear. To better understand the dynamics of Ag-specific CD4(+) T cells during ART, we assessed the frequency, functional capacity, and memory profile of CD4(+) T cells specific for Mycobacterium tuberculosis and CMV in 15 HIV-infected individuals before and 1 y after ART initiation. After ART initiation, the frequency of M. tuberculosis-specific CD4(+) T cells showed little change, whereas CMV-specific CD4(+) T cells were significantly lower (p = 0.003). There was no difference in the polyfunctional or memory profile of Ag-specific CD4(+) T cells before and after ART. The replenishment of Ag-specific CD4(+) T cells correlated with the memory differentiation profile of these cells prior to ART. Pathogen-specific CD4(+) T cells exhibiting a late differentiated profile (CD45RO(+)CD27(-)) had a lower capacity to replenish (p = 0.019; r = -0.5) compared with cells with an early differentiated profile (CD45RO(+)CD27(+); p = 0.04; r = 0.45). In conclusion, restoration of copathogen-specific memory CD4(+) T cells during treated HIV infection is related to their memory phenotype, in which early differentiated cells (such as most M. tuberculosis-specific cells) have a higher replenishment capacity compared with late differentiated cells (such as most CMV-specific cells). These data identify an important, hitherto unrecognized, factor that may limit restoration of copathogen immunity in HIV-infected individuals on ART.

  16. Sustained interactions between T cell receptors and antigens promote the differentiation of CD4memory T cells.

    PubMed

    Kim, Chulwoo; Wilson, Theodore; Fischer, Kael F; Williams, Matthew A

    2013-09-19

    During CD4⁺ T cell activation, T cell receptor (TCR) signals impact T cell fate, including recruitment, expansion, differentiation, trafficking, and survival. To determine the impact of TCR signals on the fate decision of activated CD4⁺ T cells to become end-stage effector or long-lived memory T helper 1 (Th1) cells, we devised a deep-sequencing-based approach that allowed us to track the evolution of TCR repertoires after acute infection. The transition of effector Th1 cells into the memory pool was associated with a significant decrease in repertoire diversity, and the major histocompatibility complex (MHC) class II tetramer off rate, but not tetramer avidity, was a key predictive factor in the representation of individual clonal T cell populations at the memory stage. We conclude that stable and sustained interactions with antigens during the development of Th1 responses to acute infection are a determinative factor in promoting the differentiation of Th1 memory cells.

  17. Loss of multi-epitope specificity in memory CD4(+) T cell responses to B. pertussis with age.

    PubMed

    Han, Wanda G H; van Twillert, Inonge; Poelen, Martien C M; Helm, Kina; van de Kassteele, Jan; Verheij, Theo J M; Versteegh, Florens G A; Boog, Claire J P; van Els, Cécile A C M

    2013-01-01

    Pertussis is still occurring in highly vaccinated populations, affecting individuals of all ages. Long-lived Th1 CD4(+) T cells are essential for protective immunity against pertussis. For better understanding of the limited immunological memory to Bordetella pertussis, we used a panel of Pertactin and Pertussis toxin specific peptides to interrogate CD4(+) T cell responses at the epitope level in a unique cohort of symptomatic pertussis patients of different ages, at various time intervals after infection. Our study showed that pertussis epitope-specific T cell responses contained Th1 and Th2 components irrespective of the epitope studied, time after infection, or age. In contrast, the breadth of the pertussis-directed CD4(+) T cell response seemed dependent on age and closeness to infection. Multi-epitope specificity long-term after infection was lost in older age groups. Detailed knowledge on pertussis specific immune mechanisms and their insufficiencies is important for understanding resurgence of pertussis in highly vaccinated populations.

  18. Polarized granzyme release is required for antigen-driven transendothelial migration of human effector memory CD4 T cells.

    PubMed

    Manes, Thomas D; Pober, Jordan S

    2014-12-15

    Human effector memory CD4 T cells may transmigrate across endothelial cell (EC) monolayers either in response to inflammatory chemokines or in response to TCR recognition of Ag presented on the surface of the EC. The kinetics, morphologic manifestations, and molecular requirements of chemokine- and TCR-driven transendothelial migration (TEM) differ significantly. In this study, we report that, whereas the microtubule organizing center (MTOC) and cytosolic granules follow the nucleus across the endothelium in a uropod during chemokine-driven TEM, MTOC reorientation to the contact region between the T cell and the EC, accompanied by dynein-driven transport of granzyme-containing granules to and exocytosis at the contact region, are early events in TCR-driven, but not chemokine-driven TEM. Inhibitors of either granule function or granzyme proteolytic activity can arrest TCR-driven TEM, implying a requirement for granule discharge in the process. In the final stages of TCR-driven TEM, the MTOC precedes, rather than follows, the nucleus across the endothelium. Thus, TCR-driven TEM of effector memory CD4 T cells appears to be a novel process that more closely resembles immune synapse formation than it does conventional chemotaxis.

  19. CD4 and CD8 T cells participate in the immune memory response against Vaccinia virus after a previous natural infection☆

    PubMed Central

    Medeiros-Silva, Daniela Carla; dos Santos Moreira-Silva, Eduardo Augusto; Assis Silva Gomes, Juliana de; da Fonseca, Flávio Guimarães; Correa-Oliveira, Rodrigo

    2013-01-01

    The present study evaluates the immune response of memory CD4+ and CD8+ T cells from patients following a natural Vaccinia virus (VACV) infection. A total of 42 individuals were involved in the study being: 22 previously infected individuals (vaccinated or not against smallpox) and 20 non-infected individuals (vaccinated or not). A short-term in vitro stimulation with UV-inactivated VACV of whole blood cells was performed. Our study showed that previously infected individuals have a lower percentage of CD4+ T cells expressing lymph-node homing receptors (CD4+CD62L+CCR7+) and higher percentage of memory CD4+ T cells subsets (CD4+CD45ROHigh) when compared with non-infected subjects, after in vitro viral stimulation. We also showed that infected individuals presented higher percentages of CD4+ and CD8+ memory T lymphocytes expressing IFN-γ when compared to non-infected individuals. We verified that the percentage of CD4+ and CD8+ T memory cells expressing TNF-α was higher in infected and non-infected vaccinated subjects when compared with non-infected unvaccinated individual. We also observed that previously infected individuals have higher percentages of CD8+ T cells expressing lymph-node homing receptors (CCR7+ and CD62L+) and that the memory T cells expressing IFN-γ and TNF-α were at higher percentages in the whole blood cells from infected and non-infected vaccinated individuals, when compared to unvaccinated non-infected subjects. Thus, our findings suggest that CD4+ and CD8+ T cells are involved in the immune memory response against Vaccinia virus natural infection. PMID:24600565

  20. TCR stimulation without co-stimulatory signals induces expression of "tolerogenic" genes in memory CD4 T cells but does not compromise cell proliferation.

    PubMed

    Xie, Aini; Zheng, Xiong; Khattar, Mithun; Schroder, Paul; Stepkowski, Stanislaw; Xia, Jiahong; Chen, Wenhao

    2015-02-01

    Memory T cells resist co-stimulatory blockade and present a unique therapeutic challenge in transplantation and autoimmune diseases. Herein, we determined whether memory T cells express less "tolerogenic" genes than naïve T cells to reinforce a proliferative response under the deprivation of co-stimulatory signals. The expression of ∼40 tolerogenic genes in memory and naïve CD4(+) T cells was thus assessed during an in vitro TCR stimulation without co-stimulation. Briefly, upon TCR stimulation with an anti-CD3 mAb alone, memory CD4(+) T cells exhibited more proliferation than naïve CD4(+) T cells. To our surprise, at 24h upon anti-CD3 mAb stimulation, memory CD4(+) T cells expressed more than a 5-fold higher level of the transcription factor Egr2 and a 20-fold higher level of the transmembrane E3 ubiquitin ligase GRAIL than those in naïve T cells. Hence, the high-level expression of tolerogenic genes, Egr2 and GRAIL, in memory CD4(+) T cells does not prevent cell proliferation. Importantly, anti-CD3 mAb-stimulated memory CD4(+) T cells expressed high protein/gene levels of phosphorylated STAT5, Nedd4, Bcl-2, and Bcl-XL. Therefore, co-stimulation-independent proliferation of memory CD4(+) T cells may be due to elevated expression of molecules that support cell proliferation and survival, but not lack of tolerogenic molecules.

  1. CD4 T cells with effector memory phenotype and function develop in the sterile environment of the fetus.

    PubMed

    Zhang, Xiaoming; Mozeleski, Brian; Lemoine, Sebastien; Dériaud, Edith; Lim, Annick; Zhivaki, Dania; Azria, Elie; Le Ray, Camille; Roguet, Gwenaelle; Launay, Odile; Vanet, Anne; Leclerc, Claude; Lo-Man, Richard

    2014-05-28

    The T cell compartment is considered to be naïve and dedicated to the development of tolerance during fetal development. We have identified and characterized a population of fetally developed CD4 T cells with an effector memory phenotype (TEM), which are present in cord blood. This population is polyclonal and has phenotypic features similar to those of conventional adult memory T cells, such as CD45RO expression. These cells express low levels of CD25 but are distinct from regulatory T cells because they lack Foxp3 expression. After T cell receptor activation, neonatal TEM cells readily produced tumor necrosis factor-α (TNF-α) and granulocyte-macrophage colony-stimulating factor (GM-CSF). We also detected interferon-γ (IFN-γ)-producing T helper 1 (TH1) cells and interleukin-4 (IL-4)/IL-13-producing TH2-like cells, but not IL-17-producing cells. We used chemokine receptor expression patterns to divide this TEM population into different subsets and identified distinct transcriptional programs using whole-genome microarray analysis. IFN-γ was found in CXCR3(+) TEM cells, whereas IL-4 was found in both CXCR3(+) TEM cells and CCR4(+) TEM cells. CCR6(+) TEM cells displayed a genetic signature that corresponded to TH17 cells but failed to produce IL-17A. However, the TH17 function of TEM cells was observed in the presence of IL-1β and IL-23. In summary, in the absence of reported pathology or any major infectious history, T cells with a memory-like phenotype develop in an environment thought to be sterile during fetal development and display a large variety of inflammatory effector functions associated with CD4 TH cells at birth.

  2. CD28 is required for induction and maintenance of immunological memory in toxin-reactive CD4+ T cells in vivo.

    PubMed

    Fukada, Kenji; Koyanagi, Madoka; Arimura, Yutaka; Ogiuchi, Hideki; Uchiyama, Takehiko; Yagi, Junji

    2005-12-01

    We previously reported that Vbeta3+ CD4+ T cells maintained a protracted expansion, with the phenotypes of memory Th2 cells, for 30 days in C57BL/6 (B6) mice implanted with SEA-containing mini-osmotic pumps. In the present study, we followed the fate of Vbeta3+ CD4+ T cells in CD28-/- mice. Vbeta3+ CD4+ T cells increased to a degree similar to that of B6 Vbeta3+ CD4+ T cells until day 10 after implantation, then declined rapidly reaching the control level by 28 days. Remaining Vbeta3+ CD4+ T cells at that time did not exhibit memory phenotypes nor Th2-deviated responses. The rapid drop in Vbeta3+ CD4+ T cells in CD28-/- mice was attributable to upregulated induction of apoptosis owing to marginal inductions of Bcl-2 and Bcl-xL. Collectively, these data indicate CD28 to play critical roles in the generation and maintenance of SEA-reactive CD4+ T cells in vivo.

  3. Dexamethasone and Monophosphoryl Lipid A-Modulated Dendritic Cells Promote Antigen-Specific Tolerogenic Properties on Naive and Memory CD4+ T Cells

    PubMed Central

    Maggi, Jaxaira; Schinnerling, Katina; Pesce, Bárbara; Hilkens, Catharien M.; Catalán, Diego; Aguillón, Juan C.

    2016-01-01

    Tolerogenic dendritic cells (DCs) are a promising tool to control T cell-mediated autoimmunity. Here, we evaluate the ability of dexamethasone-modulated and monophosphoryl lipid A (MPLA)-activated DCs [MPLA-tolerogenic DCs (tDCs)] to exert immunomodulatory effects on naive and memory CD4+ T cells in an antigen-specific manner. For this purpose, MPLA-tDCs were loaded with purified protein derivative (PPD) as antigen and co-cultured with autologous naive or memory CD4+ T cells. Lymphocytes were re-challenged with autologous PPD-pulsed mature DCs (mDCs), evaluating proliferation and cytokine production by flow cytometry. On primed-naive CD4+ T cells, the expression of regulatory T cell markers was evaluated and their suppressive ability was assessed in autologous co-cultures with CD4+ effector T cells and PPD-pulsed mDCs. We detected that memory CD4+ T cells primed by MPLA-tDCs presented reduced proliferation and proinflammatory cytokine expression in response to PPD and were refractory to subsequent stimulation. Naive CD4+ T cells were instructed by MPLA-tDCs to be hyporesponsive to antigen-specific restimulation and to suppress the induction of T helper cell type 1 and 17 responses. In conclusion, MPLA-tDCs are able to modulate antigen-specific responses of both naive and memory CD4+ T cells and might be a promising strategy to “turn off” self-reactive CD4+ effector T cells in autoimmunity. PMID:27698654

  4. Subsets of Memory CD4+ T Cell and Bactericidal Antibody Response to Neisseria meningitidis Serogroup C after Immunization of HIV-Infected Children and Adolescents

    PubMed Central

    Milagres, Lucimar G.; Costa, Priscilla R.; Silva, Giselle P.; Carvalho, Karina I.; Pereira-Manfro, Wânia F.; Ferreira, Bianca; Barreto, Daniella M.; Frota, Ana Cristina C.; Hofer, Cristina B.; Kallas, Esper G.

    2014-01-01

    Meningococcal disease is endemic in Brazil, with periodic outbreaks and case fatality rates reach as high as 18 to 20% of cases. Conjugate vaccines against meningococci are immunogenic in healthy children. However, we have previously shown a poor bactericidal antibody response to a Men C conjugate vaccine in Brazilian HIV-infected children and adolescents after a single vaccine administration. The goal of the present work was to investigate associations between bactericidal antibody response induced by MenC vaccine and the frequency and activation profile (expression of CD38, HLA-DR and CCR5 molecules) of total CD4+ memory T cell sub-populations in HIV-1-infected children and adolescents. Responders to vaccination against MenC had a predominance (about 44%) of CD4+ TINTERMEDIATE subset followed by TTRANSITIONAL memory subset (23 to 26%). Importantly, CD4+ TINT frequency was positively associated with bactericidal antibody response induced by vaccination. The positive correlation persisted despite the observation that the frequency TINT CD38+HLA-DR+ was higher in responders. In contrast, CD4+ TCENTRAL MEMORY (TCM) subset negatively correlated with bactericidal antibodies. In conclusion, these data indicate that less differentiated CD+ T cells, like TCM may be constantly differentiating into intermediate and later differentiated CD4+ T cell subsets. These include CD4 TINT subset which showed a positive association with bactericidal antibodies. PMID:25532028

  5. Impaired CD4+ and T-helper 17 cell memory response to Streptococcus pneumoniae is associated with elevated glucose and percent glycated hemoglobin A1c in Mexican Americans with type 2 diabetes mellitus

    PubMed Central

    Martinez, Perla J.; Mathews, Christine; Actor, Jeffrey K.; Hwang, Shen-An; Brown, Eric L.; De Santiago, Heather K.; Fisher Hoch, Susan P.; Mccormick, Joseph B.; Mirza, Shaper

    2014-01-01

    Individuals with type 2 diabetes are significantly more susceptible to pneumococcal infections than healthy individuals of the same age. Increased susceptibility is the result of impairments in both innate and adaptive immune systems. Given the central role of T-helper 17 (Th17) and T-regulatory (Treg) cells in pneumococcal infection and their altered phenotype in diabetes, this study was designed to analyze the Th17 and Treg cell responses to a whole heat-killed capsular type 2 strain of Streptococcus pneumoniae. Patients with diabetes demonstrated a lower frequency of total CD+T-cells, which showed a significant inverse association with elevated fasting blood glucose. Measurement of specific subsets indicated that those with diabetes had, low intracellular levels of interleukin (IL)-17, and lower pathogen-specific memory CD4+ and IL-17+ cell numbers. No significant difference was observed in the frequency of CD4+ and Th17 cells between those with and without diabetes. However, stratification of data by obesity indicated a significant increase in frequency of CD4+ and Th17 cells in obese individuals with diabetes compared with nonobese individual with diabetes. The memory CD+T-cell response was associated inversely with both fasting blood glucose and percent glycated hemoglobin A1c. This study demonstrated that those with type 2 diabetes have a diminished pathogen-specific memory CD4+ and Th17 response, and low percentages of CD+T-cells in response to S. pneumoniae stimulation. PMID:23927943

  6. Central Muscarinic Cholinergic Activation Alters Interaction between Splenic Dendritic Cell and CD4+CD25- T Cells in Experimental Colitis

    PubMed Central

    Pavlov, Valentin A.; Tracey, Kevin J.; Khafipour, Ehsan; Ghia, Jean-Eric

    2014-01-01

    Background The cholinergic anti-inflammatory pathway (CAP) is based on vagus nerve (VN) activity that regulates macrophage and dendritic cell responses in the spleen through alpha-7 nicotinic acetylcholine receptor (a7nAChR) signaling. Inflammatory bowel disease (IBD) patients present dysautonomia with decreased vagus nerve activity, dendritic cell and T cell over-activation. The aim of this study was to investigate whether central activation of the CAP alters the function of dendritic cells (DCs) and sequential CD4+/CD25−T cell activation in the context of experimental colitis. Methods The dinitrobenzene sulfonic acid model of experimental colitis in C57BL/6 mice was used. Central, intracerebroventricular infusion of the M1 muscarinic acetylcholine receptor agonist McN-A-343 was used to activate CAP and vagus nerve and/or splenic nerve transection were performed. In addition, the role of α7nAChR signaling and the NF-kB pathway was studied. Serum amyloid protein (SAP)-A, colonic tissue cytokines, IL-12p70 and IL-23 in isolated splenic DCs, and cytokines levels in DC-CD4+CD25−T cell co-culture were determined. Results McN-A-343 treatment reduced colonic inflammation associated with decreased pro-inflammatory Th1/Th17 colonic and splenic cytokine secretion. Splenic DCs cytokine release was modulated through α7nAChR and the NF-kB signaling pathways. Cholinergic activation resulted in decreased CD4+CD25−T cell priming. The anti-inflammatory efficacy of central cholinergic activation was abolished in mice with vagotomy or splenic neurectomy. Conclusions Suppression of splenic immune cell activation and altered interaction between DCs and T cells are important aspects of the beneficial effect of brain activation of the CAP in experimental colitis. These findings may lead to improved therapeutic strategies in the treatment of IBD. PMID:25295619

  7. Dopaminergic Receptors on CD4+ T Naive and Memory Lymphocytes Correlate with Motor Impairment in Patients with Parkinson’s Disease

    PubMed Central

    Kustrimovic, Natasa; Rasini, Emanuela; Legnaro, Massimiliano; Bombelli, Raffaella; Aleksic, Iva; Blandini, Fabio; Comi, Cristoforo; Mauri, Marco; Minafra, Brigida; Riboldazzi, Giulio; Sanchez-Guajardo, Vanesa; Marino, Franca; Cosentino, Marco

    2016-01-01

    Parkinson’s disease (PD) is characterized by loss of dopaminergic neurons in substantia nigra pars compacta, α-synuclein (α-syn)-rich intraneuronal inclusions (Lewy bodies), and microglial activation. Emerging evidence suggests that CD4+ T lymphocytes contribute to neuroinflammation in PD. Since the mainstay of PD treatment is dopaminergic substitution therapy and dopamine is an established transmitter connecting nervous and immune systems, we examined CD4+ T naive and memory lymphocytes in PD patients and in healthy subjects (HS), with specific regard to dopaminergic receptor (DR) expression. In addition, the in vitro effects of α-syn were assessed on CD4+ T naive and memory cells. Results showed extensive association between DR expression in T lymphocytes and motor dysfunction, as assessed by UPDRS Part III score. In total and CD4+ T naive cells expression of D1-like DR decrease, while in T memory cells D2-like DR increase with increasing score. In vitro, α-syn increased CD4+ T memory cells, possibly to a different extent in PD patients and in HS, and affected DR expression with cell subset-specific patterns. The present results support the involvement of peripheral adaptive immunity in PD, and may contribute to develop novel immunotherapies for PD, as well as to better use of current dopaminergic antiparkinson drugs. PMID:27652978

  8. Identification of Caucasian CD4 T cell epitopes on the circumsporozoite protein of Plasmodium vivax. T cell memory.

    PubMed

    Bilsborough, J; Carlisle, M; Good, M F

    1993-07-15

    We have identified a population of Caucasians with a defined past history of infection with Plasmodium vivax malaria. Using purified synthetic peptides overlapping the sequence of the circumsporozoite protein, we determined the percentage of individuals whose T cells proliferated or secreted IFN-gamma in response to peptide stimulation, for both this population and a population of nonmalaria-exposed control individuals. A number of peptides were recognized by both groups, but 11 peptides were uniquely recognized by the exposed population, and thus represented malaria-specific T cell epitopes. CD4 T cells were found to be responsible for the proliferative response. Humans last exposed to vivax sporozoites as long ago as 49 yr responded as well or better to these malaria-specific epitopes as individuals exposed within the previous month. Since such malaria-induced memory response may not be a feature of Plasmodium falciparum infections, and since P. falciparum does not have a persisting hypnozoite stage, our data argue that the persistence of T cell memory to vivax epitopes may result from antigenic persistence in the liver.

  9. Adenovirus vector vaccination induces expansion of memory CD4 T cells with a mucosal homing phenotype that are readily susceptible to HIV-1

    PubMed Central

    Benlahrech, Adel; Harris, Julian; Meiser, Andrea; Papagatsias, Timos; Hornig, Julia; Hayes, Peter; Lieber, Andre; Athanasopoulos, Takis; Bachy, Veronique; Csomor, Eszter; Daniels, Rod; Fisher, Kerry; Gotch, Frances; Seymour, Len; Logan, Karen; Barbagallo, Romina; Klavinskis, Linda; Dickson, George; Patterson, Steven

    2009-01-01

    In the recently halted HIV type 1 (HIV-1) vaccine STEP trial, individuals that were seropositive for adenovirus serotype 5 (Ad5) showed increased rates of HIV-1 infection on vaccination with an Ad5 vaccine. We propose that this was due to activation and expansion of Ad5-specific mucosal-homing memory CD4 T cells. To test this hypothesis, Ad5 and Ad11 antibody titers were measured in 20 healthy volunteers. Dendritic cells (DCs) from these individuals were pulsed with replication defective Ad5 or Ad11 and co-cultured with autologous lymphocytes. Cytokine profiles, proliferative capacity, mucosal migration potential, and susceptibility to HIV infection of the adenovirus-stimulated memory CD4 T cells were measured. Stimulation of T cells from healthy Ad5-seropositive but Ad11-seronegative individuals with Ad5, or serologically distinct Ad11 vectors induced preferential expansion of adenovirus memory CD4 T cells expressing α4β7 integrins and CCR9, indicating a mucosal-homing phenotype. CD4 T-cell proliferation and IFN-γ production in response to Ad stimulation correlated with Ad5 antibody titers. However, Ad5 serostatus did not correlate with total cytokine production upon challenge with Ad5 or Ad11. Expanded Ad5 and Ad11 memory CD4 T cells showed an increase in CCR5 expression and higher susceptibility to infection by R5 tropic HIV-1. This suggests that adenoviral-based vaccination against HIV-1 in individuals with preexisting immunity against Ad5 results in preferential expansion of HIV-susceptible activated CD4 T cells that home to mucosal tissues, increases the number of virus targets, and leads to a higher susceptibility to HIV acquisition. PMID:19918060

  10. Decreased Numbers of CD4+ Naive and Effector Memory T Cells, and CD8+ Naïve T Cells, are Associated with Trichloroethylene Exposure

    PubMed Central

    Hosgood, H. Dean; Zhang, Luoping; Tang, Xiaojiang; Vermeulen, Roel; Qiu, Chuangyi; Shen, Min; Smith, Martyn T.; Ge, Yichen; Ji, Zhiying; Xiong, Jun; He, Jian; Reiss, Boris; Liu, Songwang; Xie, Yuxuan; Guo, Weihong; Galvan, Noe; Li, Laiyu; Hao, Zhenyue; Rothman, Nathaniel; Huang, Hanlin; Lan, Qing

    2012-01-01

    Trichloroethylene (TCE) is a volatile chlorinated organic compound that is commonly used as a solvent for lipophilic compounds. Although recognized as an animal carcinogen, TCE’s carcinogenic potential in humans is still uncertain. We have carried out a cross-sectional study of 80 workers exposed to TCE and 96 unexposed controls matched on age and sex in Guangdong, China to study TCE’s early biologic effects. We previously reported that the total lymphocyte count and each of the major lymphocyte subsets (i.e., CD4+ T cells, CD8+ T cells, natural killer cells, and B cells) were decreased in TCE-exposed workers compared to controls, suggesting a selective effect on lymphoid progenitors, and/or lymphocyte survival. To explore which T lymphocyte subsets are affected in the same study population, we investigated the effect of TCE exposure on the numbers of CD4+ naïve and memory T cells, CD8+ naïve and memory T cells, and regulatory T cells by FACS analysis. Linear regression of each subset was used to test for differences between exposed workers and controls adjusting for potential confounders. We observed that CD4+ and CD8+ naïve T cell counts were about 8% (p = 0.056) and 17% (p = 0.0002) lower, respectively, among exposed workers. CD4+ effector memory T cell counts were decreased by about 20% among TCE-exposed workers compared to controls (p = 0.001). The selective targeting of TCE on CD8+ naive and possibly CD4+ naive T cells, and CD4+ effector memory T cells, provide further insights into the immunosuppression-related response of human immune cells upon TCE exposure. PMID:22649769

  11. Obesity-Induced Metabolic Stress Leads to Biased Effector Memory CD4(+) T Cell Differentiation via PI3K p110δ-Akt-Mediated Signals.

    PubMed

    Mauro, Claudio; Smith, Joanne; Cucchi, Danilo; Coe, David; Fu, Hongmei; Bonacina, Fabrizia; Baragetti, Andrea; Cermenati, Gaia; Caruso, Donatella; Mitro, Nico; Catapano, Alberico L; Ammirati, Enrico; Longhi, Maria P; Okkenhaug, Klaus; Norata, Giuseppe D; Marelli-Berg, Federica M

    2017-03-07

    Low-grade systemic inflammation associated to obesity leads to cardiovascular complications, caused partly by infiltration of adipose and vascular tissue by effector T cells. The signals leading to T cell differentiation and tissue infiltration during obesity are poorly understood. We tested whether saturated fatty acid-induced metabolic stress affects differentiation and trafficking patterns of CD4(+) T cells. Memory CD4(+) T cells primed in high-fat diet-fed donors preferentially migrated to non-lymphoid, inflammatory sites, independent of the metabolic status of the hosts. This was due to biased CD4(+) T cell differentiation into CD44(hi)-CCR7(lo)-CD62L(lo)-CXCR3(+)-LFA1(+) effector memory-like T cells upon priming in high-fat diet-fed animals. Similar phenotype was observed in obese subjects in a cohort of free-living people. This developmental bias was independent of any crosstalk between CD4(+) T cells and dendritic cells and was mediated via direct exposure of CD4(+) T cells to palmitate, leading to increased activation of a PI3K p110δ-Akt-dependent pathway upon priming.

  12. Human Infant Memory B Cell and CD4+ T Cell Responses to HibMenCY-TT Glyco-Conjugate Vaccine

    PubMed Central

    Fuery, Angela; Richmond, Peter C.; Currie, Andrew J.

    2015-01-01

    Carrier-specific T cell and polysaccharide-specific B cell memory responses are not well characterised in infants following glyco-conjugate vaccination. We aimed to determine if the number of Meningococcal (Men) C- and Y- specific memory B cells and; number and quality of Tetanus Toxoid (TT) carrier-specific memory CD4+ T cells are associated with polysaccharide-specific IgG post HibMenCY-TT vaccination. Healthy infants received HibMenCY-TT vaccine at 2, 4 and 6 months with a booster at 12 months. Peripheral blood mononuclear cells were isolated and polysaccharide-specific memory B cells enumerated using ELISpot. TT-specific memory CD4+ T cells were detected and phenotyped based on CD154 expression and intracellular TNF-α, IL-2 and IFN-γ expression following stimulation. Functional polysaccharide-specific IgG titres were measured using the serum bactericidal activity (SBA) assay. Polysaccharide-specific Men C- but not Men Y- specific memory B cell frequencies pre-boost (12 months) were significantly associated with post-boost (13 months) SBA titres. Regression analysis showed no association between memory B cell frequencies post-priming (at 6 or 7 months) and SBA at 12 months or 13 months. TT-specific CD4+ T cells were detected at frequencies between 0.001 and 0.112 as a percentage of CD3+ T cells, but their numbers were not associated with SBA titres. There were significant negative associations between SBA titres at M13 and cytokine expression at M7 and M12. Conclusion: Induction of persistent polysaccharide-specific memory B cells prior to boosting is an important determinant of secondary IgG responses in infants. However, polysaccharide-specific functional IgG responses appear to be independent of the number and quality of circulating carrier-specific CD4+ T cells after priming. PMID:26191794

  13. TCR-driven transendothelial migration of human effector memory CD4 T cells involves Vav, Rac, and myosin IIA.

    PubMed

    Manes, Thomas D; Pober, Jordan S

    2013-04-01

    Human effector memory (EM) CD4 T cells may be recruited from the blood into a site of inflammation in response either to inflammatory chemokines displayed on or specific Ag presented by venular endothelial cells (ECs), designated as chemokine-driven or TCR-driven transendothelial migration (TEM), respectively. We have previously described differences in the morphological appearance of transmigrating T cells as well as in the molecules that mediate T cell-EC interactions distinguishing these two pathways. In this study, we report that TCR-driven TEM requires ZAP-70-dependent activation of a pathway involving Vav, Rac, and myosin IIA. Chemokine-driven TEM also uses ZAP-70, albeit in a quantitatively and spatially different manner of activation, and is independent of Vav, Rac, and mysosin IIA, depending instead on an as-yet unidentified GTP exchange factor that activates Cdc42. The differential use of small Rho family GTPases to activate the cytoskeleton is consistent with the morphological differences observed in T cells that undergo TEM in response to these distinct recruitment signals.

  14. CD4(+) memory T cells retain surface expression of CD31 independently of thymic function in patients with lymphoproliferative disorders following autologous hematopoietic stem-cell transplantation.

    PubMed

    Batorov, Egor V; Tikhonova, Marina A; Kryuchkova, Irina V; Sergeevicheva, Vera V; Sizikova, Svetlana A; Ushakova, Galina Y; Batorova, Dariya S; Gilevich, Andrey V; Ostanin, Alexander A; Shevela, Ekaterina Y; Chernykh, Elena R

    2017-03-14

    High-dose chemotherapy with autologous hematopoietic stem-cell transplantation (AHSCT) causes severe and long-lasting immunodeficiency in patients with lymphoproliferative disorders. The thymus begins to restore the T-cell repertoire approximately from the sixth month post-transplant. We assessed the dynamics of post-transplant recovery of CD4(+)CD45RA(+)CD31(+) T cells, "recent thymic emigrants" (RTEs), and a poorly described subtype of CD4(+)CD45RA(-)CD31(+) T cells in 90 patients with lymphoproliferative disorders following high-dose chemotherapy with AHSCT. Relative and absolute counts of CD4(+)CD31(+) naïve and memory T cells were evaluated before AHSCT, at the day of engraftment, and 6- and 12-month post-transplant. The pre-transplant count of CD4(+)CD45RA(+)CD31(+) T cells was lower than in healthy controls, and did not reach donors' values during the 12-month period. The pre-transplant number of CD4(+)CD45RA(-)CD31(+) T cells was higher than in healthy controls and was restored rapidly following AHSCT. Post-transplant mediastinal radiotherapy reduced counts of RTEs and elongated recovery period. Non-thymic tissue irradiation did not reduce this subset. The obtained data indicate that homeostatic proliferation may decrease the significance of CD31 expression on CD4(+)CD45RA(+) T cells as a marker of RTEs, and suggest that evaluation of RTEs recovery by flow cytometry requires an accurate gating strategy to exclude CD31(+) memory T cells.

  15. Nuclear PKC-θ facilitates rapid transcriptional responses in human memory CD4+ T cells through p65 and H2B phosphorylation

    PubMed Central

    Li, Jasmine; Hardy, Kristine; Phetsouphanh, Chan; Tu, Wen Juan; Sutcliffe, Elissa L.; McCuaig, Robert; Sutton, Christopher R.; Zafar, Anjum; Munier, C. Mee Ling; Zaunders, John J.; Xu, Yin; Theodoratos, Angelo; Tan, Abel; Lim, Pek Siew; Knaute, Tobias; Masch, Antonia; Zerweck, Johannes; Brezar, Vedran; Milburn, Peter J.; Dunn, Jenny; Casarotto, Marco G.; Turner, Stephen J.; Seddiki, Nabila; Kelleher, Anthony D.

    2016-01-01

    ABSTRACT Memory T cells are characterized by their rapid transcriptional programs upon re-stimulation. This transcriptional memory response is facilitated by permissive chromatin, but exactly how the permissive epigenetic landscape in memory T cells integrates incoming stimulatory signals remains poorly understood. By genome-wide ChIP-sequencing ex vivo human CD4+ T cells, here, we show that the signaling enzyme, protein kinase C theta (PKC-θ) directly relays stimulatory signals to chromatin by binding to transcriptional-memory-responsive genes to induce transcriptional activation. Flanked by permissive histone modifications, these PKC-enriched regions are significantly enriched with NF-κB motifs in ex vivo bulk and vaccinia-responsive human memory CD4+ T cells. Within the nucleus, PKC-θ catalytic activity maintains the Ser536 phosphorylation on the p65 subunit of NF-κB (also known as RelA) and can directly influence chromatin accessibility at transcriptional memory genes by regulating H2B deposition through Ser32 phosphorylation. Furthermore, using a cytoplasm-restricted PKC-θ mutant, we highlight that chromatin-anchored PKC-θ integrates activating signals at the chromatin template to elicit transcriptional memory responses in human memory T cells. PMID:27149922

  16. Virus-specific CD4+ and CD8+ cytotoxic T-cell responses and long-term T-cell memory in individuals vaccinated against polio.

    PubMed

    Wahid, Rahnuma; Cannon, Martin J; Chow, Marie

    2005-05-01

    The presence of poliovirus (PV)-specific CD4(+) T cells in individuals vaccinated against polio has been shown, but CD8(+) T-cell responses have not been described. Here, we functionally characterize the CD4(+) T-cell response and show for the first time that dendritic cells and macrophages can stimulate PV-specific CD8(+) T-cell responses in vitro from vaccinees. Both CD4(+) T and CD8(+) T cells secrete gamma interferon in response to PV antigens and are cytotoxic via the perforin/granzyme B-mediated pathway. Furthermore, the T cells also recognize and kill Sabin 1 vaccine-infected targets. The macrophage-stimulated CD4(+) T and CD8(+) T cells most likely represent memory T cells that persist for long periods in vaccinated individuals. Thus, immunity to PV vaccination involves not only an effective neutralizing antibody titer but also long-term CD4(+) and CD8(+) cytotoxic T-cell responses.

  17. Simultaneous activation of viral antigen-specific memory CD4+ and CD8+ T-cells using mRNA-electroporated CD40-activated autologous B-cells.

    PubMed

    Van den Bosch, Glenn A; Van Gulck, Ellen; Ponsaerts, Peter; Nijs, Griet; Lenjou, Marc; Apers, Ludwig; Kint, Ilse; Heyndrickx, Leo; Vanham, Guido; Van Bockstaele, Dirk R; Berneman, Zwi N; Van Tendeloo, Viggo F I

    2006-01-01

    Recently, it has become obvious that not only CD8 T-cells, but also CD4 T-helper cells are required for the induction of an effective, long-lasting cellular immune response. In view of the clinical importance of cytomegalovirus (CMV) and human immunodeficiency virus (HIV) infection, we developed 2 strategies to simultaneously reactivate viral antigen-specific memory CD4 and CD8 T-cells of CMV-seropositive and HIV-seropositive subjects using mRNA-electroporated autologous CD40-activated B cells. In the setting of HIV, we provide evidence that CD40-activated B cells can be cultured from HAART-naive HIV-1 seropositive patients. These cells not only express and secrete the HIV p24 antigen after electroporation with codon-optimized HIV-1 gag mRNA, but can also be used to in vitro reactivate Gag antigen-specific interferon-gamma-producing CD4 and CD8 autologous T-cells. For the CMV-specific approach, we applied mRNA coding for the pp65 protein coupled to the lysosomal-associated membrane protein-1 to transfect CD40-activated B cells to induce CMV antigen-specific CD4 and CD8 T-cells. More detailed analysis of the activated interferon-gamma-producing CMV pp65 tetramer positive CD8 T-cells revealed an effector memory phenotype with the capacity to produce interleukin-2. Our findings clearly show that the concomitant activation of both CD4 and CD8 (memory) T-cells using mRNA-electroporated CD40-B cells is feasible in CMV and HIV-1-seropositive persons, which indicates the potential value of this approach for application in cellular immunotherapy of infectious diseases.

  18. Altered T-bet dominance in IFN-γ-decoupled CD4+ T cells with attenuated cytokine storm and preserved memory in influenza.

    PubMed

    Dutta, Avijit; Miaw, Shi-Chuen; Yu, Jhang-Sian; Chen, Tse-Ching; Lin, Chun-Yen; Lin, Yung-Chang; Chang, Chia-Shiang; He, Yueh-Chia; Chuang, Sheng-Hao; Yen, Ming-I; Huang, Ching-Tai

    2013-04-15

    Cytokine storm has been postulated as one of the major causes of mortality in patients with severe respiratory viral infections such as influenza. With the help of an influenza Ag- specific mouse experimental system, we report that CD4(+) T cells contribute effector cytokines leading to lung inflammation in acute influenza. Although virus can no longer be detected from tissues 14 d postinfection, virus-derived Ag continues to drive a CD4(+) T cell response after viral clearance. Ag-specific CD4(+) T cells proliferate and evolve into memory CD4(+) T cells efficiently, but the production of effector cytokines is seriously hampered during this phase. This decoupling of proliferation and effector cytokine production doesn't appear in conjunction with increased suppression by regulatory T cells or decreased induction of transcription factors. Rather, GATA-3 and ROR-γt levels are elevated when compared with cells that have effector cytokine production. T-bet dominance over GATA-3 and ROR-γt decreases with the disarmament of effector cytokine production. Importantly, upon reinfection, these decoupled cells produce elevated levels of IFN-γ and were effective in virus eradication. These results provide a mechanism through altered T-bet dominance to dampen the cytokine storm without impeding the generation of memory T cells in influenza virus infection.

  19. Mycobacterium tuberculosis PstS1 amplifies IFN-γ and induces IL-17/IL-22 responses by unrelated memory CD4+ T cells via dendritic cell activation.

    PubMed

    Palma, Carla; Schiavoni, Giovanna; Abalsamo, Laura; Mattei, Fabrizio; Piccaro, Giovanni; Sanchez, Massimo; Fernandez, Carmen; Singh, Mahavir; Gabriele, Lucia

    2013-09-01

    The immunological mechanisms that modulate protection during Mycobacterium tuberculosis (Mtb) infection or vaccination are not fully understood. Secretion of IFN-γ and, to a lesser extent, of IL-17 by CD4(+) T cells plays a major role both in protection and immunopathology. Few Mtb Ags interacting with DCs affect priming, activation, and regulation of Ag-unrelated CD4(+) T-cell responses. Here we demonstrate that PstS1, a 38 kDa-lipoprotein of Mtb, promotes Ag-independent activation of memory T lymphocytes specific for Ag85B or Ag85A, two immunodominant protective Ags of Mtb. PstS1 expands CD4(+) and CD8(+) memory T cells, amplifies secretion of IFN-γ and IL-22 and induces IL-17 production by effector memory cells in an Ag-unrelated manner in vitro and in vivo. These effects were mediated through the stimulation of DCs, particularly of the CD8α(-) subtype, which respond to PstS1 by undergoing phenotypic maturation and by secreting IL-6, IL-1β and, to a lower extent, IL-23. IL-6 secretion by PstS1-stimulated DCs was required for IFN-γ, and to a lesser extent for IL-22 responses by Ag85B-specific memory T cells. These results may open new perspectives for immunotherapeutic strategies to control Th1/Th17 immune responses in Mtb infections and in vaccinations against tuberculosis.

  20. CD4 T Helper Cells Instruct Lymphopenia-Induced Memory-Like CD8 T Cells for Control of Acute LCMV Infection

    PubMed Central

    Schmitt, Michaela E. R.; Sitte, Selina; Voehringer, David

    2016-01-01

    Lymphopenic conditions lead to expansion of memory-like T cells (TML), which develop from naïve T cells by spontaneous proliferation. TML cells are often increased in the elderly population, AIDS patients, and patients recovering from radio- or chemotherapy. At present, it is unclear whether TML cells can efficiently respond to foreign antigen and participate in antiviral immunity. To address this question, we analyzed the immune response during acute low-dose infection with lymphocytic choriomeningitis virus-WE in T cell lymphopenic CD4Cre/R-diphtheria toxin alpha (DTA) mice in which most peripheral T cells show a TML phenotype. On day 8 after infection, the total number of effector T cells and polyfunctional IFN-γ and TNF-α producing CD8 T cells were three- to fivefold reduced in CD4Cre/R-DTA mice as compared to controls. Viral clearance and the humoral immune response were severely impaired in CD4Cre/R-DTA mice although CTLs efficiently killed transferred target cells in vivo. Transfer of naïve CD4 T cells but not anti-PD-L1 blockade restored the expansion of antigen-specific polyfunctional CD8 T cells and resulted in lower viral titers. This finding indicates that under lymphopenic conditions endogenous CD4 TML cell lack the capacity to promote expansion of CTLs. However, CD8 TML cells retain sufficient functional plasticity to participate in antiviral immunity in the presence of appropriate help by fully functional CD4 T cells. This capacity might be exploited to develop treatments for improvement of CD8 T cell functions under various clinical settings of lymphopenia. PMID:28066432

  1. NK cells require antigen-specific memory CD4+ T cells to mediate superior effector functions during HSV-2 recall responses in vitro.

    PubMed

    Chen, Branson; Lee, Amanda J; Chew, Marianne V; Ashkar, Ali A

    2016-12-14

    Natural killer (NK) cells have an important role in mounting protective innate responses against genital herpes simplex virus type 2 (HSV-2) infections. However their role as effectors in adaptive immune responses against HSV-2 is unclear. Here, we demonstrate that NK cells from C57BL/6 mice in an ex vivo splenocyte culture produce significantly more interferon γ (IFN-γ) upon re-exposure to HSV-2 antigens in a mouse model of genital HSV-2 immunization. We find that naïve NK cells do not require any prior stimulation or priming to be activated to produce IFN-γ. Our results demonstrate that HSV-2-experienced CD4(+) T cells have a crucial role in coordinating NK cell activation and that their presence during HSV-2 antigen presentation is required to activate NK cells in this model of secondary immune response. We also examined the requirement of cell-to-cell contacts for both CD4(+) T cells and NK cells. NK cells are dependent on direct interactions with other HSV-2-experienced splenocytes, and CD4(+) T cells need to be in close proximity to NK cells to activate them. This study revealed that NK cells do not exhibit any memory toward HSV-2 antigens and, in fact, require specific interactions with HSV-2-experienced CD4(+) T cells to produce IFN-γ.

  2. Activated Memory CD4+ T Helper Cells Repopulate the Intestine Early following Antiretroviral Therapy of Simian Immunodeficiency Virus-Infected Rhesus Macaques but Exhibit a Decreased Potential To Produce Interleukin-2

    PubMed Central

    Mattapallil, Joseph J.; Smit-McBride, Zeljka; Dailey, Peter; Dandekar, Satya

    1999-01-01

    Using the simian immunodeficiency virus (SIV)-infected rhesus macaque model, we performed a longitudinal study to determine the effect of antiretroviral therapy on the phenotype and functional potential of CD4+ T cells repopulating intestinal mucosa in human immunodeficiency virus infection. Severe depletion of CD4+ and CD4+ CD8+ T cells occurred in the intestinal mucosa during primary SIV infection. The majority of these cells were of activated memory phenotype. Phosphonate 9-[2-(phosphomethoxypropyl]adenine (PMPA) treatment led to a moderate suppression of intestinal viral loads and repopulation of intestinal mucosa by predominantly activated memory CD4+ T-helper cells. This repopulation was independent of the level of viral suppression. Compared to preinfection values, the frequency of naive CD4+ T cells increased following PMPA therapy, suggesting that new CD4+ T cells were repopulating the intestinal mucosa. Repopulation by CD4+ CD8+ T cells was not observed in either jejunum or colon lamina propria. The majority of CD4+ T cells repopulating the intestinal mucosa following PMPA therapy were CD29hi and CD11ahi. A subset of repopulating intestinal CD4+ T cells expressed Ki-67 antigen, indicating that local proliferation may play a role in the repopulation process. Although the majority of repopulating CD4+ T cells in the intestinal mucosa were functionally capable of providing B- and T-cell help, as evidenced by their expression of CD28, these CD4+ T cells were found to have a reduced capacity to produce interleukin-2 (IL-2) compared to the potential of CD4+ T cells prior to SIV infection. Persistent viral infection may play a role in suppressing the potential of repopulating CD4+ T cells to produce IL-2. Hence, successful antiretroviral therapy should aim at complete suppression of viral loads in mucosal lymphoid tissues, such as intestinal mucosa. PMID:10400763

  3. Intracellular expression of interleukin-4 and interferon-γ by a Mycobacterium tuberculosis antigen-stimulated CD4+ CD57+ T-cell subpopulation with memory phenotype in tuberculosis patients

    PubMed Central

    Jiménez-Martínez, Maria C; Linares, Marisela; Báez, Renata; Montaño, Luis F; Martínez-Cairo, Salvador; Gorocica, Patricia; Chávez, Raúl; Zenteno, Edgar; Lascurain, Ricardo

    2004-01-01

    In some chronic pathological conditions, antigen persistence activates and expands the CD4+ CD57+ T-cell subset. The host immune response against tuberculosis infection is maintained through the continuous presence of antigen-stimulated effector/memory helper T cells. To determine whether CD4+ CD57+ T cells were also expanded in human tuberculosis, we analysed (by flow cytometry) the phenotype of peripheral blood CD4+ T cells from 30 tuberculosis patients and 30 healthy controls. We observed a significant increase in the CD4+ CD57+ T-cell subset in tuberculosis patients in comparison to healthy controls (P < 0.001). Most CD4+ CD57+ T cells exhibited a CD28− CD45RO+ CD62L− phenotype, which is associated with memory cells. In vitro, a higher number of antigen-stimulated CD4+ CD57+ T cells produced intracellular interferon-γ and interleukin-4 compared with antigen-stimulated CD4+ CD57− T cells (P < 0.001). These findings suggest that the majority of CD4+ CD57+ T cells correspond to a phenotype of activated memory T cells. PMID:14678204

  4. Opioid growth factor and low-dose naltrexone impair central nervous system infiltration by CD4 + T lymphocytes in established experimental autoimmune encephalomyelitis, a model of multiple sclerosis.

    PubMed

    Hammer, Leslie A; Waldner, Hanspeter; Zagon, Ian S; McLaughlin, Patricia J

    2016-01-01

    Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS), characterized by infiltrating myelin-reactive T lymphocytes and demyelinating lesions. Experimental autoimmune encephalomyelitis (EAE) is the animal model widely utilized to study MS. EAE is mediated by CD4(+) T cells and can be induced in EAE-susceptible mice through immunization with a myelin antigen, such as proteolipid protein 139-151 (PLP139-151) in SJL mice. In this PLP-induced EAE model, autoreactive CD4(+) T cells migrate from peripheral tissues into the CNS where they are reactivated resulting in CNS damage. Th1 and Th17 cells produce the pro-inflammatory cytokines IFNγ and IL-17, respectively, that have been shown to have pathogenic roles in EAE and MS. Anti-inflammatory Th2, IL-4 secreting cells, have been indicated to inhibit EAE exacerbation. However, given the inflammatory environment of EAE, Th2 effector cells are outnumbered by Th1/Th17 cells. Regulatory CD4(+) T cells suppress immune reactions and have been demonstrated to be dysfunctional in MS patients. Opioid growth factor (OGF), chemically termed [Met(5)]-enkephalin, is a negative growth factor that interacts with the OGF receptor. The OGF-OGFr axis can be activated through exogenous administration of OGF or a low dosage of naltrexone (LDN), an opioid antagonist. We have previously demonstrated that modulation of the OGF-OGFr axis results in alleviation from relapse-remitting EAE, and that CNS-infiltrating CD3(+) T cells are diminished with exogenous OGF or intermittent blockade with LDN administration. In this paper, we aimed to determine whether OGF or LDN alter the Th effector responses of CD4(+) T lymphocytes within the CNS in established EAE. We report in these studies that the numbers of CD4(+) T lymphocytes in the CNS of EAE mice are decreased following treatment with OGF for five days but not LDN. However, modulation of the OGF-OGFr axis did not result in changes to CD4(+) Th effector cell responses

  5. A pilot study showing associations between frequency of CD4(+) memory cell subsets at diagnosis and duration of partial remission in type 1 diabetes.

    PubMed

    Moya, Rosita; Robertson, Hannah Kathryn; Payne, Dawson; Narsale, Aditi; Koziol, Jim; Davies, Joanna Davida

    2016-05-01

    In some patients with type 1 diabetes the dose of insulin required to achieve euglycemia is substantially reduced soon after diagnosis. This partial remission is associated with β-cell function and good glucose control. The purpose of this study was to assess whether frequencies of CD4(+) T cell subsets in children newly diagnosed with type 1 diabetes are associated with length of partial remission. We found that the frequency of CD4(+) memory cells, activated Treg cells and CD25(+) cells that express a high density of the IL-7 receptor, CD127 (CD127(hi)) are strongly associated with length of partial remission. Prediction of length of remission via Cox regression is significantly enhanced when CD25(+) CD127(hi) cell frequency is combined with either Insulin Dependent Adjusted A1c (IDAA1c), or glycosylated hemoglobin (HbA1c), or C-peptide levels at diagnosis. CD25(+) CD127(hi) cells do not express Foxp3, LAG-3 and CD49b, indicating that they are neither Treg nor Tr1 cells.

  6. Impaired selective cytokine production by CD4(+) T cells in Common Variable Immunodeficiency associated with the absence of memory B cells.

    PubMed

    Berrón-Ruiz, Laura; López-Herrera, Gabriela; Vargas-Hernández, Alexander; Santos-Argumedo, Leopoldo; López-Macías, Constantino; Isibasi, Armando; Segura-Méndez, Nora Hilda; Bonifaz, Laura

    2016-05-01

    Common Variable Immunodeficiency (CVID) is a primary immunodeficiency characterized by B cell dysfunction and decreased serum immunoglobulin. CVID patients are classified by the absence or presence of memory B cells. In addition, T cell defects have been demonstrated in only a proportion of CVID patients. The aim of this study was to evaluate the function of CD4(+) T cells from CVID patients and its association with memory B cells. Patients were classified according to their Freiburg groups: group Ia and Ib, with decreased switched memory B cells (<0.4 of PBL), and group II, with normal B cell subsets. Their T cell function was evaluated after stimulation. We observed normal and even increased CD4(+) T cell proliferation in group Ia (p=0.0277). The proliferation positively correlated with the clinical severity score (r=0.4796). We observed lower levels of IL-17A and IL-10 in group Ia (p=0.0177, 0.0109) and Ib (p=0.0009, 0.0084) patients. Group Ib patients also had low levels of IL-13 and IL-9 (p=0.0169, 0.010). Group II patients had similar cytokine production to that of the controls. BAFFR expression was reduced in groups Ia (p=0.0001) and Ib (p=0.0002) and showed an inverse correlation with the severity score (p=0.0262; r=0.5371). ICOS expression was reduced in group Ia (p=0.0364), and PD-1 was increased in group Ib (p=0.0432) patients. This study shows a selective impairment in cytokine production in group Ia patients, which was more extensive than in group Ib patients. The impairment was associated with BAFFR expression in B cells, with ICOS and PD-1 in T cells and, remarkably, with the absence of memory B cells and with the disease severity. Our results suggest that the evaluation of cytokine expression by T cells in combination with the study of B cell memory could be important for understand the pathogenesis of CVID patients.

  7. IFN-γ-producing CD4+ T cells promote generation of protective germinal center-derived IgM+ B cell memory against Salmonella Typhi.

    PubMed

    Perez-Shibayama, Christian; Gil-Cruz, Cristina; Pastelin-Palacios, Rodolfo; Cervantes-Barragan, Luisa; Hisaki, Emiliano; Chai, Qian; Onder, Lucas; Scandella, Elke; Regen, Tommy; Waisman, Ari; Isibasi, Armando; Lopez-Macias, Constantino; Ludewig, Burkhard

    2014-06-01

    Abs play a significant role in protection against the intracellular bacterium Salmonella Typhi. In this article, we investigated how long-term protective IgM responses can be elicited by a S. Typhi outer-membrane protein C- and F-based subunit vaccine (porins). We found that repeated Ag exposure promoted a CD4(+) T cell-dependent germinal center reaction that generated mutated IgM-producing B cells and was accompanied by a strong expansion of IFN-γ-secreting T follicular helper cells. Genetic ablation of individual cytokine receptors revealed that both IFN-γ and IL-17 are required for optimal germinal center reactions and production of porin-specific memory IgM(+) B cells. However, more profound reduction of porin-specific IgM B cell responses in the absence of IFN-γR signaling indicated that this cytokine plays a dominant role. Importantly, mutated IgM mAbs against porins exhibited bactericidal capacity and efficiently augmented S. Typhi clearance. In conclusion, repeated vaccination with S. Typhi porins programs type I T follicular helper cell responses that contribute to the diversification of B cell memory and promote the generation of protective IgM Abs.

  8. Differential Regulation of Self-reactive CD4+ T Cells in Cervical Lymph Nodes and Central Nervous System during Viral Encephalomyelitis

    PubMed Central

    Savarin, Carine; Bergmann, Cornelia C.; Hinton, David R.; Stohlman, Stephen A.

    2016-01-01

    Viral infections have long been implicated as triggers of autoimmune diseases, including multiple sclerosis (MS), a central nervous system (CNS) inflammatory demyelinating disorder. Epitope spreading, molecular mimicry, cryptic antigen, and bystander activation have been implicated as mechanisms responsible for activating self-reactive (SR) immune cells, ultimately leading to organ-specific autoimmune disease. Taking advantage of coronavirus JHM strain of mouse hepatitis virus (JHMV)-induced demyelination, this study demonstrates that the host also mounts counteractive measures to specifically limit expansion of endogenous SR T cells. In this model, immune-mediated demyelination is associated with induction of SR T cells after viral control. However, their decline during persisting infection, despite ongoing demyelination, suggests an active control mechanism. Antigen-specific IL-10-secreting CD4+ T cells (Tr1) and Foxp3+ regulatory T cells (Tregs), both known to control autoimmunity and induced following JHMV infection, were assessed for their relative in vivo suppressive function of SR T cells. Ablation of Foxp3+ Tregs in chronically infected DEREG mice significantly increased SR CD4+ T cells within cervical lymph nodes (CLN), albeit without affecting their numbers or activation within the CNS compared to controls. In contrast, infected IL-27 receptor deficient (IL-27R−/−) mice, characterized by a drastic reduction of Tr1 cells, revealed that SR CD4+ T cells in CLN remained unchanged but were specifically increased within the CNS. These results suggest that distinct Treg subsets limit SR T cells in the draining lymph nodes and CNS to maximize suppression of SR T-cell-mediated autoimmune pathology. The JHMV model is thus valuable to decipher tissue-specific mechanisms preventing autoimmunity. PMID:27708643

  9. Differential Regulation of Self-reactive CD4(+) T Cells in Cervical Lymph Nodes and Central Nervous System during Viral Encephalomyelitis.

    PubMed

    Savarin, Carine; Bergmann, Cornelia C; Hinton, David R; Stohlman, Stephen A

    2016-01-01

    Viral infections have long been implicated as triggers of autoimmune diseases, including multiple sclerosis (MS), a central nervous system (CNS) inflammatory demyelinating disorder. Epitope spreading, molecular mimicry, cryptic antigen, and bystander activation have been implicated as mechanisms responsible for activating self-reactive (SR) immune cells, ultimately leading to organ-specific autoimmune disease. Taking advantage of coronavirus JHM strain of mouse hepatitis virus (JHMV)-induced demyelination, this study demonstrates that the host also mounts counteractive measures to specifically limit expansion of endogenous SR T cells. In this model, immune-mediated demyelination is associated with induction of SR T cells after viral control. However, their decline during persisting infection, despite ongoing demyelination, suggests an active control mechanism. Antigen-specific IL-10-secreting CD4(+) T cells (Tr1) and Foxp3(+) regulatory T cells (Tregs), both known to control autoimmunity and induced following JHMV infection, were assessed for their relative in vivo suppressive function of SR T cells. Ablation of Foxp3(+) Tregs in chronically infected DEREG mice significantly increased SR CD4(+) T cells within cervical lymph nodes (CLN), albeit without affecting their numbers or activation within the CNS compared to controls. In contrast, infected IL-27 receptor deficient (IL-27R(-/-)) mice, characterized by a drastic reduction of Tr1 cells, revealed that SR CD4(+) T cells in CLN remained unchanged but were specifically increased within the CNS. These results suggest that distinct Treg subsets limit SR T cells in the draining lymph nodes and CNS to maximize suppression of SR T-cell-mediated autoimmune pathology. The JHMV model is thus valuable to decipher tissue-specific mechanisms preventing autoimmunity.

  10. Cross-reactive memory CD4+ T cells alter the CD8+ T-cell response to heterologous secondary dengue virus infections in mice in a sequence-specific manner.

    PubMed

    Beaumier, Coreen M; Rothman, Alan L

    2009-06-01

    Secondary dengue virus (DENV) infection is a major factor contributing to the risk for severe disease, an effect that depends upon the sequence of infection with different DENV serotypes. We previously reported sequence-dependent effects of secondary DENV infection on CD8+ T-cell responses in mice. To further evaluate the effect of infection sequence, we analyzed DENV-specific CD4+ T-cell responses and their relationship to the CD8+ T-cell response. Serotype cross-reactivity of CD4+ T-cell responses also depended upon the sequence of serotypes in this model. Furthermore, adoptive transfer of memory CD4+ T cells altered the response of memory CD8+ T cells to secondary infection. These data demonstrate the interaction of different components of the T-cell response in determining the immunological outcome of secondary DENV infection.

  11. Stress-activated Dendritic Cells (DC) Induce Dual Interleukin (IL)-15- and IL1β-mediated Pathways, Which May Elicit CD4+ Memory T Cells and Interferon (IFN)-stimulated Genes.

    PubMed

    Wang, Yufei; Lavender, Paul; Watson, Julie; Arno, Matthew; Lehner, Thomas

    2015-06-19

    The prevailing evidence suggests that immunological memory does not require antigenic re-stimulation but is maintained by low level tonic stimulation. We examined the hypothesis that stress agents contribute to tonic cellular activation and maintain immunological memory. Stimulation of monocyte-derived dendritic cells (DC) with stress agents elicits reactive oxygen species and HSP70. NFκB is activated, which up-regulates membrane-associated (ma) IL-15, caspase-1 and IL-1β. Co-culture of stress-treated DC with mononuclear cells activates IL-15 and IL-1β receptors on CD4(+) T cells, eliciting CD40L, proliferation, and up-regulation of CD45RO(+) memory T cells. The transcription factors Tbet(high) and RORγt are up-regulated, whereas FoxP3 is down-regulated, resulting in enhanced Th1 and Th17 expression and the corresponding cytokines. The interaction between maIL-15 expressed by DC and IL-15R on CD4(+) T cells results in one pathway and the corresponding cells expressing IL-1β and IL1βR as a second pathway. Importantly, inhibition studies with IL-15 antibodies and IL-1βR inhibitor suggest that both pathways may be required for optimum CD4(+) CD45RO(+) memory T cell expression. Type 1 IFN expression in splenic CD11c DC of stress-treated mice demonstrated a significant increase of IFN-α in CD11c CD317(+) and CD8α(+) DC. Analysis of RNA in human CD4(+) memory T cells showed up-regulation of type 1 IFN-stimulated genes and inhibition with histone methyltransferase inhibitor. We suggest the paradigm that stress-induced tonic stimulation might be responsible for the robust persistence of the immune response in vaccination and that epigenetic changes are involved in maintaining CD4(+) T cell memory.

  12. The human immunodeficiency virus type 1 (HIV-1) CD4 receptor and its central role in promotion of HIV-1 infection.

    PubMed Central

    Bour, S; Geleziunas, R; Wainberg, M A

    1995-01-01

    Interactions between the viral envelope glycoprotein gp120 and the cell surface receptor CD4 are responsible for the entry of human immunodeficiency virus type 1 (HIV-1) into host cells in the vast majority of cases. HIV-1 replication is commonly followed by the disappearance or receptor downmodulation of cell surface CD4. This potentially renders cells nonsusceptible to subsequent infection by HIV-1, as well as by other viruses that use CD4 as a portal of entry. Disappearance of CD4 from the cell surface is mediated by several different viral proteins that act at various stages through the course of the viral life cycle, and it occurs in T-cell lines, peripheral blood CD4+ lymphocytes, and monocytes of both primary and cell line origin. At the cell surface, gp120 itself and in the form of antigen-antibody complexes can trigger cellular pathways leading to CD4 internalization. Intracellularly, the mechanisms leading to CD4 downmodulation by HIV-1 are multiple and complex; these include degradation of CD4 by Vpu, formation of intracellular complexes between CD4 and the envelope precursor gp160, and internalization by the Nef protein. Each of the above doubtless contributes to the ultimate depletion of cell surface CD4, although the relative contribution of each mechanism and the manner in which they interact remain to be definitively established. PMID:7708013

  13. Recombinant Bivalent Fusion Protein rVE Induces CD4+ and CD8+ T-Cell Mediated Memory Immune Response for Protection Against Yersinia enterocolitica Infection

    PubMed Central

    Singh, Amit K.; Kingston, Joseph J.; Gupta, Shishir K.; Batra, Harsh V.

    2015-01-01

    Studies investigating the correlates of immune protection against Yersinia infection have established that both humoral and cell mediated immune responses are required for the comprehensive protection. In our previous study, we established that the bivalent fusion protein (rVE) comprising immunologically active regions of Y. pestis LcrV (100–270 aa) and YopE (50–213 aa) proteins conferred complete passive and active protection against lethal Y. enterocolitica 8081 challenge. In the present study, cohort of BALB/c mice immunized with rVE or its component proteins rV, rE were assessed for cell mediated immune responses and memory immune protection against Y. enterocolitica 8081. rVE immunization resulted in extensive proliferation of both CD4 and CD8 T cell subsets; significantly high antibody titer with balanced IgG1: IgG2a/IgG2b isotypes (1:1 ratio) and up-regulation of both Th1 (TNF-α, IFN-γ, IL-2, and IL-12) and Th2 (IL-4) cytokines. On the other hand, rV immunization resulted in Th2 biased IgG response (11:1 ratio) and proliferation of CD4+ T-cell; rE group of mice exhibited considerably lower serum antibody titer with predominant Th1 response (1:3 ratio) and CD8+ T-cell proliferation. Comprehensive protection with superior survival (100%) was observed among rVE immunized mice when compared to the significantly lower survival rates among rE (37.5%) and rV (25%) groups when IP challenged with Y. enterocolitica 8081 after 120 days of immunization. Findings in this and our earlier studies define the bivalent fusion protein rVE as a potent candidate vaccine molecule with the capability to concurrently stimulate humoral and cell mediated immune responses and a proof of concept for developing efficient subunit vaccines against Gram negative facultative intracellular bacterial pathogens. PMID:26733956

  14. CD4+ Th1 cells promote CD8+ Tc1 cell survival, memory response, tumor localization and therapy by targeted delivery of interleukin 2 via acquired pMHC I complexes.

    PubMed

    Huang, Hui; Hao, Siguo; Li, Fang; Ye, Zhenmin; Yang, Junbao; Xiang, Jim

    2007-02-01

    The cooperative role of CD4+ helper T (Th) cells has been reported for CD8+ cytotoxic T (Tc) cells in tumor eradication. However, its molecular mechanisms have not been well elucidated. We have recently demonstrated that CD4+ Th cells can acquire major histocompatibility complex/peptide I (pMHC I) complexes and costimulatory molecules by dendritic cell (DC) activation, and further stimulate naïve CD8+ T cell proliferation and activation. In this study, we used CD4+ Th1 and CD8+ Tc1 cells derived from ovalbumin (OVA)-specific T cell receptor (TCR) transgenic OT II and OT I mice to study CD4+ Th1 cell's help effects on active CD8+ Tc1 cells and the molecular mechanisms involved in CD8+ Tc1-cell immunotherapy of OVA-expressing EG7 tumors. Our data showed that CD4+ Th1 cells with acquired pMHC I by OVA-pulsed DC (DCOVA) stimulation are capable of prolonging survival and reducing apoptosis formation of active CD8+ Tc1 cells in vitro, and promoting CD8+ Tc1 cell tumor localization and memory responses in vivo by 3-folds. A combined adoptive T-cell therapy of CD8+ Tc1 with CD4+ Th1 cells resulted in regression of well-established EG7 tumors (5 mm in diameter) in all 10/10 mice. The CD4+ Th1's help effect is mediated via the helper cytokine IL-2 specifically targeted to CD8+ Tc1 cells in vivo by acquired pMHC I complexes. Taken together, these results will have important implications for designing adoptive T-cell immunotherapy protocols in treatment of solid tumors.

  15. Loss of memory CD4+ T-cells in semi-wild mandrills (Mandrillus sphinx) naturally infected with species-specific simian immunodeficiency virus SIVmnd-1

    PubMed Central

    Greenwood, Edward J. D.; Schmidt, Fabian; Liégeois, Florian; Kondova, Ivanela; Herbert, Anaïs; Ngoubangoye, Barthelemy; Heeney, Jonathan L.

    2014-01-01

    Simian immunodeficiency virus (SIV) infection is found in a number of African primate species and is thought to be generally non-pathogenic. However, studies of wild primates are limited to two species, with SIV infection appearing to have a considerably different outcome in each. Further examination of SIV-infected primates exposed to their natural environment is therefore warranted. We performed a large cross-sectional study of a cohort of semi-wild mandrills with naturally occurring SIV infection, including 39 SIV-negative and 33 species-specific SIVmnd-1-infected animals. This study was distinguished from previous reports by considerably greater sample size, examination of exclusively naturally infected animals in semi-wild conditions and consideration of simian T-lymphotropic virus (STLV) status in addition to SIVmnd-1 infection. We found that SIVmnd-1 infection was associated with a significant and progressive loss of memory CD4+ T-cells. Limited but significant increases in markers of immune activation in the T-cell populations, significant increases in plasma neopterin and changes to B-cell subsets were also observed in SIV-infected animals. However, no increase in plasma soluble CD14 was observed. Histological examination of peripheral lymph nodes suggested that SIVmnd-1 infection was not associated with a significant disruption of the lymph node architecture. Whilst this species has evolved numerous strategies to resist the development of AIDS, significant effects of SIV infection could be observed when examined in a natural environment. STLVmnd-1 infection also had significant effects on some markers relevant to understanding SIV infection and thus should be considered in studies of SIV infection of African primates where present. PMID:24214347

  16. Key Role of Effector Memory CD4+ T Lymphocytes in a Short-Incubation Heparin-Binding Hemagglutinin Gamma Interferon Release Assay for the Detection of Latent Tuberculosis

    PubMed Central

    Wyndham-Thomas, Chloé; Corbière, Véronique; Dirix, Violette; Smits, Kaatje; Domont, Fanny; Libin, Myriam; Loyens, Marc; Locht, Camille

    2014-01-01

    The treatment of latent tuberculosis infection (LTBI) in target populations is one of the current WHO strategies for preventing active tuberculosis (TB) infection and reducing the Mycobacterium tuberculosis reservoir. Therefore, powerful LTBI screening tools are indispensable. A gamma interferon release assay (IGRA) in response to the stimulation of peripheral blood mononuclear cells by the latency antigen native heparin-binding hemagglutinin (nHBHA-IGRA) has proven its potential for this purpose. We have evaluated its possible optimization through a reduction of incubation time from 96 to 24 h, while compensating for this by adding interleukin 7 (IL-7) to the medium. We have also investigated the phenotypes of the gamma interferon (IFN-γ)-producing cells after both short and long incubation times. One hundred thirty-one nonimmunocompromised patients were recruited from 3 Brussels-based university hospitals. They were divided into 1 of 4 subgroups according to their M. tuberculosis infection status (LTBI, TB infection, undetermined M. tuberculosis infection status, and noninfected controls). The novel 24-h nHBHA-IGRA was performed for all subjects, and a simultaneous 96-h classical HBHA-IGRA was performed for 79 individuals. The results showed a good correlation between the two tests, and the novel 24-h nHBHA-IGRA maintained the principal advantages of the classical test, namely, a high specificity for LTBI diagnosis, an absence of interference of Mycobacterium bovis BCG vaccination during infancy, and a relative discrimination between LTBI and TB infection. Whereas the commercialized IGRAs show a greater sensitivity for recent than for remote M. tuberculosis infections, the 24-h nHBHA-IGRA appears to have comparable diagnostic powers for recent and remote LTBI. The IFN-γ detected by the 24-h nHBHA-IGRA was mainly secreted by effector memory CD4+ T lymphocytes, a finding suggestive of continuous HBHA presentation during latency. PMID:24391135

  17. Distributed trace using central performance counter memory

    DOEpatents

    Satterfield, David L; Sexton, James C

    2013-10-22

    A plurality of processing cores, are central storage unit having at least memory connected in a daisy chain manner, forming a daisy chain ring layout on an integrated chip. At least one of the plurality of processing cores places trace data on the daisy chain connection for transmitting the trace data to the central storage unit, and the central storage unit detects the trace data and stores the trace data in the memory co-located in with the central storage unit.

  18. Distributed trace using central performance counter memory

    DOEpatents

    Satterfield, David L.; Sexton, James C.

    2013-01-22

    A plurality of processing cores, are central storage unit having at least memory connected in a daisy chain manner, forming a daisy chain ring layout on an integrated chip. At least one of the plurality of processing cores places trace data on the daisy chain connection for transmitting the trace data to the central storage unit, and the central storage unit detects the trace data and stores the trace data in the memory co-located in with the central storage unit.

  19. High Quality Long-Term CD4+ and CD8+ Effector Memory Populations Stimulated by DNA-LACK/MVA-LACK Regimen in Leishmania major BALB/c Model of Infection

    PubMed Central

    Sánchez-Sampedro, Lucas; Gómez, Carmen Elena; Mejías-Pérez, Ernesto; S. Sorzano, Carlos Oscar; Esteban, Mariano

    2012-01-01

    Heterologous vaccination based on priming with a plasmid DNA vector and boosting with an attenuated vaccinia virus MVA recombinant, with both vectors expressing the Leishmania infantum LACK antigen (DNA-LACK and MVA-LACK), has shown efficacy conferring protection in murine and canine models against cutaneus and visceral leishmaniasis, but the immune parameters of protection remain ill defined. Here we performed by flow cytometry an in depth analysis of the T cell populations induced in BALB/c mice during the vaccination protocol DNA-LACK/MVA-LACK, as well as after challenge with L. major parasites. In the adaptive response, there is a polyfunctional CD4+ and CD8+ T cell activation against LACK antigen. At the memory phase the heterologous vaccination induces high quality LACK-specific long-term CD4+ and CD8+ effector memory cells. After parasite challenge, there is a moderate boosting of LACK-specific CD4+ and CD8+ T cells. Anti-vector responses were largely CD8+-mediated. The immune parameters induced against LACK and triggered by the combined vaccination DNA/MVA protocol, like polyfunctionality of CD4+ and CD8+ T cells with an effector phenotype, could be relevant in protection against leishmaniasis. PMID:22715418

  20. Distinct CD4 T-cell effects on primary versus recall CD8 T-cell responses during viral encephalomyelitis

    PubMed Central

    Hwang, Mihyun; Phares, Timothy W; Hinton, David R; Stohlman, Stephen A; Bergmann, Cornelia C; Min, Booki

    2015-01-01

    CD4 T-cell help is not a universal requirement for effective primary CD8 T cells but is essential to generate memory CD8 T cells capable of recall responses. This study examined how CD4 T cells affect primary and secondary anti-viral CD8 T-cell responses within the central nervous system (CNS) during encephalomyelitis induced by sublethal gliatropic coronavirus. CD4 T-cell depletion before infection did not impair peripheral expansion, interferon-γ production, CNS recruitment or initial CNS effector capacity of virus-specific CD8 T cells ex vivo. Nevertheless, impaired virus control in the absence of CD4 T cells was associated with gradually diminished CNS CD8 T-cell interferon-γ production. Furthermore, within the CD8 T-cell population short-lived effector cells were increased and memory precursor effector cells were significantly decreased, consistent with higher T-cell turnover. Transfer of memory CD8 T cells to reduce viral load in CD4-depleted mice reverted the recipient CNS CD8 T-cell phenotype to that in wild-type control mice. However, memory CD8 T cells primed without CD4 T cells and transferred into infected CD4-sufficient recipients expanded less efficiently and were not sustained in the CNS, contrasting with their helped counterparts. These data suggest that CD4 T cells are dispensable for initial expansion, CNS recruitment and differentiation of primary resident memory CD8 T cells as long as the duration of antigen exposure is limited. By contrast, CD4 T cells are essential to prolong primary CD8 T-cell function in the CNS and imprint memory CD8 T cells for recall responses. PMID:25187405

  1. Preferential effects of leptin on CD4 T cells in central and peripheral immune system are critically linked to the expression of leptin receptor

    SciTech Connect

    Kim, So Yong; Lim, Ju Hyun; Choi, Sung Won; Kim, Miyoung; Kim, Seong-Tae; Kim, Min-Seon; Cho, You Sook; Chun, Eunyoung; Lee, Ki-Young

    2010-04-09

    Leptin can enhance thymopoiesis and modulate the T-cell immune response. However, it remains controversial whether these effects correlate with the expression of leptin receptor, ObR. We herein addressed this issue by using in vivo animal models and in vitro culture systems. Leptin treatment in both ob/ob mice and normal young mice induced increases of CD4 SP thymocytes in thymus and CD4 T cells in the periphery. Interestingly, expression of the long form ObR was significantly restricted to DN, DP and CD4 SP, but not CD8 SP thymocytes. Moreover, in the reaggregated DP thymocyte cultures with leptin plus TSCs, leptin profoundly induced differentiation of CD4 SP but not CD8 SP thymocytes, suggesting that the effects of leptin on thymocyte differentiation might be closely related to the expression of leptin receptor in developing thymocytes. Surprisingly, ObR expression was markedly higher in peripheral CD4 T cells than that in CD8 T cells. Furthermore, leptin treatment with or without IL-2 and PHA had preferential effects on cell proliferation of CD4 T cells compared to that of CD8 T cells. Collectively, these data provide evidence that the effects of leptin on differentiation and proliferation of CD4 T cells might be closely related to the expression of leptin receptor.

  2. HIV-1 tropism for the central nervous system: Brain-derived envelope glycoproteins with lower CD4 dependence and reduced sensitivity to a fusion inhibitor

    SciTech Connect

    Martin-Garcia, Julio . E-mail: julio.martin-garcia@drexelmed.edu; Cao, Wei; Varela-Rohena, Angel; Plassmeyer, Matthew L.; Gonzalez-Scarano, Francisco

    2006-03-01

    We previously described envelope glycoproteins of an HIV-1 isolate adapted in vitro for growth in microglia that acquired a highly fusogenic phenotype and lower CD4 dependence, as well as resistance to inhibition by anti-CD4 antibodies. Here, we investigated whether similar phenotypic changes are present in vivo. Envelope clones from the brain and spleen of an HIV-1-infected individual with neurological disease were amplified, cloned, and sequenced. Phylogenetic analysis demonstrated clustering of sequences according to the tissue of origin, as expected. Functional clones were then used in cell-to-cell fusion assays to test for CD4 and co-receptor utilization and for sensitivity to various antibodies and inhibitors. Both brain- and spleen-derived envelope clones mediated fusion in cells expressing both CD4 and CCR5 and brain envelopes also used CCR3 as co-receptor. We found that the brain envelopes had a lower CD4 dependence, since they efficiently mediated fusion in the presence of low levels of CD4 on the target cell membrane, and they were significantly more resistant to blocking by anti-CD4 antibodies than the spleen-derived envelopes. In contrast, we observed no difference in sensitivity to the CCR5 antagonist TAK-779. However, brain-derived envelopes were significantly more resistant than those from spleen to the fusion inhibitor T-1249 and concurrently showed slightly greater fusogenicity. Our results suggest an increased affinity for CD4 of brain-derived envelopes that may have originated from in vivo adaptation to replication in microglial cells. Interestingly, we note the presence of envelopes more resistant to a fusion inhibitor in the brain of an untreated, HIV-1-infected individual.

  3. Alterations in levels of CD28-/CD8+ suppressor cell precursor and CD45RO+/CD4+ memory T lymphocytes in the peripheral blood of multiple sclerosis patients.

    PubMed Central

    Crucian, B; Dunne, P; Friedman, H; Ragsdale, R; Pross, S; Widen, R

    1995-01-01

    A comprehensive peripheral blood immunophenotype analysis of 16 multiple sclerosis (MS) patients was performed by three-color flow cytometric analysis, and the results were compared with those for age-matched healthy controls. The cell subsets quantified included T cells (CD3+), B cells (CD19+), NK cells (CD56+), CD4+ and CD8+ T cells, cytotoxic (CD28+) and suppressor precursor (CD28-) CD8+ T cells, CD45RA+ and CD45RO+ T cells (CD4+ and CD8+), and CD5+ T and B cells. Analysis of MS patients' peripheral blood revealed essentially normal levels of total T, B, and NK cells. In agreement with results obtained by other investigators, it was found that MS patients had an increased CD4/CD8 ratio, primarily due to a decrease in CD8+ T cells. MS patients were found to have a significantly decreased level of suppressor precursor (CD28-) CD8+ T cells compared with that of controls but to have normal levels of cytotoxic (CD28+) CD8+ T cells. These data indicate that MS patients do not have a general decrease in CD8+ T cells but that they have a specific decrease in the suppressor precursor subset only and normal levels of cytotoxic CD8+ T cells. MS patients also had a significant increase in memory (CD45RO+) CD4+ T cells and displayed a trend towards a decrease in naive (CD45RA+) T cells in the peripheral blood. PMID:7697540

  4. Blimp-1–mediated CD4 T cell exhaustion causes CD8 T cell dysfunction during chronic toxoplasmosis

    PubMed Central

    Cobb, Dustin A.; Bhadra, Rajarshi

    2016-01-01

    CD8, but not CD4, T cells are considered critical for control of chronic toxoplasmosis. Although CD8 exhaustion has been previously reported in Toxoplasma encephalitis (TE)–susceptible model, our current work demonstrates that CD4 not only become exhausted during chronic toxoplasmosis but this dysfunction is more pronounced than CD8 T cells. Exhausted CD4 population expressed elevated levels of multiple inhibitory receptors concomitant with the reduced functionality and up-regulation of Blimp-1, a transcription factor. Our data demonstrates for the first time that Blimp-1 is a critical regulator for CD4 T cell exhaustion especially in the CD4 central memory cell subset. Using a tamoxifen-dependent conditional Blimp-1 knockout mixed bone marrow chimera as well as an adoptive transfer approach, we show that CD4 T cell–intrinsic deletion of Blimp-1 reversed CD8 T cell dysfunction and resulted in improved pathogen control. To the best of our knowledge, this is a novel finding, which demonstrates the role of Blimp-1 as a critical regulator of CD4 dysfunction and links it to the CD8 T cell dysfunctionality observed in infected mice. The critical role of CD4-intrinsic Blimp-1 expression in mediating CD4 and CD8 T cell exhaustion may provide a rational basis for designing novel therapeutic approaches. PMID:27481131

  5. Naïve subset develops the most important alloreactive response among human CD4+ T lymphocytes in human leukocyte antigen-identical related setting.

    PubMed

    Chérel, Mathilde; Choufi, Bachra; Trauet, Jacques; Cracco, Pascale; Dessaint, Jean-Paul; Yakoub-Agha, Ibrahim; Labalette, Myriam

    2014-06-01

    In longitudinal clinical studies, receiving a high percentage of allogeneic donor-derived CD4(+) CCR7(+) T cells, which include naïve and central memory subsets have been correlated with increased incidence and severity of acute GVHD. Whether naïve and central memory CD4(+) T-cell subsets contribute more or equally to alloimmune responses are still unclear in human. The aim of this study was to investigate in vitro the alloreactive response of purified naïve, central memory, and effector memory CD4(+) T-cell subsets in HLA identical setting. By coculturing monocyte-derived dendritic cells and purified CD4(+) T-cell subsets, from healthy HLA-identical male and female sibling pairs, we found that naïve CD4(+) CCR7(+) CD45RA(+) T cells developed the highest proliferative response upon stimulation by minor histocompatibility antigens and were progressively driven to produce high levels of interferon-γ, tumor necrosis factor, and interleukin-6. Comparatively, the central memory CD4(+) CCR7(+) CD45RA(neg) subset proliferated to a lower extent and produced very low amounts of pro-inflammatory cytokines while the CCR7(neg) effector memory CD4(+) subset was unresponsive. This study demonstrates the superior capacity of naïve CD4(+) T cells to mount a primary alloreactive response as compared to central memory T cells. Their proliferative response associated with a pro-inflammatory differentiation makes them potentially acute GVHD inducers. These in vitro results in line with what we have observed in clinical studies and may also lend support to approaches of partial selective T-cell depletion for GVHD prevention.

  6. Potent HIV-specific responses are enriched in a unique subset of CD8+ T cells that coexpresses CD4 on its surface.

    PubMed

    Zloza, Andrew; Schenkel, Jason M; Tenorio, Allan R; Martinson, Jeffrey A; Jeziorczak, Paul M; Al-Harthi, Lena

    2009-10-29

    In humans, approximately 3% of peripheral CD8+ T cells coexpress CD4 dimly on their surface and hence are designated as CD4(dim)CD8(bright) T cells. We evaluated the contribution of this CD4(dim)CD8(bright) T-cell population to anti-HIV immunity. We demonstrate that CD4(dim)CD8(bright) T cells generate greater than 55% of CD8+ T-cell antigen recognition and effector response to HIV, as evaluated by multiple parameters for assessing T-cell antiviral immunity, including HIV tetramer recognition, cytokine production, and cytolytic potential. Inhibition of major histocompatibility class II (MHC-II) on target cells or CD4 on CD4(dim)CD8(bright) T cells diminishes their anti-HIV responses, suggesting that CD4 on effector cells and MHC-II on target cells provides an additional arm of contact between effector and target cells which is critical to CD4(dim)CD8(bright) T-cell function. CD4(dim)CD8(bright) T cells also exhibit features that are indicative of central memory T cells. Finally, CD4(dim)CD8(bright) T cells are elevated in blood of HIV+ long-term nonprogressors in comparison to HIV- donors. Collectively, our findings show that CD4(dim)CD8(bright) T cells designate an enriched antiviral subpopulation of CD8+ T cells that should be targeted for therapeutic intervention or evaluation of vaccine efficacy.

  7. Idiopathic CD4 Lymphocytopenia

    PubMed Central

    Régent, Alexis; Autran, Brigitte; Carcelain, Guislaine; Cheynier, Rémi; Terrier, Benjamin; Charmeteau-De Muylder, Bénédicte; Krivitzky, Alain; Oksenhendler, Eric; Costedoat-Chalumeau, Nathalie; Hubert, Pascale; Lortholary, Olivier; Dupin, Nicolas; Debré, Patrice; Guillevin, Loïc; Mouthon, Luc

    2014-01-01

    Abstract Idiopathic CD4 T lymphocytopenia (ICL) is a rare and severe condition with limited available data. We conducted a French multicenter study to analyze the clinical and immunologic characteristics of a cohort of patients with ICL according to the Centers for Disease Control criteria. We recruited 40 patients (24 female) of mean age 44.2 ± 12.2 (19–70) years. Patients underwent T-lymphocyte phenotyping and lymphoproliferation assay at diagnosis, and experiments related to thymic function and interferon (IFN)-γ release by natural killer (NK) cell were performed. Mean follow-up was 6.9 ± 6.7 (0.14–24.3) years. Infectious, autoimmune, and neoplastic events were recorded, as were outcomes of interleukin 2 therapy. In all, 25 patients had opportunistic infections (12 with human papillomavirus infection), 14 had autoimmune symptoms, 5 had malignancies, and 8 had mild or no symptoms. At the time of diagnosis, the mean cell counts were as follows: mean CD4 cell count: 127/mm3 (range, 4–294); mean CD8: 236/mm3 (range, 1–1293); mean CD19: 113/mm3 (range, 3–547); and mean NK cell count: 122/mm3 (range, 5–416). Most patients had deficiency in CD8, CD19, and/or NK cells. Cytotoxic function of NK cells was normal, and patients with infections had a significantly lower NK cell count than those without (p = 0.01). Patients with autoimmune manifestations had increased CD8 T-cell count. Proliferation of thymic precursors, as assessed by T-cell rearrangement excision circles, was increased. Six patients died (15%). CD4 T-cell count <150/mm3 and NK cell count <100/mm3 were predictors of death. In conclusion, ICL is a heterogeneous disorder often associated with deficiencies in CD8, CD19, and/or NK cells. Long-term prognosis may be related to initial CD4 and NK cell deficiency. PMID:24646462

  8. Analysis of the In Vivo Turnover of CD4+ T-Cell Subsets in Chronically SIV-Infected Sooty Mangabeys.

    PubMed

    Ortiz, Alexandra M; Carnathan, Diane G; Yu, Joana; Sheehan, Katherine M; Kim, Peter; Reynaldi, Arnold; Vanderford, Thomas H; Klatt, Nichole R; Brenchley, Jason M; Davenport, Miles P; Silvestri, Guido

    2016-01-01

    Aberrant turnover of memory CD4+ T-cells is central to Acquired Immunodeficiency Syndrome (AIDS) progression. Understanding the relationship between the turnover of CD4+ subsets and immunological homeostasis during simian immunodeficiency virus (SIV) infection in natural hosts may provide insight into mechanisms of immune regulation that may serve as models for therapeutic intervention in Human Immunodeficiency Virus (HIV)-infected persons. Sooty mangabeys (SMs) have naturally evolved with SIV to avoid AIDS progression while maintaining healthy peripheral CD4+ T-cell counts and thus represent a model by which therapeutic interventions for AIDS progression might be elucidated. To assess the relationship between the turnover of CD4+ subsets and immunological homeostasis during SIV infection in non-progressive hosts, we treated 6 SIV-uninfected and 9 SIV-infected SMs with 2'-bromo-5'-deoxyuridine (BrdU) for 14 days and longitudinally assessed CD4+ T-cell subset turnover by polychromatic flow cytometry. We observed that, in SIV-infected SMs, turnover of CD4+ T-cell naïve and central, transitional, and effector memory subsets is comparable to that in uninfected animals. Comparable turnover of CD4+ T-cell subsets irrespective of SIV-infection status likely contributes to the lack of aberrant immune activation and disease progression observed after infection in non-progressive hosts.

  9. Analysis of the In Vivo Turnover of CD4+ T-Cell Subsets in Chronically SIV-Infected Sooty Mangabeys

    PubMed Central

    Ortiz, Alexandra M.; Carnathan, Diane G.; Yu, Joana; Sheehan, Katherine M.; Kim, Peter; Reynaldi, Arnold; Vanderford, Thomas H.; Klatt, Nichole R.; Brenchley, Jason M.; Davenport, Miles P.; Silvestri, Guido

    2016-01-01

    Aberrant turnover of memory CD4+ T-cells is central to Acquired Immunodeficiency Syndrome (AIDS) progression. Understanding the relationship between the turnover of CD4+ subsets and immunological homeostasis during simian immunodeficiency virus (SIV) infection in natural hosts may provide insight into mechanisms of immune regulation that may serve as models for therapeutic intervention in Human Immunodeficiency Virus (HIV)-infected persons. Sooty mangabeys (SMs) have naturally evolved with SIV to avoid AIDS progression while maintaining healthy peripheral CD4+ T-cell counts and thus represent a model by which therapeutic interventions for AIDS progression might be elucidated. To assess the relationship between the turnover of CD4+ subsets and immunological homeostasis during SIV infection in non-progressive hosts, we treated 6 SIV-uninfected and 9 SIV-infected SMs with 2’-bromo-5’-deoxyuridine (BrdU) for 14 days and longitudinally assessed CD4+ T-cell subset turnover by polychromatic flow cytometry. We observed that, in SIV-infected SMs, turnover of CD4+ T-cell naïve and central, transitional, and effector memory subsets is comparable to that in uninfected animals. Comparable turnover of CD4+ T-cell subsets irrespective of SIV-infection status likely contributes to the lack of aberrant immune activation and disease progression observed after infection in non-progressive hosts. PMID:27227993

  10. Short Communication: Low Immune Activation Is Associated with Higher Frequencies of Central Memory T Cell Subset in a Cohort of Indian Long-Term Nonprogressors.

    PubMed

    Saxena, Vandana; Bichare, Shubhangi; Singh, Dharmendra; Ghate, Manisha; Godbole, Sheela; Kulkarni, Smita; Gangakhedkar, Raman; Paranjape, Ramesh; Thakar, Madhuri

    2017-02-01

    Persistent immune activation in human immunodeficiency virus (HIV) infection is responsible for alterations in immune system such as activation, apoptosis, and reduced frequencies. Reduced immune activation is known to be associated with virus control. Limited information is available on the influence of pan-immune activation on memory responses. Hence, we compared the T cell activation and memory profile in HIV-infected individuals exhibiting disease control such as long-term nonprogressors (LTNPs) and progressors. The activated CD4(+) and CD8(+) T cells were significantly lower and the CD4(+) and CD8(+) central memory T cell phenotypes were significantly higher in the LTNPs compared to the progressors. In addition, we observed significant inverse association between the T cell activation and frequencies of central memory T cells. Our findings indicate that patients with absence of disease progression have preserved central memory T cell population associated with lesser immune activation.

  11. Induction of Plasmodium falciparum-Specific CD4+ T Cells and Memory B Cells in Gabonese Children Vaccinated with RTS,S/AS01E and RTS,S/AS02D

    PubMed Central

    Agnandji, Selidji T.; Fendel, Rolf; Mestré, Michaël; Janssens, Michel; Vekemans, Johan; Held, Jana; Gnansounou, Ferdinand; Haertle, Sonja; von Glasenapp, Isabel; Oyakhirome, Sunny; Mewono, Ludovic; Moris, Philippe; Lievens, Marc; Demoitie, Marie-Ange; Dubois, Patrice M.; Villafana, Tonya; Jongert, Erik; Olivier, Aurelie; Cohen, Joe; Esen, Meral; Kremsner, Peter G.; Lell, Bertrand; Mordmüller, Benjamin

    2011-01-01

    The recombinant circumsporozoite protein (CS) based vaccine, RTS,S, confers protection against Plasmodium falciparum infection in controlled challenge trials and in field studies. The RTS,S recombinant antigen has been formulated with two adjuvant systems, AS01 and AS02, which have both been shown to induce strong specific antibody responses and CD4 T cell responses in adults. As infants and young children are particularly susceptible to malaria infection and constitute the main target population for a malaria vaccine, we have evaluated the induction of adaptive immune responses in young children living in malaria endemic regions following vaccination with RTS,S/AS01E and RTS,S/AS02D. Our data show that a CS-specific memory B cell response is induced one month after the second and third vaccine dose and that CS-specific antibodies and memory B cells persist up to 12 months after the last vaccine injection. Both formulations also induced low but significant amounts of CS-specific IL-2+ CD4+ T cells one month after the second and third vaccine dose, upon short-term in vitro stimulation of whole blood cells with peptides covering the entire CS derived sequence in RTS,S. These results provide evidence that both RTS,S/AS01E and RTS,S/AS02D induced adaptive immune responses including antibodies, circulating memory B cells and CD4+ T cells directed against P. falciparum CS protein. Trial Registration ClinicalTrials.gov NCT00307021 PMID:21494604

  12. Loss of methylation at the IFNG promoter and CNS-1 is associated with the development of functional IFN-γ memory in human CD4(+) T lymphocytes.

    PubMed

    Dong, Jun; Chang, Hyun-Dong; Ivascu, Claudia; Qian, Yu; Rezai, Soheila; Okhrimenko, Anna; Cosmi, Lorenzo; Maggi, Laura; Eckhardt, Florian; Wu, Peihua; Sieper, Joachim; Alexander, Tobias; Annunziato, Francesco; Gossen, Manfred; Li, Jun; Radbruch, Andreas; Thiel, Andreas

    2013-03-01

    Cytokine memory for IFN-γ production by effector/memory Th1 cells plays a key role in both protective and pathological immune responses. To understand the epigenetic mechanism determining the ontogeny of effector/memory Th1 cells characterized by stable effector functions, we identified a T-cell-specific methylation pattern at the IFNG promoter and CNS-1 in ex vivo effector/memory Th1 cells, and investigated methylation dynamics of these regions during the development of effector/memory Th1 cells. During Th1 differentiation, demethylation occurred at both the promoter and CNS-1 regions of IFNG as early as 16 h, and this process was independent of cell proliferation and DNA synthesis. Using an IFN-γ capture assay, we found early IFN-γ-producing cells from 2-day differentiating cultures acquired "permissive" levels of demethylation and developed into effector/memory Th1 cells undergoing progressive demethylation at the IFNG promoter and CNS-1 when induced by IL-12. Methylation levels of these regions in effector/memory Th1 cells of peripheral blood from rheumatoid arthritis patients correlated inversely with reduced frequencies of IFN-γ-producers, coincident with recruitment of effector/memory Th1 cells to the site of inflammation. Thus, after termination of TCR stimulation, IL-12 signaling potentiates the stable functional IFN-γ memory in effector/memory Th1 cells characterized by hypomethylation at the IFNG promoter and CNS-1.

  13. Progesterone Levels Associate with a Novel Population of CCR5+CD38+ CD4 T Cells Resident in the Genital Mucosa with Lymphoid Trafficking Potential.

    PubMed

    Swaims-Kohlmeier, Alison; Haaland, Richard E; Haddad, Lisa B; Sheth, Anandi N; Evans-Strickfaden, Tammy; Lupo, L Davis; Cordes, Sarah; Aguirre, Alfredo J; Lupoli, Kathryn A; Chen, Cheng-Yen; Ofotukun, Igho; Hart, Clyde E; Kohlmeier, Jacob E

    2016-07-01

    The female genital tract (FGT) provides a means of entry to pathogens, including HIV, yet immune cell populations at this barrier between host and environment are not well defined. We initiated a study of healthy women to characterize resident T cell populations in the lower FGT from lavage and patient-matched peripheral blood to investigate potential mechanisms of HIV sexual transmission. Surprisingly, we observed FGT CD4 T cell populations were primarily CCR7(hi), consistent with a central memory or recirculating memory T cell phenotype. In addition, roughly half of these CCR7(hi) CD4 T cells expressed CD69, consistent with resident memory T cells, whereas the remaining CCR7(hi) CD4 T cells lacked CD69 expression, consistent with recirculating memory CD4 T cells that traffic between peripheral tissues and lymphoid sites. HIV susceptibility markers CCR5 and CD38 were increased on FGT CCR7(hi) CD4 T cells compared with blood, yet migration to the lymphoid homing chemokines CCL19 and CCL21 was maintained. Infection with GFP-HIV showed that FGT CCR7(hi) memory CD4 T cells are susceptible HIV targets, and productive infection of CCR7(hi) memory T cells did not alter chemotaxis to CCL19 and CCL21. Variations of resident CCR7(hi) FGT CD4 T cell populations were detected during the luteal phase of the menstrual cycle, and longitudinal analysis showed the frequency of this population positively correlated to progesterone levels. These data provide evidence women may acquire HIV through local infection of migratory CCR7(hi) CD4 T cells, and progesterone levels predict opportunities for HIV to access these novel target cells.

  14. Increased Mucosal CD4+ T Cell Activation in Rhesus Macaques following Vaccination with an Adenoviral Vector

    PubMed Central

    Bukh, Irene; Calcedo, Roberto; Roy, Soumitra; Carnathan, Diane G.; Grant, Rebecca; Qin, Qiuyue; Boyd, Surina; Ratcliffe, Sarah J.; Veeder, Christin L.; Bellamy, Scarlett L.; Betts, Michael R.

    2014-01-01

    ABSTRACT The possibility that vaccination with adenovirus (AdV) vectors increased mucosal T cell activation remains a central hypothesis to explain the potential enhancement of HIV acquisition within the Step trial. Modeling this within rhesus macaques is complicated because human adenoviruses, including human adenovirus type 5 (HAdV-5), are not endogenous to macaques. Here, we tested whether vaccination with a rhesus macaque-derived adenoviral vector (simian adenovirus 7 [SAdV-7]) enhances mucosal T cell activation within rhesus macaques. Following intramuscular SAdV-7 vaccination, we observed a pronounced increase in SAdV-7-specific CD4+ T cell responses in peripheral blood and, more dramatically, in rectal mucosa tissue. Vaccination also induced a significant increase in the frequency of activated memory CD4+ T cells in SAdV-7- and HAdV-5-vaccinated animals in the rectal mucosa but not in peripheral blood. These fluctuations within the rectal mucosa were also associated with a pronounced decrease in the relative frequency of naive resting CD4+ T cells. Together, these results indicate that peripheral vaccination with an AdV vector can increase the activation of mucosal CD4+ T cells, potentially providing an experimental model to further evaluate the role of host-vector interactions in increased HIV acquisition after AdV vector vaccination. IMPORTANCE The possibility that vaccination with a human adenovirus 5 vector increased mucosal T cell activation remains a central hypothesis to explain the potential enhancement of human immunodeficiency virus (HIV) acquisition within the Step trial. In this study, we tested whether vaccination with a rhesus macaque-derived adenoviral vector in rhesus macaques enhances mucosal CD4+ T cell activation, the main cell target of simian immunodeficiency virus (SIV)/HIV. The results showed that vaccination with an adenoviral vector indeed increases activation of mucosal CD4+ T cells and potentially increases susceptibility to SIV

  15. Treatment with Interleukin-7 Restores Host Defense against Pneumocystis in CD4+ T-Lymphocyte-Depleted Mice

    PubMed Central

    Samuelson, D. R.; Assouline, B.; Morre, M.; Shellito, J. E.

    2015-01-01

    Pneumocystis pneumonia (PCP) is a major cause of morbidity and mortality in patients with HIV infection. CD4+ T lymphocytes are critical for host defense against this infection, but in the absence of CD4+ T lymphocytes, CD8+ T lymphocytes may provide limited host defense. The cytokine interleukin-7 (IL-7) functions to enhance lymphocyte proliferation, survival, and recruitment of immune cells to sites of infection. However, there is little known about the role of IL-7 in PCP or its potential use as an immunotherapeutic agent. We hypothesized that treatment with recombinant human IL-7 (rhIL-7) would augment host defense against Pneumocystis and accelerate pathogen clearance in CD4-depleted mice. Control and CD4-depleted mice were infected with Pneumocystis, and rhIL-7 was administered via intraperitoneal injection. Our studies indicate that endogenous murine IL-7 is part of the normal host response to Pneumocystis murina and that administration of rhIL-7 markedly enhanced clearance of Pneumocystis in CD4-depleted mice. Additionally, we observed increased recruitment of CD8+ T lymphocytes to the lungs and decreased apoptosis of pulmonary CD8+ T lymphocytes in rhIL-7-treated animals compared to those in untreated mice. The antiapoptotic effect of rhIL-7 was associated with increased levels of Bcl-2 protein in T lymphocytes. rhIL-7 immunotherapy in CD4-depleted mice also increased the number of gamma interferon (IFN-γ)-positive CD8+ central memory T lymphocytes in the lungs. We conclude that rhIL-7 has a potent therapeutic effect in the treatment of murine Pneumocystis pneumonia in CD4-depleted mice. This therapeutic effect is mediated through enhanced recruitment of CD8+ T cells and decreased apoptosis of lung T lymphocytes, with a preferential action on central memory CD8+ T lymphocytes. PMID:26483405

  16. Potent HIV-specific responses are enriched in a unique subset of CD8+ T cells that coexpresses CD4 on its surface

    PubMed Central

    Zloza, Andrew; Schenkel, Jason M.; Tenorio, Allan R.; Martinson, Jeffrey A.; Jeziorczak, Paul M.

    2009-01-01

    In humans, approximately 3% of peripheral CD8+ T cells coexpress CD4 dimly on their surface and hence are designated as CD4dimCD8bright T cells. We evaluated the contribution of this CD4dimCD8bright T-cell population to anti-HIV immunity. We demonstrate that CD4dimCD8bright T cells generate greater than 55% of CD8+ T-cell antigen recognition and effector response to HIV, as evaluated by multiple parameters for assessing T-cell antiviral immunity, including HIV tetramer recognition, cytokine production, and cytolytic potential. Inhibition of major histocompatibility class II (MHC-II) on target cells or CD4 on CD4dimCD8bright T cells diminishes their anti-HIV responses, suggesting that CD4 on effector cells and MHC-II on target cells provides an additional arm of contact between effector and target cells which is critical to CD4dimCD8bright T-cell function. CD4dimCD8bright T cells also exhibit features that are indicative of central memory T cells. Finally, CD4dimCD8bright T cells are elevated in blood of HIV+ long-term nonprogressors in comparison to HIV− donors. Collectively, our findings show that CD4dimCD8bright T cells designate an enriched antiviral subpopulation of CD8+ T cells that should be targeted for therapeutic intervention or evaluation of vaccine efficacy. PMID:19700667

  17. Characterization of CD4 and CD8 T cells producing IFN-γ in human latent and active tuberculosis.

    PubMed

    Rueda, Cesar M; Marín, Nancy D; García, Luis F; Rojas, Mauricio

    2010-11-01

    Patients with pulmonary tuberculosis (PTB) frequently have reduced IFN-γ production in response to mycobacterial antigens, compared to individuals with latent Mycobacterium tuberculosis infection (LTBi). However, it is not clear whether this reduced responsiveness is restricted to a particular T cell subset. Herein, PBMCs from 26 PTB patients, 30 household contacts (HHCs) of PTB, and 30 tuberculin positive (TST+) healthy subjects not recently exposed to PTB, were stained with CFSE and stimulated non-specific (PPD) for 120 h, and specific (CFP-10/ESAT-6) and latency (HSpX) mycobacterial antigens for 144 h and the percentage of CD4(+) and CD8(+)IFN-γ(+) T cells responding determined by flow cytometry, in addition to their memory phenotype by the CD45RO and CD27 expression. PTB had decreased frequency of both CD4(+) and CD8(+) precursor cells, as well as decreased number of CD4(+)IFN-γ(+) cells in response to all antigens, whereas CD8(+)IFN-γ(+) cells were decreased in response to PPD and ESAT-6, but not to CFP-10 and HSpX. HHCs exhibited the highest precursor frequencies and IFN-γ responses, irrespective of the antigen employed. The CD4(+)/CD8(+) cell ratios showed that in response to PPD CD4(+) precursor and IFN-γ-producer cells are more frequent than their CD8(+) counterparts, and that PTB have a decreased CD4(+)IFN-γ(+)/CD8(+)IFN-γ(+) ratio in response to PPD, CFP-10, and ESAT-6. CD4(+)IFN-γ(+) and CD8(+)IFN-γ(+) cells exhibited a central memory phenotype (CD45RO(+)CD27(+)), irrespective of the group of subjects and the antigen used for stimulation. In conclusion, PTB patients had a decreased percentage of CD4(+) and CD8(+) precursor cells and CD4(+)IFN-γ(+). HHCs exhibited the highest frequency of CD4(+) and CD8(+) precursors and CD4(+)IFN-γ(+)-producing cells.

  18. Comparative evaluation of the CD4+CD8+ and CD4+CD8- lymphocytes in the immune response to porcine rubulavirus.

    PubMed

    Hernández, J; Garfias, Y; Nieto, A; Mercado, C; Montaño, L F; Zenteno, E

    2001-05-30

    The porcine immune system is unique in the expression of CD4+CD8+ (double-positive, DP) lymphocytes. These cells have been associated with immunological memory due to their gradual increase with age, the expression of memory phenotype and their ability to respond to recall viral antigen. This work analyzes the biological function of CD4+CD8- and CD4+CD8+ lymphocytes in the immune response to porcine rubulavirus (PRv). CD4+CD8- cells isolated from pigs 3 weeks after infection with porcine rubulavirus proliferated in response to homologous virus and generated lymphoblasts which were predominantly of the CD4+CD8+ phenotype, whereas stimulation with mitogen induced proliferation but did not switch the phenotype. CD4+CD8- lymphocytes isolated after 10 weeks of infection proliferated in response to phytohemagglutinin (PHA) but did not proliferate in response to homologous virus and did not change their phenotype, whereas CD4+CD8+ lymphocytes proliferated in response to PHA and to viral antigen. The cytokine profile of both lymphocyte populations showed the presence of IL-2 and IL-10 transcripts, quantitation demonstrated that CD4+CD8+ cells expressed mainly IL-10, whereas CD4+CD8- lymphocytes expressed primarily IL-2. Our results show that CD4+CD8- lymphocytes in the early phase of porcine rubulavirus infection can be converted to double-positive cells expressing IL-10 in an antigen-dependent manner, and that CD4+CD8- T-cells late in infection do not acquire CD8.

  19. Increased TNF-alpha/IFN-gamma/IL-2 and decreased TNF-alpha/IFN-gamma production by central memory T cells are associated with protective responses against bovine tuberculosis following BCG vaccination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Central memory T cells (Tcm’s) and polyfunctional CD4 T responses contribute to vaccine-elicited protection with both human and bovine tuberculosis (TB); however, their combined role in protective immunity to TB is unclear. To address this question, we evaluated polyfunctional cytokine responses by ...

  20. Plasmodium vivax infection induces expansion of activated naïve/memory T cells and differentiation into a central memory profile.

    PubMed

    Silva, Ana Luiza Teixeira; Lacerda, Marcus Vinícius; Fujiwara, Ricardo Toshio; Bueno, Lilian Lacerda; Braga, Erika Martins

    2013-11-01

    Immunity to malaria is widely believed to wane in the absence of reinfection, but direct evidence for the presence or absence of durable immunological memory to malaria is limited. Here, we characterized the profile of circulating naïve and memory (including central and effector) CD4⁺ T cells responses of individuals naturally infected by Plasmodium vivax. In the current study, we demonstrated that acute P. vivax infection induces a significant increase in the absolute number of both naïve and memory cells, which were responsible for the production of anti-inflammatory (IL-10) and pro-inflammatory (IFN-γ) cytokines. Finally, we described the profile of memory cell subtypes (T(CM)-CD45RO(high)CCR7⁺ and T(EM)-CD45RO(high)CCR7⁻), as well as the pattern of cell migration based on CD62L selectin expression, demonstrating that P. vivax-infected donors presented with a predominantly central memory cell profile. Our results indicate that the expansion of both naïve and memory T cells, responsible for the production of both pro-inflammatory and regulatory cytokines, which might also contribute to the modulation of immune responses during P. vivax infection.

  1. Cytomegalovirus upregulates expression of CCR5 in central memory cord blood mononuclear cells, which may facilitate in utero HIV type 1 transmission.

    PubMed

    Johnson, Erica L; Howard, Chanie L; Thurman, Joy; Pontiff, Kyle; Johnson, Elan S; Chakraborty, Rana

    2015-01-15

    Administration of combination antiretroviral therapy to human immunodeficiency virus type 1 (HIV-1)-infected pregnant women significantly reduces vertical transmission. In contrast, maternal co-opportunistic infection with primary or reactivated cytomegalovirus (CMV) or other pathogens may facilitate in utero transmission of HIV-1 by activation of cord blood mononuclear cells (CBMCs). Here we examine the targets and mechanisms that affect fetal susceptibility to HIV-1 in utero. Using flow cytometry, we demonstrate that the fraction of CD4(+)CD45RO(+) and CD4(+)CCR5(+) CBMCs is minimal, which may account for the low level of in utero HIV-1 transmission. Unstimulated CD4(+) CBMCs that lack CCR5/CD45RO showed reduced levels of HIV-1 infection. However, upon in vitro stimulation with CMV, CBMCs undergo increased proliferation to upregulate the fraction of T central memory cells and expression of CCR5, which enhances susceptibility to HIV-1 infection in vitro. These data suggest that activation induced by CMV in vivo may alter CCR5 expression in CD4(+) T central memory cells to promote in utero transmission of HIV-1.

  2. Delineating CD4 dependency of HIV-1: Adaptation to infect low level CD4 expressing target cells widens cellular tropism but severely impacts on envelope functionality

    PubMed Central

    Beauparlant, David; Rusert, Peter; Magnus, Carsten; Weber, Jacqueline; Uhr, Therese; Clapham, Paul R.; Metzner, Karin J.

    2017-01-01

    A hallmark of HIV-1 infection is the continuously declining number of the virus’ predominant target cells, activated CD4+ T cells. With diminishing CD4+ T cell levels, the capacity to utilize alternate cell types and receptors, including cells that express low CD4 receptor levels such as macrophages, thus becomes crucial. To explore evolutionary paths that allow HIV-1 to acquire a wider host cell range by infecting cells with lower CD4 levels, we dissected the evolution of the envelope-CD4 interaction under in vitro culture conditions that mimicked the decline of CD4high target cells, using a prototypic subtype B, R5-tropic strain. Adaptation to CD4low targets proved to severely alter envelope functions including trimer opening as indicated by a higher affinity to CD4 and loss in shielding against neutralizing antibodies. We observed a strikingly decreased infectivity on CD4high target cells, but sustained infectivity on CD4low targets, including macrophages. Intriguingly, the adaptation to CD4low targets altered the kinetic of the entry process, leading to rapid CD4 engagement and an extended transition time between CD4 and CCR5 binding during entry. This phenotype was also observed for certain central nervous system (CNS) derived macrophage-tropic viruses, highlighting that the functional perturbation we defined upon in vitro adaptation to CD4low targets occurs in vivo. Collectively, our findings suggest that CD4low adapted envelopes may exhibit severe deficiencies in entry fitness and shielding early in their evolution. Considering this, adaptation to CD4low targets may preferentially occur in a sheltered and immune-privileged environment such as the CNS to allow fitness restoring compensatory mutations to occur. PMID:28264054

  3. Mucosal vaccination with attenuated Mycobacterium tuberculosis induces strong central memory responses and protects against tuberculosis

    PubMed Central

    Kaushal, Deepak; Foreman, Taylor W.; Gautam, Uma S.; Alvarez, Xavier; Adekambi, Toidi; Rangel-Moreno, Javier; Golden, Nadia A.; Johnson, Ann-Marie F.; Phillips, Bonnie L.; Ahsan, Muhammad H.; Russell-Lodrigue, Kasi E.; Doyle, Lara A.; Roy, Chad J.; Didier, Peter J.; Blanchard, James L.; Rengarajan, Jyothi; Lackner, Andrew A.; Khader, Shabaana A.; Mehra, Smriti

    2015-01-01

    Tuberculosis (TB) is a global pandaemic, partially due to the failure of vaccination approaches. Novel anti-TB vaccines are therefore urgently required. Here we show that aerosol immunization of macaques with the Mtb mutant in SigH (MtbΔsigH) results in significant recruitment of inducible bronchus-associated lymphoid tissue (iBALT) as well as CD4+ and CD8+ T cells expressing activation and proliferation markers to the lungs. Further, the findings indicate that pulmonary vaccination with MtbΔsigH elicited strong central memory CD4+ and CD8+ T-cell responses in the lung. Vaccination with MtbΔsigH results in significant protection against a lethal TB challenge, as evidenced by an approximately three log reduction in bacterial burdens, significantly diminished clinical manifestations and granulomatous pathology and characterized by the presence of profound iBALT. This highly protective response is virtually absent in unvaccinated and BCG-vaccinated animals after challenge. These results suggest that future TB vaccine candidates can be developed on the basis of MtbΔsigH. PMID:26460802

  4. A rationally designed CD4 analogue inhibits experimental allergic encephalomyelitis

    NASA Astrophysics Data System (ADS)

    Jameson, Bradford A.; McDonnell, James M.; Marini, Joseph C.; Korngold, Robert

    1994-04-01

    EXPERIMENTAL allergic encephalomyelitis (EAE) is an acute inflammatory autoimmune disease of the central nervous system that can be elicited in rodents and is the major animal model for the study of multiple sclerosis (MS)1,2. The pathogenesis of both EAE and MS directly involves the CD4+ helper T-cell subset3-5. Anti-CD4 monoclonal antibodies inhibit the development of EAE in rodents6-9, and are currently being used in human clinical trials for MS. We report here that similar therapeutic effects can be achieved in mice using a small (rationally designed) synthetic analogue of the CD4 protein surface. It greatly inhibits both clinical incidence and severity of EAE with a single injection, but does so without depletion of the CD4+ subset and without the inherent immunogenicity of an antibody. Furthermore, this analogue is capable of exerting its effects on disease even after the onset of symptoms.

  5. Chronic exposure to trichloroethylene increases DNA methylation of the Ifng promoter in CD4(+) T cells.

    PubMed

    Gilbert, Kathleen M; Blossom, Sarah J; Erickson, Stephen W; Broadfoot, Brannon; West, Kirk; Bai, Shasha; Li, Jingyun; Cooney, Craig A

    2016-10-17

    CD4(+) T cells in female MRL+/+ mice exposed to solvent and water pollutant trichloroethylene (TCE) skew toward effector/memory CD4(+) T cells, and demonstrate seemingly non-monotonic alterations in IFN-γ production. In the current study we examined the mechanism for this immunotoxicity using effector/memory and naïve CD4(+) T cells isolated every 6 weeks during a 40 week exposure to TCE (0.5mg/ml in drinking water). A time-dependent effect of TCE exposure on both Ifng gene expression and IFN-γ protein production was observed in effector/memory CD4(+) T cells, with an increase after 22 weeks of exposure and a decrease after 40 weeks of exposure. No such effect of TCE was observed in naïve CD4(+) T cells. A cumulative increase in DNA methylation in the CpG sites of the promoter of the Ifng gene was observed in effector/memory, but not naïve, CD4(+) T cells over time. Also unique to the Ifng promoter was an increase in methylation variance in effector/memory compared to naïve CD4(+) T cells. Taken together, the CpG sites of the Ifng promoter in effector/memory CD4(+) T cells were especially sensitive to the effects of TCE exposure, which may help explain the regulatory effect of the chemical on this gene.

  6. Expression of CCR7 and CD45RA in CD4+ and CD8+ subsets in cerebrospinal fluid of 134 patients with inflammatory and non-inflammatory neurological diseases

    PubMed Central

    Mullen, Katherine M.; Gocke, Anne R.; Allie, Rameeza; Ntranos, Achilles; Grishkan, Inna V.; Pardo, Carlos; Calabresi, Peter A.

    2012-01-01

    We investigated CD45RA and CCR7 expression in CD4+ and CD8+ subsets of cerebrospinal fluid (CSF) lymphocytes, both immediately ex vivo and after stimulation, from 134 patients with a variety of inflammatory and non-inflammatory neurological diseases. Most inflammatory diseases had a higher CD4+: CD8+ ratio and higher percentage of effector memory T cells (TEM) than non-inflammatory controls, excluding active infection. Moreover, we found that patients with highly elevated cell counts in the CSF tended to have a lower percentage of central memory T cells (TCM) than patients with low or absent pleiocytosis, with a concomitant increase in TEM. We also found that samples with elevated IgG index or presence of oligoclonal bands had a significantly higher CD4+:CD8+ ratio than normal samples, consistent with increased CD4+ help for intrathecal IgG synthesis by B cells. PMID:22633193

  7. Chemokine Transfer by Liver Sinusoidal Endothelial Cells Contributes to the Recruitment of CD4+ T Cells into the Murine Liver

    PubMed Central

    Neumann, Katrin; Erben, Ulrike; Kruse, Nils; Wechsung, Katja; Schumann, Michael; Klugewitz, Katja

    2015-01-01

    Leukocyte adhesion and transmigration are central features governing immune surveillance and inflammatory reactions in body tissues. Within the liver sinusoids, chemokines initiate the first crucial step of T-cell migration into the hepatic tissue. We studied molecular mechanisms involved in endothelial chemokine supply during hepatic immune surveillance and liver inflammation and their impact on the recruitment of CD4+ T cells into the liver. In the murine model of Concanavalin A-induced T cell-mediated hepatitis, we showed that hepatic expression of the inflammatory CXC chemokine ligands (CXCL)9 and CXCL10 strongly increased whereas homeostatic CXCL12 significantly decreased. Consistently, CD4+ T cells expressing the CXC chemokine receptor (CXCR)3 accumulated within the inflamed liver tissue. In histology, CXCL9 was associated with liver sinusoidal endothelial cells (LSEC) which represent the first contact site for T-cell immigration into the liver. LSEC actively transferred basolaterally internalized CXCL12, CXCL9 and CXCL10 via clathrin-coated vesicles to CD4+ T cells leading to enhanced transmigration of CXCR4+ total CD4+ T cells and CXCR3+ effector/memory CD4+ T cells, respectively in vitro. LSEC-expressed CXCR4 mediated CXCL12 transport and blockage of endothelial CXCR4 inhibited CXCL12-dependent CD4+ T-cell transmigration. In contrast, CXCR3 was not involved in the endothelial transport of its ligands CXCL9 and CXCL10. The clathrin-specific inhibitor chlorpromazine blocked endothelial chemokine internalization and CD4+ T-cell transmigration in vitro as well as migration of CD4+ T cells into the inflamed liver in vivo. Moreover, hepatic accumulation of CXCR3+ CD4+ T cells during T cell-mediated hepatitis was strongly reduced after administration of chlorpromazine. These data demonstrate that LSEC actively provide perivascularly expressed homeostatic and inflammatory chemokines by CXCR4- and clathrin-dependent intracellular transport mechanisms thereby

  8. Prime, Shock, and Kill: Priming CD4 T Cells from HIV Patients with a BCL-2 Antagonist before HIV Reactivation Reduces HIV Reservoir Size

    PubMed Central

    Cummins, Nathan W.; Sainski, Amy M.; Dai, Haiming; Natesampillai, Sekar; Pang, Yuan-Ping; Bren, Gary D.; de Araujo Correia, Maria Cristina Miranda; Sampath, Rahul; Rizza, Stacey A.; O'Brien, Daniel; Yao, Joseph D.

    2016-01-01

    ABSTRACT Understanding how some HIV-infected cells resist the cytotoxicity of HIV replication is crucial to enabling HIV cure efforts. HIV killing of CD4 T cells that replicate HIV can involve HIV protease-mediated cleavage of procaspase 8 to generate a fragment (Casp8p41) that directly binds and activates the mitochondrial proapoptotic protein BAK. Here, we demonstrate that Casp8p41 also binds with nanomolar affinity to the antiapoptotic protein Bcl-2, which sequesters Casp8p41 and prevents apoptosis. Further, we show that central memory CD4 T cells (TCM) from HIV-infected individuals have heightened expression of BCL-2 relative to procaspase 8, possibly explaining the persistence of HIV-infected TCM despite generation of Casp8p41. Consistent with this hypothesis, the selective BCL-2 antagonist venetoclax induced minimal killing of uninfected CD4 T cells but markedly increased the death of CD4 T cells and diminished cell-associated HIV DNA when CD4 T cells from antiretroviral therapy (ART)-suppressed HIV patients were induced with αCD3/αCD28 to reactivate HIV ex vivo. Thus, priming CD4 T cells from ART suppressed HIV patients with a BCL-2 antagonist, followed by HIV reactivation, achieves reductions in cell-associated HIV DNA, whereas HIV reactivation alone does not. IMPORTANCE HIV infection is incurable due to a long-lived reservoir of HIV+ memory CD4 T cells, and no clinically relevant interventions have been identified that reduce the number of these HIV DNA-containing cells. Since postintegration HIV replication can result in HIV protease generation of Casp8p41, which activates BAK, causing infected CD4 T cell death, we sought to determine whether this occurs in memory CD4 T cells. Here, we demonstrate that memory CD4 T cells can generate Casp8p41 and yet are intrinsically resistant to death induced by diverse stimuli, including Casp8p41. Furthermore, BCL-2 expression is relatively increased in these cells and directly binds and inhibits Casp8p41's

  9. ROSTRUM IN MEMORIAL SECTION ALONG CENTRAL DRIVE, WITH BIVOUAC OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    ROSTRUM IN MEMORIAL SECTION ALONG CENTRAL DRIVE, WITH BIVOUAC OF THE DEAD MONUMENT AT FAR LEFT. VIEW TO EAST. - Baton Rouge National Cemetery, 220 North 19th Street, Baton Rouge, East Baton Rouge Parish, LA

  10. [The impact of donor naive and memory T cell subsets on patient outcome following allogeneic stem cell transplantation: relationship between infused donor CD4+/CCR7+ T cell subsets and acute graft-versus-host disease].

    PubMed

    Choufi, B; Thiant, S; Trauet, J; Cliquennois, M; Cherrel, M; Boulanger, F; Coiteux, V; Magro, L; Labalette, M; Yakoub-Agha, I

    2014-06-01

    In a previous prospective study on 62 patients who underwent an HLA-matched allogeneic stem cell transplantation, we have observed that proportion of donor-derived CCR7(+)/CD4(+) T cells in the graft provided a predictive indicator of acute GVHD without interfering on chronic GVHD and relapse rate. Here we present our results on a confirmatory cohort of 137 consecutive patients. Indeed patients who received more than 76% of CCR7(+)/CD4(+) T cells in the graft developed more often acute GVHD be it of low or high grade than those who did not. Determination of the CCR7(+)/CCR7(neg) ratio of CD4(+) T cells in the graft provides a predictive indicator of acute GVHD and could help to define strategies of partial selective T cell depleted transplantation.

  11. Early effector cells survive the contraction phase in malaria infection and generate both central and effector memory T cells.

    PubMed

    Opata, Michael M; Carpio, Victor H; Ibitokou, Samad A; Dillon, Brian E; Obiero, Joshua M; Stephens, Robin

    2015-06-01

    CD4 T cells orchestrate immunity against blood-stage malaria. However, a major challenge in designing vaccines to the disease is poor understanding of the requirements for the generation of protective memory T cells (Tmem) from responding effector T cells (Teff) in chronic parasite infection. In this study, we use a transgenic mouse model with T cells specific for the merozoite surface protein (MSP)-1 of Plasmodium chabaudi to show that activated T cells generate three distinct Teff subsets with progressive activation phenotypes. The earliest observed Teff subsets (CD127(-)CD62L(hi)CD27(+)) are less divided than CD62L(lo) Teff and express memory genes. Intermediate (CD62L(lo)CD27(+)) effector subsets include the most multicytokine-producing T cells, whereas fully activated (CD62L(lo)CD27(-)) late effector cells have a terminal Teff phenotype (PD-1(+), Fas(hi), AnnexinV(+)). We show that although IL-2 promotes expansion, it actually slows terminal effector differentiation. Using adoptive transfer, we show that only early Teff survive the contraction phase and generate the terminal late Teff subsets, whereas in uninfected recipients, they become both central and effector Tmem. Furthermore, we show that progression toward full Teff activation is promoted by increased duration of infection, which in the long-term promotes Tem differentiation. Therefore, we have defined markers of progressive activation of CD4 Teff at the peak of malaria infection, including a subset that survives the contraction phase to make Tmem, and show that Ag and cytokine levels during CD4 T cell expansion influence the proportion of activated cells that can survive contraction and generate memory in malaria infection.

  12. Toll-Like Receptor 3 Signalling Up-Regulates Expression of the HIV Co-Receptor G-Protein Coupled Receptor 15 on Human CD4+ T Cells

    PubMed Central

    Kiene, Miriam; Rethi, Bence; Jansson, Marianne; Dillon, Stephanie; Lee, Eric; Lantto, Rebecka; Wilson, Cara; Pöhlmann, Stefan; Chiodi, Francesca

    2014-01-01

    Background Many HIV-2 and SIV isolates, as well as some HIV-1 strains, can use the orphan 7-transmembrane receptor GPR15 as co-receptor for efficient entry into host cells. GPR15 is expressed on central memory and effector memory CD4+ T cells in healthy individuals and a subset of these cells is susceptible to HIV-1 and SIV infection. However, it has not been determined whether GPR15 expression is altered in the context of HIV-1 infection. Results Here, we show that GPR15 expression in CD4+ T cells is markedly up-regulated in some HIV-1 infected individuals compared to the rest of the infected patients and to healthy controls. Infection of the PM1 T cell line with primary HIV-1 isolates was found to up-regulate GPR15 expression on the infected cells, indicating that viral components can induce GPR15 expression. Up-regulation of GPR15 expression on CD4+ T cells was induced by activation of Toll-like receptor 3 signalling via TIR-domain-containing adapter-inducing interferon-β (TRIF) and was more prominent on gut-homing compared to lymph node-homing CD4+ T cells. Conclusion These results suggest that infection-induced up-regulation of GPR15 expression could increase susceptibility of CD4+ T cells to HIV infection and target cell availability in the gut in some infected individuals. PMID:24558379

  13. Jug r 2-reactive CD4+ T-cells have a dominant immune role in walnut allergy

    PubMed Central

    Archila, Luis Diego; Jeong, David; Pascal, Mariona; Bartra, Joan; Juan, Manel; Robinson, David; Farrington, Mary L.; Kwok, William.W.

    2015-01-01

    Background Allergic reactions to walnut can be life threatening. While IgE epitopes of walnut have been studied, CD4+ T-cell specific epitopes for walnut remain uncharacterized. Particularly, the relationship of both phenotype and frequency of walnut specific T-cells to the disease have not been examined. Objectives We sought to provide a thorough phenotypic analysis for walnut reactive T-cells in allergic and non-allergic subjects. Particularly, the relationship of phenotypes and frequencies of walnut specific T-cells with the disease. Methods CD154 up-regulation assay was used to examine CD4+ T-cell reactivity towards walnut allergens.Jug r 1, Jug r 2 and Jug r 3. Tetramer-Guided epitope mapping approach was utilized to identify HLA-restricted CD4+ T-cells epitopes in Jug r 2. Direct ex vivo staining with peptide-major histocompatibility complex class II (pMHC-II) tetramers enabled the comparison of frequency and phenotype of Jug r 2-specific CD4+ T-cells between allergic and non-allergic subjects. Jug r 2-specific T-cell-clones were also generated and mRNA transcription factor levels were assessed by RT qPCR. Intracellular cytokine staining (ICS) assays were performed for further phenotypical analyses. Results Jug r 2 was identified as the major allergen that elicited CD4+ T-cell responses. Multiple Jug r 2 T-cell epitopes were identified. The majority of these T-cells in allergic subjects have a CCR4+ TCM (central memory) phenotype. A subset of these T-cells express CCR4+CCR6+ irrespectively of the asthmatic status of the allergic subjects. ICS confirmed these TH2, TH2/TH17 and TH17-like heterogenic profiles. Jug r 2-specific T-cell-clones from allergic subjects mainly expressed GATA3; nonetheless, a portion of T-cell clones expressed either GATA3 and RORC, or RORC, confirming the presence of TH2, TH2/TH17 and TH17 cells. Conclusions Jug r 2 specific responses dominate walnut T-cell responses in subjects with walnut allergy. Jug r 2 central memory CD4+ cells

  14. Pregnancy persistently affects memory T cell populations.

    PubMed

    Kieffer, Tom E C; Faas, Marijke M; Scherjon, Sicco A; Prins, Jelmer R

    2017-02-01

    Pregnancy is an immune challenge to the maternal immune system. The effects of pregnancy on maternal immunity and particularly on memory T cells during and after pregnancy are not fully known. This observational study aims to show the short term and the long term effects of pregnancy on the constitution, size and activation status of peripheral human memory T-lymphocyte populations. Effector memory (EM) and central memory (CM) T-lymphocytes were analyzed using flow cytometry of peripheral blood from 14 nulligravid, 12 primigravid and 15 parous women that were on average 18 months postpartum. The short term effects were shown by the significantly higher CD4+ EM cell and activated CD4+ memory cell proportions in primigravid women compared to nulligravid women. The persistent effects found in this study were the significantly higher proportions of CD4+ EM, CD4+ CM and activated memory T cells in parous women compared to nulligravid women. In contrast to CD4+ cells, activation status of CD8+ memory cells did not differ between the groups. This study shows that pregnancy persistently affects the pre-pregnancy CD4+ memory cell pool in human peripheral blood. During pregnancy, CD4+ T-lymphocytes might differentiate into EM cells followed by persistent higher proportions of CD4+ CM and EM cells postpartum. The persistent effects of pregnancy on memory T cells found in this study support the hypothesis that memory T cells are generated during pregnancy and that these cells could be involved in the lower complication risks in multiparous pregnancies in humans.

  15. Innate-like CD4 T cells selected by thymocytes suppress adaptive immune responses against bacterial infections

    PubMed Central

    Qiao, Yu; Gray, Brian M.; Sofi, Mohammed H.; Bauler, Laura D.; Eaton, Kathryn A.; O'Riordan, Mary X. D.; Chang, Cheong-Hee

    2012-01-01

    We have reported a new innate-like CD4 T cell population that expresses cell surface makers of effector/memory cells and produce Th1 and Th2 cytokines immediately upon activation. Unlike conventional CD4 T cells that are selected by thymic epithelial cells, these CD4 T cells, named T-CD4 T cells, are selected by MHC class II expressing thymocytes. Previously, we showed that the presence of T-CD4 T cells protected mice from airway inflammation suggesting an immune regulatory role of T-CD4 T cells. To further understand the function of T-CD4 T cells, we investigated immune responses mediated by T-CD4 T cells during bacterial infection because the generation of antigen specific CD4 T cells contributes to clearance of infection and for the development of immune memory. The current study shows a suppressive effect of T-CD4 T cells on both CD8 and CD4 T cell-mediated immune responses during Listeria and Helicobacter infections. In the mouse model of Listeria monocytogenes infection, T-CD4 T cells resulted in decreasedfrequency of Listeria-specific CD8 T cells and the killing activity of them. Furthermore, mice with T-CD4 T cells developed poor immune memory, demonstrated by reduced expansion of antigen-specific T cells and high bacterial burden upon re-infection. Similarly, the presence of T-CD4 T cells suppressed the generation of antigen-specific CD4 T cells in Helicobacter pylori infected mice. Thus, our studies reveal a novel function of T-CD4 T cells in suppressing anti-bacterial immunity. PMID:23264931

  16. Analysis of subsets of B cells, Breg, CD4Treg and CD8Treg cells in adult patients with primary selective IgM deficiency

    PubMed Central

    Louis, Ankmalika Gupta; Agrawal, Sudhanshu; Gupta, Sudhir

    2016-01-01

    Primary selective IgM deficiency (SIGMD) is a rare and recently IUIS-recognized primary immunodeficiency disease with increased susceptibility to infections, allergy, and autoimmune diseases. The pathogenesis of selective IgM remains unclear. The objective of the study was to understand the pathogenesis of selective IgM deficiency via a comprehensive analysis of subsets of B cells, naïve and memory subsets of CD4+ and CD8+ T cells, and Breg, CD4Treg, and CD8Treg cells. Twenty adult patients with SIGMD (serum IgM 4 mg/dl-32 mg/dl) and age-and gender-matched healthy controls were studied. Naïve B cells, transitional B cells, marginal zone B cells, germinal center B cells, IgM memory B cells, switched memory B cells, plasmablasts, CD21low B cells, B1 cells, CXCR3+ naive and memory B cells; naïve, central memory, and effector memory subsets of CD4+ and CD8+ T cells, and CD4Treg, CD8Treg and Breg were phenotypically analyzed using multicolor flow cytometry. A significant increase in CD21low, IgM memory B cells, Breg and CD8Treg, and a significant decreased in germinal center B cells, and CXCR3+ naïve and memory B cells were observed in SIGMD. These alterations in subsets of B cells, and Breg and CD8Treg cells may play a role in the pathogenesis of SIGMD. PMID:27168952

  17. Effects of MF59 Adjuvant on Induction of Isotype-Switched IgG Antibodies and Protection after Immunization with T-Dependent Influenza Virus Vaccine in the Absence of CD4+ T Cells

    PubMed Central

    Ko, Eun-Ju; Lee, Young-Tae; Kim, Ki-Hye; Jung, Yu-Jin; Lee, Youri; Denning, Timothy L.

    2016-01-01

    ABSTRACT CD4+ T cells play a central role in orchestrating adaptive immunity. To better understand the roles of CD4+ T cells in the effects of adjuvants, we investigated the efficacy of a T-dependent influenza virus split vaccine with MF59 or alum in CD4 knockout (CD4KO) and wild-type (WT) mice. CD4+ T cells were required for the induction of IgG antibody responses to the split vaccine and the effects of alum adjuvant. In contrast, MF59 was found to be highly effective in raising isotype-switched IgG antibodies to a T-dependent influenza virus split vaccine in CD4KO mice or CD4-depleted WT mice equivalent to those in intact WT mice, thus overcoming the deficiency of CD4+ T cells in helping B cells and inducing immunity against influenza virus. Vaccination with the MF59-adjuvanted influenza virus vaccine was able to induce protective CD8+ T cells and long-lived antibody-secreting cells in CD4KO mice. The effects of MF59 adjuvant in CD4KO mice might be associated with uric acid, inflammatory cytokines, and the recruitment of multiple immune cells at the injection site, but their cellularity and phenotypes were different from those in WT mice. These findings suggest a new paradigm of CD4-independent adjuvant mechanisms, providing the rationales to improve vaccine efficacy in infants, the elderly, immunocompromised patients, as well as healthy adults. IMPORTANCE MF59-adjuvanted influenza vaccines were licensed for human vaccination, but the detailed mechanisms are not fully elucidated. CD4+ T cells are required to induce antibody isotype switching and long-term memory responses. In contrast, we discovered that MF59 was highly effective in inducing isotype-switched IgG antibodies and long-term protective immune responses to a T-dependent influenza vaccine independent of CD4+ T cells. These findings are highly significant for the following reasons: (i) MF59 can overcome a defect of CD4+ T cells in inducing protective immunity to vaccination with a T-dependent influenza

  18. Cloning, expression, and characterization of fugu CD4, the first ectothermic animal CD4.

    PubMed

    Suetake, Hiroaki; Araki, Kyosuke; Suzuki, Yuzuru

    2004-08-01

    We have cloned and sequenced the first ectothermic animal CD4 gene from fugu, Takifugu rubripes, using a public database of the third draft sequence of the fugu genome. The fugu CD4 gene encodes a predicted protein of 463 amino acids containing four extracellular immunoglobulin (Ig)-like domains, a transmembrane region, and a cytoplasmic tail. Fugu CD4 shares low identity of about 15-20% with avian and mammalian CD4 proteins. Unlike avian and mammalian CD4, fugu CD4 lacks the Cys pair of the first Ig-like domain, but has a unique possible disulfide bond in the third domain. These differences suggest that fugu CD4 may have a different structure that could affect binding of major histocompatibility complex class II molecules and subsequent T-cell activation. In the putative fugu cytoplasmic region, the protein tyrosine kinase p56lck binding motif is conserved. The predicted fugu CD4 gene is composed of 12 exons, differing from other CD4 genes, but showing conserved synteny and many conserved sequence motifs in the promoter region. RT-PCR analysis demonstrated that the fugu CD4 gene is expressed predominantly in lymphoid tissues. We also show that fugu CD4 can be expressed on the surface of cells via transfection. Molecular characterization of CD4 in fish provides insights into the evolution of both the CD4 molecule and the immune system.

  19. Evaluation of immunological cross-reactivity between clade A9 high-risk human papillomavirus types on the basis of E6-Specific CD4+ memory T cell responses.

    PubMed

    van den Hende, Muriel; Redeker, Anke; Kwappenberg, Kitty M C; Franken, Kees L M C; Drijfhout, Jan W; Oostendorp, Jaap; Valentijn, A Rob P M; Fathers, Loraine M; Welters, Marij J P; Melief, Cornelis J M; Kenter, Gemma G; van der Burg, Sjoerd H; Offringa, Rienk

    2010-10-15

    CD4(+) T cell responses against the E6 oncoprotein of human papillomavirus (HPV) type 16 and 5 closely related members of clade A9 (HPV31, 33, 35, 52, and 58) were charted in peripheral blood mononuclear cell cultures from healthy subjects and patients who underwent HPV16 E6/E7-specific vaccination. Initial analyses with overlapping peptide arrays showed that approximately one-half of the responding subjects displayed reactivity against corresponding E6 peptides from >or=2 HPV types. This suggested immunological cross-reactivity and complicated retrospective evaluation of the infection history of the healthy subjects. Importantly, further dissection of the response by means of enriched and clonal T cell cultures (with protein antigen instead of peptides) revealed that CD4(+) T cells that are capable of efficiently reacting against E6 antigen from multiple HPV types are rare and only occur when epitope sequences are highly conserved. Our data indicate that natural and vaccine-induced HPV16 E6-specific CD4(+) T cell responses are unlikely to mediate efficient cross-protection against other clade A9 members.

  20. CXCR5+CD4+ follicular helper T cells accumulate in resting human lymph nodes and have superior B cell helper activity.

    PubMed

    Havenith, Simone H C; Remmerswaal, Ester B M; Idu, Mirza M; van Donselaar-van der Pant, Karlijn A M I; van der Bom, Nelly; Bemelman, Fréderike J; van Leeuwen, Ester M M; ten Berge, Ineke J M; van Lier, René A W

    2014-03-01

    Although many relevant immune reactions are initiated in the lymph nodes, this compartment has not been systematically studied in humans. Analyses have been performed on immune cells derived from tonsils, but as this tissue is most often inflamed, generalization of these data is difficult. Here, we analyzed the phenotype and function of the human CD4(+) T-cell subsets and lineages in paired resting lymph node and peripheral blood samples. Naive, central memory cells and effector memory cells as well as Th1, Th2, Th17 and Treg cells were equally represented in both compartments. On the other hand, cytotoxic CD4(+) T cells were strikingly absent in the lymph nodes. CXCR5(+)CD4(+) T cells, representing putative follicular Th (Tfh) cells were over-represented in lymph nodes and expressed higher levels of Tfh markers than their peripheral blood counterparts. Compared with the circulating pool, lymph-node-derived CXCR5(+)CD4(+) T cells were superior in providing help to B cells. Thus, functionally competent Tfh cells accumulate in resting human lymph nodes, providing a swift induction of naive and memory antibody responses upon antigenic challenge.

  1. Analysis of Populations of Memory T-Helper Cells Expressing CXCR3 and CCR6 Chemokine Receptors in Peripheral Blood of Patients with Chronic Viral Hepatitis C.

    PubMed

    Elezov, D S; Kudryavtsev, I V; Arsent'ev, N A; Basin, V V; Esaulenko, E V; Semenov, A V; Totolyan, A A

    2015-12-01

    Flow cytometry was employed to examine the content of major populations of memory T helper cells and expression of chemokine receptors CXCR3 and CCR6 on their surface in peripheral blood drawn from virtually healthy people and the patients with chronic viral hepatitis C. The following combination of monoclonal antibodies had been used: CD62LFITC/CD45RA-PE/CD3-ECD/CCR6-PC7/CXCR3-APC/CD4-APC-Cy7. In comparison with control group, the patients with chronic hepatitis C had a smaller number of populations of naïve CD4(+) T cells and central memory CD4(+) T cells but a greater number of terminally differentiated effector memory CD4(+) T cells and effector memory CD4(+) T cells. No differences were revealed between CD4(+) T cell populations of both groups in expression of CXCR3 and CCR6 receptors.

  2. Apoptotic Effects of Antilymphocyte Globulins on Human Pro-inflammatory CD4+CD28− T-cells

    PubMed Central

    Duftner, Christina; Dejaco, Christian; Hengster, Paul; Bijuklic, Klaudija; Joannidis, Michael; Margreiter, Raimund; Schirmer, Michael

    2012-01-01

    Background Pro-inflammatory, cytotoxic CD4+CD28− T-cells with known defects in apoptosis have been investigated as markers of premature immuno-senescence in various immune-mediated diseases. In this study we evaluated the influence of polyclonal antilymphocyte globulins (ATG-Fresenius, ATG-F) on CD4+CD28− T-cells in vivo and in vitro. Principal Findings Surface and intracellular three colour fluorescence activated cell sorting analyses of peripheral blood mononuclear cells from 16 consecutive transplant recipients and short-term cell lines were performed. In vivo, peripheral levels of CD3+CD4+CD28− T-cells decreased from 3.7±7.1% before to 0±0% six hours after ATG-F application (P = 0.043) in 5 ATG-F treated but not in 11 control patients (2.9±2.9% vs. 3.9±3.0%). In vitro, ATG-F induced apoptosis even in CD4+CD28− T-cells, which was 4.3-times higher than in CD4+CD28+ T-cells. ATG-F evoked apoptosis was partially reversed by the broad-spectrum caspase inhibitor benzyloxycarbonyl (Cbz)-Val-Ala-Asp(OMe)-fluoromethylketone (zVAD-fmk) and prednisolon-21-hydrogensuccinate. ATG-F triggered CD25 expression and production of pro-inflammatory cytokines, and induced down-regulation of the type 1 chemokine receptors CXCR-3, CCR-5, CX3CR-1 and the central memory adhesion molecule CD62L predominately in CD4+CD28− T-cells. Conclusion In summary, in vivo depletion of peripheral CD3+CD4+CD28− T-cells by ATG-F in transplant recipients was paralleled in vitro by ATG-F induced apoptosis. CD25 expression and chemokine receptor down-regulation in CD4+CD28− T-cells only partly explain the underlying mechanism. PMID:22479483

  3. Sublingual therapeutic immunization with a polyvalent bacterial preparation in patients with recurrent respiratory infections: immunomodulatory effect on antigen-specific memory CD4+ T cells and impact on clinical outcome

    PubMed Central

    Alecsandru, D; Valor, L; Sánchez-Ramón, S; Gil, J; Carbone, J; Navarro, J; Rodríguez, J J; Rodríguez-Sainz, C; Fernández-Cruz, E

    2011-01-01

    Recurrent respiratory tract infections (RRTIs) are common clinical conditions in individuals with alterations of the immune function. A prospective open pilot study in a cohort of patients with RRTIs has been performed to assess whether sublingual immunization with a polyvalent bacterial vaccine could exert an immunomodulatory effect on the antigen-specific immunological responses and have an impact on the clinical outcome. Seventeen patients with RRTIs were recruited. An oral polyvalent bacterial preparation (Bactek®) was administered to all patients daily for 6 months. Immunological assessment was performed at baseline and at the end of immunization. Immunological measurements included: T cell-specific proliferations of CD3+CD4+ and CD3+CD8+ to Bactek® antigens, total immunoglobulin levels, antibodies to pneumococcal polysaccharide and tetanus toxoid and B, T and natural killer (NK) cell subsets. There was a significant increase in the proliferative capacity of CD3+CD4+ T cells specific to Bactek® antigens at month 6 in comparison to baseline (P < 0·0001). A significant increase in total CD3+ T cells was also observed (P < 0·05). No significant differences were observed between baseline and month 6 in levels of total immunoglobulins, specific antibodies and B, T or NK cell subsets. A significant reduction in the patient's rate of RRTIs was observed compared with 1 year prior to initiation of therapy (P < 0·0001). The results demonstrate that long-term administration of a sublingual polyvalent bacterial preparation in patients with RRTIs exerts an immune stimulating effect on CD4+ T helper cell responses to bacterial antigens which could be associated with clinical benefit. PMID:21391984

  4. Plasticity of Human CD4 T Cell Subsets

    PubMed Central

    Geginat, Jens; Paroni, Moira; Maglie, Stefano; Alfen, Johanna Sophie; Kastirr, Ilko; Gruarin, Paola; De Simone, Marco; Pagani, Massimiliano; Abrignani, Sergio

    2014-01-01

    Human beings are exposed to a variety of different pathogens, which induce tailored immune responses and consequently generate highly diverse populations of pathogen-specific T cells. CD4+ T cells have a central role in adaptive immunity, since they provide essential help for both cytotoxic T cell- and antibody-mediated responses. In addition, CD4+ regulatory T cells are required to maintain self-tolerance and to inhibit immune responses that could damage the host. Initially, two subsets of CD4+ helper T cells were identified that secrete characteristic effector cytokines and mediate responses against different types of pathogens, i.e., IFN-γ secreting Th1 cells that fight intracellular pathogens, and IL-4 producing Th2 cells that target extracellular parasites. It is now well established that this dichotomy is insufficient to describe the complexity of CD4+ T cell differentiation, and in particular the human CD4 compartment contains a myriad of T cell subsets with characteristic capacities to produce cytokines and to home to involved tissues. Moreover, it has become increasingly clear that these T cell subsets are not all terminally differentiated cells, but that the majority is plastic and that in particular central memory T cells can acquire different properties and functions in secondary immune responses. In addition, there is compelling evidence that helper T cells can acquire regulatory functions upon chronic stimulation in inflamed tissues. The plasticity of antigen-experienced human T cell subsets is highly relevant for translational medicine, since it opens new perspectives for immune-modulatory therapies for chronic infections, autoimmune diseases, and cancer. PMID:25566245

  5. Expression of CD4 by human megakaryocytes.

    PubMed Central

    Basch, R S; Kouri, Y H; Karpatkin, S

    1990-01-01

    The CD4 antigen, which serves as the receptor for human immunodeficiency virus type 1 (HIV-1) on T cells, has been detected on human megakaryocytes. Recent evidence of impaired thrombopoiesis in HIV-1-related thrombocytopenia suggested that these cells could be directly infected by the virus and prompted a search for a receptor on megakaryocytes of normal subjects that could permit entry of HIV-1. Bone marrow specimens from uninfected normal control subjects were centrifuged over Ficoll-Hypaque (1.077 g/ml) and analyzed by three-color analysis with a flow cytometer utilizing monoclonal antibodies against CD4 and a glycoprotein present on the surface of megakaryocytes and platelets (GPIIb/IIIa; CD41), as well as 7-aminoactinomycin D, a stain for DNA. Cells presumed to be megakaryocytes were identified by having a DNA content greater than tetraploid and staining brightly with anti-CD41. Approximately 0.4% of the nucleated cells of the marrow met these criteria. Twenty-five percent of these megakaryocytes stained as brightly as CD4+ T cells. Several clones of antibody recognizing different epitopes of the CD4 molecule gave similar results. Platelets were CD4-. Staining of megakaryocytes with anti-CD4 was confirmed by direct microscopic examination of Percoll-gradient-enriched megakaryocytes employing two-color (CD4-phycoerythrin and CD41-fluorescein) immunofluorescence analysis and phase-contrast microscopy. The proportion of double-labeled cells among 112 phase-contrast-identifiable megakaryocytes from five bone marrow specimens varied between 20% and 26% with a mean and SD of 22% +/- 2.5%. Thus some human megakaryocytes express CD4 on their surface that should be capable of binding the HIV-1 gp120 envelope protein. This could serve as a portal of entry for HIV-1. Images PMID:2236021

  6. CD4 CTL, a Cytotoxic Subset of CD4+ T Cells, Their Differentiation and Function

    PubMed Central

    Takeuchi, Arata; Saito, Takashi

    2017-01-01

    CD4+ T cells with cytotoxic activity (CD4 CTL) have been observed in various immune responses. These cells are characterized by their ability to secrete granzyme B and perforin and to kill the target cells in an MHC class II-restricted fashion. Although CD4 CTLs were once thought to be an in vitro artifact associated with long-term culturing, they have since been identified in vivo and shown to play important roles in antiviral and antitumor immunity, as well as in inflammation. Functional characterization of CD4 CTL suggests their potential significance for therapeutic purposes. However, in order to develop effective CD4 CTL therapy it is necessary to understand the differentiation and generation of these cells. Although the mechanisms regulating development of various CD4+ Th subsets have been clarified in terms of the cytokine and transcription factor requirement, the CD4 CTL differentiation mechanism remains elusive. These cells are thought to be most closely related to Th1 cells secreting IFNγ and regulated by eomesodermin and/or T-bet transcription factors for their differentiation. However, our studies and those of others have identified CD4 CTLs within other CD4+ T cell subsets, including naïve T cells. We have identified class I-restricted T cell-associated molecule as a marker of CD4 CTL and, by using this marker, we detected a subset of naïve T cells that have the potential to differentiate into CD4 CTL. CD4 CTL develops at sites of infections as well as inflammation. In this review, we summarize recent findings about the generation of CD4 CTL and propose a model with several differentiation pathways. PMID:28280496

  7. Yellow fever vaccination elicits broad functional CD4+ T cell responses that recognize structural and nonstructural proteins.

    PubMed

    James, Eddie A; LaFond, Rebecca E; Gates, Theresa J; Mai, Duy T; Malhotra, Uma; Kwok, William W

    2013-12-01

    Yellow fever virus (YFV) can induce acute, life-threatening disease that is a significant health burden in areas where yellow fever is endemic, but it is preventable through vaccination. The live attenuated 17D YFV strain induces responses characterized by neutralizing antibodies and strong T cell responses. This vaccine provides an excellent model for studying human immunity. While several studies have characterized YFV-specific antibody and CD8(+) T cell responses, less is known about YFV-specific CD4(+) T cells. Here we characterize the epitope specificity, functional attributes, and dynamics of YFV-specific T cell responses in vaccinated subjects by investigating peripheral blood mononuclear cells by using HLA-DR tetramers. A total of 112 epitopes restricted by seven common HLA-DRB1 alleles were identified. Epitopes were present within all YFV proteins, but the capsid, envelope, NS2a, and NS3 proteins had the highest epitope density. Antibody blocking demonstrated that the majority of YFV-specific T cells were HLA-DR restricted. Therefore, CD4(+) T cell responses could be effectively characterized with HLA-DR tetramers. Ex vivo tetramer analysis revealed that YFV-specific T cells persisted at frequencies ranging from 0 to 100 cells per million that are detectable years after vaccination. Longitudinal analysis indicated that YFV-specific CD4(+) T cells reached peak frequencies, often exceeding 250 cells per million, approximately 2 weeks after vaccination. As frequencies subsequently declined, YFV-specific cells regained CCR7 expression, indicating a shift from effector to central memory. Cells were typically CXCR3 positive, suggesting Th1 polarization, and produced gamma interferon and other cytokines after reactivation in vitro. Therefore, YFV elicits robust early effector CD4(+) T cell responses that contract, forming a detectable memory population.

  8. Molecular signatures distinguish human central memory from effector memory CD8 T cell subsets.

    PubMed

    Willinger, Tim; Freeman, Tom; Hasegawa, Hitoshi; McMichael, Andrew J; Callan, Margaret F C

    2005-11-01

    Memory T cells are heterogeneous in terms of their phenotype and functional properties. We investigated the molecular profiles of human CD8 naive central memory (T(CM)), effector memory (T(EM)), and effector memory RA (T(EMRA)) T cells using gene expression microarrays and phospho-protein-specific intracellular flow cytometry. We demonstrate that T(CM) have a gene expression and cytokine signaling signature that lies between that of naive and T(EM) or T(EMRA) cells, whereas T(EM) and T(EMRA) are closely related. Our data define the molecular basis for the different functional properties of central and effector memory subsets. We show that T(EM) and T(EMRA) cells strongly express genes with known importance in CD8 T cell effector function. In contrast, T(CM) are characterized by high basal and cytokine-induced STAT5 phosphorylation, reflecting their capacity for self-renewal. Altogether, our results distinguish T(CM) and T(EM)/T(EMRA) at the molecular level and are consistent with the concept that T(CM) represent memory stem cells.

  9. HIV persists in CCR6+CD4+ T cells from colon and blood during antiretroviral therapy

    PubMed Central

    Gosselin, Annie; Wiche Salinas, Tomas Raul; Planas, Delphine; Wacleche, Vanessa S.; Zhang, Yuwei; Fromentin, Rémi; Chomont, Nicolas; Cohen, Éric A.; Shacklett, Barbara; Mehraj, Vikram; Ghali, Maged P.; Routy, Jean-Pierre; Ancuta, Petronela

    2017-01-01

    Objectives: The objective of this article is to investigate the contribution of colon and blood CD4+ T-cell subsets expressing the chemokine receptor CCR6 to HIV persistence during antiretroviral therapy. Design: Matched sigmoid biopsies and blood samples (n = 13) as well as leukapheresis (n = 20) were collected from chronically HIV-infected individuals receiving antiretroviral therapy. Subsets of CD4+ T cells with distinct differentiation/polarization profiles were identified using surface markers as follows: memory (TM, CD45RA−), central memory (TCM; CD45RA−CCR7+), effector (TEM/TM; CD45RA−CCR7−), Th17 (CCR6+CCR4+), Th1Th17 (CCR6+CXCR3+), Th1 (CCR6−CXCR3+), and Th2 (CCR6−CCR4+). Methods: We used polychromatic flow cytometry for cell sorting, nested real-time PCR for HIV DNA quantification, ELISA and flow cytometry for HIV p24 quantification. HIV reactivation was induced by TCR triggering in the presence/absence of all-trans retinoic acid. Results: Compared with blood, the frequency of CCR6+ TM was higher in the colon. In both colon and blood compartments, CCR6+ TM were significantly enriched in HIV DNA when compared with their CCR6− counterparts (n = 13). In blood, integrated HIV DNA levels were significantly enriched in CCR6+ versus CCR6− TCM of four of five individuals and CCR6+ versus CCR6− TEM of three of five individuals. Among blood TCM, Th17 and Th1Th17 contributed the most to the pool of cells harboring integrated HIV DNA despite their reduced frequency compared with Th2, which were infected the least. HIV reactivation was induced by TCR triggering and/or retinoic acid exposure at higher levels in CCR6+ versus CCR6− TM, TCM, and TEM. Conclusion: CCR6 is a marker for colon and blood CD4+ T cells enriched for replication-competent HIV DNA. Novel eradication strategies should target HIV persistence in CCR6+CD4+ T cells from various anatomic sites. PMID:27835617

  10. Immune reconstitution but persistent activation after 48 weeks of antiretroviral therapy in youth with pre-therapy CD4 >350 in ATN 061

    PubMed Central

    Rudy, Bret J.; Kapogiannis, Bill G.; Worrell, Carol; Squires, Kathleen; Bethel, James; Li, Su; Wilson, Craig M.; Agwu, Allison; Emmanuel, Patricia; Price, Georgine; Hudey, Stephanie; Goodenow, Maureen M.; Sleasman, John W.

    2015-01-01

    Measures of immune outcomes in youth who initiate combination antiretroviral therapy (cART) early in HIV infection are limited. Design Adolescent Trials Network 061 examined changes over 48 weeks of cART in T cell subsets and markers of T cell and macrophage activation in subjects with pre-therapy CD4>350. All subjects had optimal viral suppression from weeks 24 through 48. Methods Subjects (n=48) initiated cART with tenofovir/emtricitabine plus ritonavir-boosted atazanavir. Data were collected at baseline and weeks 12, 24, and 48. Trends were compared to uninfected controls. Results Significant increases over 48 weeks were noted in all CD4 populations including total, naïve, central memory (CM), and effector memory RO (EM RO) and effector memory RA (EM RA) while numbers of CM and EMRO CD8 cells declined significantly. By week 48, CD4 naïve cells were similar to controls while CM CD4 cells remained significantly lower and EM RO and EM RA subsets were significantly higher. CD38 and HLA DR expression, both individually and when co-expressed, decreased over 48 weeks of cART on CD8 cells but remained significantly higher than controls at week 48. In contrast, markers of macrophage activation measured by sCD14 and sCD163 in plasma did not change with cART and were significantly higher than controls. Conclusion In youth initiating early cART, CD4 cell reconstitution is robust with decreases in CD8 cells. However CD8 T cell and macrophage activation persists at higher levels than uninfected controls. PMID:25942459

  11. TCRαβ+/CD4+ Large Granular Lymphocytosis

    PubMed Central

    Lima, Margarida; Almeida, Julia; dos Anjos Teixeira, Maria; Alguero, Maria del Carmen; Santos, Ana Helena; Balanzategui, Ana; Queirós, Maria Luís; Bárcena, Paloma; Izarra, Antonio; Fonseca, Sónia; Bueno, Clara; Justiça, Benvindo; Gonzalez, Marcos; San Miguel, Jesús F.; Orfao, Alberto

    2003-01-01

    Large granular lymphocyte (LGL) leukemia is a well-recognized disease of mature T-CD8+ or less frequently natural killer cells; in contrast, monoclonal expansions of CD4+ T-LGL have only been sporadically reported in the literature. In the present article we have explored throughout a period of 56 months the incidence of monoclonal expansions of CD4+ T-LGL in a population of 2.2 million inhabitants and analyzed the immunophenotype and the pattern of cytokine production of clonal CD4+ T cells of a series of 34 consecutive cases. Like CD8+ T-LGL leukemias, CD4+ T-LGL leukemia patients have an indolent disease; however, in contrast to CD8+ T-LGL leukemias, they do not show cytopenias and autoimmune phenomena and they frequently have associated neoplasias, which is usually determining the clinical course of the disease. Monoclonal CD4+ T-LGLshowed expression of TCRαβ, variable levels of CD8 (CD8−/+dim) and a homogeneous typical cytotoxic (granzyme B+, CD56+, CD57+, CD11b+/−) and activated/memory T cell (CD2+bright, CD7−/+dim, CD11a+bright, CD28−, CD62L− HLA-DR+) immunophenotype. In addition, they exhibited a Th1 pattern of cytokine production [interferon-γ++, tumor necrosis factor-α++, interleukin (IL-2)−/+, IL-4−, IL-10−, IL-13−]. Phenotypic analysis of the TCR-Vβ repertoire revealed large monoclonal TCR-Vβ expansions; only a restricted number of TCR-Vβ families were represented in the 34 cases analyzed. These findings suggest that monoclonal TCRαβ+/CD4+/NKa+/CD8−/+dim T-LGL represent a subgroup of monoclonal LGL lymphoproliferative disorders different from both CD8+ T-LGL and natural killer cell-type LGL leukemias. Longer follow-up periods are necessary to determine the exact significance of this clonal disorder. PMID:12875995

  12. Idiopathic CD4 lymphocytopenia with sensorimotor polyneuropathy

    PubMed Central

    Puri, Vinod; Duggal, Ashish Kumar; Chaudhry, Neera

    2016-01-01

    A, 21-years-old, male, presented with acute onset, gradually progressive, predominantly distal, symmetrical weakness of both upper and lower limbs with arreflexia. He had impaired sensations in glove and stocking distribution with distal gradient. He was found to have absolute CD4 + cell count of 188 cells/μL, absolute CD8 cell count, 532 cells/μL and CD4: CD8 ratio of 0.35. Electrophysiology revealed reduced to absent CMAP amplitude as well as SNAPs in various nerves of upper and lower limbs, along with normal conduction velocity and normal F wave latencies. Pattern evoked visual potentials were prolonged, on both sides, P100 being 130 ms, on right and 108 ms, on left side. In the follow up of 2 years, he showed spontaneous but gradual clinical improvement but his electrophysiological parameters as well as CD 4+ cells count did not show any significant improvement. PMID:27570393

  13. Emerging technologies for point-of-care CD4 T-lymphocyte counting

    PubMed Central

    Boyle, David S.; Hawkins, Kenneth R.; Steele, Matthew S.; Singhal, Mitra; Cheng, Xuanhong

    2012-01-01

    A CD4 T-lymphocyte count determines eligibility for antiretroviral therapy (ART) with patients recently diagnosed with HIV and also monitors the efficacy of ART treatment thereafter. ART slows the progression of HIV to AIDS. In the developing world, CD4 tests are often performed in centralized laboratories, typically in urban areas. The expansion of ART programs into rural areas has created a need for rapid CD4 counting as logistical barriers can delay the timely dissemination of test results and affect patient care through delay in intervention or loss of follow-up care. CD4 measurement at the point-of-care (POC) in rural areas could help facilitating ART and monitoring of treatment. This review highlights recent technology developments with applications towards determining CD4 counts at the POC. PMID:21798607

  14. Low-dose IL-2 selectively activates subsets of CD4+ Tregs and NK cells

    PubMed Central

    Hirakawa, Masahiro; Matos, Tiago; Liu, Hongye; Koreth, John; Kim, Haesook T.; Paul, Nicole E.; Murase, Kazuyuki; Whangbo, Jennifer; Alho, Ana C.; Nikiforow, Sarah; Cutler, Corey; Ho, Vincent T.; Armand, Philippe; Alyea, Edwin P.; Antin, Joseph H.; Blazar, Bruce R.; Lacerda, Joao F.; Soiffer, Robert J.

    2016-01-01

    CD4+ regulatory T cells (CD4Tregs) play a critical role in the maintenance of immune tolerance and prevention of chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation. IL-2 supports the proliferation and survival of CD4Tregs and previous studies have demonstrated that IL-2 induces selective expansion of CD4Tregs and improves clinical manifestations of chronic GVHD. However, mechanisms for selective activation of CD4Tregs and the effects of low-dose IL-2 on other immune cells are not well understood. Using mass cytometry, we demonstrate that low concentrations of IL-2 selectively induce STAT5 phosphorylation in Helios+ CD4Tregs and CD56brightCD16– NK cells in vitro. Preferential activation and expansion of Helios+ CD4Tregs and CD56brightCD16– NK cells was also demonstrated in patients with chronic GVHD receiving low-dose IL-2. With prolonged IL-2 treatment for 48 weeks, phenotypic changes were also observed in Helios– CD4Tregs. The effects of low-dose IL-2 therapy on conventional CD4+ T cells and CD8+ T cells were limited to increased expression of PD-1 on effector memory T cells. These studies reveal the selective effects of low-dose IL-2 therapy on Helios+ CD4Tregs and CD56bright NK cells that constitutively express high-affinity IL-2 receptors as well as the indirect effects of prolonged exposure to low concentrations of IL-2 in vivo. PMID:27812545

  15. The Differentiation and Protective Function of Cytolytic CD4 T Cells in Influenza Infection

    PubMed Central

    Brown, Deborah M.; Lampe, Anna T.; Workman, Aspen M.

    2016-01-01

    CD4 T cells that recognize peptide antigen in the context of class II MHC can differentiate into various subsets that are characterized by their helper functions. However, increasing evidence indicates that CD4 cells with direct cytolytic activity (CD4 CTL) play a role in chronic as well as acute infections, such as influenza A virus (IAV) infection. In the last couple of decades, techniques to measure the frequency and activity of these cytolytic cells has demonstrated their abundance in infections, such as human immunodeficiency virus, mouse pox, murine gamma herpes virus, cytomegalovirus, Epstein–Barr virus, and influenza among others. We now appreciate a greater role for CD4 CTL as direct effectors in viral infections and antitumor immunity through their ability to acquire perforin-mediated cytolytic activity and contribution to lysis of virally infected targets or tumors. As early as the 1980s, CD4 T cell clones with cytolytic potential were identified after influenza virus infection, yet much of this early work was dependent on in vitro culture and little was known about the physiological relevance of CD4 CTL. Here, we discuss the direct role CD4 CTL play in protection against lethal IAV infection and the factors that drive the generation of perforin-mediated lytic activity in CD4 cells in vivo during IAV infection. While focusing on CD4 CTL generated during IAV infection, we pull comparisons from the literature in other antiviral and antitumor systems. Further, we highlight what is currently known about CD4 CTL secondary and memory responses, as well as vaccination strategies to induce these potent killer cells that provide an extra layer of cell-mediated immune protection against heterosubtypic IAV infection. PMID:27014272

  16. ICOS-ligand expression on plasmacytoid dendritic cells supports breast cancer progression by promoting the accumulation of immunosuppressive CD4+ T cells.

    PubMed

    Faget, Julien; Bendriss-Vermare, Nathalie; Gobert, Michael; Durand, Isabelle; Olive, Daniel; Biota, Cathy; Bachelot, Thomas; Treilleux, Isabelle; Goddard-Leon, Sophie; Lavergne, Emilie; Chabaud, Sylvie; Blay, Jean Yves; Caux, Christophe; Ménétrier-Caux, Christine

    2012-12-01

    Human breast tumors are infiltrated by memory CD4(+) T cells along with increased numbers of regulatory T cells (Treg) and plasmacytoid dendritic cells (pDC) that facilitate immune escape and correlate with poor prognosis. Here, we report that inducible costimulatory molecule (ICOS), a T cell costimulatory molecule of the CTLA4/PD1/CD28 family, is expressed mostly by tumor-associated Treg in primary breast tumors. A large proportion of these ICOS(+) Treg were Ki67(+) and this evident proliferative expansion was found to rely on interactions with tumor-associated pDC. Indeed, tumor-associated Treg highly expanded in presence of pDC but failed to proliferate under CD3/CD28 signal. In vitro experiments revealed that the addition of a neutralizing anti-ICOS antibody blocked pDC-induced Treg expansion and interleukin-10 secretion by memory CD4(+) T cells, establishing a pivotal role for ICOS in this process. Supporting these findings, the presence of ICOS(+) cells in clinical specimens of breast cancer correlated with a poor prognosis. Together, our results highlight an important relationship between Treg and pDC in breast tumors, and show that ICOS/ICOS-L interaction is a central event in immunosuppression of tumor-associated memory CD4(+) T cells. These findings strongly rationalize antibody-mediated ICOS blockade as a powerful clinical strategy to correct immune escape and promote therapeutic responses in breast cancer.

  17. Modulation of CD4 by suramin.

    PubMed Central

    Allen, P D; Johnston, D H; Macey, M G; Williams, N S; Newland, A C

    1993-01-01

    Suramin is a polysulphonated compound which can selectively bind to, and inhibit the activity of, a wide range of growth factors. There has been renewed interest recently in suramin as an anti-cancer agent and therefore we have studied its effects on lymphocyte subset populations and recombinant human IL-2 (rhIL-2) activation on lymphocytes in vitro. In the presence of rhIL-2 (1000 U/ml), suramin (200 micrograms/ml) caused a decrease in percentage of cells expressing the predominantly T cell antigen CD3; no change in percentage of cells expressing the T suppressor/cytotoxic subset antigen, CD8; a small rise in those expressing the natural killer cell antigen, CD56; and a large significant fall in those expressing the T helper subset antigen CD4 (48.51% versus 27.97%; P < 0.001). CD4 modulation by suramin was also found on the CD4+ cell lines CEM and MOLT-4. The effect of suramin on rhIL-2-induced activation antigen expression remains equivocal, since a small rise in CD25 expression and small falls in CD71 and HLA-Dr expression were recorded. The modulatory effect of suramin on CD4 expression was not reversible over a 96-h culture period in its continued presence. However, on removal of suramin by extensive washing, recovery of CD4 expression was detected within 24 h. Suramin-induced modulation, but not PMA-induced modulation, could be partially inhibited by preincubation with tyrphostin (12 microM), a tyrosine kinase inhibitor. PMID:8419075

  18. Fusion proteins of HIV-1 envelope glycoprotein gp120 with CD4-induced antibodies showed enhanced binding to CD4 and CD4 binding site antibodies

    SciTech Connect

    Chen, Weizao; Feng, Yang; Wang, Yanping; Zhu, Zhongyu; Dimitrov, Dimiter S.

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer Some recombinant HIV-1 gp120s do not preserve their conformations on gp140s. Black-Right-Pointing-Pointer We hypothesize that CD4i antibodies could induce conformational changes in gp120. Black-Right-Pointing-Pointer CD4i antibodies enhance binding of CD4 and CD4bs antibodies to gp120. Black-Right-Pointing-Pointer CD4i antibody-gp120 fusion proteins could have potential as vaccine immunogens. -- Abstract: Development of successful AIDS vaccine immunogens continues to be a major challenge. One of the mechanisms by which HIV-1 evades antibody-mediated neutralizing responses is the remarkable conformational flexibility of its envelope glycoprotein (Env) gp120. Some recombinant gp120s do not preserve their conformations on gp140s and functional viral spikes, and exhibit decreased recognition by CD4 and neutralizing antibodies. CD4 binding induces conformational changes in gp120 leading to exposure of the coreceptor-binding site (CoRbs). In this study, we test our hypothesis that CD4-induced (CD4i) antibodies, which target the CoRbs, could also induce conformational changes in gp120 leading to better exposed conserved neutralizing antibody epitopes including the CD4-binding site (CD4bs). We found that a mixture of CD4i antibodies with gp120 only weakly enhanced CD4 binding. However, such interactions in single-chain fusion proteins resulted in gp120 conformations which bound to CD4 and CD4bs antibodies better than the original or mutagenically stabilized gp120s. Moreover, the two molecules in the fusion proteins synergized with each other in neutralizing HIV-1. Therefore, fusion proteins of gp120 with CD4i antibodies could have potential as components of HIV-1 vaccines and inhibitors of HIV-1 entry, and could be used as reagents to explore the conformational flexibility of gp120 and mechanisms of entry and immune evasion.

  19. Apoptotic depletion of CD4+ T cells in idiopathic CD4+ T lymphocytopenia.

    PubMed Central

    Laurence, J; Mitra, D; Steiner, M; Lynch, D H; Siegal, F P; Staiano-Coico, L

    1996-01-01

    Progressive loss of CD4+ T lymphocytes, accompanied by opportunistic infections characteristic of the acquired immune deficiency syndrome, ahs been reported in the absence of any known etiology. The pathogenesis of this syndrome, a subset of idiopathic CD4+ T lymphocytopenia (ICL), is uncertain. We report that CD4+ T cells from seven of eight ICL patients underwent accelerated programmed cell death, a process facilitated by T cell receptor cross-linking. Apoptosis was associated with enhanced expression of Fas and Fas ligand in unstimulated cell populations, and partially inhibited by soluble anti-Fas mAb. In addition, apoptosis was suppressed by aurintricarboxylic acid, an inhibitor of calcium-dependent endonucleases and proteases, in cells from four of seven patients, The in vivo significance of these findings was supported by three factors: the absence of accelerated apoptosis in persons with stable, physiologic CD4 lymphopenia without clinical immune deficiency; detection of serum antihistone H2B autoantibodies, one consequence of DNA fragmentation, in some patients; and its selectivity, with apoptosis limited to the CD4 population in some, and occurring among CD8+ T cells predominantly in those individuals with marked depletion of both CD4+ T lymphocytes linked to clinical immune suppression have evidence for accelerated T cell apoptosis in vitro that may be pathophysiologic and amenable to therapy with apoptosis inhibitors. PMID:8609222

  20. CD4-Induced Antibodies Promote Association of the HIV-1 Envelope Glycoprotein with CD4-Binding Site Antibodies

    PubMed Central

    Fellinger, Christoph H.; Prasad, Neha R.; Zhou, Amber S.; Kondur, Hema R.; Joshi, Vinita R.; Quinlan, Brian D.; Farzan, Michael

    2016-01-01

    ABSTRACT The HIV-1 envelope glycoprotein (Env) is a trimer of gp120/gp41 heterodimers that mediates viral entry. Env binds cellular CD4, an association which stabilizes a conformation favorable to its subsequent association with a coreceptor, typically CCR5 or CXCR4. The CD4- and coreceptor-binding sites serve as epitopes for two classes of HIV-1-neutralizing antibodies: CD4-binding site (CD4bs) and CD4-induced (CD4i) antibodies, respectively. Here we observed that, at a fixed total concentration, mixtures of the CD4i antibodies (E51 or 412d) and the CD4bs antibody VRC01 neutralized the HIV-1 isolates 89.6, ADA, SG3, and SA32 more efficiently than either antibody alone. We found that E51, and to a lesser extent 412d and 17b, promoted association of four CD4bs antibodies to the Env trimer but not to monomeric gp120. We further demonstrated that the binding of the sulfotyrosine-binding pocket by CCR5mim2-Ig was sufficient for promoting CD4bs antibody binding to Env. Interestingly, the relationship is not reciprocal: CD4bs antibodies were not as efficient as CD4-Ig at promoting E51 or 412d binding to Env trimer. Consistent with these observations, CD4-Ig, but none of the CD4bs antibodies tested, substantially increased HIV-1 infection of a CD4-negative, CCR5-positive cell line. We conclude that the ability of CD4i antibodies to promote VRC01 association with Env trimers accounts for the increase potency of VRC01 and CD4i antibody mixtures. Our data further suggest that potent CD4bs antibodies avoid inducing Env conformations that bind CD4i antibodies or CCR5. IMPORTANCE Potent HIV-1-neutralizing antibodies can prevent viral transmission and suppress an ongoing infection. Here we show that CD4-induced (CD4i) antibodies, which recognize the conserved coreceptor-binding site of the HIV-1 envelope glycoprotein (Env), can increase the association of Env with potent broadly neutralizing antibodies that recognize the CD4-binding site (CD4bs antibodies). We further show that

  1. Tuberculosis Therapy Modifies the Cytokine Profile, Maturation State, and Expression of Inhibitory Molecules on Mycobacterium tuberculosis-Specific CD4+ T-Cells

    PubMed Central

    Saharia, Kapil K.; Petrovas, Constantinos; Ferrando-Martinez, Sara; Leal, Manuel; Luque, Rafael; Ive, Prudence; Luetkemeyer, Anne; Havlir, Diane; Koup, Richard A.

    2016-01-01

    Background Little is known about the expression of inhibitory molecules cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed-death-1 (PD-1) on Mycobacterium tuberculosis (Mtb)-specific CD4 T-cells and how their expression is impacted by TB treatment. Methods Cryopreserved PBMCs from HIV-TB co-infected and TB mono-infected patients with untreated and treated tuberculosis (TB) disease were stimulated for six hours with PPD and stained. Using polychromatic flow cytometry, we characterized the differentiation state, cytokine profile, and inhibitory molecule expression on PPD-specific CD4 T-cells. Results In our HIV-TB co-infected cohort, TB treatment increased the proportion of PPD-specific CD4 T-cells co-producing IFN-γ+IL-2+TNF-α+ and IFN-γ+IL-2+ (p = 0.0004 and p = 0.0002, respectively) while decreasing the proportion of PPD-specific CD4 T-cells co-producing IFN-γ+MIP1-β+TNF-α+ and IFN-γ+MIP1-β+. The proportion of PPD-specific CD4 T-cells expressing an effector memory phenotype decreased (63.6% vs 51.6%, p = 0.0015) while the proportion expressing a central memory phenotype increased (7.8% vs. 21.7%, p = 0.001) following TB treatment. TB treatment reduced the proportion of PPD-specific CD4 T-cells expressing CTLA-4 (72.4% vs. 44.3%, p = 0.0005) and PD-1 (34.5% vs. 29.2%, p = 0.03). Similar trends were noted in our TB mono-infected cohort. Conclusion TB treatment alters the functional profile of Mtb-specific CD4 T-cells reflecting shifts towards a less differentiated maturational profile and decreases PD-1 and CTLA-4 expression. These could serve as markers of reduced mycobacterial burden. Further study is warranted. PMID:27367521

  2. Long-Lived CD4+IFN-γ+ T Cells rather than Short-Lived CD4+IFN-γ+IL-10+ T Cells Initiate Rapid IL-10 Production To Suppress Anamnestic T Cell Responses during Secondary Malaria Infection

    PubMed Central

    Villegas-Mendez, Ana; Inkson, Colette A.; Shaw, Tovah N.; Strangward, Patrick

    2016-01-01

    CD4+ T cells that produce IFN-γ are the source of host-protective IL-10 during primary infection with a number of different pathogens, including Plasmodium spp. The fate of these CD4+IFN-γ+IL-10+ T cells following clearance of primary infection and their subsequent influence on the course of repeated infections is, however, presently unknown. In this study, utilizing IFN-γ–yellow fluorescent protein (YFP) and IL-10–GFP dual reporter mice, we show that primary malaria infection–induced CD4+YFP+GFP+ T cells have limited memory potential, do not stably express IL-10, and are disproportionately lost from the Ag-experienced CD4+ T cell memory population during the maintenance phase postinfection. CD4+YFP+GFP+ T cells generally exhibited a short-lived effector rather than effector memory T cell phenotype postinfection and expressed high levels of PD-1, Lag-3, and TIGIT, indicative of cellular exhaustion. Consistently, the surviving CD4+YFP+GFP+ T cell–derived cells were unresponsive and failed to proliferate during the early phase of secondary infection. In contrast, CD4+YFP+GFP− T cell–derived cells expanded rapidly and upregulated IL-10 expression during secondary infection. Correspondingly, CD4+ T cells were the major producers within an accelerated and amplified IL-10 response during the early stage of secondary malaria infection. Notably, IL-10 exerted quantitatively stronger regulatory effects on innate and CD4+ T cell responses during primary and secondary infections, respectively. The results in this study significantly improve our understanding of the durability of IL-10–producing CD4+ T cells postinfection and provide information on how IL-10 may contribute to optimized parasite control and prevention of immune-mediated pathology during repeated malaria infections. PMID:27630165

  3. In situ depletion of CD4+ T cells in human skin by Zanolimumab.

    PubMed

    Villadsen, L S; Skov, L; Dam, T N; Dagnaes-Hansen, F; Rygaard, J; Schuurman, J; Parren, P W H I; van de Winkel, J G J; Baadsgaard, O

    2007-02-01

    CD4(+) T cells, in activated or malignant form, are involved in a number of diseases including inflammatory skin diseases such as psoriasis, and T cell lymphomas such as the majority of cutaneous T cell lymphomas (CTCL). Targeting CD4 with an antibody that inhibits and/or eliminates disease-driving T cells in situ may therefore be a useful approach in the treatment of inflammatory and malignant skin diseases. Depletion of CD4(+) T cells in intact inflamed human skin tissue by Zanolimumab, a fully human therapeutic monoclonal antibody (IgG1, kappa) against CD4, was studied in a human psoriasis xenograft mouse model. Zanolimumab treatment was shown to induce a significant reduction in the numbers of inflammatory mononuclear cells in upper dermis. This reduction in inflammatory mononuclear cells in situ was primarily due to a significant reduction in the numbers of skin-infiltrating CD4(+), but not CD8(+) CD3(+) T cells. The capacity of Zanolimumab to deplete the CD4(+) T cells in the skin may be of importance in diseases where CD4(+) T cells play a central role. Indeed, in a phase II clinical trial Zanolimumab has shown a dose-dependent clinical response in patients with CTCL and the antibody is currently in a phase III clinical trial for CTCL, a disease for which there is no safe and effective treatment available today.

  4. CD4⁺ follicular helper T cell infiltration predicts breast cancer survival.

    PubMed

    Gu-Trantien, Chunyan; Loi, Sherene; Garaud, Soizic; Equeter, Carole; Libin, Myriam; de Wind, Alexandre; Ravoet, Marie; Le Buanec, Hélène; Sibille, Catherine; Manfouo-Foutsop, Germain; Veys, Isabelle; Haibe-Kains, Benjamin; Singhal, Sandeep K; Michiels, Stefan; Rothé, Françoise; Salgado, Roberto; Duvillier, Hugues; Ignatiadis, Michail; Desmedt, Christine; Bron, Dominique; Larsimont, Denis; Piccart, Martine; Sotiriou, Christos; Willard-Gallo, Karen

    2013-07-01

    CD4⁺ T cells are critical regulators of immune responses, but their functional role in human breast cancer is relatively unknown. The goal of this study was to produce an image of CD4⁺ T cells infiltrating breast tumors using limited ex vivo manipulation to better understand the in vivo differences associated with patient prognosis. We performed comprehensive molecular profiling of infiltrating CD4⁺ T cells isolated from untreated invasive primary tumors and found that the infiltrating T cell subpopulations included follicular helper T (Tfh) cells, which have not previously been found in solid tumors, as well as Th1, Th2, and Th17 effector memory cells and Tregs. T cell signaling pathway alterations included a mixture of activation and suppression characterized by restricted cytokine/chemokine production, which inversely paralleled lymphoid infiltration levels and could be reproduced in activated donor CD4⁺ T cells treated with primary tumor supernatant. A comparison of extensively versus minimally infiltrated tumors showed that CXCL13-producing CD4⁺ Tfh cells distinguish extensive immune infiltrates, principally located in tertiary lymphoid structure germinal centers. An 8-gene Tfh signature, signifying organized antitumor immunity, robustly predicted survival or preoperative response to chemotherapy. Our identification of CD4⁺ Tfh cells in breast cancer suggests that they are an important immune element whose presence in the tumor is a prognostic factor.

  5. CD4+ follicular helper T cell infiltration predicts breast cancer survival

    PubMed Central

    Gu-Trantien, Chunyan; Loi, Sherene; Garaud, Soizic; Equeter, Carole; Libin, Myriam; de Wind, Alexandre; Ravoet, Marie; Le Buanec, Hélène; Sibille, Catherine; Manfouo-Foutsop, Germain; Veys, Isabelle; Haibe-Kains, Benjamin; Singhal, Sandeep K.; Michiels, Stefan; Rothé, Françoise; Salgado, Roberto; Duvillier, Hugues; Ignatiadis, Michail; Desmedt, Christine; Bron, Dominique; Larsimont, Denis; Piccart, Martine; Sotiriou, Christos; Willard-Gallo, Karen

    2013-01-01

    CD4+ T cells are critical regulators of immune responses, but their functional role in human breast cancer is relatively unknown. The goal of this study was to produce an image of CD4+ T cells infiltrating breast tumors using limited ex vivo manipulation to better understand the in vivo differences associated with patient prognosis. We performed comprehensive molecular profiling of infiltrating CD4+ T cells isolated from untreated invasive primary tumors and found that the infiltrating T cell subpopulations included follicular helper T (Tfh) cells, which have not previously been found in solid tumors, as well as Th1, Th2, and Th17 effector memory cells and Tregs. T cell signaling pathway alterations included a mixture of activation and suppression characterized by restricted cytokine/chemokine production, which inversely paralleled lymphoid infiltration levels and could be reproduced in activated donor CD4+ T cells treated with primary tumor supernatant. A comparison of extensively versus minimally infiltrated tumors showed that CXCL13-producing CD4+ Tfh cells distinguish extensive immune infiltrates, principally located in tertiary lymphoid structure germinal centers. An 8-gene Tfh signature, signifying organized antitumor immunity, robustly predicted survival or preoperative response to chemotherapy. Our identification of CD4+ Tfh cells in breast cancer suggests that they are an important immune element whose presence in the tumor is a prognostic factor. PMID:23778140

  6. Foxp3-dependent Transformation of Human Primary CD4+ T Lymphocytes by the Retroviral Protein Tax

    PubMed Central

    Chen, Li; Liu, Dan; Zhang, Yang; Zhang, Huan; Cheng, Hua

    2015-01-01

    The retroviral Tax proteins of human T cell leukemia virus type 1 and 2 (HTLV-1 and -2) are highly homologous viral transactivators. Both viral proteins can immortalize human primary CD4+ memory T cells, but when expressed alone they rarely transform T cells. In the present study, we found that the Tax proteins displayed a differential ability to immortalize human CD4+Foxp3+ T cells with characteristic expression of CTLA-4 and GITR. Because epidermal growth factor receptor (EGFR) was reportedly expressed and activated in a subset of CD4+Foxp3+ T cells, we introduced an activated EGFR into Tax-immortalized CD4+Foxp3+ T cells. We observed that these modified cells were grown independently of exogenous IL-2, correlating with a T cell transformation phenotype. In Tax-immortalized CD4+Foxp3- T cells, ectopic expression of Foxp3 was a prerequisite for Tax transformation of T cells. Accordingly, treatment of the transformed T cells with erlotinib, a selective inhibitor of EGFR, induced degradation of EGFR in lysosome, consequently causing T cell growth inhibition. Further, we identified autophagy as a crucial cellular survival pathway for the transformed T cells. Silencing key autophagy molecules including Beclin1, Atg5 and PI3 kinase class III (PI3KC3) resulted in drastic impairment of T cell growth. Our data, therefore, unveiled a previously unidentified role of Foxp3 in T cell transformation, providing a molecular basis for HTLV-1 transformation of CD4+Foxp3+ T cells. PMID:26381169

  7. Foxp3-dependent transformation of human primary CD4+ T lymphocytes by the retroviral protein tax.

    PubMed

    Chen, Li; Liu, Dan; Zhang, Yang; Zhang, Huan; Cheng, Hua

    2015-10-23

    The retroviral Tax proteins of human T cell leukemia virus type 1 and 2 (HTLV-1 and -2) are highly homologous viral transactivators. Both viral proteins can immortalize human primary CD4+ memory T cells, but when expressed alone they rarely transform T cells. In the present study, we found that the Tax proteins displayed a differential ability to immortalize human CD4+Foxp3+ T cells with characteristic expression of CTLA-4 and GITR. Because epidermal growth factor receptor (EGFR) was reportedly expressed and activated in a subset of CD4+Foxp3+ T cells, we introduced an activated EGFR into Tax-immortalized CD4+Foxp3+ T cells. We observed that these modified cells were grown independently of exogenous IL-2, correlating with a T cell transformation phenotype. In Tax-immortalized CD4+Foxp3- T cells, ectopic expression of Foxp3 was a prerequisite for Tax transformation of T cells. Accordingly, treatment of the transformed T cells with erlotinib, a selective inhibitor of EGFR, induced degradation of EGFR in lysosome, consequently causing T cell growth inhibition. Further, we identified autophagy as a crucial cellular survival pathway for the transformed T cells. Silencing key autophagy molecules including Beclin1, Atg5 and PI3 kinase class III (PI3KC3) resulted in drastic impairment of T cell growth. Our data, therefore, unveiled a previously unidentified role of Foxp3 in T cell transformation, providing a molecular basis for HTLV-1 transformation of CD4+Foxp3+ T cells.

  8. The Story of CD4+CD28− T Cells Revisited: Solved or Still Ongoing?

    PubMed Central

    Maly, Kathrin

    2015-01-01

    CD4+CD28− T cells are a unique type of proinflammatory T cells characterised by blockade of costimulatory CD28 receptor expression at the transcriptional level, which is still reversible by IL-12. In healthy individuals older than 65 years, these cells may accumulate to up to 50% of total CD4+ T lymphocytes as in many immune-mediated diseases, immunodeficiency, and specific infectious diseases. Here we focus on CD4+CD28− T cells in chronic immune-mediated diseases, summarizing various phenotypic and functional characteristics, which vary depending on the underlying disease, disease activity, and concurrent treatment. CD4+CD28− T cells present as effector/memory cells with increased replicative history and oligoclonality but reduced apoptosis. As an alternative costimulatory signal instead of CD28, not only natural killer cell receptors and Toll-like receptors, but also CD47, CTLA-4, OX40, and 4-1BB have to be considered. The proinflammatory and cytotoxic capacities of these cells indicate an involvement in progression and maintenance of chronic immune-mediated disease. So far it has been shown that treatment with TNF-α blockers, abatacept, statins, and polyclonal antilymphocyte globulins (ATG) mediates reduction of the CD4+CD28− T cell level. The clinical relevance of targeting CD4+CD28− T cells as a therapeutic option has not been examined so far. PMID:25834833

  9. Canine peripheral blood CD4(+)CD8(+) double-positive Tcell subpopulations exhibit distinct Tcell phenotypes and effector functions.

    PubMed

    Rothe, Kathrin; Bismarck, Doris; Büttner, Mathias; Alber, Gottfried; von Buttlar, Heiner

    2017-03-01

    Canine peripheral blood CD4(+)CD8α(+) double-positive (dp) Tcells represent a small population of T lymphocytes that are not only derived from single-positive (sp) CD4(+) but also from CD8(+) Tcells. Dp Tcells can be subdivided in three different subpopulations according to their expression levels of CD4 and CD8α, i.e. the CD4(dim)CD8α(bright), CD4(bright)CD8α(bright), and the CD4(bright)CD8α(dim) subsets. Previously we could show that total canine peripheral CD4(+)CD8α(+) dp Tcells have features of activated Tcells. Here we demonstrate that the individual dp Tcell subsets distinctly differ in their activation status and phenotype. Thus, among the dp Tcell subsets the CD4(dim)CD8α(bright) subpopulation has the lowest and the CD4(bright)CD8α(bright) subset the highest frequency of CD25(+) cells pointing to the CD4(bright)CD8α(bright) subset with the highest activation status. Consistent with that, analysis of CD44 vs. CD62L expression demonstrates that the CD4(bright)CD8α(bright) subset contains the highest frequencies of effector-memory Tcells (TEM). Upon in vitro stimulation, the CD4(bright)CD8α(bright) and CD4(dim)CD8α(bright) dp Tcell subsets show the highest frequencies of IFN-γ producing cells. Expression of granzyme B was found exclusively in the CD4(dim)CD8α(bright) dp Tcell subset indicating cytotoxic potential of this dp Tcell subset. Furthermore, T-bet expression was restricted to the CD4(dim)CD8α(bright) subset, while Foxp3(+) regulatory Tcells were detected in the CD4(bright)CD8α(dim) dp Tcell subset. In conclusion, canine dp Tcells are phenotypically and functionally heterogeneous consistent with the diverse characteristics of their single-positive CD4(+) and CD8(+) Tcell progenitors. The data provide the basis for future in vivo studies to elucidate the role of individual dp Tcell subsets in host defense and/or immune pathological diseases of dogs.

  10. Adoptive transfer of effector CD8+ T cells derived from central memory cells establishes persistent T cell memory in primates.

    PubMed

    Berger, Carolina; Jensen, Michael C; Lansdorp, Peter M; Gough, Mike; Elliott, Carole; Riddell, Stanley R

    2008-01-01

    The adoptive transfer of antigen-specific T cells that have been expanded ex vivo is being actively pursued to treat infections and malignancy in humans. The T cell populations that are available for adoptive immunotherapy include both effector memory and central memory cells, and these differ in phenotype, function, and homing. The efficacy of adoptive immunotherapy requires that transferred T cells persist in vivo, but identifying T cells that can reproducibly survive in vivo after they have been numerically expanded by in vitro culture has proven difficult. Here we show that in macaques, antigen-specific CD8(+) T cell clones derived from central memory T cells, but not effector memory T cells, persisted long-term in vivo, reacquired phenotypic and functional properties of memory T cells, and occupied memory T cell niches. These results demonstrate that clonally derived CD8+ T cells isolated from central memory T cells are distinct from those derived from effector memory T cells and retain an intrinsic capacity that enables them to survive after adoptive transfer and revert to the memory cell pool. These results could have significant implications for the selection of T cells to expand or to engineer for adoptive immunotherapy of human infections or malignancy.

  11. Interaction between the cytoplasmic domains of HIV-1 Vpu and CD4: role of Vpu residues involved in CD4 interaction and in vitro CD4 degradation.

    PubMed

    Margottin, F; Benichou, S; Durand, H; Richard, V; Liu, L X; Gomas, E; Benarous, R

    1996-09-15

    The Vpu and CD4 cytoplasmic domains were found, by using a two-hybrid assay in yeast, to interact in the absence of their membrane anchor domains. Studies on several deletion and point mutants revealed that the overall structure of the Vpu cytoplasmic domain is required for this interaction. The Vpu amino acid residues involved in the interaction with CD4 were identified. Deletion of the C-terminal residues of Vpu, required for CD4 degradation, as well as the double mutation on the casein kinase II phosphorylation sites S52N-S56N, also involved in CD4 degradation, resulted in the loss of interaction with CD4 and in the inability to induce CD4 degradation. These results suggest that the ability of Vpu to mediate the degradation of CD4 is linked to its capacity to physically interact with CD4. However, additional mutagenesis on the S52 site revealed that the interaction between the cytoplasmic domains of Vpu and CD4 is not sufficient for in vitro Vpu-mediated CD4 degradation.

  12. Identification of a CD4 T cell epitope that is globally conserved among outer membrane proteins (OMPs) OMP7, OMP8, and OMP9 of anaplasma marginale strains and with OMP7 from the A. marginale subsp. centrale vaccine strain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Within the protective outer membrane fraction of Anaplasma marginale, several vaccine candidates have emerged, including a family of outer membrane proteins (OMPs) 7-9, which share sequence identity with each other and with the single protein OMP7 in the vaccine strain A. marginale subsp. centrale. ...

  13. Quantification of cells with specific phenotypes I: determination of CD4+ cell count per microliter in reconstituted lyophilized human PBMC prelabeled with anti-CD4 FITC antibody.

    PubMed

    Stebbings, Richard; Wang, Lili; Sutherland, Janet; Kammel, Martin; Gaigalas, Adolfas K; John, Manuela; Roemer, Bodo; Kuhne, Maren; Schneider, Rudolf J; Braun, Michael; Engel, Andrea; Dikshit, Dinesh K; Abbasi, Fatima; Marti, Gerald E; Sassi, Maria Paola; Revel, Laura; Kim, Sook-Kyung; Baradez, Marc-Olivier; Lekishvili, Tamara; Marshall, Damian; Whitby, Liam; Jing, Wang; Ost, Volker; Vonsky, Maxim; Neukammer, Jörg

    2015-03-01

    A surface-labeled lyophilized lymphocyte (sLL) preparation has been developed using human peripheral blood mononuclear cells prelabeled with a fluorescein isothiocyanate conjugated anti-CD4 monoclonal antibody. The sLL preparation is intended to be used as a reference material for CD4+ cell counting including the development of higher order reference measurement procedures and has been evaluated in the pilot study CCQM-P102. This study was conducted across 16 laboratories from eight countries to assess the ability of participants to quantify the CD4+ cell count of this reference material and to document cross-laboratory variability plus associated measurement uncertainties. Twelve different flow cytometer platforms were evaluated using a standard protocol that included calibration beads used to obtain quantitative measurements of CD4+ T cell counts. There was good overall cross-platform and counting method agreement with a grand mean of the laboratory calculated means of (301.7 ± 4.9) μL(-1) CD4+ cells. Excluding outliers, greater than 90% of participant data agreed within ±15%. A major contribution to variation of sLL CD4+ cell counts was tube to tube variation of the calibration beads, amounting to an uncertainty of 3.6%. Variation due to preparative steps equated to an uncertainty of 2.6%. There was no reduction in variability when data files were centrally reanalyzed. Remaining variation was attributed to instrument specific differences. CD4+ cell counts obtained in CCQM-P102 are in excellent agreement and show the robustness of both the measurements and the data analysis and hence the suitability of sLL as a reference material for interlaboratory comparisons and external quality assessment.

  14. Quantification of Cells with Specific Phenotypes I: Determination of CD4+ Cell Count Per Microliter in Reconstituted Lyophilized Human PBMC Prelabeled with Anti-CD4 FITC Antibody

    PubMed Central

    Stebbings, Richard; Wang, Lili; Sutherland, Janet; Kammel, Martin; Gaigalas, Adolfas K; John, Manuela; Roemer, Bodo; Kuhne, Maren; Schneider, Rudolf J; Braun, Michael; Engel, Andrea; Dikshit, Dinesh K; Abbasi, Fatima; Marti, Gerald E; Paola Sassi, Maria; Revel, Laura; Kim, Sook-Kyung; Baradez, Marc-Olivier; Lekishvili, Tamara; Marshall, Damian; Whitby, Liam; Jing, Wang; Ost, Volker; Vonsky, Maxim; Neukammer, Jörg

    2015-01-01

    A surface-labeled lyophilized lymphocyte (sLL) preparation has been developed using human peripheral blood mononuclear cells prelabeled with a fluorescein isothiocyanate conjugated anti-CD4 monoclonal antibody. The sLL preparation is intended to be used as a reference material for CD4+ cell counting including the development of higher order reference measurement procedures and has been evaluated in the pilot study CCQM-P102. This study was conducted across 16 laboratories from eight countries to assess the ability of participants to quantify the CD4+ cell count of this reference material and to document cross-laboratory variability plus associated measurement uncertainties. Twelve different flow cytometer platforms were evaluated using a standard protocol that included calibration beads used to obtain quantitative measurements of CD4+ T cell counts. There was good overall cross-platform and counting method agreement with a grand mean of the laboratory calculated means of (301.7 ± 4.9) μL−1 CD4+ cells. Excluding outliers, greater than 90% of participant data agreed within ±15%. A major contribution to variation of sLL CD4+ cell counts was tube to tube variation of the calibration beads, amounting to an uncertainty of 3.6%. Variation due to preparative steps equated to an uncertainty of 2.6%. There was no reduction in variability when data files were centrally reanalyzed. Remaining variation was attributed to instrument specific differences. CD4+ cell counts obtained in CCQM-P102 are in excellent agreement and show the robustness of both the measurements and the data analysis and hence the suitability of sLL as a reference material for interlaboratory comparisons and external quality assessment. © 2015 The Authors. Published by Wiley Periodicals, Inc. PMID:25655255

  15. Homeostatically Maintained Resting Naive CD4+ T Cells Resist Latent HIV Reactivation

    PubMed Central

    Tsunetsugu-Yokota, Yasuko; Kobayahi-Ishihara, Mie; Wada, Yamato; Terahara, Kazutaka; Takeyama, Haruko; Kawana-Tachikawa, Ai; Tokunaga, Kenzo; Yamagishi, Makoto; Martinez, Javier P.; Meyerhans, Andreas

    2016-01-01

    Homeostatic proliferation (HSP) is a major mechanism by which long-lived naïve and memory CD4+ T cells are maintained in vivo and suggested to contribute to the persistence of the latent HIV-1 reservoir. However, while many in vitro latency models rely on CD4+ T cells that were initially differentiated via T-cell receptor (TCR) stimulation into memory/effector cells, latent infection of naïve resting CD4+ T cells maintained under HSP conditions has not been fully addressed. Here, we describe an in vitro HSP culture system utilizing the cytokines IL-7 and IL-15 that allows studying latency in naïve resting CD4+ T cells. CD4+ T cells isolated from several healthy donors were infected with HIV pseudotypes expressing GFP and cultured under HSP conditions or TCR conditions as control. Cell proliferation, phenotype, and GFP expression were analyzed by flow cytometry. RNA expression was quantified by qRT-PCR. Under HSP culture conditions, latently HIV-1 infected naïve cells are in part maintained in the non-dividing (= resting) state. Although a few HIV-1 provirus+ cells were present in these resting GFP negative cells, the estimated level of GFP transcripts per infected cell seems to indicate a block at the post-transcriptional level. Interestingly, neither TCR nor the prototypic HDAC inhibitor SAHA were able to reactivate HIV-1 provirus from these cells. This lack of reactivation was not due to methylation of the HIV LTR. These results point to a mechanism of HIV control in HSP-cultured resting naïve CD4+ T cells that may be distinct from that in TCR-stimulated memory/effector T cells. PMID:27990142

  16. CD4 T-Cell Subsets in Malaria: TH1/TH2 Revisited

    PubMed Central

    Perez-Mazliah, Damian; Langhorne, Jean

    2015-01-01

    CD4+ T-cells have been shown to play a central role in immune control of infection with Plasmodium parasites. At the erythrocytic stage of infection, IFN-γ production by CD4+ T-cells and CD4+ T-cell help for the B-cell response are required for control and elimination of infected red blood cells. CD4+ T-cells are also important for controlling Plasmodium pre-erythrocytic stages through the activation of parasite-specific CD8+ T-cells. However, excessive inflammatory responses triggered by the infection have been shown to drive pathology. Early classical experiments demonstrated a biphasic CD4+ T-cell response against erythrocytic stages in mice, in which T helper (Th)1 and antibody-helper CD4+ T-cells appear sequentially during a primary infection. While IFN-γ-producing Th1 cells do play a role in controlling acute infections, and they contribute to acute erythrocytic-stage pathology, it became apparent that a classical Th2 response producing IL-4 is not a critical feature of the CD4+ T-cell response during the chronic phase of infection. Rather, effective CD4+ T-cell help for B-cells, which can occur in the absence of IL-4, is required to control chronic parasitemia. IL-10, important to counterbalance inflammation and associated with protection from inflammatory-mediated severe malaria in both humans and experimental models, was originally considered be produced by CD4+ Th2 cells during infection. We review the interpretations of CD4+ T-cell responses during Plasmodium infection, proposed under the original Th1/Th2 paradigm, in light of more recent advances, including the identification of multifunctional T-cells such as Th1 cells co-expressing IFN-γ and IL-10, the identification of follicular helper T-cells (Tfh) as the predominant CD4+ T helper subset for B-cells, and the recognition of inherent plasticity in the fates of different CD4+ T-cells. PMID:25628621

  17. Antibody raised against soluble CD4-rgp120 complex recognizes the CD4 moiety and blocks membrane fusion without inhibiting CD4-gp120 binding

    PubMed Central

    1990-01-01

    We studied the humoral response of mice immunized with soluble CD4- rgp120 complex, testing polyclonal and monoclonal antibodies (mAbs) with the aim of identifying molecular changes that take place after the first interaction between human immunodeficiency virus and the cell surface. The antisera had a paradoxically high syncytia-blocking titer associated with anti-CD4 specificity, while their capacity to inhibit CD4-gp120 binding was relatively modest. One of the mAbs produced from these responders blocks syncytia formation but does not inhibit CD4 interaction with gp120. Apparently, this mAb interacts with the CD4 moiety of CD4-gp120 complex and prevents a post-binding event necessary for membrane fusion and viral infection. PMID:2212945

  18. Casp8p41: The Protean Mediator of Death in CD4 T-cells that Replicate HIV

    PubMed Central

    Sampath, Rahul; Cummins, Nathan W.; Badley, Andrew D.

    2016-01-01

    HIV cure is now the focus of intense research after Timothy Ray Brown (the Berlin patient) set the precedent of being the first and only person cured. A major barrier to achieving this goal on a meaningful scale is an elimination of the latent reservoir, which is thought to comprise CD4-positive cells that harbor integrated, replication-competent HIV provirus. These cells do not express viral proteins, are indistinguishable from uninfected CD4 cells, and are thought to be responsible for HIV viral rebound—that occurs within weeks of combination anti retroviral therapy (cART) interruption. Modalities to engineer transcriptional stimulation (reactivation) of this dormant integrated HIV provirus, leading to expression of cytotoxic viral proteins, are thought to be a specific way to eradicate the latently infected CD4 pool and are becoming increasingly relevant in the era of HIV cure. HIV protease is one such protein produced after HIV reactivation that cleaves procaspase-8 to generate a novel protein Casp8p41. Casp8p41 then binds to the BH3 domain of BAK, leading to BAK oligomerization, mitochondrial depolarization, and apoptosis. In central memory T cells (TCMs) from HIV-infected patients, an elevated Bcl-2/procaspase-8 ratio was observed, and Casp8p41 binding to Bcl-2 was associated with a lack of reactivation-induced cell death. This was reversed by priming cells with a specific Bcl-2 antagonist prior to reactivation, resulting in increased cell death and decreased HIV DNA in a Casp8p41-dependent pathway. This review describes the biology, clinical relevance, and implications of Casp8p41 for a potential cure. PMID:27721655

  19. MHC class II tetramer analyses in AE37-vaccinated prostate cancer patients reveal vaccine-specific polyfunctional and long-lasting CD4(+) T-cells.

    PubMed

    Anastasopoulou, Eleftheria A; Voutsas, Ioannis F; Papamichail, Michael; Baxevanis, Constantin N; Perez, Sonia A

    2016-07-01

    Realizing the basis for generating long-lasting clinical responses in cancer patients after therapeutic vaccinations provides the means to further ameliorate clinical efficacy. Peptide cancer vaccines stimulating CD4(+) T helper cells are often promising for inducing immunological memory and persistent CD8(+) cytotoxic T cell responses. Recent reports from our clinical trial with the AE37 vaccine, which is a HER2 hybrid polypeptide, documented its efficacy to induce CD4(+) T cell immunity, which was associated with clinical improvements preferentially among HLA-DRB1*11(+) prostate cancer patients. Here, we performed in-depth investigation of the CD4(+) T cell response against the AE37 vaccine. We used the DR11/AE37 tetramer in combination with multicolor flow cytometry to identify and characterize AE37-specific CD4(+) T cells regarding memory and Tregs phenotype in HLA-DRB1*11(+) vaccinated patients. To verify vaccine-specific immunological memory in vivo, we also assessed AE37-specific CD4(+) T cells in defined CD4(+) memory subsets by cell sorting. Finally, vaccine-induced AE37-specific CD4(+) T cells were assessed regarding their functional profile. AE37-specific memory CD4(+) T cells could be detected in peptide-stimulated cultures from prostate cancer patients following vaccination even 4 y post-vaccination. The vast majority of vaccine-induced AE37-specific CD4(+) T cells exhibited a multifunctional, mostly Th1 cytokine signature, with the potential of granzyme B production. In contrast, we found relatively low frequencies of Tregs among AE37-specific CD4(+) T cells. This is the first report on the identification of vaccine-induced HER2-specific multifunctional long-lasting CD4(+) T cells in vaccinated prostate cancer patients.

  20. Naf1 Regulates HIV-1 Latency by Suppressing Viral Promoter-Driven Gene Expression in Primary CD4+ T Cells.

    PubMed

    Li, Chuan; Wang, Hai-Bo; Kuang, Wen-Dong; Ren, Xiao-Xin; Song, Shu-Ting; Zhu, Huan-Zhang; Li, Qiang; Xu, Li-Ran; Guo, Hui-Jun; Wu, Li; Wang, Jian-Hua

    2017-01-01

    HIV-1 latency is characterized by reversible silencing of viral transcription driven by the long terminal repeat (LTR) promoter of HIV-1. Cellular and viral factors regulating LTR activity contribute to HIV-1 latency, and certain repressive cellular factors modulate viral transcription silencing. Nef-associated factor 1 (Naf1) is a host nucleocytoplasmic shuttling protein that regulates multiple cellular signaling pathways and HIV-1 production. We recently reported that nuclear Naf1 promoted nuclear export of unspliced HIV-1 gag mRNA, leading to increased Gag production. Here we demonstrate new functions of Naf1 in regulating HIV-1 persistence. We found that Naf1 contributes to the maintenance of HIV-1 latency by inhibiting LTR-driven HIV-1 gene transcription in a nuclear factor kappa B-dependent manner. Interestingly, Naf1 knockdown significantly enhanced viral reactivation in both latently HIV-1-infected Jurkat T cells and primary central memory CD4(+) T cells. Furthermore, Naf1 knockdown in resting CD4(+) T cells from HIV-1-infected individuals treated with antiretroviral therapy significantly increased viral reactivation upon T-cell activation, suggesting an important role of Naf1 in modulating HIV-1 latency in vivo Our findings provide new insights for a better understanding of HIV-1 latency and suggest that inhibition of Naf1 activity to activate latently HIV-1-infected cells may be a potential therapeutic strategy.

  1. CD4-binding site alterations in CCR5-using HIV-1 envelopes influencing gp120-CD4 interactions and fusogenicity

    SciTech Connect

    Sterjovski, Jasminka; Churchill, Melissa J.; Roche, Michael; Ellett, Anne; Farrugia, William; Wesselingh, Steven L.; Cunningham, Anthony L.; Ramsland, Paul A.; Gorry, Paul R.

    2011-02-20

    CD4-binding site (CD4bs) alterations in gp120 contribute to different pathophysiological phenotypes of CCR5-using (R5) HIV-1 strains, but the potential structural basis is unknown. Here, we characterized functionally diverse R5 envelope (Env) clones (n = 16) to elucidate potential structural alterations within the gp120 CD4bs that influence Env function. Initially, we showed that the magnitude of gp120-CD4-binding correlates with increased fusogenicity and reduced CD4 dependence. Analysis of three-dimensional gp120 structural models revealed two CD4bs variants, D279 and N362, that were associated with reduced CD4 dependence. Further structural analysis showed that a wider aperture of the predicted CD4bs cavity, as constrained by the inner-most atoms at the gp120 V1V2 stem and the V5 loop, was associated with amino acid alterations within V5 and correlated with increased gp120-CD4 binding and increased fusogenicity. Our results provide evidence that the gp120 V5 loop may alter CD4bs conformation and contribute to increased gp120-CD4 interactions and Env fusogenicity.

  2. CD4 aptamer-RORγt shRNA chimera inhibits IL-17 synthesis by human CD4(+) T cells.

    PubMed

    Song, Pingfang; Chou, Yuan K; Zhang, Xiaowei; Meza-Romero, Roberto; Yomogida, Kentaro; Benedek, Gil; Chu, Cong-Qiu

    2014-10-03

    Cell type specific delivery of RNAi to T cells has remained to be a challenge. Here we describe an aptamer mediated delivery of shRNA to CD4(+) T cells targeting RORγt to suppress Th17 cells. A cDNA encoding CD4 aptamer and RORγt shRNA was constructed and the chimeric CD4 aptamer-RORγt shRNA (CD4-AshR-RORγt) was generated using in vitro T7 RNA transcription. 2'-F-dCTP and 2'-F-dUTP were incorporated into CD4-AshR-RORγt for RNase resistance. CD4-AshR-RORγt was specifically uptaken by CD4(+) Karpas 299 cells and primary human CD4(+) T cells. The RORγt shRNA moiety of CD4-AshR-RORγt chimera was cleaved and released by Dicer. Furthermore, CD4-AshR-RORγt suppressed RORγt gene expression in Karpas 299 cells and CD4(+) T cells and consequently inhibited Th17 cell differentiation and IL-17 production. These results demonstrate that aptamer-facilitated cell specific delivery of shRNA represents a novel approach for efficient RNAi delivery and is potentially to be developed for therapeutics targeting specific T cells subtypes.

  3. Virions of primary human immunodeficiency virus type 1 isolates resistant to soluble CD4 (sCD4) neutralization differ in sCD4 binding and glycoprotein gp120 retention from sCD4-sensitive isolates.

    PubMed Central

    Moore, J P; McKeating, J A; Huang, Y X; Ashkenazi, A; Ho, D D

    1992-01-01

    Primary isolates of human immunodeficiency virus type 1 (HIV-1) are much less sensitive to neutralization by soluble CD4 (sCD4) and sCD4-immunoglobulin (Ig) chimeras (CD4-IgG) than are HIV-1 strains adapted to growth in cell culture. We demonstrated that there are significant reductions (10- to 30-fold) in the binding of sCD4 and CD4-IgG to intact virions of five primary isolates compared with sCD4-sensitive, cell culture-adapted isolates RF and IIIB. However, soluble envelope glycoproteins (gp120) derived from the primary isolate virions, directly by detergent solubilization or indirectly by recombinant DNA technology, differed in affinity from RF and IIIB gp120 by only one- to threefold. The reduced binding of sCD4 to these primary isolate virions must therefore be a consequence of the tertiary or quaternary structure of the envelope glycoproteins in their native, oligomeric form on the viral surface. In addition, the rate and extent of sCD4-induced gp120 shedding from these primary isolates was lower than that from RF. We suggest that reduced sCD4 binding and increased gp120 retention together account for the relative resistance of these primary isolates to neutralization by sCD4 and CD4-IgG and that virions of different HIV-1 isolates vary both in the mechanism of sCD4 binding and in subsequent conformational changes in their envelope glycoproteins. PMID:1727487

  4. CD4+ T-Cell-Independent Secondary Immune Responses to Pneumocystis Pneumonia

    PubMed Central

    de la Rua, Nicholas M.; Samuelson, Derrick R.; Charles, Tysheena P.; Welsh, David A.; Shellito, Judd E.

    2016-01-01

    Pneumocystis pneumonia is a major cause of morbidity and mortality among immunocompromised patients, especially in the context of HIV/AIDS. In the murine model of Pneumocystis pneumonia, CD4+ T-cells are required for clearance of a primary infection of Pneumocystis, but not the memory recall response. We hypothesized that the memory recall response in the absence of CD4+ T-cells is mediated by a robust memory humoral response, CD8+ T-cells, and IgG-mediated phagocytosis by alveolar macrophages. To investigate the role of CD8+ T-cells and alveolar macrophages in the immune memory response to Pneumocystis, mice previously challenged with Pneumocystis were depleted of CD8+ T-cells or alveolar macrophages prior to re-infection. Mice depleted of CD4+ T-cells prior to secondary challenge cleared Pneumocystis infection within 48 h identical to immunocompetent mice during a secondary memory recall response. However, loss of CD8+ T-cells or macrophages prior to the memory recall response significantly impaired Pneumocystis clearance. Specifically, mice depleted of CD8+ T-cells or alveolar macrophages had significantly higher fungal burden in the lungs. Furthermore, loss of alveolar macrophages significantly skewed the lung CD8+ T-cell response toward a terminally differentiated effector memory population and increased the percentage of IFN-γ+ CD8+ T-cells. Finally, Pneumocystis-infected animals produced significantly more bone marrow plasma cells and Pneumocystis-specific IgG significantly increased macrophage-mediated killing of Pneumocystis in vitro. These data suggest that secondary immune memory responses to Pneumocystis are mediated, in part, by CD8+ T-cells, alveolar macrophages, and the production of Pneumocystis-specific IgG. PMID:27242785

  5. CD4(+) T-Cell-Independent Secondary Immune Responses to Pneumocystis Pneumonia.

    PubMed

    de la Rua, Nicholas M; Samuelson, Derrick R; Charles, Tysheena P; Welsh, David A; Shellito, Judd E

    2016-01-01

    Pneumocystis pneumonia is a major cause of morbidity and mortality among immunocompromised patients, especially in the context of HIV/AIDS. In the murine model of Pneumocystis pneumonia, CD4(+) T-cells are required for clearance of a primary infection of Pneumocystis, but not the memory recall response. We hypothesized that the memory recall response in the absence of CD4(+) T-cells is mediated by a robust memory humoral response, CD8(+) T-cells, and IgG-mediated phagocytosis by alveolar macrophages. To investigate the role of CD8(+) T-cells and alveolar macrophages in the immune memory response to Pneumocystis, mice previously challenged with Pneumocystis were depleted of CD8(+) T-cells or alveolar macrophages prior to re-infection. Mice depleted of CD4(+) T-cells prior to secondary challenge cleared Pneumocystis infection within 48 h identical to immunocompetent mice during a secondary memory recall response. However, loss of CD8(+) T-cells or macrophages prior to the memory recall response significantly impaired Pneumocystis clearance. Specifically, mice depleted of CD8(+) T-cells or alveolar macrophages had significantly higher fungal burden in the lungs. Furthermore, loss of alveolar macrophages significantly skewed the lung CD8(+) T-cell response toward a terminally differentiated effector memory population and increased the percentage of IFN-γ(+) CD8(+) T-cells. Finally, Pneumocystis-infected animals produced significantly more bone marrow plasma cells and Pneumocystis-specific IgG significantly increased macrophage-mediated killing of Pneumocystis in vitro. These data suggest that secondary immune memory responses to Pneumocystis are mediated, in part, by CD8(+) T-cells, alveolar macrophages, and the production of Pneumocystis-specific IgG.

  6. Dynamic Modulation of Expression of Lentiviral Restriction Factors in Primary CD4(+) T Cells following Simian Immunodeficiency Virus Infection.

    PubMed

    Rahmberg, Andrew R; Rajakumar, Premeela A; Billingsley, James M; Johnson, R Paul

    2017-04-01

    Although multiple restriction factors have been shown to inhibit HIV/SIV replication, little is known about their expression in vivo Expression of 45 confirmed and putative HIV/SIV restriction factors was analyzed in CD4(+) T cells from peripheral blood and the jejunum in rhesus macaques, revealing distinct expression patterns in naive and memory subsets. In both peripheral blood and the jejunum, memory CD4(+) T cells expressed higher levels of multiple restriction factors compared to naive cells. However, relative to their expression in peripheral blood CD4(+) T cells, jejunal CCR5(+) CD4(+) T cells exhibited significantly lower expression of multiple restriction factors, including APOBEC3G, MX2, and TRIM25, which may contribute to the exquisite susceptibility of these cells to SIV infection. In vitro stimulation with anti-CD3/CD28 antibodies or type I interferon resulted in upregulation of distinct subsets of multiple restriction factors. After infection of rhesus macaques with SIVmac239, the expression of most confirmed and putative restriction factors substantially increased in all CD4(+) T cell memory subsets at the peak of acute infection. Jejunal CCR5(+) CD4(+) T cells exhibited the highest levels of SIV RNA, corresponding to the lower restriction factor expression in this subset relative to peripheral blood prior to infection. These results illustrate the dynamic modulation of confirmed and putative restriction factor expression by memory differentiation, stimulation, tissue microenvironment and SIV infection and suggest that differential expression of restriction factors may play a key role in modulating the susceptibility of different populations of CD4(+) T cells to lentiviral infection.IMPORTANCE Restriction factors are genes that have evolved to provide intrinsic defense against viruses. HIV and simian immunodeficiency virus (SIV) target CD4(+) T cells. The baseline level of expression in vivo and degree to which expression of restriction factors is

  7. The effect of CD4 receptor downregulation and its downstream signaling molecules on HIV-1 latency

    SciTech Connect

    Kim, Kyung-Chang; Kim, Hyeon Guk; Roh, Tae-Young; Park, Jihwan; Jung, Kyung-Min; Lee, Joo-Shil; Choi, Sang-Yun; Kim, Sung Soon; Choi, Byeong-Sun

    2011-01-14

    Research highlights: {yields} CD4 receptors were downregulated on the surface of HIV-1 latently infected cells. {yields} CD4 downstream signaling molecules were suppressed in HIV-1 latently infected cells. {yields} HIV-1 progeny can be reactivated by induction of T-cell activation signal molecules. {yields} H3K4me3 and H3K9ac were highly enriched in CD4 downstream signaling molecules. {yields} HIV-1 latency can be maintained by the reduction of downstream signaling molecules. -- Abstract: HIV-1 can establish a latent infection in memory CD4 + T cells to evade the host immune response. CD4 molecules can act not only as the HIV-1 receptor for entry but also as the trigger in an intracellular signaling cascade for T-cell activation and proliferation via protein tyrosine kinases. Novel chronic HIV-1-infected A3.01-derived (NCHA) cells were used to examine the involvement of CD4 downstream signaling in HIV-1 latency. CD4 receptors in NCHA cells were dramatically downregulated on its surface but were slightly decreased in whole-cell lysates. The expression levels of CD4 downstream signaling molecules, including P56{sup Lck}, ZAP-70, LAT, and c-Jun, were sharply decreased in NCHA cells. The lowered histone modifications of H3K4me3 and H3K9ac correlated with the downregulation of P56{sup Lck}, ZAP-70, and LAT in NCHA cells. AP-1 binding activity was also reduced in NCHA cells. LAT and c-Jun suppressed in NCHA cells were highly induced after PMA treatment. In epigenetic analysis, other signal transduction molecules which are associated with active and/or latent HIV-1 infection showed normal states in HIV-1 latently infected cells compared to A3.01 cells. In conclusion, we demonstrated that the HIV-1 latent state is sustained by the reduction of downstream signaling molecules via the downregulation of CD4 and the attenuated activity of transcription factor as AP-1. The HIV-1 latency model via T-cell deactivation may provide some clues for the development of the new

  8. Immunologic memory in cutaneous leishmaniasis.

    PubMed

    Scott, Phillip

    2005-12-01

    Leishmania major infections induce solid immunity to reinfection. Experimental studies in mice indicate that the CD4+ T cells responsible for this immunity include two populations: parasite-dependent T effector cells and parasite-independent central memory T (Tcm) cells. While there currently is no vaccine for leishmaniasis, the existence of a long-lived population of Tcm cells that does not require the continued presence of live parasites suggests that a vaccine that expands these cells might be efficacious.

  9. HIV-1 CD4-induced (CD4i) gp120 epitope vaccines promote B and T-cell responses that contribute to reduced viral loads in rhesus macaques.

    PubMed

    Thomas, Michael A; Tuero, Iskra; Demberg, Thorsten; Vargas-Inchaustegui, Diego A; Musich, Thomas; Xiao, Peng; Venzon, David; LaBranche, Celia; Montefiori, David C; DiPasquale, Janet; Reed, Steven G; DeVico, Anthony; Fouts, Timothy; Lewis, George K; Gallo, Robert C; Robert-Guroff, Marjorie

    2014-12-01

    To target the HIV CD4i envelope epitope, we primed rhesus macaques with replicating Ad-rhFLSC (HIV-1BaLgp120 linked to macaque CD4 D1 and D2), with or without Ad-SIVgag and Ad-SIVnef. Macaques were boosted with rhFLSC protein. Memory T-cells in PBMC, bronchoalveolar lavage and rectal tissue, antibodies with neutralizing and ADCC activity, and Env-specific secretory IgA in rectal secretions were elicited. Although protective neutralizing antibody levels were induced, SHIVSF162P4 acquisition following rectal challenge was not prevented. Rapid declines in serum ADCC activity, Env-specific memory B cells in PBMC and bone marrow, and systemic and mucosal memory T cells were observed immediately post-challenge together with delayed anamnestic responses. Innate immune signaling resulting from persisting Ad replication and the TLR-4 booster adjuvant may have been in conflict and reoriented adaptive immunity. A different adjuvant paired with replicating Ad, or a longer post-prime interval allowing vector clearance before boosting might foster persistent T- and B-cell memory.

  10. Antigen affinity and antigen dose exert distinct influences on CD4 T-cell differentiation.

    PubMed

    Keck, Simone; Schmaler, Mathias; Ganter, Stefan; Wyss, Lena; Oberle, Susanne; Huseby, Eric S; Zehn, Dietmar; King, Carolyn G

    2014-10-14

    Cumulative T-cell receptor signal strength and ensuing T-cell responses are affected by both antigen affinity and antigen dose. Here we examined the distinct contributions of these parameters to CD4 T-cell differentiation during infection. We found that high antigen affinity positively correlates with T helper (Th)1 differentiation at both high and low doses of antigen. In contrast, follicular helper T cell (TFH) effectors are generated after priming with high, intermediate, and low affinity ligand. Unexpectedly, memory T cells generated after priming with very low affinity antigen remain impaired in their ability to generate secondary Th1 effectors, despite being recalled with high affinity antigen. These data challenge the view that only strongly stimulated CD4 T cells are capable of differentiating into the TFH and memory T-cell compartments and reveal that differential strength of stimulation during primary T-cell activation imprints unique and long lasting T-cell differentiation programs.

  11. Range of CD4-Bound Conformations of HIV-1 gp120, as Defined Using Conditional CD4-Induced Antibodies

    PubMed Central

    Kaplan, Gilad; Roitburd-Berman, Anna; Lewis, George K.

    2016-01-01

    ABSTRACT The HIV envelope binds cellular CD4 and undergoes a range of conformational changes that lead to membrane fusion and delivery of the viral nucleocapsid into the cellular cytoplasm. This binding to CD4 reveals cryptic and highly conserved epitopes, the molecular nature of which is still not fully understood. The atomic structures of CD4 complexed with gp120 core molecules (a form of gp120 in which the V1, V2, and V3 loops and N and C termini have been truncated) have indicated that a hallmark feature of the CD4-bound conformation is the bridging sheet minidomain. Variations in the orientation of the bridging sheet hairpins have been revealed when CD4-liganded gp120 was compared to CD4-unliganded trimeric envelope structures. Hence, there appears to be a number of conformational transitions possible in HIV-1 monomeric gp120 that are affected by CD4 binding. The spectrum of CD4-bound conformations has been interrogated in this study by using a well-characterized panel of conditional, CD4-induced (CD4i) monoclonal antibodies (MAbs) that bind HIV-1 gp120 and its mutations under various conditions. Two distinct CD4i epitopes of the outer domain were studied: the first comprises the bridging sheet, while the second contains elements of the V2 loop. Furthermore, we show that the unliganded extended monomeric core of gp120 (coree) assumes an intermediate CD4i conformation in solution that further undergoes detectable rearrangements upon association with CD4. These discoveries impact both accepted paradigms concerning gp120 structure and the field of HIV immunogen design. IMPORTANCE Elucidation of the conformational transitions that the HIV-1 envelope protein undergoes during the course of entry into CD4+ cells is fundamental to our understanding of HIV biology. The binding of CD4 triggers a range of gp120 structural rearrangements that could present targets for future drug design and development of preventive vaccines. Here we have systematically interrogated and

  12. Computational modeling of heterogeneity and function of CD4+ T cells

    PubMed Central

    Carbo, Adria; Hontecillas, Raquel; Andrew, Tricity; Eden, Kristin; Mei, Yongguo; Hoops, Stefan; Bassaganya-Riera, Josep

    2014-01-01

    The immune system is composed of many different cell types and hundreds of intersecting molecular pathways and signals. This large biological complexity requires coordination between distinct pro-inflammatory and regulatory cell subsets to respond to infection while maintaining tissue homeostasis. CD4+ T cells play a central role in orchestrating immune responses and in maintaining a balance between pro- and anti- inflammatory responses. This tight balance between regulatory and effector reactions depends on the ability of CD4+ T cells to modulate distinct pathways within large molecular networks, since dysregulated CD4+ T cell responses may result in chronic inflammatory and autoimmune diseases. The CD4+ T cell differentiation process comprises an intricate interplay between cytokines, their receptors, adaptor molecules, signaling cascades and transcription factors that help delineate cell fate and function. Computational modeling can help to describe, simulate, analyze, and predict some of the behaviors in this complicated differentiation network. This review provides a comprehensive overview of existing computational immunology methods as well as novel strategies used to model immune responses with a particular focus on CD4+ T cell differentiation. PMID:25364738

  13. Probing the effect of force on HIV-1 receptor CD4.

    PubMed

    Perez-Jimenez, Raul; Alonso-Caballero, Alvaro; Berkovich, Ronen; Franco, David; Chen, Ming-Wei; Richard, Patricia; Badilla, Carmen L; Fernandez, Julio M

    2014-10-28

    Cell-surface proteins are central for the interaction of cells with their surroundings and are also associated with numerous diseases. These molecules are exposed to mechanical forces, but the exact relation between force and the functions and pathologies associated with cell-surface proteins is unclear. An important cell-surface protein is CD4, the primary receptor of HIV-1. Here we show that mechanical force activates conformational and chemical changes on CD4 that may be important during viral attachment. We have used single-molecule force spectroscopy and analysis on HIV-1 infectivity to demonstrate that the mechanical extension of CD4 occurs in a time-dependent manner and correlates with HIV-1 infectivity. We show that Ibalizumab, a monoclonal antibody that blocks HIV-1, prevents the mechanical extension of CD4 domains 1 and 2. Furthermore, we demonstrate that thiol/disulfide exchange in CD4 requires force for exposure of cryptic disulfide bonds. This mechanical perspective provides unprecedented information that can change our understanding on how viruses interact with their hosts.

  14. Probing the Effect of Force on HIV-1 Receptor CD4

    PubMed Central

    2015-01-01

    Cell-surface proteins are central for the interaction of cells with their surroundings and are also associated with numerous diseases. These molecules are exposed to mechanical forces, but the exact relation between force and the functions and pathologies associated with cell-surface proteins is unclear. An important cell-surface protein is CD4, the primary receptor of HIV-1. Here we show that mechanical force activates conformational and chemical changes on CD4 that may be important during viral attachment. We have used single-molecule force spectroscopy and analysis on HIV-1 infectivity to demonstrate that the mechanical extension of CD4 occurs in a time-dependent manner and correlates with HIV-1 infectivity. We show that Ibalizumab, a monoclonal antibody that blocks HIV-1, prevents the mechanical extension of CD4 domains 1 and 2. Furthermore, we demonstrate that thiol/disulfide exchange in CD4 requires force for exposure of cryptic disulfide bonds. This mechanical perspective provides unprecedented information that can change our understanding on how viruses interact with their hosts. PMID:25299596

  15. Administration of interleukin-7 increases CD4 T cells in idiopathic CD4 lymphocytopenia

    PubMed Central

    Porter, Brian O.; DerSimonian, Rebecca; Kovacs, Stephen B.; Thompson, William L.; Perez-Diez, Ainhoa; Freeman, Alexandra F.; Roby, Gregg; Mican, JoAnn; Pau, Alice; Rupert, Adam; Adelsberger, Joseph; Higgins, Jeanette; Bourgeois, Jeffrey S.; Jensen, Stig M. R.; Morcock, David R.; Burbelo, Peter D.; Osnos, Leah; Maric, Irina; Natarajan, Ven; Croughs, Therese; Yao, Michael D.; Estes, Jacob D.; Sereti, Irini

    2016-01-01

    Idiopathic CD4 lymphopenia (ICL) is a rare syndrome defined by low CD4 T-cell counts (<300/µL) without evidence of HIV infection or other known cause of immunodeficiency. ICL confers an increased risk of opportunistic infections and has no established treatment. Interleukin-7 (IL-7) is fundamental for thymopoiesis, T-cell homeostasis, and survival of mature T cells, which provides a rationale for its potential use as an immunotherapeutic agent for ICL. We performed an open-label phase 1/2A dose-escalation trial of 3 subcutaneous doses of recombinant human IL-7 (rhIL-7) per week in patients with ICL who were at risk of disease progression. The primary objectives of the study were to assess safety and the immunomodulatory effects of rhIL-7 in ICL patients. Injection site reactions were the most frequently reported adverse events. One patient experienced a hypersensitivity reaction and developed non-neutralizing anti-IL-7 antibodies. Patients with autoimmune diseases that required systemic therapy at screening were excluded from the study; however, 1 participant developed systemic lupus erythematosus while on study and was excluded from further rhIL-7 dosing. Quantitatively, rhIL-7 led to an increase in the number of circulating CD4 and CD8 T cells and tissue-resident CD3 T cells in the gut mucosa and bone marrow. Functionally, these T cells were capable of producing cytokines after mitogenic stimulation. rhIL-7 was well tolerated at biologically active doses and may represent a promising therapeutic intervention in ICL. This trial was registered at www.clinicaltrials.gov as #NCT00839436. PMID:26675348

  16. Low SAMHD1 expression following T-cell activation and proliferation renders CD4+ T cells susceptible to HIV-1

    PubMed Central

    Ruffin, Nicolas; Brezar, Vedran; Ayinde, Diana; Lefebvre, Cécile; Wiesch, Julian Schulze Zur; van Lunzen, Jan; Bockhorn, Maximilian; Schwartz, Olivier; Hocini, Hakim; Lelievre, Jean-Daniel; Banchereau, Jacques; Levy, Yves; Seddiki, Nabila

    2015-01-01

    Objectives: HIV-1 replication depends on the state of cell activation and division. It is established that SAMHD1 restricts HIV-1 infection of resting CD4+ T cells. The modulation of SAMHD1 expression during T-cell activation and proliferation, however, remains unclear, as well as a role for SAMHD1 during HIV-1 pathogenesis. Methods: SAMHD1 expression was assessed in CD4+ T cells after their activation and in-vitro HIV-1 infection. We performed phenotype analyzes using flow cytometry on CD4+ T cells from peripheral blood and lymph nodes from cohorts of HIV-1-infected individuals under antiretroviral treatment or not, and controls. Results: We show that SAMHD1 expression decreased during CD4+ T-cell proliferation in association with an increased susceptibility to in-vitro HIV-1 infection. Additionally, circulating memory CD4+ T cells are enriched in cells with low levels of SAMHD1. These SAMHD1low cells are highly differentiated, exhibit a large proportion of Ki67+ cycling cells and are enriched in T-helper 17 cells. Importantly, memory SAMHD1low cells were depleted from peripheral blood of HIV-infected individuals. We also found that follicular helper T cells present in secondary lymphoid organs lacked the expression of SAMHD1, which was accompanied by a higher susceptibility to HIV-1 infection in vitro. Conclusion: We demonstrate that SAMHD1 expression is decreased during CD4+ T-cell activation and proliferation. Also, CD4+ T-cell subsets known to be more susceptible to HIV-1 infection, for example, T-helper 17 and follicular helper T cells, display lower levels of SAMHD1. These results pin point a role for SAMHD1 expression in HIV-1 infection and the concomitant depletion of CD4+ T cells. PMID:25715102

  17. CD4 cell count and CD4/CD8 ratio increase during rituximab maintenance in granulomatosis with polyangiitis patients

    PubMed Central

    Nossent, Johannes C.

    2016-01-01

    Introduction Rituximab (RTX) is a B cell-depleting agent approved for the treatment of granulomatosis with polyangiitis (GPA). RTX reduces antibody producing precursor plasma cells and inhibits B and T cells interaction. Infections related to T cell immunodeficiency are not infrequent during RTX treatment. Our study investigated CD4 cell count and CD4/CD8 ratio in GPA patients during the first two years of long-term RTX treatment. Methods A single centre cohort study of 35 patients who received median total cumulative dose of cyclophosphamide (CYC) of 15 g and were treated with RTX 2 g followed by retreatment with either 2 g once annually or 1 g biannually. Serum levels of total immunoglobulin (Ig) and lymphocytes subsets were recorded at RTX initiation and at 3, 6, 12, 18 and 24 months. Low CD4 count and inverted CD4/CD8 ratio were defined as CD4 < 0.3 × 109/l and ratio < 1. Results The CD4 cell count and CD4/CD8 ratio decreased slightly following the initial RTX treatment and then increased gradually during maintenance treatment. While the proportion of patients with low CD4 cell count decreased from 43% at baseline to 18% at 24 months, the ratio remained inverted in 40%. Oral daily prednisolone dose at baseline, CYC exposure and the maintenance regimen did not influence the CD4 cell count and ratio. Being older (p = 0.012) and having a higher CRP (p = 0.044) and ESR (p = 0.024) at baseline significantly increased the risk of inverted CD4/CD8 ratio at 24 months. Inverted ratio at baseline associated with lower total Ig levels during the study. Conclusions Overall, the CD4 and CD4/CD8 ratio increased during maintenance RTX therapy in GPA with no discernible impact of other immunosuppressive therapy. However the increase in CD4 was not followed by an increase in the CD4/CD8 ratio, especially in older patients. Inverted CD4/CD8 ratio associated with lower Ig levels, suggesting a more profound B cell depleting effect of RTX with a relative increase in CD8

  18. Cytotoxic CD4 T Cells: Differentiation, Function, and Application to Dengue Virus Infection

    PubMed Central

    Tian, Yuan; Sette, Alessandro; Weiskopf, Daniela

    2016-01-01

    Dengue virus (DENV) has spread through most tropical and subtropical areas of the world and represents a serious public health problem. The control of DENV infection has not yet been fully successful due to lack of effective therapeutics or vaccines. Nevertheless, a better understanding of the immune responses against DENV infection may reveal new strategies for eliciting and improving antiviral immunity. T cells provide protective immunity against various viral infections by generating effector cells that cooperate to eliminate antigens and memory cells that can survive for long periods with enhanced abilities to control recurring pathogens. Following activation, CD8 T cells can migrate to sites of infection and kill infected cells, whereas CD4 T cells contribute to the elimination of pathogens by trafficking to infected tissues and providing help to innate immune responses, B cells, as well as CD8 T cells. However, it is now evident that CD4 T cells can also perform cytotoxic functions and induce the apoptosis of target cells. Importantly, accumulating studies demonstrate that cytotoxic CD4 T cells develop following DENV infections and may play a crucial role in protecting the host from severe dengue disease. We review our current understanding of the differentiation and function of cytotoxic CD4 T cells, with a focus on DENV infection, and discuss the potential of harnessing these cells for the prevention and treatment of DENV infection and disease. PMID:28003809

  19. Cytotoxic CD4 T Cells: Differentiation, Function, and Application to Dengue Virus Infection.

    PubMed

    Tian, Yuan; Sette, Alessandro; Weiskopf, Daniela

    2016-01-01

    Dengue virus (DENV) has spread through most tropical and subtropical areas of the world and represents a serious public health problem. The control of DENV infection has not yet been fully successful due to lack of effective therapeutics or vaccines. Nevertheless, a better understanding of the immune responses against DENV infection may reveal new strategies for eliciting and improving antiviral immunity. T cells provide protective immunity against various viral infections by generating effector cells that cooperate to eliminate antigens and memory cells that can survive for long periods with enhanced abilities to control recurring pathogens. Following activation, CD8 T cells can migrate to sites of infection and kill infected cells, whereas CD4 T cells contribute to the elimination of pathogens by trafficking to infected tissues and providing help to innate immune responses, B cells, as well as CD8 T cells. However, it is now evident that CD4 T cells can also perform cytotoxic functions and induce the apoptosis of target cells. Importantly, accumulating studies demonstrate that cytotoxic CD4 T cells develop following DENV infections and may play a crucial role in protecting the host from severe dengue disease. We review our current understanding of the differentiation and function of cytotoxic CD4 T cells, with a focus on DENV infection, and discuss the potential of harnessing these cells for the prevention and treatment of DENV infection and disease.

  20. Central load reduces peripheral processing: Evidence from incidental memory of background speech.

    PubMed

    Halin, Niklas; Marsh, John E; Sörqvist, Patrik

    2015-12-01

    Is there a trade-off between central (working memory) load and peripheral (perceptual) processing? To address this question, participants were requested to undertake an n-back task in one of two levels of central/cognitive load (i.e., 1-back or 2-back) in the presence of a to-be-ignored story presented via headphones. Participants were told to ignore the background story, but they were given a surprise memory test of what had been said in the background story, immediately after the n-back task was completed. Memory was poorer in the high central load (2-back) condition in comparison with the low central load (1-back) condition. Hence, when people compensate for higher central load, by increasing attentional engagement, peripheral processing is constrained. Moreover, participants with high working memory capacity (WMC) - with a superior ability for attentional engagement - remembered less of the background story, but only in the low central load condition. Taken together, peripheral processing - as indexed by incidental memory of background speech - is constrained when task engagement is high.

  1. Effector CD4+ T cell expression signatures and immune-mediated disease associated genes.

    PubMed

    Zhang, Wei; Ferguson, John; Ng, Sok Meng; Hui, Ken; Goh, Gerald; Lin, Aiping; Esplugues, Enric; Flavell, Richard A; Abraham, Clara; Zhao, Hongyu; Cho, Judy H

    2012-01-01

    Genome-wide association studies (GWAS) in immune-mediated diseases have identified over 150 associated genomic loci. Many of these loci play a role in T cell responses, and regulation of T cell differentiation plays a critical role in immune-mediated diseases; however, the relationship between implicated disease loci and T cell differentiation is incompletely understood. To further address this relationship, we examined differential gene expression in naïve human CD4+ T cells, as well as in in vitro differentiated Th1, memory Th17-negative and Th17-enriched CD4+ T cells subsets using microarray and RNASeq. We observed a marked enrichment for increased expression in memory CD4+ compared to naïve CD4+ T cells of genes contained among immune-mediated disease loci. Within memory T cells, expression of disease-associated genes was typically increased in Th17-enriched compared to Th17-negative cells. Utilizing RNASeq and promoter methylation studies, we identified a differential regulation pattern for genes solely expressed in Th17 cells (IL17A and CCL20) compared to genes expressed in both Th17 and Th1 cells (IL23R and IL12RB2), where high levels of promoter methylation are correlated to near zero RNASeq levels for IL17A and CCL20. These findings have implications for human Th17 celI plasticity and for the regulation of Th17-Th1 expression signatures. Importantly, utilizing RNASeq we found an abundant isoform of IL23R terminating before the transmembrane domain that was enriched in Th17 cells. In addition to molecular resolution, we find that RNASeq provides significantly improved power to define differential gene expression and identify alternative gene variants relative to microarray analysis. The comprehensive integration of differential gene expression between cell subsets with disease-association signals, and functional pathways provides insight into disease pathogenesis.

  2. Peripheral and central CB1 cannabinoid receptors control stress-induced impairment of memory consolidation

    PubMed Central

    Busquets-Garcia, Arnau; Gomis-González, Maria; Srivastava, Raj Kamal; Cutando, Laura; Ortega-Alvaro, Antonio; Ruehle, Sabine; Remmers, Floortje; Bindila, Laura; Bellocchio, Luigi; Marsicano, Giovanni; Lutz, Beat; Maldonado, Rafael

    2016-01-01

    Stressful events can generate emotional memories linked to the traumatic incident, but they also can impair the formation of nonemotional memories. Although the impact of stress on emotional memories is well studied, much less is known about the influence of the emotional state on the formation of nonemotional memories. We used the novel object-recognition task as a model of nonemotional memory in mice to investigate the underlying mechanism of the deleterious effect of stress on memory consolidation. Systemic, hippocampal, and peripheral blockade of cannabinoid type-1 (CB1) receptors abolished the stress-induced memory impairment. Genetic deletion and rescue of CB1 receptors in specific cell types revealed that the CB1 receptor population specifically in dopamine β-hydroxylase (DBH)-expressing cells is both necessary and sufficient for stress-induced impairment of memory consolidation, but CB1 receptors present in other neuronal populations are not involved. Strikingly, pharmacological manipulations in mice expressing CB1 receptors exclusively in DBH+ cells revealed that both hippocampal and peripheral receptors mediate the impact of stress on memory consolidation. Thus, CB1 receptors on adrenergic and noradrenergic cells provide previously unrecognized cross-talk between central and peripheral mechanisms in the stress-dependent regulation of nonemotional memory consolidation, suggesting new potential avenues for the treatment of cognitive aspects on stress-related disorders. PMID:27528659

  3. Central Nervous Insulin Signaling in Sleep-Associated Memory Formation and Neuroendocrine Regulation

    PubMed Central

    Feld, Gordon B; Wilhem, Ines; Benedict, Christian; Rüdel, Benjamin; Klameth, Corinna; Born, Jan; Hallschmid, Manfred

    2016-01-01

    The neurochemical underpinnings of sleep's contribution to the establishment and maintenance of memory traces are largely unexplored. Considering that intranasal insulin administration to the CNS improves memory functions in healthy and memory-impaired humans, we tested whether brain insulin signaling and sleep interact to enhance memory consolidation in healthy participants. We investigated the effect of intranasal insulin on sleep-associated neurophysiological and neuroendocrine parameters and memory consolidation in 16 men and 16 women (aged 18–30 years), who learned a declarative word-pair task and a procedural finger sequence tapping task in the evening before intranasal insulin (160 IU) or placebo administration and 8 h of nocturnal sleep. On the subsequent evening, they learned interfering word-pairs and a new finger sequence before retrieving the original memories. Insulin increased growth hormone concentrations in the first night-half and EEG delta power during the second 90 min of non-rapid-eye-movement sleep. Insulin treatment impaired the acquisition of new contents in both the declarative and procedural memory systems on the next day, whereas retrieval of original memories was unchanged. Results indicate that sleep-associated memory consolidation is not a primary mediator of insulin's acute memory-improving effect, but that the peptide acts on mechanisms that diminish the subsequent encoding of novel information. Thus, by inhibiting processes of active forgetting during sleep, central nervous insulin might reduce the interfering influence of encoding new information. PMID:26448203

  4. Central Nervous Insulin Signaling in Sleep-Associated Memory Formation and Neuroendocrine Regulation.

    PubMed

    Feld, Gordon B; Wilhem, Ines; Benedict, Christian; Rüdel, Benjamin; Klameth, Corinna; Born, Jan; Hallschmid, Manfred

    2016-05-01

    The neurochemical underpinnings of sleep's contribution to the establishment and maintenance of memory traces are largely unexplored. Considering that intranasal insulin administration to the CNS improves memory functions in healthy and memory-impaired humans, we tested whether brain insulin signaling and sleep interact to enhance memory consolidation in healthy participants. We investigated the effect of intranasal insulin on sleep-associated neurophysiological and neuroendocrine parameters and memory consolidation in 16 men and 16 women (aged 18-30 years), who learned a declarative word-pair task and a procedural finger sequence tapping task in the evening before intranasal insulin (160 IU) or placebo administration and 8 h of nocturnal sleep. On the subsequent evening, they learned interfering word-pairs and a new finger sequence before retrieving the original memories. Insulin increased growth hormone concentrations in the first night-half and EEG delta power during the second 90 min of non-rapid-eye-movement sleep. Insulin treatment impaired the acquisition of new contents in both the declarative and procedural memory systems on the next day, whereas retrieval of original memories was unchanged. Results indicate that sleep-associated memory consolidation is not a primary mediator of insulin's acute memory-improving effect, but that the peptide acts on mechanisms that diminish the subsequent encoding of novel information. Thus, by inhibiting processes of active forgetting during sleep, central nervous insulin might reduce the interfering influence of encoding new information.

  5. Critical role of CD4 T cells in maintaining lymphoid tissue structure for immune cell homeostasis and reconstitution.

    PubMed

    Zeng, Ming; Paiardini, Mirko; Engram, Jessica C; Beilman, Greg J; Chipman, Jeffrey G; Schacker, Timothy W; Silvestri, Guido; Haase, Ashley T

    2012-08-30

    Loss of the fibroblastic reticular cell (FRC) network in lymphoid tissues during HIV-1 infection has been shown to impair the survival of naive T cells and limit immune reconstitution after antiretroviral therapy. What causes this FRC loss is unknown. Because FRC loss correlates with loss of both naive CD4 and CD8 T-cell subsets and decreased lymphotoxin-β, a key factor for maintenance of FRC network, we hypothesized that loss of naive T cells is responsible for loss of the FRC network. To test this hypothesis, we assessed the consequences of antibody-mediated depletion of CD4 and CD8 T cells in rhesus macaques and sooty mangabeys. We found that only CD4 T-cell depletion resulted in FRC loss in both species and that this loss was caused by decreased lymphotoxin-β mainly produced by the CD4 T cells. We further found the same dependence of the FRC network on CD4 T cells in HIV-1-infected patients before and after antiretroviral therapy and in other immunodeficiency conditions, such as CD4 depletion in cancer patients induced by chemotherapy and irradiation. CD4 T cells thus play a central role in the maintenance of lymphoid tissue structure necessary for their own homeostasis and reconstitution.

  6. Increased TNF-α/IFN-γ/IL-2 and Decreased TNF-α/IFN-γ Production by Central Memory T Cells Are Associated with Protective Responses against Bovine Tuberculosis Following BCG Vaccination

    PubMed Central

    Maggioli, Mayara F.; Palmer, Mitchell V.; Thacker, Tyler C.; Vordermeier, Hans Martin; McGill, Jodi L.; Whelan, Adam O.; Larsen, Michelle H.; Jacobs, William R.; Waters, W. Ray

    2016-01-01

    Central memory T cell (Tcm) and polyfunctional CD4 T cell responses contribute to vaccine-elicited protection with both human and bovine tuberculosis (TB); however, their combined role in protective immunity to TB is unclear. To address this question, we evaluated polyfunctional cytokine responses by CD4 T cell effector/memory populations from bacille Calmette–Guerin (BCG) vaccinated and non-vaccinated calves by flow cytometry prior to and after aerosol challenge with virulent Mycobacterium bovis. Polyfunctional cytokine expression patterns in the response by Tcm, effector memory, and effector T cell subsets were similar between BCG-vaccinated and M. bovis-infected calves, only differing in magnitude (i.e., infected > vaccinated). BCG vaccination, however, did alter the kinetics of the ensuing response to virulent M. bovis infection. Early after challenge (3 weeks post-infection), non-vaccinates had greater antigen-specific interferon-γ (IFN-γ)/tumor necrosis factor-α (TNF-α) and lesser IFN-γ/TNF-α/IL-2 responses by Tcm cells than did vaccinated animals. Importantly, these differences were also associated with mycobacterial burden upon necropsy. Polyfunctional responses to ESAT-6:CFP10 (antigens not synthesized by BCG strains) were detected in memory subsets, as well as in effector cells, as early as 3 weeks after challenge. These findings suggest that cell fate divergence may occur early after antigen priming in the response to bovine TB and that memory and effector T cells may expand concurrently during the initial phase of the immune response. In summary, robust IFN-γ/TNF-α response by Tcm cells is associated with greater mycobacterial burden, while IFN-γ/TNF-α/IL-2 response by Tcm cells are indicative of a protective response to bovine TB. PMID:27799930

  7. CD4+ T cell activation in multiple sclerosis.

    PubMed

    Verselis, S J; Goust, J M

    1987-02-01

    Interleukin-2 (IL-2) production by CD4-enriched T cells from multiple sclerosis (MS) patients and normal individuals stimulated with concanavalin A (conA) and/or autologous and allogeneic B lymphoid cell lines (B-LCL) was evaluated 24, 48 and 96 h after stimulation. ConA-stimulated CD4+ cells from MS patients did not produce significantly more IL-2 than normal CD4+ cells. In contrast, autologous B-LCL-induced IL-2 production by MS CD4+ cells significantly (P = 0.026) exceeded that produced by normal CD4+ cells identically stimulated after 24 h in culture. Differences in IL-2 production by CD4+ cells from MS patients reached highest significance using allogeneic B-LCL, whose stimulatory capacity was similar, whether established from normal individuals or MS patients. This increased IL-2 production in response to B-LCL may represent a supranormal response of CD4+ cells from MS patients to class II major histocompatibility (MHC)-associated stimuli. It suggests that the deficiency of suppressor T cell functions postulated to play a role in MS does not arise from a lack of IL-2 induction and might indicate that bursts of IL-2 production could play a role in MS.

  8. Characterization of a polymorphism of CD4 in miniature swine.

    PubMed

    Sundt, T M; LeGuern, C; Germana, S; Smith, C V; Nakajima, K; Lunney, J K; Sachs, D H

    1992-05-15

    A polymorphism of CD4 in miniature swine has been identified by failure of cells from some animals to react with mAb 74-12-4. The phenotypic, molecular genetic, and functional characteristics of these animals have been defined. Cells from heterozygous animals bear approximately 50% the number of 74-12-4-reactive molecules on their surface as do cells from animals homozygous for the wild type. Animals of both phenotypes demonstrate similar flow cytometric profiles for CD8+ T cells. Northern blot analysis confirms the presence of mRNA for CD4 among PBL of animals failing to stain with 74-12-4. CD4 allelism is confirmed by Southern blot analysis, revealing RFLP. Function of the CD4 subset in vivo, as demonstrated by antibody production against a T cell-dependent Ag, is similar between animals of both phenotypes. Proliferative responses to PHA and alloantigen stimulation by a full haplotype mismatch or a class II mismatch alone are equivalent for animals of both phenotypes. These data suggest that the allelic form of CD4, designated CD4.2 in contrast to the wild-type CD4.1, is capable of performing normally as an accessory molecule in the generation of immune responses. Furthermore, antixenogeneic responses to C57B10.BR were equivalent, suggesting that both CD4 molecular types may be capable of interacting with xenogeneic class II molecules. Although the polymorphism includes differences in exons 3 and 4, regions thought to encode portions of the molecule interacting with MHC class II, these results imply that this naturally occurring CD4 polymorphism does not affect the interaction with class II molecules.

  9. Isolated cutaneous cryptococcosis in clinically unsuspected idiopathic CD4 lymphocytopenia

    PubMed Central

    Sharma, Divya; Singh, Neha; Kaushal, Seema; Jain, Shyama

    2014-01-01

    Idiopathic CD4 lymphocytopenia first defined in 1992 by the U.S. Centers for Disease Control and Prevention, as the repeated presence of a CD4+ T-lymphocyte count of fewer than 300 cells/cumm or of <20% of total T-cells with no evidence of human immunodeficiency virus (HIV) infection and therapy that might cause depressed CD4 T-cells. Most of the cases present with systemic opportunistic infections. We report a case without risk factors or laboratory evidence of HIV infection, presenting with cutaneous cryptococcal infection, diagnosed on cytology. PMID:25745296

  10. HIV-1 Nef mutations abrogating downregulation of CD4 affect other Nef functions and show reduced pathogenicity in transgenic mice

    SciTech Connect

    Hanna, Zaher . E-mail: Zaher.Hanna@ircm.qc.ca; Priceputu, Elena; Hu, Chunyan; Vincent, Patrick; Jolicoeur, Paul

    2006-03-01

    HIV-1 Nef has the ability to downmodulate CD4 cell surface expression. Several studies have shown that CD4 downregulation is required for efficient virus replication and high infectivity. However, the pathophysiological relevance of this phenomenon in vivo, independently of its role in sustaining high virus loads, remains unclear. We studied the impact of the CD4 downregulation function of Nef on its pathogenesis in vivo, in the absence of viral replication, in the CD4C/HIV transgenic (Tg) mouse model. Two independent Nef mutants (RD35/36AA and D174K), known to abrogate CD4 downregulation, were tested in Tg mice. Flow cytometry analysis showed that downregulation of murine CD4 was severely decreased or abrogated on Tg T cells expressing respectively Nef{sup RD35/36AA} and Nef{sup D174K}. Similarly, the severe depletion of double-positive CD4{sup +}CD8{sup +} and of single-positive CD4{sup +}CD8{sup -} thymocytes, usually observed with Nef{sup Wt}, was not detected in Nef{sup RD35/36AA} and Nef{sup D174K} Tg mice. However, both mutant Tg mice showed a partial depletion of peripheral CD4{sup +} T cells. This was accompanied, as previously reported for Net{sup Wt} Tg mice, by the presence of an activated/memory-like phenotype (CD69{sup +}, CD25{sup +}, CD44{sup +}, CD45RB{sup Low}, CD62{sup Low}) of CD4{sup +} T cells expressing Nef{sup RD35/36AA} and to a lesser extent Nef{sup D174K}. In addition, both mutants retained the ability to block CD4{sup +} T cell proliferation in vitro after anti-CD3 stimulation, but not to enhance apoptosis/death of CD4{sup +} T cells. Therefore, it appears that Nef-mediated CD4 downregulation is associated with thymic defects, but segregates independently of the activated/memory-like phenotype, of the partial depletion and of the impaired in vitro proliferation of peripheral CD4{sup +} T cells. Histopathological assessment revealed the total absence of or decrease severity and frequency of organ AIDS-like diseases (lung, heart and kidney

  11. HIV-1 Nef mutations abrogating downregulation of CD4 affect other Nef functions and show reduced pathogenicity in transgenic mice.

    PubMed

    Hanna, Zaher; Priceputu, Elena; Hu, Chunyan; Vincent, Patrick; Jolicoeur, Paul

    2006-03-01

    HIV-1 Nef has the ability to downmodulate CD4 cell surface expression. Several studies have shown that CD4 downregulation is required for efficient virus replication and high infectivity. However, the pathophysiological relevance of this phenomenon in vivo, independently of its role in sustaining high virus loads, remains unclear. We studied the impact of the CD4 downregulation function of Nef on its pathogenesis in vivo, in the absence of viral replication, in the CD4C/HIV transgenic (Tg) mouse model. Two independent Nef mutants (RD35/36AA and D174K), known to abrogate CD4 downregulation, were tested in Tg mice. Flow cytometry analysis showed that downregulation of murine CD4 was severely decreased or abrogated on Tg T cells expressing respectively Nef(RD35/36AA) and Nef(D174K). Similarly, the severe depletion of double-positive CD4+CD8+ and of single-positive CD4+CD8- thymocytes, usually observed with Nef(Wt), was not detected in Nef(RD35/36AA) and Nef(D174K) Tg mice. However, both mutant Tg mice showed a partial depletion of peripheral CD4+ T cells. This was accompanied, as previously reported for Net(Wt) Tg mice, by the presence of an activated/memory-like phenotype (CD69+, CD25+, CD44+, CD45RB(Low), CD62(Low)) of CD4+ T cells expressing Nef(RD35/36AA) and to a lesser extent Nef(D174K). In addition, both mutants retained the ability to block CD4+ T cell proliferation in vitro after anti-CD3 stimulation, but not to enhance apoptosis/death of CD4+ T cells. Therefore, it appears that Nef-mediated CD4 downregulation is associated with thymic defects, but segregates independently of the activated/memory-like phenotype, of the partial depletion and of the impaired in vitro proliferation of peripheral CD4+ T cells. Histopathological assessment revealed the total absence of or decrease severity and frequency of organ AIDS-like diseases (lung, heart and kidney pathologies) in respectively Nef(RD35/36AA) and Nef(D174K) Tg mice, relative to those developing in Nef(Wt) Tg

  12. High frequency of central memory regulatory T cells allows detection of liver recipients at risk of early acute rejection within the first month after transplantation.

    PubMed

    Boix-Giner, Francisco; Millan, Olga; San Segundo, David; Muñoz-Cacho, Pedro; Mancebo, Esther; Llorente, Santiago; Rafael-Valdivia, Lourdes; Rimola, Antoni; Fábrega, Emilio; Mrowiec, Anna; Allende, Luis; Minguela, Alfredo; Bolarín, Jose M; Paz-Artal, Estela; López-Hoyos, Marcos; Brunet, Mercé; Muro, Manuel

    2016-02-01

    Several studies have analyzed the potential of T regulatory cells (Treg cells) as biomarkers of acute rejection (AR). The aim of the present multicenter study was to correlate the percentage of peripheral Treg cells in liver graft recipients drawn at baseline up to 12 months after transplantation with the presence of AR. The percentage of central memory (cm) Treg cells (CD4(+)CD25(high)CD45RO(+)CD62L(+)) was monitored at pre-transplant and at 1 and 2 weeks, and 1, 2, 3 and 6 months and 1 year post-transplantation. The same validation standard operating procedures were used in all participating centers. Fifteen patients developed AR (23.4%). Hepatitis C virus recurrence was observed in 16 recipients, who displayed low peripheral blood cmTreg levels compared with patients who did not. A steady increase of cmTregs was observed during the first month after transplantation with statistically significant differences between AR and non-AR patients. The high frequency of memory Treg cells allowed us to monitor rejection episodes during the first month post-transplantation. On the basis of these data, we developed a prediction model for assessing risk of AR that can provide clinicians with useful information for managing patients individually and customizing immunosuppressive therapies.

  13. High frequency of central memory regulatory T cells allows detection of liver recipients at risk of early acute rejection within the first month after transplantation

    PubMed Central

    Boix-Giner, Francisco; Millan, Olga; San Segundo, David; Muñoz-Cacho, Pedro; Mancebo, Esther; Llorente, Santiago; Rafael-Valdivia, Lourdes; Rimola, Antoni; Fábrega, Emilio; Mrowiec, Anna; Allende, Luis; Minguela, Alfredo; Bolarín, Jose M.; Paz-Artal, Estela; López-Hoyos, Marcos; Brunet, Mercé

    2016-01-01

    Several studies have analyzed the potential of T regulatory cells (Treg cells) as biomarkers of acute rejection (AR). The aim of the present multicenter study was to correlate the percentage of peripheral Treg cells in liver graft recipients drawn at baseline up to 12 months after transplantation with the presence of AR. The percentage of central memory (cm) Treg cells (CD4+CD25highCD45RO+CD62L+) was monitored at pre-transplant and at 1 and 2 weeks, and 1, 2, 3 and 6 months and 1 year post-transplantation. The same validation standard operating procedures were used in all participating centers. Fifteen patients developed AR (23.4%). Hepatitis C virus recurrence was observed in 16 recipients, who displayed low peripheral blood cmTreg levels compared with patients who did not. A steady increase of cmTregs was observed during the first month after transplantation with statistically significant differences between AR and non-AR patients. The high frequency of memory Treg cells allowed us to monitor rejection episodes during the first month post-transplantation. On the basis of these data, we developed a prediction model for assessing risk of AR that can provide clinicians with useful information for managing patients individually and customizing immunosuppressive therapies. PMID:26270267

  14. Effector memory and central memory NY-ESO-1-specific re-directed T cells for treatment of multiple myeloma.

    PubMed

    Schuberth, P C; Jakka, G; Jensen, S M; Wadle, A; Gautschi, F; Haley, D; Haile, S; Mischo, A; Held, G; Thiel, M; Tinguely, M; Bifulco, C B; Fox, B A; Renner, C; Petrausch, U

    2013-04-01

    The cancer-testis antigen NY-ESO-1 is a potential target antigen for immune therapy expressed in a subset of patients with multiple myeloma. We generated chimeric antigen receptors (CARs) recognizing the immunodominant NY-ESO-1 peptide 157-165 in the context of HLA-A*02:01 to re-direct autologous CD8(+) T cells towards NY-ESO-1(+) myeloma cells. These re-directed T cells specifically lysed NY-ESO-1(157-165)/HLA-A*02:01-positive cells and secreted IFNγ. A total of 40% of CCR7(-) re-directed T cells had an effector memory phenotype and 5% a central memory phenotype. Based on CCR7 cell sorting, effector and memory CAR-positive T cells were separated and CCR7(+) memory cells demonstrated after antigen-specific re-stimulation downregulation of CCR7 as sign of differentiation towards effector cells accompanied by an increased secretion of memory signature cytokines such as IL-2. To evaluate NY-ESO-1 as potential target antigen, we screened 78 bone marrow biopsies of multiple myeloma patients where NY-ESO-1 protein was found to be expressed by immunohistochemistry in 9.7% of samples. Adoptively transferred NY-ESO-1-specific re-directed T cells protected mice against challenge with endogenously NY-ESO-1-positive myeloma cells in a xenograft model. In conclusion, re-directed effector- and central memory T cells specifically recognized NY-ESO-1(157-165)/ HLA-A*02:01-positive cells resulting in antigen-specific functionality in vitro and in vivo.

  15. Extensive CD4 and CD8 T-cell cross-reactivity between alphaherpesviruses1

    PubMed Central

    Dong, Lichun; Russell, Ronnie M.; Barlow, Russell S.; Haas, Juergen G.; Ramchandani, Meena S.; Johnston, Christine; Buus, Soren; Redwood, Alec J.; White, Katie D.; Mallal, Simon A.; Phillips, Elizabeth J.; Posavad, Christine M.; Wald, Anna; Koelle, David M.

    2015-01-01

    The alphaherpesvirinae subfamily includes HSV types 1 and 2 and the sequence-divergent pathogen varicella zoster virus (VZV). T cells, controlled by TCR and HLA molecules that tolerate limited epitope amino acid variation, might cross-react between these microbes. We show that memory PBMC expansion with either HSV or VZV enriches for CD4 T cell lines that recognize the other agent at the whole virus, protein, and peptide levels, consistent with bi-directional cross-reactivity. HSV-specific CD4 T cells recovered from HSV seronegative persons can be partially explained by such VZV cross-reactivity. HSV-1-reactive CD8 T cells also cross-react with VZV-infected cells, full-length VZV proteins, and VZV peptides, and kill VZV-infected dermal fibroblasts. Mono- and cross-reactive CD8 T cells use distinct TCRB CDR3 sequences. Cross-reactivity to VZV is reconstituted by cloning and expressing TCRA/TCRB receptors from T-cells that are initially isolated using HSV reagents. Overall, we define 13 novel CD4 and CD8 HSV-VZV cross-reactive epitopes and strongly imply additional cross-reactive peptide sets. Viral proteins can harbor both CD4 and CD8 HSV/VZV cross-reactive epitopes. Quantitative estimates of HSV/VZV cross-reactivity for both CD4 and CD8 T cells vary from 10-50%. Based on these findings, we hypothesize host herpesvirus immune history may influence the pathogenesis and clinical outcome of subsequent infections or vaccinations for related pathogens, and that cross-reactive epitopes and TCRs may be useful for multi-alphaherpesvirus vaccine design and adoptive cellular therapy. PMID:26810224

  16. Circumvention of regulatory CD4(+) T cell activity during cross-priming strongly enhances T cell-mediated immunity.

    PubMed

    Heit, Antje; Gebhardt, Friedemann; Lahl, Katharina; Neuenhahn, Michael; Schmitz, Frank; Anderl, Florian; Wagner, Hermann; Sparwasser, Tim; Busch, Dirk H; Kastenmüller, Kathrin

    2008-06-01

    Immunization with purified antigens is a safe and practical vaccination strategy but is generally unable to induce sustained CD8(+) T cell-mediated protection against intracellular pathogens. Most efforts to improve the CD8(+) T cell immunogenicity of these vaccines have focused on co-administration of adjuvant to support cross-presentation and dendritic cell maturation. In addition, it has been shown that CD4(+) T cell help during the priming phase contributes to the generation of protective CD8(+) memory T cells. In this report we demonstrate that the depletion of CD4(+) T cells paradoxically enhances long-lasting CD8-mediated protective immunity upon protein vaccination. Functional and genetic in vivo inactivation experiments attribute this enhancement primarily to MHC class II-restricted CD4(+) regulatory T cells (Treg), which appear to physiologically suppress the differentiation process towards long-living effector memory T cells. Since, in functional terms, this suppression by Treg largely exceeds the positive effects of conventional CD4(+) T cell help, even the absence of all CD4(+) T cells or lack of MHC class II-mediated interactions on priming dendritic cells result in enhanced CD8(+) T cell immunogenicity. These findings have important implications for the improvement of vaccines against intracellular pathogens or tumors, especially in patients with highly active Treg.

  17. Myeloma-like cast nephropathy caused by human recombinant soluble CD4 (sCD4) in monkeys.

    PubMed Central

    Bugelski, P. J.; Solleveld, H. A.; Fong, K. L.; Klinkner, A. M.; Hart, T. K.; Morgan, D. G.

    1992-01-01

    CD4 is the receptor for human immunodeficiency virus (HIV) on lymphocytes and macrophages. Soluble CD4 (sCD4), a recombinant truncated form of CD4, has been shown to inhibit HIV-1 in vitro and is being tested as a therapy for AIDS. Preclinical studies in cynomolgus monkeys revealed a protein cast nephropathy after four daily intravenous doses of 100 mg/kg/day. Renal lesions were not found in monkeys that received 10 mg/kg/day. The renal lesions consisted of proteinaceous tubular casts associated with multinucleate giant cells and neutrophils located in the tubules of the distal nephron. The affected tubules were surrounded by an interstitial mixed inflammatory cell infiltrate. By electron microscopy, the casts were composed of moderately electron dense, paracrystalline material. Immunostaining demonstrated that the casts contained sCD4-derived material and Tamm-Horsfall protein. Moreover, biochemical analysis of urine showed that a portion of sCD4 was excreted as intact protein. Because infection with HIV-1 can be associated with clinically significant nephropathy, these data suggest that renal function should be closely monitored in patients receiving soluble forms of CD4. Images Figure 1 Figure 2 Figure 3 PMID:1546739

  18. GM-CSF Production Allows the Identification of Immunoprevalent Antigens Recognized by Human CD4+ T Cells Following Smallpox Vaccination

    PubMed Central

    Judkowski, Valeria; Bunying, Alcinette; Ge, Feng; Appel, Jon R.; Law, Kingyee; Sharma, Atima; Raja- Gabaglia, Claudia; Norori, Patricia; Santos, Radleigh G.; Giulianotti, Marc A.; Slifka, Mark K.; Douek, Daniel C.; Graham, Barney S.; Pinilla, Clemencia

    2011-01-01

    The threat of bioterrorism with smallpox and the broad use of vaccinia vectors for other vaccines have led to the resurgence in the study of vaccinia immunological memory. The importance of the role of CD4+ T cells in the control of vaccinia infection is well known. However, more CD8+ than CD4+ T cell epitopes recognized by human subjects immunized with vaccinia virus have been reported. This could be, in part, due to the fact that most of the studies that have identified human CD4+ specific protein-derived fragments or peptides have used IFN-γ production to evaluate vaccinia specific T cell responses. Based on these findings, we reasoned that analyzing a large panel of cytokines would permit us to generate a more complete analysis of the CD4 T cell responses. The results presented provide clear evidence that TNF-α is an excellent readout of vaccinia specificity and that other cytokines such as GM-CSF can be used to evaluate the reactivity of CD4+ T cells in response to vaccinia antigens. Furthermore, using these cytokines as readout of vaccinia specificity, we present the identification of novel peptides from immunoprevalent vaccinia proteins recognized by CD4+ T cells derived from smallpox vaccinated human subjects. In conclusion, we describe a “T cell–driven” methodology that can be implemented to determine the specificity of the T cell response upon vaccination or infection. Together, the single pathogen in vitro stimulation, the selection of CD4+ T cells specific to the pathogen by limiting dilution, the evaluation of pathogen specificity by detecting multiple cytokines, and the screening of the clones with synthetic combinatorial libraries, constitutes a novel and valuable approach for the elucidation of human CD4+ T cell specificity in response to large pathogens. PMID:21931646

  19. Interleukin-2 Therapy Induces CD4 Downregulation, Which Decreases Circulating CD4 T Cell Counts, in African Green Monkeys

    PubMed Central

    Mudd, Joseph C.; Perkins, Molly R.; DiNapoli, Sarah R.; Hirsch, Vanessa M.

    2016-01-01

    ABSTRACT African green monkeys (AGMs) are natural hosts of simian immunodeficiency virus (SIVAGM). Because these animals do not develop simian AIDS despite maintaining high viral loads, there is considerable interest in determining how these animals have evolved to avoid SIV disease progression. Unlike nonnatural hosts of SIV, adult AGMs maintain low levels of CD4+ T cells at steady states and also have a large population of virus-resistant CD8αα T cells that lack CD4 expression despite maintaining T helper cell functionalities. In recent work, we have shown that homeostatic cytokines can induce CD4 downregulation in AGM T cells in vitro. Through administering therapeutic doses of recombinant human interleukin-2 (IL-2) to AGMs, we show here that this mechanism is operative in vivo. IL-2 therapy induced transient yet robust proliferation in all major T cell subsets. Within the CD4+ T cell population, those that were induced into cycle by IL-2 exhibited characteristics of CD4-to-CD8αα conversion. In all animals receiving IL-2, circulating CD4+ T cell counts and proportions tended to be lower and CD4− CD8αα+ T cell counts tended to be higher. Despite reductions in circulating target cells, the viral load was unaffected over the course of study. IMPORTANCE The data in this study identify that homeostatic cytokines can downregulate CD4 in vivo and, when given therapeutically, can induce AGMs to sustain very low levels of circulating CD4+ T cells without showing signs of immunodeficiency. PMID:27053558

  20. Decentralization of CD4 testing in resource-limited settings: 7 years of experience in six African countries.

    PubMed

    Marinucci, F; Medina-Moreno, S; Paterniti, A D; Wattleworth, M; Redfield, R R

    2011-05-01

    Improving access to CD4 testing in resource-limited settings can be achieved through both centralized and decentralized testing networks. Decentralized testing models are more suitable for countries where the HIV epidemic affects a large portion of rural populations. Timely access to accurate CD4 results is crucial at the primary level of the health system. For the past 7 years, the Institute of Human Virology of the University of Maryland School of Medicine has implemented a flexible and sustainable three-phase model: (1) site assessment and improvement, (2) appropriate technology selection with capacity building through practical training and laboratory mentoring, and (3) quality management system strengthening and monitoring, to support accessibility to reliable CD4 counting at the point of service. CD4 testing capacity was established in 122 of 229 (53%) laboratories supported in Nigeria, Uganda, Kenya, Zambia, Tanzania, and Rwanda. Among those in rural settings, 46% (69/151) had CD4 testing available at site level, with a functioning flow cytometer installed at 28% (8/29) and 50% (61/122) of level 1 and level 2 sites, respectively. To strengthen local capacity, a total of 1,152 laboratory technicians were trained through 188 training sessions provided both on-site and at central locations. The overall quality of CD4 total testing procedure was assessed at 76% (92/121) of the laboratories, with 25% (23/92), 34% (31/92), and 33% (30/92) of them reporting excellent, good, and satisfactory performance. Balancing country-specific factors with the location of the clinic, number of patients, and the expected workload, was crucial in adapting this flexible model for decentralizing CD4 testing. The close collaboration with local governments and private vendors was key to successfully expanding access to CD4 testing within the framework of HIV care and treatment programs and for the sustainability of medical laboratories in resource-limited settings.

  1. Dysregulation of CD4(+) T Cell Subsets in Intracranial Aneurysm.

    PubMed

    Zhang, Hai-Feng; Zhao, Ming-Guang; Liang, Guo-Biao; Yu, Chun-Yong; He, Wenxiu; Li, Zhi-Qing; Gao, Xu

    2016-02-01

    Intracranial aneurysms (IAs) and potential IA rupture are one of the direct causes of permanent brain damage and mortality. Interestingly, the major risk factors of IA development, including hemodynamic stress, hypertension, smoking, and genetic predispositions, are closely associated with a proinflammatory immune status. Therefore, we examined the roles of CD4(+) T cells in IA pathogenesis. IA patients exhibited peripheral CD4(+) T-cell imbalance, with overrepresented T helper 1 (Th1) and Th17 activities and underrepresented Th2 and regulatory T (Treg) activities, including increased IFN-γ, TNF-α, and IL-17 production and decreased IL-10 production from total CD4(+) T cells. Chemokine receptors CXCR3 and CCR6 were used to identify Th1, Th2, and Th17 cell subsets, and CD4(+)CD25(hi) was used to identify Treg cells. Based on these markers, the data then showed altered cytokine production by each cell type and shifted subpopulation frequency. Moreover, this shift in frequency was directly correlated with IA severity. To examine the underlying mechanism of CD4(+) T cell skewing, we cocultured CD4(+) T cells with autologous monocytes and found that coculture with monocytes could significantly increase IFN-γ and IL-17 production through contact-independent mechanisms, demonstrating that monocytes could potentially contribute to the altered CD4(+) T cell composition in IA. Analyzing mRNA transcripts revealed significantly upregulated IL-1β and TNF-α expression by monocytes from IA patients. We found a loss of CD4(+) T cell subset balance that was likely to promote a higher state of inflammation in IA, which may exacerbate the disease through a positive feedback loop.

  2. Cyclotriazadisulfonamides: promising new CD4-targeted anti-HIV drugs.

    PubMed

    Vermeire, Kurt; Schols, Dominique

    2005-08-01

    It is imperative to continue efforts to identify novel effective therapies that can assist in containing the spread of HIV. Recently acquired knowledge about the HIV entry process points to new strategies to block viral entry. For most HIV strains, the successful infection of their target cells is mainly dependent on the presence of the CD4 surface molecule, which serves as the primary virus receptor. The attachment of the viral envelope to this cellular CD4 receptor can be considered as an ideal target with multiple windows of opportunity for therapeutic intervention. Therefore, drugs that interfere with the CD4 receptor, and thus inhibit viral entry, may be promising agents for the treatment of AIDS. The CD4-targeted HIV entry inhibitors cyclotriazadisulfonamides represent a novel class of small molecule antiviral agents with a unique mode of action. The lead compound, CADA, specifically interacts with the cellular CD4 receptor and is active against a wide variety of HIV strains at submicromolar levels when evaluated in different cell-types such as T cells, monocytes and dendritic cells. Moreover, a strict correlation has been demonstrated between anti-HIV activity and CD4 interaction of about 20 different CADA analogues. In addition, CADA acted synergistically in combination with all other FDA-approved anti-HIV drugs as well as with compounds that target the main HIV co-receptors. In this article, the characteristics of cyclotriazadisulfonamide compounds are presented and the possible application of CADA as a microbicide is also discussed.

  3. Establishment of HIV-1 latency in resting CD4+ T cells depends on chemokine-induced changes in the actin cytoskeleton.

    PubMed

    Cameron, Paul U; Saleh, Suha; Sallmann, Georgina; Solomon, Ajantha; Wightman, Fiona; Evans, Vanessa A; Boucher, Genevieve; Haddad, Elias K; Sekaly, Rafick-Pierre; Harman, Andrew N; Anderson, Jenny L; Jones, Kate L; Mak, Johnson; Cunningham, Anthony L; Jaworowski, Anthony; Lewin, Sharon R

    2010-09-28

    Eradication of HIV-1 with highly active antiretroviral therapy (HAART) is not possible due to the persistence of long-lived, latently infected resting memory CD4(+) T cells. We now show that HIV-1 latency can be established in resting CD4(+) T cells infected with HIV-1 after exposure to ligands for CCR7 (CCL19), CXCR3 (CXCL9 and CXCL10), and CCR6 (CCL20) but not in unactivated CD4(+) T cells. The mechanism did not involve cell activation or significant changes in gene expression, but was associated with rapid dephosphorylation of cofilin and changes in filamentous actin. Incubation with chemokine before infection led to efficient HIV-1 nuclear localization and integration and this was inhibited by the actin stabilizer jasplakinolide. We propose a unique pathway for establishment of latency by direct HIV-1 infection of resting CD4(+) T cells during normal chemokine-directed recirculation of CD4(+) T cells between blood and tissue.

  4. Central Auditory Dysfunction in Older People with Memory Impairment or Alzheimer's Dementia

    PubMed Central

    Gates, George A.; Anderson, Melissa L.; Feeney, M. Patrick; McCurry, Susan M.; Larson, Eric B.

    2009-01-01

    Central auditory function is commonly compromised in people with a diagnosis of Alzheimer's disease (AD) and may precede the onset of clinical dementia by several years. Given that screening for AD in its earliest stages might someday be useful for emerging therapies aimed at limiting progression, we inquired whether central auditory testing might be suitable for identifying people at risk for dementia. To address this question, we performed a battery of behavioral central auditory tests in a cohort of 313 older people enrolled in a dementia surveillance research program. The cohort consisted of three groups: controls without memory loss (N=232), targets with mild memory impairment but without dementia (N=64), and targets with a dementia diagnosis (N=17). The auditory tests were the Synthetic Sentence Identification with Ipsilateral Competing Message (SSI), the Dichotic Sentence Identification test (DSI), the Dichotic Digits Test (DDT), and the Pitch Pattern Sequence (PPS) test. Additional control was provided by electrophysiologic testing to assess the integrity of the primary auditory pathways. The mean score on each central auditory test worsened significantly across the three memory groups even after adjusting for age and peripheral hearing status, being poorest in the pAD group and moderately reduced in the memory-impaired group compared to the mean scores in the control group. Heterogeneity of results was noted in all three groups. The electrophysiologic tests did not differ across the three groups. Central auditory function was affected by mild memory impairment. The Dichotic Sentence Identification in the free report mode appears to be the central auditory test most sensitive to the presence of memory impairment. Although central auditory testing requires specialized equipment and training, the objectivity of these tests is appealing. We recommend that comprehensive auditory testing be considered and further evaluated for its potential value as a baseline

  5. OX40 controls effector CD4+ T-cell expansion, not follicular T helper cell generation in acute Listeria infection.

    PubMed

    Marriott, Clare L; Mackley, Emma C; Ferreira, Cristina; Veldhoen, Marc; Yagita, Hideo; Withers, David R

    2014-08-01

    To investigate the importance of OX40 signals for physiological CD4(+) T-cell responses, an endogenous antigen-specific population of CD4(+) T cells that recognise the 2W1S peptide was assessed and temporal control of OX40 signals was achieved using blocking or agonistic antibodies (Abs) in vivo. Following infection with Listeria monocytogenes expressing 2W1S peptide, OX40 was briefly expressed by the responding 2W1S-specific CD4(+) T cells, but only on a subset that co-expressed effector cell markers. This population was specifically expanded by Ab-ligation of OX40 during priming, which also caused skewing of the memory response towards effector memory cells. Strikingly, this greatly enhanced effector response was accompanied by the loss of T follicular helper (TFH) cells and germinal centres. Mice deficient in OX40 and CD30 showed normal generation of TFH cells but impaired numbers of 2W1S-specific effector cells. OX40 was not expressed by 2W1S-specific memory cells, although it was rapidly up-regulated upon challenge whereupon Ab-ligation of OX40 specifically affected the effector subset. In summary, these data indicate that for CD4(+) T cells, OX40 signals are important for generation of effector T cells rather than TFH cells in this response to acute bacterial infection.

  6. Loss of CD4 membrane expression and CD4 mRNA during acute human immunodeficiency virus replication

    PubMed Central

    1988-01-01

    Using mAbs and genomic probe to the CD4 molecule, the HIV receptor, we demonstrated that HIV replication induces the disappearance of its functional receptor from the cell surface by two distinct mechanisms. First, after being expressed onto the cell surface, HIV envelope gp110 will complex CD4, efficiently masking the CD4 epitope used by the virus to bind its receptor. This phenomenon occurs on the surface of each infected cell and is not due to the release of soluble gp110; infection with recombinant HIV/vaccinia viruses expressing a mutated HIV env gene designed to prevent gp110 release from the cell surface induces a similar gp/CD4 complexes formation. Second, virus replication induces a dramatic and rapid loss of CD4 mRNA transcripts, preventing new CD4 molecules from being synthesized. These two mechanisms of receptor modulation could have been developed to avoid reinfection of cells replicating the virus as well as to produce more infectious particles. These results suggest that the classical virus interference documented for other retroviruses might not only be due to receptor/envelope interaction, but might also depend on receptor gene expression. PMID:3264318

  7. Circulating CXCR5+CD4+ T cells assist in the survival and growth of primary diffuse large B cell lymphoma cells through interleukin 10 pathway.

    PubMed

    Cha, Zhanshan; Qian, Guangfang; Zang, Yan; Gu, Haihui; Huang, Yanyan; Zhu, Lishuang; Li, Jinqi; Liu, Yang; Tu, Xiaohua; Song, Haihan; Qian, Baohua

    2017-01-01

    Diffuse large B cell lymphoma (DLBCL) is a common and aggressive cancer caused by the malignant transformation of B cells. Although it has been established that the follicular helper T (Tfh) cells play a central role in B cell development, little information is available on their involvement in DLBCL pathogenesis. We studied the role of the peripheral Tfh equivalent, the CXCR5(+) CD4(+) T cells, in DLBCL. Data showed that compared to CXCR5(-) CD4(+) T cells, CXCR5(+) CD4(+) T cells were significantly more effective at promoting the proliferation as well as inhibiting the apoptosis of primary autologous DLBCL tumor cells. Surprisingly, we found that at equal cell numbers, CXCR5(+) CD4(+) T cells in DLBCL patients secreted significantly less interleukin (IL)-21 than CXCR5(-) CD4(+) T cells, while the level of IL-10 secretion was significant elevated in the CXCR5(+) compartment compared to the CXCR5(-) compartment. Neutralization of IL-10 in the primary DLBCL-CXCR5(+) CD4(+) T cell coculture compromised the CXCR5(+) CD4(+) T cell-mediated pro-tumor effects, in a manner that was dependent on the concentration of anti-IL-10 antibodies. The CXCR5(+) compartment also contained significantly lower frequencies of cytotoxic CD4(+) T cells than the CXCR5(-) compartment. In conclusion, our investigations discovered a previously unknown pro-tumor role of CXCR5-expressing circulating CD4(+) T cells, which assisted the survival and proliferation of primary DLBCL cells through IL-10.

  8. Impairment of visual memory for objects in natural scenes by simulated central scotomata.

    PubMed

    Geringswald, Franziska; Porracin, Eleonora; Pollmann, Stefan

    2016-01-01

    Because of the close link between foveal vision and the spatial deployment of attention, typically only objects that have been foveated during scene exploration may form detailed and persistent memory representations. In a recent study on patients suffering from age-related macular degeneration, however, we found surprisingly accurate visual long-term memory for objects in scenes. Normal exploration patterns that the patients had learned to rereference saccade targets to an extrafoveal retinal location. This rereferencing may allow use of an extrafoveal location as a focus of attention for efficient object encoding into long-term memory. Here, we tested this hypothesis in normal-sighted observers with gaze-contingent central scotoma simulations. As these observers were inexperienced in scene exploration with central vision loss and had not developed saccadic rereferencing, we expected deficits in long-term memory for objects. We used the same change detection task as in our patient study, probing sensitivity to object changes after a period of free scene exploration. Change detection performance was significantly reduced for two types of scotoma simulation diminishing foveal and parafoveal vision--a visible gray disc and a more subtle image warping--compared with unimpaired controls, confirming our hypothesis. The impact of a smaller scotoma covering specifically foveal vision was less distinct, leading to a marginally significant decrease of long-term memory performance compared with controls. We conclude that attentive encoding of objects is deficient when central vision is lost as long as successful saccadic rereferencing has not yet developed.

  9. Central coherence, organizational strategy, and visuospatial memory in children and adolescents with anorexia nervosa.

    PubMed

    Rose, Mark; Frampton, Ian J; Lask, Bryan

    2014-01-01

    The vast majority of studies in anorexia nervosa that have investigated the domains of central coherence, organizational strategy, and visuospatial memory have focused on adult samples. In addition, studies investigating visuospatial memory have focused on free recall. No study to date has reported the association between recognition memory and central coherence or organizational strategy in younger people with this disorder, yet the capacity to recognize previously seen visual stimuli may contribute to overall visuospatial ability. Therefore, we investigate these domains in children and adolescents with anorexia nervosa compared to age- and gender-matched healthy controls. There were no significant group differences in immediate, delayed, or recognition memory, central coherence, or organization strategy. When compared with controls, patients with anorexia nervosa scored significantly higher on accuracy and took significantly longer when copying the Rey Complex Figure Task. Caution must be taken when interpreting these findings due to lower-than-expected scores in memory performance in the control group and because of a potential lack of sensitivity in the measures used when assessing this younger population. For neuropsychological functions where no normative data exist, we need a deeper, more thorough knowledge of the developmental trajectory and its assessment in young people in the general population before drawing conclusions in anorexia nervosa.

  10. Difficulties in precise quantitation of CD4+ T lymphocytes for clinical trials: a review.

    PubMed

    Fei, D T; Paxton, H; Chen, A B

    1993-09-01

    Maintenance of CD4+ T helper lymphocyte counts has been used as a surrogate marker of efficacy for drugs in the treatment of AIDS. In a multicenter clinical trial, subtle improvement of CD4+ T cell counts may be masked and misinterpreted if care is not paid to likely sources that can contribute to the variability of measurement of CD4+ T lymphocytes. This review addresses major areas that can contribute to the variability of measurement of CD4+ T lymphocytes, with emphasis on applications to multicenter clinical trials, and proposes areas of improvement that may not be well recognized by the medical community. Whereas there are excellent guidelines for immunophenotyping, equal attention is needed in hematologic enumeration of WBC and absolute lymphocytes. In particular, allowing the margin of error acceptable to blood cell standards for HIV-infected specimens is unsatisfactory. Special attention should also be given to the stability of lymphocytes in the anticoagulant during storage, the lysing method, the quality assurance programs as well as intrasubject fluctuations which may be derived from exercise, medications and diurnal variations. Awareness of these contributing factors by physicians and technical analysts will expedite the discovery of potential therapy in the treatment of AIDS. For a multicenter clinical trial, it is advisable to select a centralized laboratory adopting a uniform protocol with regard to sample preparation and handling, using more stringent quality controls for hematologic analysers, calibration of instruments and immunophenotyping. Pending a true reference standard that can monitor the variation of the entire analytical procedure, we anticipate that future interlaboratory quality assurance programs will include absolute T lymphocyte count, an important parameter for assessing the accuracy and consistency of CD4+ T helper cell counts generated from a laboratory.

  11. Dissociation of the CD4 downregulation and viral infectivity enhancement functions of human immunodeficiency virus type 1 Nef.

    PubMed Central

    Goldsmith, M A; Warmerdam, M T; Atchison, R E; Miller, M D; Greene, W C

    1995-01-01

    Recent evidence indicates that the nef gene of human immunodeficiency virus type 1 augments rather than inhibits viral replication in both cell culture and in vivo models. In addition, nef alters various normal cellular processes, including the display of CD4 on the cell surface. However, it remains unknown whether the enhancement of infectivity and the downregulation of CD4 represent linked or independent biologic properties of this single protein. In the present studies, mutational analyses were performed to define structure-function relationships within the Nef protein that mediate these effects. To assess the functional consequences of these mutations, sensitive and reliable assays were developed to quantitate the viral infectivity enhancement and CD4 downregulation functions of Nef. The results indicate that membrane-targeting sequences at the N terminus of Nef are important for both functions of Nef, while certain other conserved regions are dispensable for both functions. A conserved proline-X-X repeat segment in the central core of the protein, which is reminiscent of an SH3-binding domain, is critical for the enhancement of infectivity function but is dispensable for CD4 downregulation. However, the downregulation of CD4 by Nef appears to involve a two-step process requiring the initial dissociation of p56lck from CD4 to permit engagement of the endocytic apparatus by CD4. Together, these findings demonstrate that the infectivity enhancement and CD4 downregulation activities of human immunodeficiency virus type 1 Nef can be dissociated. Thus, these processes may be independent of one another in the viral replication cycle. PMID:7769669

  12. Working Memory and Mental Arithmetic: A Case for Dual Central Executive Resources

    ERIC Educational Resources Information Center

    Ketelsen, Kirk; Welsh, Marilyn

    2010-01-01

    The current study was designed to examine the possible existence of two limited-capacity pools of central executive resources: one each for verbal and visuospatial processing. Ninety-one college students (M age = 19.0, SD = 2.2) were administered a verbal working memory task that involved updating numbers in 2-, 3-, and 4-load conditions. The task…

  13. A Central Capacity Limit to the Simultaneous Storage of Visual and Auditory Arrays in Working Memory

    ERIC Educational Resources Information Center

    Saults, J. Scott; Cowan, Nelson

    2007-01-01

    If working memory is limited by central capacity (e.g., the focus of attention; N. Cowan, 2001), then storage limits for information in a single modality should apply also to the simultaneous storage of information from different modalities. The authors investigated this by combining a visual-array comparison task with a novel auditory-array…

  14. Bovine central memory T cells are highly proliferative in response to bovine tuberculosis infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term (i.e., 14 days) cultured IFN-gamma ELISPOT assays measure central memory T cell (Tcm) responses in both humans and cattle. With bovine tuberculosis, vaccine-elicited long-term IFN-gamma ELISPOT responses correlate with protection. In other species, Tcm’s pose low activation threshold and a...

  15. Bovine central memory T cells are highly proliferative in response to bovine tuberculosis infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term (i.e., 14 days) cultured IFN-gamma responses of peripheral blood mononuclear cells are used as a correlate of T cell central memory (Tcm) responses in both humans and cattle. With bovine tuberculosis, vaccine-elicited long-term IFN-gamma ELISPOT assays are a correlate of protection. Recent...

  16. Identification and characterization of a second CD4-like gene in teleost fish.

    PubMed

    Dijkstra, Johannes Martinus; Somamoto, Tomonori; Moore, Lindsey; Hordvik, Ivar; Ototake, Mitsuru; Fischer, Uwe

    2006-02-01

    In fish, T cell subdivision is not well studied, although CD8 and CD4 homologues have been reported. This study describes a second teleost CD4-like gene, CD4-like 2 (CD4L-2). Two rainbow trout copies of this gene were found, -2a and -2b, encoding molecules sharing 81% aa identity. The 2a/2b duplication may be related to tetraploid ancestry of salmonid fishes. In the Fugu genome CD4L-2 lies head to tail with an earlier reported, very different CD4-like gene [Suetake, H., Araki, K., Suzuki, Y., 2004. Cloning, expression, and characterization of fugu CD4, the first ectothermic animal CD4. Immunogenetics 56, 368-374], which was designated CD4L-1 in the present article. The flanking genes of the Fugu CD4L-1 and CD4L-2 are reminiscent of the genes surrounding CD4 and LAG-3 in mammals. However, neither synteny nor phylogenetic analysis could decide between CD4 and LAG-3 identity for the fish CD4L genes. CD4L-1 and CD4L-2 share a tyrosine protein kinase p56(lck) binding motif in the cytoplasmic tail with CD4 but not with LAG-3. Trout CD4L-2 expression is highest in the thymus, similar to mammalian and chicken CD4, whereas Fugu CD4L-1 expression was highest in the spleen. However, CD4L-2 encodes only two IG-like domains, whereas CD4L-1, CD4 and LAG-3 encode four. The CD4-like genes 1 and 2 in fish apparently went through an evolution different from that of LAG-3 and CD4 in higher vertebrates.

  17. Normalization of CD4+ T Cell Metabolism Reverses Lupus

    PubMed Central

    Yin, Yiming; Choi, Seung-Chul; Xu, Zhiwei; Perry, Daniel J.; Seay, Howard; Croker, Byron P.; Sobel, Eric S.; Brusko, Todd M.; Morel, Laurence

    2015-01-01

    Systemic Lupus Erythematosus (SLE) is an autoimmune disease in which autoreactive CD4+ T cells play an essential role. CD4+ T cells rely on glycolysis for inflammatory effector functions, but recent studies have shown that mitochondrial metabolism supports their chronic activation. How these processes contribute to lupus is unclear. Here, we show that both glycolysis and mitochondrial oxidative metabolism are elevated in CD4+ T cells from lupus-prone B6.Sle1.Sle2.Sle3 (TC) mice as compared to non-autoimmune controls. In vitro, both the mitochondrial metabolism inhibitor metformin and the glucose metabolism inhibitor 2-Deoxy-D-glucose (2DG) reduced IFNγ production, although at different stages of activation. Metformin also restored the defective IL-2 production by TC CD4+ T cells. In vivo, treatment of TC mice and other lupus models with a combination of metformin and 2DG normalized T cell metabolism and reversed disease biomarkers. Further, CD4+ T cells from SLE patients also exhibited enhanced glycolysis and mitochondrial metabolism that correlated with their activation status, and their excessive IFNγ production was significantly reduced by metformin in vitro. These results suggest that normalization of T cell metabolism through the dual inhibition of glycolysis and mitochondrial metabolism is a promising therapeutic venue for SLE. PMID:25673763

  18. Idiopathic CD4+ lymphocytopenia: natural history and prognostic factors

    PubMed Central

    Falloon, Judith; Bennett, John E.; Shaw, Pamela A.; Chaitt, Doreen; Baseler, Michael W.; Adelsberger, Joseph W.; Metcalf, Julia A.; Polis, Michael A.; Kovacs, Stephen J.; Kovacs, Joseph A.; Davey, Richard T.; Lane, H. Clifford; Masur, Henry

    2008-01-01

    Idiopathic CD4+ lymphocytopenia (ICL) is a rare non–HIV-related syndrome with unclear natural history and prognosis. This prospective natural history cohort study describes the clinical course, CD4 T lymphocyte kinetics, outcome, and prognostic factors of ICL. Thirty-nine patients (17 men, 22 women) 25 to 85 years old with ICL were evaluated between 1992 and 2006, and 36 were followed for a median of 49.5 months. Cryptococcal and nontuberculous mycobacterial infections were the major presenting opportunistic infections. Seven patients presented with no infection. In 32, CD4 T-cell counts remained less than 300/mm3 throughout the study period and in 7 normalized after an average of 31 months. Overall, 15 (41.6%) developed an opportunistic infection in follow-up, 5 (13.8%) of which were “AIDS-defining clinical conditions,” and 4 (11.1%) developed autoimmune diseases. Seven patients died, 4 from ICL-related opportunistic infections, within 42 months after diagnosis. Immunologic analyses revealed increased activation and turnover in CD4 but not CD8 T lymphocytes. CD8 T lymphocytopenia (< 180/mm3) and the degree of CD4 T cell activation (measured by HLA-DR expression) at presentation were associated with adverse outcome (opportunistic infection-related death; P = .003 and .02, respectively). This trial is registered at http://clinicaltrials.gov as #NCT00001319. PMID:18456875

  19. Immune-responsiveness of CD4+ T cells during Streptococcus suis serotype 2 infection

    PubMed Central

    Lecours, Marie-Pier; Letendre, Corinne; Clarke, Damian; Lemire, Paul; Galbas, Tristan; Benoit-Biancamano, Marie-Odile; Thibodeau, Jacques; Gottschalk, Marcelo; Segura, Mariela

    2016-01-01

    The pathogenesis of Streptococcus suis infection, a major swine and human pathogen, is only partially understood and knowledge on the host adaptive immune response is critically scarce. Yet, S. suis virulence factors, particularly its capsular polysaccharide (CPS), enable this bacterium to modulate dendritic cell (DC) functions and potentially impair the immune response. This study aimed to evaluate modulation of T cell activation during S. suis infection and the role of DCs in this response. S. suis-stimulated total mouse splenocytes readily produced TNF-α, IL-6, IFN-γ, CCL3, CXCL9, and IL-10. Ex vivo and in vivo analyses revealed the involvement of CD4+ T cells and a Th1 response. Nevertheless, during S. suis infection, levels of the Th1-derived cytokines TNF-α and IFN-γ were very low. A transient splenic depletion of CD4+ T cells and a poor memory response were also observed. Moreover, CD4+ T cells secreted IL-10 and failed to up-regulate optimal levels of CD40L and CD69 in coculture with DCs. The CPS hampered release of several T cell-derived cytokines in vitro. Finally, a correlation was established between severe clinical signs of S. suis disease and impaired antibody responses. Altogether, these results suggest S. suis interferes with the adaptive immune response. PMID:27905502

  20. Expanding Roles for CD4 T Cells and Their Subpopulations in Tumor Immunity and Therapy

    PubMed Central

    Dobrzanski, Mark J.

    2013-01-01

    The importance of CD4 T cells in orchestrating the immune system and their role in inducing effective T cell-mediated therapies for the treatment of patients with select established malignancies are undisputable. Through a complex and balanced array of direct and indirect mechanisms of cellular activation and regulation, this functionally diverse family of lymphocytes can potentially promote tumor eradication, long-term tumor immunity, and aid in establishing and/or rebalancing immune cell homeostasis through interaction with other immune cell populations within the highly dynamic tumor environment. However, recent studies have uncovered additional functions and roles for CD4 T cells, some of which are independent of other lymphocytes, that can not only influence and contribute to tumor immunity but paradoxically promote tumor growth and progression. Here, we review the recent advances in our understanding of the various CD4 T cell lineages and their signature cytokines in disease progression and/or regression. We discuss their direct and indirect mechanistic interplay among themselves and with other responding cells of the antitumor response, their potential roles and abilities for “plasticity” and memory cell generation within the hostile tumor environment, and their potentials in cancer treatment and immunotherapy. PMID:23533029

  1. Identification of novel Mycobacterium tuberculosis CD4 T-cell antigens via high throughput proteome screening

    PubMed Central

    Nayak, Kaustuv; Jing, Lichen; Russell, Ronnie M.; Davies, D. Huw; Hermanson, Gary; Molina, Douglas M.; Liang, Xiaowu; Sherman, David R.; Kwok, William W.; Yang, Junbao; Kenneth, John; Ahamed, Syed F.; Chandele, Anmol; Kaja, Murali-Krishna; Koelle, David M.

    2015-01-01

    Elicitation of CD4 IFN-gamma T cell responses to Mycobacterium tuberculosis (MTB) is a rational vaccine strategy to prevent clinical tuberculosis. Diagnosis of MTB infection is based on T-cell immune memory to MTB antigens. The MTB proteome contains over four thousand open reading frames (ORFs). We conducted a pilot antigen identification study using 164 MTB proteins and MTB-specific T-cells expanded in vitro from 12 persons with latent MTB infection. Enrichment of MTB-reactive T-cells from PBMC used cell sorting or an alternate system compatible with limited resources. MTB proteins were used as single antigens or combinatorial matrices in proliferation and cytokine secretion readouts. Overall, our study found that 44 MTB proteins were antigenic, including 27 not previously characterized as CD4 T-cell antigens. Antigen truncation, peptide, NTM homology, and HLA class II tetramer studies confirmed malate synthase G (encoded by gene Rv1837) as a CD4 T-cell antigen. This simple, scalable system has potential utility for the identification of candidate MTB vaccine and biomarker antigens. PMID:25857935

  2. Unusual CD4+CD28− T Cells and Their Pathogenic Role in Chronic Inflammatory Disorders

    PubMed Central

    Lee, Ga Hye

    2016-01-01

    CD28 is a primary co-stimulatory receptor that is essential for successful T cell activation, proliferation, and survival. While ubiquitously expressed on naive T cells, the level of CD28 expression on memory T cells is largely dependent on the T-cell differentiation stage in humans. Expansion of circulating T cells lacking CD28 was originally considered a hallmark of age-associated immunological changes in humans, with a progressive loss of CD28 following replicative senescence with advancing age. However, an increasing body of evidence has revealed that there is a significant age-inappropriate expansion of CD4+CD28− T cells in patients with a variety of chronic inflammatory diseases, suggesting that these cells play a role in their pathogenesis. In fact, expanded CD4+CD28− T cells can produce large amounts of proinflammatory cytokines such as IFN-γ and TNF-α and also have cytotoxic potential, which may cause tissue damage and development of pathogenesis in many inflammatory disorders. Here we review the characteristics of CD4+CD28− T cells as well as the recent advances highlighting the contribution of these cells to several disease conditions. PMID:28035207

  3. Functional deficits of pertussis-specific CD4+ T cells in infants compared to adults following DTaP vaccination

    PubMed Central

    Sharma, S K; Pichichero, M E

    2012-01-01

    Understanding the immune responses that explain why infants require multiple doses of pertussis vaccine to achieve protection against infection is a high priority. The objective of this study was to compare the function and phenotypes of antigen-specific CD4+ T cells in adults (n = 12), compared to infants (n = 20), following vaccination with acellular pertussis (DTaP) vaccine. Peripheral blood mononuclear cells (PBMCs) were stimulated with pertussis toxoid (PT), pertactin (PRN) and filamentous haemagglutinin (FHA). Multi-parameter flow cytometry was used to delineate CD4+ T cell populations and phenotypes producing interferon (IFN)-γ, interleukin (IL)-2, tumour necrosis factor (TNF)-α and IL-4. Based on surface CD69 expression, infants demonstrated activation of vaccine antigen-specific CD4+ T cells similar to adults. However, among infants, Boolean combinations of gates suggested that type 1 (Th-1) CD4+ T cell responses were confined largely to TNF-α+IL-2+IFN-γ- or TNF-α+IL-2-IFN-γ-. A significantly lower percentage of polyfunctional T helper type 1 (Th1) responses (TNF-α+IFN-γ+IL-2+) and type 2 (Th2) responses (IL-4) were present in the infants compared to adults. Moreover, a significantly higher percentage of infants' functional CD4+ T cells were restricted to CD45RA-CCR7+CD27+ phenotype, consistent with early-stage differentiated pertussis-specific memory CD4+ T cells. We show for the first time that DTaP vaccination-induced CD4+ T cells in infants are functionally and phenotypically dissimilar from those of adults. PMID:22861368

  4. Downmodulation of CCR7 by HIV-1 Vpu results in impaired migration and chemotactic signaling within CD4⁺ T cells.

    PubMed

    Ramirez, Peter W; Famiglietti, Marylinda; Sowrirajan, Bharatwaj; DePaula-Silva, Ana Beatriz; Rodesch, Christopher; Barker, Edward; Bosque, Alberto; Planelles, Vicente

    2014-06-26

    The chemokine receptor CCR7 plays a crucial role in the homing of central memory and naive T cells to peripheral lymphoid organs. Here, we show that the HIV-1 accessory protein Vpu downregulates CCR7 on the surface of CD4(+) T cells. Vpu and CCR7 were found to specifically interact and colocalize within the trans-Golgi network, where CCR7 is retained. Downmodulation of CCR7 did not involve degradation or endocytosis and was strictly dependent on Vpu expression. Stimulation of HIV-1-infected primary CD4(+) T cells with the CCR7 ligand CCL19 resulted in reduced mobilization of Ca(2+), reduced phosphorylation of Erk1/2, and impaired migration toward CCL19. Specific amino acid residues within the transmembrane domain of Vpu that were previously shown to be critical for BST-2 downmodulation (A14, A18, and W22) were also necessary for CCR7 downregulation. These results suggest that BST-2 and CCR7 may be downregulated via similar mechanisms.

  5. Development of promyelocytic leukemia zinc finger-expressing innate CD4 T cells requires stronger T-cell receptor signals than conventional CD4 T cells.

    PubMed

    Qiao, Yu; Zhu, Lingqiao; Sofi, Hanief; Lapinski, Philip E; Horai, Reiko; Mueller, Kristen; Stritesky, Gretta L; He, Xi; Teh, Hung-Sia; Wiest, David L; Kappes, Dietmar J; King, Philip D; Hogquist, Kristin A; Schwartzberg, Pamela L; Sant'Angelo, Derek B; Chang, Cheong-Hee

    2012-10-02

    MHC class II-expressing thymocytes and thymic epithelial cells can mediate CD4 T-cell selection resulting in functionally distinct thymocyte-selected CD4 (T-CD4) and epithelial-selected CD4 (E-CD4) T cells, respectively. However, little is known about how T-cell receptor (TCR) signaling influences the development of these two CD4 T-cell subsets. To study TCR signaling for T-CD4 T-cell development, we used a GFP reporter system of Nur77 in which GFP intensity directly correlates with TCR signaling strength. T-CD4 T cells expressed higher levels of GFP than E-CD4 T cells, suggesting that T-CD4 T cells received stronger TCR signaling than E-CD4 T cells during selection. Elimination of Ras GTPase-activating protein enhanced E-CD4 but decreased T-CD4 T-cell selection efficiency, suggesting a shift to negative selection. Conversely, the absence of IL-2-inducible T-cell kinase that causes poor E-CD4 T-cell selection due to insufficient TCR signaling improved T-CD4 T-cell generation, consistent with rescue from negative selection. Strong TCR signaling during T-CD4 T-cell development correlates with the expression of the transcription factor promyelocytic leukemia zinc finger protein. However, although modulation of the signaling strength affected the efficiency of T-CD4 T-cell development during positive and negative selection, the signaling strength is not as important for the effector function of T-CD4 T cells. These findings indicate that innate T-CD4 T cells, together with invariant natural killer T cells and γδ T cells, receive strong TCR signals during their development and that signaling requirements for the development and the effector functions are distinct.

  6. Importance of B cell co-stimulation in CD4+ T cell differentiation: X-linked agammaglobulinaemia, a human model

    PubMed Central

    Martini, H; Enright, V; Perro, M; Workman, S; Birmelin, J; Giorda, E; Quinti, I; Lougaris, V; Baronio, M; Warnatz, K; Grimbacher, B

    2011-01-01

    We were interested in the question of whether the congenital lack of B cells actually had any influence on the development of the T cell compartment in patients with agammaglobulinaemia. Sixteen patients with X-linked agammaglobulinaemia (XLA) due to mutations in Btk, nine patients affected by common variable immune deficiency (CVID) with <2% of peripheral B cells and 20 healthy volunteers were enrolled. The T cell phenotype was determined with FACSCalibur and CellQuest Pro software. Mann–Whitney two-tailed analysis was used for statistical analysis. The CD4 T cell memory compartment was reduced in patients with XLA of all ages. This T cell subset encompasses both CD4+CD45RO+ and CD4+CD45RO+CXCR5+ cells and both subsets were decreased significantly when compared to healthy controls: P = 0·001 and P < 0·0001, respectively. This observation was confirmed in patients with CVID who had <2% B cells, suggesting that not the lack of Bruton's tyrosine kinase but the lack of B cells is most probably the cause of the impaired CD4 T cell maturation. We postulate that this defect is a correlate of the observed paucity of germinal centres in XLA. Our results support the importance of the interplay between B and T cells in the germinal centre for the activation of CD4 T cells in humans. PMID:21488866

  7. Importance of B cell co-stimulation in CD4(+) T cell differentiation: X-linked agammaglobulinaemia, a human model.

    PubMed

    Martini, H; Enright, V; Perro, M; Workman, S; Birmelin, J; Giorda, E; Quinti, I; Lougaris, V; Baronio, M; Warnatz, K; Grimbacher, B

    2011-06-01

    We were interested in the question of whether the congenital lack of B cells actually had any influence on the development of the T cell compartment in patients with agammaglobulinaemia. Sixteen patients with X-linked agammaglobulinaemia (XLA) due to mutations in Btk, nine patients affected by common variable immune deficiency (CVID) with <2% of peripheral B cells and 20 healthy volunteers were enrolled. The T cell phenotype was determined with FACSCalibur and CellQuest Pro software. Mann-Whitney two-tailed analysis was used for statistical analysis. The CD4 T cell memory compartment was reduced in patients with XLA of all ages. This T cell subset encompasses both CD4(+)CD45RO(+) and CD4(+)CD45RO(+)CXCR5(+) cells and both subsets were decreased significantly when compared to healthy controls: P = 0·001 and P < 0·0001, respectively. This observation was confirmed in patients with CVID who had <2% B cells, suggesting that not the lack of Bruton's tyrosine kinase but the lack of B cells is most probably the cause of the impaired CD4 T cell maturation. We postulate that this defect is a correlate of the observed paucity of germinal centres in XLA. Our results support the importance of the interplay between B and T cells in the germinal centre for the activation of CD4 T cells in humans.

  8. Differential effects of CD28 costimulation upon cytokine production by CD4+ and CD8+ T cells.

    PubMed

    Rochford, Rosemary; Riggs, James E; Clavo, Anaira; Ernst, David N; Hobbs, Monte V

    2004-01-01

    The impact of CD28 ligation upon CD4+ and CD8+ T lymphocyte proliferation and cytokine production was assessed. Although costimulation increased the proliferative response of both T cell subsets, cytokine production was most markedly increased in the CD4+ subset, as evidenced by a 40-fold increase in interleukin-2 (IL-2), a 14-fold increase in interleukin-3 (IL-3) and 5-fold increases in interferon gamma and GM-colony-stimulating factor (CSF) production. The CD8+ T cell response to CD28 ligation was less marked, maxima being a 5-fold increase in IL-2 production and 2-fold increases in IL-3 and GM-CSF production. Resolution of CD4+ and CD8+ T cells into their CD44lo (naïve) and CD44hi (memory/effector) subsets revealed that naive CD4+ T cells were the most CD28-responsive subsets. CD28-mediated costimulation promotes distinct differentiation programs in CD4+ versus CD8+ T cells.

  9. Immediate Dysfunction of Vaccine-Elicited CD8+ T Cells Primed in the Absence of CD4+ T Cells

    PubMed Central

    Provine, Nicholas M.; Larocca, Rafael A.; Aid, Malika; Penaloza-MacMaster, Pablo; Badamchi-Zadeh, Alexander; Borducchi, Erica N.; Yates, Kathleen B.; Abbink, Peter; Kirilova, Marinela; Ng’ang’a, David; Bramson, Jonathan; Haining, W. Nicholas

    2016-01-01

    CD4+ T cell help is critical for optimal CD8+ T cell memory differentiation and maintenance in many experimental systems. In addition, many reports have identified reduced primary CD8+ T cell responses in the absence of CD4+ T cell help, which often coincides with reduced Ag or pathogen clearance. In this study, we demonstrate that absence of CD4+ T cells at the time of adenovirus vector immunization of mice led to immediate impairments in early CD8+ T cell functionality and differentiation. Unhelped CD8+ T cells exhibited a reduced effector phenotype, decreased ex vivo cytotoxicity, and decreased capacity to produce cytokines. This dysfunctional state was imprinted within 3 d of immunization. Unhelped CD8+ T cells expressed elevated levels of inhibitory receptors and exhibited transcriptomic exhaustion and anergy profiles by gene set enrichment analysis. Dysfunctional, impaired effector differentiation also occurred following immunization of CD4+ T cell–deficient mice with a poxvirus vector. This study demonstrates that following priming with viral vectors, CD4+ T cell help is required to promote both the expansion and acquisition of effector functions by CD8+ T cells, which is accomplished by preventing immediate dysfunction. PMID:27448585

  10. Regulation of the Neurodegenerative Process Associated to Parkinson's Disease by CD4+ T-cells.

    PubMed

    González, Hugo; Contreras, Francisco; Pacheco, Rodrigo

    2015-12-01

    Neuroinflammation constitutes a fundamental process involved in the physiopathology of Parkinson's disease (PD). Microglial cells play a central role in the outcome of neuroinflammation and consequent neurodegeneration of dopaminergic neurons in the substantia nigra. Current evidence indicates that CD4+ T-cells infiltrate the central nervous system (CNS) in PD, where they play a critical role determining the functional phenotype of microglia, thus regulating the progression of the neurodegenerative process. Here, we first analysed the pathogenic role of inflammatory phenotypes and the beneficial role of anti-inflammatory phenotypes of encephalitogenic CD4+ T-cells involved in the physiopathology of PD. Next, we discussed how alterations of neurotransmitter levels observed in the basal ganglia throughout the time course of PD progression could be strongly affecting the behaviour of encephalitogenic CD4+ T-cells and thereby the outcome of the neuroinflammatory process and the consequent neurodegeneration of dopaminergic neurons. Afterward, we integrated the evidence indicating the involvement of an antigen-specific immune response mediated by T-cells and B-cells against CNS-derived self-constituents in PD. Consistent with the involvement of a relevant autoimmune component in PD, we also reviewed the polymorphisms of both, class I and class II major histocompatibility complexes, associated to the risk of PD. Overall, this study gives an overview of how an autoimmune component involved in PD plays a fundamental role in the progression of the neurodegenerative process.

  11. How HIV-1 Nef hijacks the AP-2 clathrin adaptor to downregulate CD4.

    PubMed

    Ren, Xuefeng; Park, Sang Yoon; Bonifacino, Juan S; Hurley, James H

    2014-01-01

    The Nef protein of HIV-1 downregulates the cell surface co-receptor CD4 by hijacking the clathrin adaptor complex AP-2. The structural basis for the hijacking of AP-2 by Nef is revealed by a 2.9 Å crystal structure of Nef bound to the α and σ2 subunits of AP-2. Nef binds to AP-2 via its central loop (residues 149-179) and its core. The determinants for Nef binding include residues that directly contact AP-2 and others that stabilize the binding-competent conformation of the central loop. Residues involved in both direct and indirect interactions are required for the binding of Nef to AP-2 and for downregulation of CD4. These results lead to a model for the docking of the full AP-2 tetramer to membranes as bound to Nef, such that the cytosolic tail of CD4 is situated to interact with its binding site on Nef. DOI: http://dx.doi.org/10.7554/eLife.01754.001.

  12. Detection of central circuits implicated in the formation of novel pain memories

    PubMed Central

    Upadhyay, Jaymin; Granitzka, Julia; Bauermann, Thomas; Baumgärtner, Ulf; Breimhorst, Markus; Treede, Rolf-Detlef; Birklein, Frank

    2016-01-01

    Being able to remember physically and emotionally painful events in one’s own past may shape behavior, and can create an aversion to a variety of situations. Pain imagination is a related process that may include recall of past experiences, in addition to production of sensory and emotional percepts without external stimuli. This study aimed to understand 1) the central nervous system processes that underlie pain imagination, 2) the retrieval of pain memories, and 3) to compare the latter with visual object memory. These goals were achieved by longitudinally investigating brain function with functional magnetic resonance imaging in a unique group of healthy volunteers who had never experienced tooth pain. In these subjects, we compared brain responses elicited during three experimental conditions in the following order: imagination of tooth pain (pain imagination), remembering one’s own house (object memory), and remembrance of tooth pain following an episode of induced acute tooth pain (pain memory). Key observations stemming from group-level conjunction analyses revealed common activation in the posterior parietal cortex for both pain imagination and pain memory, while object and pain memory each had strong activation predominantly within the middle frontal gyrus. When contrasting pain imagination and memory, significant activation differences were observed in subcortical structures (ie, parahippocampus − pain imagination > pain memory; midbrain − pain memory > pain imagination). Importantly, these findings were observed in the presence of consistent and reproducible psychophysical and behavioral measures that informed on the subjects’ ability to imagine novel and familiar thoughts, as well as the subjects’ pain perception. PMID:27695361

  13. A novel differentiation pathway from CD4+ T cells to CD4− T cells for maintaining immune system homeostasis

    PubMed Central

    Zhao, X; Sun, G; Sun, X; Tian, D; Liu, K; Liu, T; Cong, M; Xu, H; Li, X; Shi, W; Tian, Y; Yao, J; Guo, H; Zhang, D

    2016-01-01

    CD4+ T lymphocytes are key players in the adaptive immune system and can differentiate into a variety of effector and regulatory T cells. Here, we provide evidence that a novel differentiation pathway of CD4+ T cells shifts the balance from a destructive T-cell response to one that favors regulation in an immune-mediated liver injury model. Peripheral CD4−CD8−NK1.1− double-negative T cells (DNT) was increased following Concanavalin A administration in mice. Adoptive transfer of DNT led to significant protection from hepatocyte necrosis by direct inhibition on the activation of lymphocytes, a process that occurred primarily through the perforin-granzyme B route. These DNT converted from CD4+ rather than CD8+ T cells, a process primarily regulated by OX40. DNT migrated to the liver through the CXCR3-CXCL9/CXCL10 interaction. In conclusion, we elucidated a novel differentiation pathway from activated CD4+ T cells to regulatory DNT cells for maintaining homeostasis of the immune system in vivo, and provided key evidence that utilizing this novel differentiation pathway has potential application in the prevention and treatment of autoimmune diseases. PMID:27077809

  14. Idiopathic CD4 lymphocytopenia presenting as refractory cryptococcal meningitis.

    PubMed

    Sharma, A; Lal, V; Modi, M; Khurana, D; Bal, S; Prabhakar, S

    2010-04-01

    Idiopathic CD4 T-lymphocytopenia (ICL) is a syndrome characterized by depletion of CD4 T-cells without evidence of human immunodeficiency virus (HIV) infection. There are a few reported cases of ICL associated with different diseases and clinical conditions, most commonly the opportunistic infections like Tuberculosis, fungal and parasitic diseases which are also seen in HIV-positive patients. We report a case without risk factors or laboratory evidence of HIV infection who presented with refractory cryptococcal meningitis and was found to have ICL.

  15. A Central Capacity Limit to the Simultaneous Storage of Visual and Auditory Arrays in Working Memory

    PubMed Central

    Saults, J. Scott; Cowan, Nelson

    2008-01-01

    If working memory is limited by central capacity (e.g., the focus of attention; Cowan, 2001) then storage limits for information in a single modality should also apply to the simultaneous storage of information from different modalities. We investigated this by combining a visual-array comparison task with a novel auditory-array comparison task in five experiments. Participants were to remember only the visual or only the auditory arrays (unimodal memory conditions) or both arrays (bimodal memory conditions). Experiments 1-2 showed significant dual-task tradeoffs for visual but not auditory capacity. In Experiments 3-5, modality-specific memory was eliminated using post-perceptual masks. Dual-task costs occurred for both modalities and the number of auditory and visual items remembered together was no more than the higher of the unimodal capacities (visual, 3-4 items). The findings suggest a central capacity supplemented by modality- or code-specific storage and point to avenues for further research on the role of processing in central storage. PMID:17999578

  16. Effect of CD4 gene expression on adenovirus replication.

    PubMed Central

    Hotta, J; Shi, L; Ginsberg, H S

    1994-01-01

    The gene encoding the CD4 receptor was introduced into KB cells to establish the KBT4 cell line, a cell line susceptible to infection with human immunodeficiency virus type 1. Adenovirus replication was found to be significantly less in these cells than in the parental KB cells. Similar decreased adenovirus type 5 (Ad5) replication occurred in HeLaT4 cells compared with the original HeLa cells. The presence of CD4 did not alter the cell surface population of KB cell adenovirus receptors, since viral adsorption was similar in the two cell lines. Moreover, addition of soluble CD4 did not reduce viral replication in either KB or KBT4 infected cells. Uncoating of viral DNA was also unchanged in KBT4 cells compared with the parental KB cells. In contrast, migration to or entrance of viral DNA into nuclei and synthesis of early viral RNAs was delayed and reduced in KBT4 cells. These effects were more pronounced for Ad7 than for Ad5. The yields of infectious viruses were the same in both cell lines, however, after transfection of naked viral DNAs to initiate infection. These results imply that the expression of the CD4 gene in KBT4 cells interfered with passage of uncoated virus across endosomal vesicles and/or transfer of uncoated core viral DNA into the nucleus. Images PMID:7933112

  17. Effect of CD4 gene expression on adenovirus replication.

    PubMed

    Hotta, J; Shi, L; Ginsberg, H S

    1994-11-01

    The gene encoding the CD4 receptor was introduced into KB cells to establish the KBT4 cell line, a cell line susceptible to infection with human immunodeficiency virus type 1. Adenovirus replication was found to be significantly less in these cells than in the parental KB cells. Similar decreased adenovirus type 5 (Ad5) replication occurred in HeLaT4 cells compared with the original HeLa cells. The presence of CD4 did not alter the cell surface population of KB cell adenovirus receptors, since viral adsorption was similar in the two cell lines. Moreover, addition of soluble CD4 did not reduce viral replication in either KB or KBT4 infected cells. Uncoating of viral DNA was also unchanged in KBT4 cells compared with the parental KB cells. In contrast, migration to or entrance of viral DNA into nuclei and synthesis of early viral RNAs was delayed and reduced in KBT4 cells. These effects were more pronounced for Ad7 than for Ad5. The yields of infectious viruses were the same in both cell lines, however, after transfection of naked viral DNAs to initiate infection. These results imply that the expression of the CD4 gene in KBT4 cells interfered with passage of uncoated virus across endosomal vesicles and/or transfer of uncoated core viral DNA into the nucleus.

  18. CD4+ T Cells: guardians of the phagosome.

    PubMed

    Tubo, Noah J; Jenkins, Marc K

    2014-04-01

    CD4(+) T cells are key cells of the adaptive immune system that use T cell antigen receptors to recognize peptides that are generated in endosomes or phagosomes and displayed on the host cell surface bound to major histocompatibility complex molecules. These T cells participate in immune responses that protect hosts from microbes such as Mycobacterium tuberculosis, Cryptococcus neoformans, Leishmania major, and Salmonella enterica, which have evolved to live in the phagosomes of macrophages and dendritic cells. Here, we review studies indicating that CD4(+) T cells control phagosomal infections asymptomatically in most individuals by secreting cytokines that activate the microbicidal activities of infected phagocytes but in a way that inhibits the pathogen but does not eliminate it. Indeed, we make the case that localized, controlled, persistent infection is necessary to maintain large numbers of CD4(+) effector T cells in a state of activation needed to eradicate systemic and more pathogenic forms of the infection. Finally, we posit that current vaccines for phagosomal infections fail because they do not produce this "periodic reminder" form of CD4(+) T cell-mediated immune control.

  19. Cellular Plasticity of CD4+ T Cells in the Intestine

    PubMed Central

    Brucklacher-Waldert, Verena; Carr, Edward J.; Linterman, Michelle A.; Veldhoen, Marc

    2014-01-01

    Barrier sites such as the gastrointestinal tract are in constant contact with the environment, which contains both beneficial and harmful components. The immune system at the epithelia must make the distinction between these components to balance tolerance, protection, and immunopathology. This is achieved via multifaceted immune recognition, highly organized lymphoid structures, and the interaction of many types of immune cells. The adaptive immune response in the gut is orchestrated by CD4+ helper T (Th) cells, which are integral to gut immunity. In recent years, it has become apparent that the functional identity of these Th cells is not as fixed as initially thought. Plasticity in differentiated T cell subsets has now been firmly established, in both health and disease. The gut, in particular, utilizes CD4+ T cell plasticity to mold CD4+ T cell phenotypes to maintain its finely poised balance of tolerance and inflammation and to encourage biodiversity within the enteric microbiome. In this review, we will discuss intestinal helper T cell plasticity and our current understanding of its mechanisms, including our growing knowledge of an evolutionarily ancient symbiosis between microbiota and malleable CD4+ T cell effectors. PMID:25339956

  20. CD4 immunodiagnostics for HIV in the developing world.

    PubMed

    Redd, Andrew D; Quinn, Thomas C

    2008-11-01

    This supplement on evaluating CD4 diagnostics for HIV is the fourth in a series of user-friendly operational guides explaining how to conduct evaluations of diagnostic tests for infectious diseases that are of public health importance in the developing world. Here, Andrew Redd and Thomas Quinn introduce the supplement.

  1. Biomarkers of CD4+ CTL cell Mediated Immunity to Tuberculosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The immune responses mediated by interactions between T-lymphocyte subsets and mycobacteria-infected macrophages are critical for control of tuberculosis. In these studies, the bovine model was used to characterize the cytolytic and mycobactericidal CD4+ T cell response induced by BCG vaccination. ...

  2. STAT5 and CD4 + T Cell Immunity

    PubMed Central

    Owen, David L.; Farrar, Michael A.

    2017-01-01

    STAT5 plays a critical role in the development and function of many cell types. Here, we review the role of STAT5 in the development of T lymphocytes in the thymus and its subsequent role in the differentiation of distinct CD4 + helper and regulatory T-cell subsets. PMID:28163905

  3. Resistance of primary isolates of human immunodeficiency virus type 1 to soluble CD4 is independent of CD4-rgp120 binding affinity.

    PubMed Central

    Ashkenazi, A; Smith, D H; Marsters, S A; Riddle, L; Gregory, T J; Ho, D D; Capon, D J

    1991-01-01

    The infection of human cells by laboratory strains of human immunodeficiency virus type 1 (HIV-1) can be blocked readily in vitro by recombinant soluble CD4 and CD4-immunoglobulin hybrid molecules. In contrast, infection by primary isolates of HIV-1 is much less sensitive to blocking in vitro by soluble CD4-based molecules. To investigate the molecular basis for this difference between HIV-1 strains, we isolated the gp120-encoding genes from several CD4-resistant and CD4-sensitive HIV-1 strains and characterized the CD4-binding properties of their recombinant gp120 (rgp120) products. Extensive amino acid sequence variation was found between the gp120 genes of CD4-resistant and CD4-sensitive HIV-1 isolates. However, the CD4-binding affinities of rgp120 from strains with markedly different CD4 sensitivities were essentially the same, and only small differences were observed in the kinetics of CD4 binding. These results suggest that the lower sensitivity of primary HIV-1 isolates to neutralization by CD4-based molecules is not due to lower binding affinity between soluble CD4 and free gp120. PMID:1871120

  4. Unexpected Cartilage Phenotype in CD4-Cre-Conditional SOS-Deficient Mice

    PubMed Central

    Guittard, Geoffrey; Gallardo, Devorah L.; Li, Wenmei; Melis, Nicolas; Lui, Julian C.; Kortum, Robert L.; Shakarishvili, Nicholas G.; Huh, Sunmee; Baron, Jeffrey; Weigert, Roberto; Kramer, Joshua A.; Samelson, Lawrence E.; Sommers, Connie L.

    2017-01-01

    RAS signaling is central to many cellular processes and SOS proteins promote RAS activation. To investigate the role of SOS proteins in T cell biology, we crossed Sos1f/f Sos2−/− mice to CD4-Cre transgenic mice. We previously reported an effect of these mutations on T cell signaling and T cell migration. Unexpectedly, we observed nodules on the joints of greater than 90% of these mutant mice at 5 months of age, especially on the carpal joints. As the mice aged further, some also displayed joint stiffness, hind limb paralysis, and lameness. Histological analysis indicated that the abnormal growth in joints originated from dysplastic chondrocytes. Second harmonic generation imaging of the carpal nodules revealed that nodules were encased by rich collagen fibrous networks. Nodules formed in mice also deficient in RAG2, indicating that conventional T cells, which undergo rearrangement of the T cell antigen receptor, are not required for this phenotype. CD4-Cre expression in a subset of cells, either immune lineage cells (e.g., non-conventional T cells) or non-immune lineage cells (e.g., chondrocytes) likely mediates the dramatic phenotype observed in this study. Disruptions of genes in the RAS signaling pathway are especially likely to cause this phenotype. These results also serve as a cautionary tale to those intending to use CD4-Cre transgenic mice to specifically delete genes in conventional T cells. PMID:28386265

  5. Fingolimod alters the transcriptome profile of circulating CD4+ cells in multiple sclerosis

    PubMed Central

    Friess, Jörg; Hecker, Michael; Roch, Luisa; Koczan, Dirk; Fitzner, Brit; Angerer, Ines Charlotte; Schröder, Ina; Flechtner, Kristin; Thiesen, Hans-Jürgen; Winkelmann, Alexander; Zettl, Uwe Klaus

    2017-01-01

    Multiple sclerosis is a demyelinating disease affecting the central nervous system. T cells are known to contribute to this immune-mediated condition. Fingolimod modulates sphingosine-1-phosphate receptors, thereby preventing the egress of lymphocytes, especially CCR7-expressing CD8+ and CD4+ T cells, from lymphoid tissues. Using Affymetrix Human Transcriptome Arrays (HTA 2.0), we performed a transcriptome profiling analysis of CD4+ cells obtained from the peripheral blood of patients with highly active relapsing-remitting multiple sclerosis. The samples were drawn before the first administration of fingolimod as well as 24 hours and 3 months after the start of therapy. Three months after treatment initiation, 890 genes were found to be differentially expressed with fold-change >2.0 and t-test p-value < 0.001, among them several microRNA precursors. A subset of 272 genes were expressed at lower levels, including CCR7 as expected, while 618 genes showed an increase in expression, e.g., CCR2, CX3CR1, CD39, CD58 as well as LYN, PAK1 and TLR2. To conclude, we studied the gene expression of CD4+ cells to evaluate the effects of fingolimod treatment, and we identified 890 genes to be altered in expression after continuous drug administration. T helper cells circulating in the blood during fingolimod therapy present a distinct gene expression signature. PMID:28155899

  6. Mosaic expression of Atrx in the mouse central nervous system causes memory deficits

    PubMed Central

    Tamming, Renee J.; Siu, Jennifer R.; Jiang, Yan; Prado, Marco A. M.; Beier, Frank

    2017-01-01

    ABSTRACT The rapid modulation of chromatin organization is thought to play a crucial role in cognitive processes such as memory consolidation. This is supported in part by the dysregulation of many chromatin-remodelling proteins in neurodevelopmental and psychiatric disorders. A key example is ATRX, an X-linked gene commonly mutated in individuals with syndromic and nonsyndromic intellectual disability. The consequences of Atrx inactivation for learning and memory have been difficult to evaluate because of the early lethality of hemizygous-null animals. In this study, we evaluated the outcome of brain-specific Atrx deletion in heterozygous female mice. These mice exhibit a mosaic pattern of ATRX protein expression in the central nervous system attributable to the location of the gene on the X chromosome. Although the hemizygous male mice die soon after birth, heterozygous females survive to adulthood. Body growth is stunted in these animals, and they have low circulating concentrations of insulin growth factor 1. In addition, they are impaired in spatial, contextual fear and novel object recognition memory. Our findings demonstrate that mosaic loss of ATRX expression in the central nervous system leads to endocrine defects and decreased body size and has a negative impact on learning and memory. PMID:28093507

  7. Evolution of the CD4 family: teleost fish possess two divergent forms of CD4 in addition to lymphocyte activation gene-3

    USGS Publications Warehouse

    Laing, K.J.; Zou, J.J.; Purcell, M.K.; Phillips, R.; Secombes, C.J.; Hansen, J.D.

    2006-01-01

    The T cell coreceptor CD4 is a transmembrane glycoprotein belonging to the Ig superfamily and is essential for cell-mediated immunity. Two different genes were identified in rainbow trout that resemble mammalian CD4. One (trout CD4) encodes four extracellular Ig domains reminiscent off mammalian CD4, whereas the other (CD4REL) codes for two Ig domains. Structural motifs within the amino acid sequences suggest that the two Ig domains of CD4REL duplicated to generate the four-domain molecule of CD4 and the related gene, lymphocyte activation gene-3. Here we present evidence that both of these molecules in trout are homologous to mammalian CD4 and that teleosts encode an additional CD4 family member, lymphocyte activation gene-3, which is a marker for activated T cells. The syntenic relationships of similar genes in other teleost and non-fish genomes provide evidence for the likely evolution of CD4-related molecules in vertebrates, with CD4REL likely representing the primordial form in fish. Expression of both CD4 genes is highest in the thymus and spleen, and mRNA expression of these genes is limited to surface IgM- lymphocytes, consistent with a role for T cell functionality. Finally, the intracellular regions of both CD4 and CD4REL possess the canonical CXC motif involved in the interaction off CD4 with p56LCK, implying that similar mechanisms for CD4 + T cell activation are present in all vertebrates. Our results therefore raise new questions about T cell development and functionality in lower vertebrates that cannot be answered by current mammalian models and, thus, is of fundamental importance for understanding the evolution of cell-mediated immunity in gnathosomes. Copyright ?? 2006 by The American Association of Immunologists, Inc.

  8. P-glycoprotein (ABCB1) activity decreases raltegravir disposition in primary CD4+P-gphigh cells and correlates with HIV-1 viral load

    PubMed Central

    Minuesa, Gerard; Arimany-Nardi, Cristina; Erkizia, Itziar; Cedeño, Samandhy; Moltó, José; Clotet, Bonaventura; Pastor-Anglada, Marçal; Martinez-Picado, Javier

    2016-01-01

    Objectives To evaluate the role of P-glycoprotein (P-gp) and multidrug-resistant-protein 1 (MRP1) on raltegravir intracellular drug disposition in CD4+ T cells, investigate the effect of HIV-1 infection on P-gp expression and correlate HIV-1 viraemia with P-gp activity in primary CD4+ T cell subsets. Methods The cellular accumulation ratio of [3H]raltegravir was quantified in CD4+ T cell lines overexpressing either P-gp (CEM-P-gp) or MRP1 (CEM-MRP1) and in primary CD3+CD4+ T cells with high (P-gphigh) and low P-gp activity (P-gplow); inhibition of efflux transporters was confirmed by the intracellular retention of calcein-AM. The correlation of P-gp activity with HIV-1 viraemia was assessed in naive and memory T cell subsets from 21 HIV-1-infected treatment-naive subjects. Results [3H]Raltegravir cellular accumulation ratio decreased in CEM-P-gp cells (P < 0.0001). XR9051 (a P-gp inhibitor) and HIV-1 PIs reversed this phenomenon. Primary CD4+P-gphigh cells accumulated less raltegravir (38.4% ± 9.6%) than P-gplow cells, whereas XR9051 also reversed this effect. In vitro HIV-1 infection of PBMCs and stimulation of CD4+ T cells increased P-gp mRNA and P-gp activity, respectively, while primary CD4+P-gphigh T cells sustained a higher HIV-1 replication than P-gplow cells. A significant correlation between HIV-1 viraemia and P-gp activity was found in different CD4+ T cell subsets, particularly memory CD4+ T cells (r = 0.792, P < 0.0001). Conclusions Raltegravir is a substrate of P-gp in CD4+ T cells. Primary CD4+P-gphigh T cells eliminate intracellular raltegravir more readily than P-gplow cells and HIV-1 viraemia correlates with P-gp overall activity. Specific CD4+P-gphigh T cell subsets could facilitate the persistence of viral replication in vivo and ultimately promote the appearance of drug resistance. PMID:27334660

  9. IL-7-Induced Proliferation of Human Naive CD4 T-Cells Relies on Continued Thymic Activity

    PubMed Central

    Silva, Susana L.; Albuquerque, Adriana S.; Matoso, Paula; Charmeteau-de-Muylder, Bénédicte; Cheynier, Rémi; Ligeiro, Dário; Abecasis, Miguel; Anjos, Rui; Barata, João T.; Victorino, Rui M. M.; Sousa, Ana E.

    2017-01-01

    Naive CD4 T-cell maintenance is critical for immune competence. We investigated here the fine-tuning of homeostatic mechanisms of the naive compartment to counteract the loss of de novo CD4 T-cell generation. Adults thymectomized in early childhood during corrective cardiac surgery were grouped based on presence or absence of thymopoiesis and compared with age-matched controls. We found that the preservation of the CD31− subset was independent of the thymus and that its size is tightly controlled by peripheral mechanisms, including prolonged cell survival as attested by Bcl-2 levels. Conversely, a significant contraction of the CD31+ naive subset was observed in the absence of thymic activity. This was associated with impaired responses of purified naive CD4 T-cells to IL-7, namely, in vitro proliferation and upregulation of CD31 expression, which likely potentiated the decline in recent thymic emigrants. Additionally, we found no apparent constraint in the differentiation of naive cells into the memory compartment in individuals completely lacking thymic activity despite upregulation of DUSP6, a phosphatase associated with increased TCR threshold. Of note, thymectomized individuals featuring some degree of thymopoiesis were able to preserve the size and diversity of the naive CD4 compartment, further arguing against complete thymectomy in infancy. Overall, our data suggest that robust peripheral mechanisms ensure the homeostasis of CD31− naive CD4 pool and point to the requirement of continuous thymic activity to the maintenance of IL-7-driven homeostatic proliferation of CD31+ naive CD4 T-cells, which is essential to secure T-cell diversity throughout life. PMID:28154568

  10. IL-7-Induced Proliferation of Human Naive CD4 T-Cells Relies on Continued Thymic Activity.

    PubMed

    Silva, Susana L; Albuquerque, Adriana S; Matoso, Paula; Charmeteau-de-Muylder, Bénédicte; Cheynier, Rémi; Ligeiro, Dário; Abecasis, Miguel; Anjos, Rui; Barata, João T; Victorino, Rui M M; Sousa, Ana E

    2017-01-01

    Naive CD4 T-cell maintenance is critical for immune competence. We investigated here the fine-tuning of homeostatic mechanisms of the naive compartment to counteract the loss of de novo CD4 T-cell generation. Adults thymectomized in early childhood during corrective cardiac surgery were grouped based on presence or absence of thymopoiesis and compared with age-matched controls. We found that the preservation of the CD31(-) subset was independent of the thymus and that its size is tightly controlled by peripheral mechanisms, including prolonged cell survival as attested by Bcl-2 levels. Conversely, a significant contraction of the CD31(+) naive subset was observed in the absence of thymic activity. This was associated with impaired responses of purified naive CD4 T-cells to IL-7, namely, in vitro proliferation and upregulation of CD31 expression, which likely potentiated the decline in recent thymic emigrants. Additionally, we found no apparent constraint in the differentiation of naive cells into the memory compartment in individuals completely lacking thymic activity despite upregulation of DUSP6, a phosphatase associated with increased TCR threshold. Of note, thymectomized individuals featuring some degree of thymopoiesis were able to preserve the size and diversity of the naive CD4 compartment, further arguing against complete thymectomy in infancy. Overall, our data suggest that robust peripheral mechanisms ensure the homeostasis of CD31(-) naive CD4 pool and point to the requirement of continuous thymic activity to the maintenance of IL-7-driven homeostatic proliferation of CD31(+) naive CD4 T-cells, which is essential to secure T-cell diversity throughout life.

  11. Role of Therapeutic Plasma Exchange in Treatment of Tumefactive Multiple Sclerosis-Associated Low CD4 and CD8 Levels

    PubMed Central

    Lew, Kristen; Mewada, Nishith; Ramanujam, Sahana; Hassanzadeh, Bahareh; Donahue, John E.; Peddareddygari, Leema Reddy; Moser, Robert; Kososky, Charles; Grewal, Raji P.

    2016-01-01

    We report a 35-year-old healthy male who developed central nervous system inflammatory demyelinating disease consistent with tumefactive multiple sclerosis. About 2 weeks after onset of symptoms and prior to initiation of therapy, the patient had lymphopenia and low CD4 and CD8 levels. His lymphocyte count was 400 cells/µl (850–3,900 cells/µl), CD4 was 193 cells/µl (490–1,740 cells/µl) and CD8 was 103 cells/µl (180–1,170 cells/µl). He was treated with intravenous methylprednisolone followed by therapeutic plasma exchange, the levels of CD4 and CD8 normalized, and ultimately, he recovered completely. PMID:27721782

  12. Non-invasive tracking of CD4+ T cells with a paramagnetic and fluorescent nanoparticle in brain ischemia

    PubMed Central

    Jin, Wei-Na; Yang, Xiaoxia; Li, Zhiguo; Li, Minshu; Shi, Samuel Xiang-Yu; Wood, Kristofer; Fu, Ying; Han, Wei; Xu, Yun; Shi, Fu-Dong; Liu, Qiang

    2015-01-01

    Recent studies have demonstrated that lymphocytes play a key role in ischemic brain injury. However, there is still a lack of viable approaches to non-invasively track infiltrating lymphocytes and reveal their key spatiotemporal events in the inflamed central nervous system (CNS). Here we describe an in vivo imaging approach for sequential monitoring of brain-infiltrating CD4+ T cells in experimental ischemic stroke. We show that magnetic resonance imaging (MRI) or Xenogen imaging combined with labeling of SPIO-Molday ION Rhodamine-B (MIRB) can be used to monitor the dynamics of CD4+ T cells in a passive transfer model. MIRB-labeled CD4+ T cells can be longitudinally visualized in the mouse brain and peripheral organs such as the spleen and liver after cerebral ischemia. Immunostaining of tissue sections showed similar kinetics of MIRB-labeled CD4+ T cells when compared with in vivo observations. Our results demonstrated the use of MIRB coupled with in vivo imaging as a valid method to track CD4+ T cells in ischemic brain injury. This approach will facilitate future investigations to identify the dynamics and key spatiotemporal events for brain-infiltrating lymphocytes in CNS inflammatory diseases. PMID:26661207

  13. CD4+ and CD8+ TCRβ repertoires possess different potentials to generate extraordinarily high-avidity T cells

    PubMed Central

    Nakatsugawa, Munehide; Rahman, Muhammed A.; Yamashita, Yuki; Ochi, Toshiki; Wnuk, Piotr; Tanaka, Shinya; Chamoto, Kenji; Kagoya, Yuki; Saso, Kayoko; Guo, Tingxi; Anczurowski, Mark; Butler, Marcus O.; Hirano, Naoto

    2016-01-01

    Recent high throughput sequencing analysis has revealed that the TCRβ repertoire is largely different between CD8+ and CD4+ T cells. Here, we show that the transduction of SIG35α, the public chain-centric HLA-A*02:01(A2)/MART127–35 TCRα hemichain, conferred A2/MART127–35 reactivity to a substantial subset of both CD8+ and CD4+ T cells regardless of their HLA–A2 positivity. T cells individually reconstituted with SIG35α and different A2/MART127–35 TCRβ genes isolated from CD4+ or CD8+ T cells exhibited a wide range of avidity. Surprisingly, approximately half of the A2/MART127–35 TCRs derived from CD4+ T cells, but none from CD8+ T cells, were stained by A2/MART127–35 monomer and possessed broader cross-reactivity. Our results suggest that the differences in the primary structure of peripheral CD4+ and CD8+ TCRβ repertoire indeed result in the differences in their ability to form extraordinarily high avidity T cells which would otherwise have been deleted by central tolerance. PMID:27030642

  14. Different regulatory and cytotoxic CD4+ T lymphocyte profiles in renal transplants with antibody-mediated chronic rejection or long-term good graft function.

    PubMed

    Giaretta, Fulvia; Bussolino, Stefania; Beltramo, Silvia; Fop, Fabrizio; Rossetti, Maura; Messina, Maria; Cantaluppi, Vincenzo; Ranghino, Andrea; Basso, Elisa; Camussi, Giovanni; Segoloni, Giuseppe Paolo; Biancone, Luigi

    2013-01-01

    Comparative analysis of the different subsets of CD4(+) T-lymphocytes may provide hints on the immunologic mechanisms operating in the long-term fate of a kidney transplant. We analyzed peripheral regulatory CD4(+) T cells (Tregs) and CD4(+) cytotoxic T lymphocytes (CTLs) in antibody-mediated chronic rejection (AMCR), in middle-term kidney transplants (2-4 years, MTKT) with good graft function and rejection-free history, in long-term kidney transplants (>15 years, LTKT) and in normal healthy subjects (NHS). Transplant groups with good prognosis (MTKT and LTKT) displayed a significant lower amount of CD4(+)CD25(high) T lymphocytes than NHS, with a trend of a higher percentage in AMCR than in MTKT and LTKT. However, CD4(+)CD25(high) Foxp3(+) cells were significantly higher in LTKT and MTKT than AMCR. Characterization of CD4(+)CD25(high) T cells showed a marked increase of intracellular CTLA-4 in the AMCR group in respect to the other transplant groups, while the expression of the surface molecule seemed to follow a reverse trend. In addition, CD27, a costimulatory receptor involved in long-term T cell survival and prevention of immune tolerance, is significantly reduced in CD4(+)CD25(high) and CD4(+)Foxp3(+) T cells in the LTKT in respect to the other transplant groups. CD4(+)CD25(high)CD45RO(+) and CD4(+)Foxp3(+)CD45RO(+) regulatory T cells with memory function were increased in LTKT compared to NHS and for the latter also in AMCR group. Finally, CD4(+)CTLs that were quantified on the basis of granzyme A expression, were more represented in AMCR patients in comparison to the other groups. Strikingly, CD27 in the CD4(+)CTLs was suppressed in LTKT and MTKT and markedly expressed in AMCR group. No significant differences in the expression of CD28 were observed among different groups. In conclusion, different profiles of Tregs and CD4(+)CTL populations correlate with different long-term conditions of kidney-transplanted patients, suggesting their role in the development

  15. Optimizing Immunization Strategies for the Induction of Antigen-Specific CD4 and CD8 T Cell Responses for Protection against Intracellular Parasites.

    PubMed

    Hofmeyer, Kimberly A; Duthie, Malcolm S; Laurance, John D; Favila, Michelle A; Van Hoeven, Neal; Coler, Rhea N; Reed, Steven G

    2016-09-01

    Immunization strategies that generate either CD4 or CD8 T cell responses are relatively well described, but less is known with regard to optimizing regimens to induce both CD4 and CD8 memory T cells. Considering the importance of both CD4 and CD8 T cells in the control of intracellular pathogens such as Leishmania donovani, we wanted to identify vaccines that could raise both CD4 and CD8 T cell responses and determine how to configure immunization strategies to generate the best combined protective T cell response. We examined responses generated against the Leishmania vaccine antigen F3 following its administration in either recombinant form with the Toll-like receptor 4 (TLR4) agonist-containing adjuvant formulation GLA-SE (F3+GLA-SE) or as a gene product delivered in an adenoviral vector (Ad5-F3). Homologous immunization strategies using only F3+GLA-SE or Ad5-F3 preferentially generated either CD4 or CD8 T cells, respectively. In contrast, heterologous strategies generated both antigen-specific CD4 and CD8 T cells. Administration of F3+GLA-SE before Ad5-F3 generated the greatest combined CD4 and CD8 responses. Cytotoxic CD8 T cell responses were highest when Th1 cells were generated prior to their induction by Ad5-F3. Finally, a single immunization with a combination of F3+GLA-SE mixed with Ad5-F3 was found to be sufficient to provide protection against experimental L. donovani infection. Taken together, our data delineate immunization regimens that induce antigen-specific CD4 and CD8 T cell memory responses, and identify a single immunization strategy that could be used to rapidly provide protection against intracellular pathogens in regions where access to health care is limited or sporadic.

  16. Avian and Human Seasonal Influenza Hemagglutinin Proteins Elicit CD4 T Cell Responses That Are Comparable in Epitope Abundance and Diversity.

    PubMed

    DiPiazza, Anthony; Richards, Katherine; Poulton, Nicholas; Sant, Andrea J

    2017-03-01

    Avian influenza viruses remain a significant concern due to their pandemic potential. Vaccine trials have suggested that humans respond poorly to avian influenza vaccines relative to seasonal vaccines. It is important to understand, first, if there is a general deficiency in the ability of avian hemagglutinin (HA) proteins to generate immune responses and, if so, what underlies this defect. This question is of particular interest because it has been suggested that in humans, the poor immunogenicity of H7 vaccines may be due to a paucity of CD4 T cell epitopes. Because of the generally high levels of cross-reactive CD4 T cells in humans, it is not possible to compare the inherent immunogenicities of avian and seasonal HA proteins in an unbiased manner. Here, we empirically examine the epitope diversity and abundance of CD4 T cells elicited by seasonal and avian HA proteins. HLA-DR1 and HLA-DR4 transgenic mice were vaccinated with purified HA proteins, and CD4 T cells to specific epitopes were identified and quantified. These studies revealed that the diversity and abundance of CD4 T cells specific for HA do not segregate on the basis of whether the HA was derived from human seasonal or avian influenza viruses. Therefore, we conclude that failure in responses to avian vaccines in humans is likely due to a lack of cross-reactive CD4 T cell memory perhaps coupled with competition with or suppression of naive, HA-specific CD4 T cells by memory CD4 T cells specific for more highly conserved proteins.

  17. Optimizing Immunization Strategies for the Induction of Antigen-Specific CD4 and CD8 T Cell Responses for Protection against Intracellular Parasites

    PubMed Central

    Hofmeyer, Kimberly A.; Laurance, John D.; Favila, Michelle A.; Van Hoeven, Neal; Coler, Rhea N.; Reed, Steven G.

    2016-01-01

    Immunization strategies that generate either CD4 or CD8 T cell responses are relatively well described, but less is known with regard to optimizing regimens to induce both CD4 and CD8 memory T cells. Considering the importance of both CD4 and CD8 T cells in the control of intracellular pathogens such as Leishmania donovani, we wanted to identify vaccines that could raise both CD4 and CD8 T cell responses and determine how to configure immunization strategies to generate the best combined protective T cell response. We examined responses generated against the Leishmania vaccine antigen F3 following its administration in either recombinant form with the Toll-like receptor 4 (TLR4) agonist-containing adjuvant formulation GLA-SE (F3+GLA-SE) or as a gene product delivered in an adenoviral vector (Ad5-F3). Homologous immunization strategies using only F3+GLA-SE or Ad5-F3 preferentially generated either CD4 or CD8 T cells, respectively. In contrast, heterologous strategies generated both antigen-specific CD4 and CD8 T cells. Administration of F3+GLA-SE before Ad5-F3 generated the greatest combined CD4 and CD8 responses. Cytotoxic CD8 T cell responses were highest when Th1 cells were generated prior to their induction by Ad5-F3. Finally, a single immunization with a combination of F3+GLA-SE mixed with Ad5-F3 was found to be sufficient to provide protection against experimental L. donovani infection. Taken together, our data delineate immunization regimens that induce antigen-specific CD4 and CD8 T cell memory responses, and identify a single immunization strategy that could be used to rapidly provide protection against intracellular pathogens in regions where access to health care is limited or sporadic. PMID:27466350

  18. Manufacture of gene-modified human T-cells with a memory stem/central memory phenotype.

    PubMed

    Gomez-Eerland, Raquel; Nuijen, Bastiaan; Heemskerk, Bianca; van Rooij, Nienke; van den Berg, Joost H; Beijnen, Jos H; Uckert, Wolfgang; Kvistborg, Pia; Schumacher, Ton N; Haanen, John B A G; Jorritsma, Annelies

    2014-10-01

    Advances in genetic engineering have made it possible to generate human T-cell products that carry desired functionalities, such as the ability to recognize cancer cells. The currently used strategies for the generation of gene-modified T-cell products lead to highly differentiated cells within the infusion product, and on the basis of data obtained in preclinical models, this is likely to impact the efficacy of these products. We set out to develop a good manufacturing practice (GMP) protocol that yields T-cell receptor (TCR) gene-modified T-cells with more favorable properties for clinical application. Here, we show the robust clinical-scale production of human peripheral blood T-cells with an early memory phenotype that express a MART-1-specific TCR. By combining selection and stimulation using anti-CD3/CD28 beads for retroviral transduction, followed by expansion in the presence of IL-7 and IL-15, production of a well-defined clinical-scale TCR gene-modified T-cell product could be achieved. A major fraction of the T-cells generated in this fashion were shown to coexpress CD62L and CD45RA, and express CD27 and CD28, indicating a central memory or memory stemlike phenotype. Furthermore, these cells produced IFNγ, TNFα, and IL-2 and displayed cytolytic activity against target cells expressing the relevant antigen. The T-cell products manufactured by this robust and validated GMP production process are now undergoing testing in a phase I/IIa clinical trial in HLA-A*02:01 MART-1-positive advanced stage melanoma patients. To our knowledge, this is the first clinical trial protocol in which the combination of IL-7 and IL-15 has been applied for the generation of gene-modified T-cell products.

  19. Manufacture of Gene-Modified Human T-Cells with a Memory Stem/Central Memory Phenotype

    PubMed Central

    Gomez-Eerland, Raquel; Nuijen, Bastiaan; Heemskerk, Bianca; van Rooij, Nienke; van den Berg, Joost H.; Beijnen, Jos H.; Uckert, Wolfgang; Kvistborg, Pia; Schumacher, Ton N.; Jorritsma, Annelies

    2014-01-01

    Abstract Advances in genetic engineering have made it possible to generate human T-cell products that carry desired functionalities, such as the ability to recognize cancer cells. The currently used strategies for the generation of gene-modified T-cell products lead to highly differentiated cells within the infusion product, and on the basis of data obtained in preclinical models, this is likely to impact the efficacy of these products. We set out to develop a good manufacturing practice (GMP) protocol that yields T-cell receptor (TCR) gene-modified T-cells with more favorable properties for clinical application. Here, we show the robust clinical-scale production of human peripheral blood T-cells with an early memory phenotype that express a MART-1-specific TCR. By combining selection and stimulation using anti-CD3/CD28 beads for retroviral transduction, followed by expansion in the presence of IL-7 and IL-15, production of a well-defined clinical-scale TCR gene-modified T-cell product could be achieved. A major fraction of the T-cells generated in this fashion were shown to coexpress CD62L and CD45RA, and express CD27 and CD28, indicating a central memory or memory stemlike phenotype. Furthermore, these cells produced IFNγ, TNFα, and IL-2 and displayed cytolytic activity against target cells expressing the relevant antigen. The T-cell products manufactured by this robust and validated GMP production process are now undergoing testing in a phase I/IIa clinical trial in HLA-A*02:01 MART-1-positive advanced stage melanoma patients. To our knowledge, this is the first clinical trial protocol in which the combination of IL-7 and IL-15 has been applied for the generation of gene-modified T-cell products. PMID:25143008

  20. Proliferation of weakly suppressive regulatory CD4+ T cells is associated with over-active CD4+ T-cell responses in HIV-positive patients with mycobacterial immune restoration disease.

    PubMed

    Seddiki, Nabila; Sasson, Sarah C; Santner-Nanan, Brigitte; Munier, Meeling; van Bockel, David; Ip, Susanna; Marriott, Debbie; Pett, Sarah; Nanan, Ralph; Cooper, David A; Zaunders, John J; Kelleher, Anthony D

    2009-02-01

    The role of Treg in patients with late-stage HIV disease, who commence combination antiretroviral therapy (cART) and develop pathogen-specific immunopathology manifesting as immune restoration disease (IRD) remains unclear. We hypothesised that Treg could be defective in either numbers and/or function and therefore unable to ensure the physiological equilibrium of the immune system in patients with IRD. Phenotypic and functional CD4(+) T-cell subsets of eight late-stage HIV patients with nadir CD4 count <50 cells/microL, who developed mycobacterial IRD upon commencing cART were compared with six therapy naive HIV(+) patients (nadir CD4 count <50 cells/microL), who did not develop an IRD after cART. Mycobacterium-avium-specific CD4(+) T cells from IRD patients produced high levels of IFN-gamma and IL-2 compared with controls (p<0.001). Surprisingly, we found a significant expansion of CD127(lo)Foxp3(+)CD25(+) Treg in IRD patients and a higher ratio of Treg to effector/memory subsets (p<0.001). In vitro suppression assays demonstrated reduced functional capacity of suppressor cells and diminished IL-10 secretion in IRD patients. Plasma levels of IL-7 were increased in patients and, interestingly, exogenous IL-7 and other cytokines strongly inhibited Treg suppression. These data suggest that despite substantial Treg expansion in IRD, their ability to induce suppression, and thereby downregulate aberrant immune responses, is compromised.

  1. Interleukin 7 up-regulates CD95 protein on CD4+ T cells by affecting mRNA alternative splicing: priming for a synergistic effect on HIV-1 reservoir maintenance.

    PubMed

    Yin, Yue; Zhang, Shaoying; Luo, Haihua; Zhang, Xu; Geng, Guannan; Li, Jun; Guo, Xuemin; Cai, Weiping; Li, Linghua; Liu, Chao; Zhang, Hui

    2015-01-02

    Interleukin-7 (IL-7) has been used as an immunoregulatory and latency-reversing agent in human immunodeficiency virus type 1 (HIV-1) infection. Although IL-7 can restore circulating CD4(+) T cell counts in HIV-1-infected patients, the anti-apoptotic and proliferative effects of IL-7 appear to benefit survival and expansion of HIV-1-latently infected memory CD4(+) T lymphocytes. IL-7 has been shown to elevate CD95 on CD4(+) T cells in HIV-1-infected individuals and prime CD4(+) T lymphocytes to CD95-mediated proliferative or apoptotic signals. Here we observed that through increasing microRNA-124, IL-7 down-regulates the splicing regulator polypyrimidine tract binding protein (PTB), leading to inclusion of the transmembrane domain-encoding exon 6 of CD95 mRNA and, subsequently, elevation of CD95 on memory CD4(+) T cells. Moreover, IL-7 up-regulates cellular FLICE-like inhibitory protein (c-FLIP) and stimulates c-Jun N-terminal kinase (JNK) phosphorylation, which switches CD95 signaling to survival mode in memory CD4(+) T lymphocytes. As a result, co-stimulation through IL-7/IL-7R and FasL/CD95 signal pathways augments IL-7-mediated survival and expansion of HIV-1-latently infected memory CD4(+) T lymphocytes. Collectively, we have demonstrated a novel mechanism for IL-7-mediated maintenance of HIV-1 reservoir.

  2. Central Engine Memory of Gamma-Ray Bursts and Soft Gamma-Ray Repeaters

    NASA Astrophysics Data System (ADS)

    Zhang, Bin-Bin; Zhang, Bing; Castro-Tirado, Alberto J.

    2016-04-01

    Gamma-ray bursts (GRBs) are bursts of γ-rays generated from relativistic jets launched from catastrophic events such as massive star core collapse or binary compact star coalescence. Previous studies suggested that GRB emission is erratic, with no noticeable memory in the central engine. Here we report a discovery that similar light curve patterns exist within individual bursts for at least some GRBs. Applying the Dynamic Time Warping method, we show that similarity of light curve patterns between pulses of a single burst or between the light curves of a GRB and its X-ray flare can be identified. This suggests that the central engine of at least some GRBs carries “memory” of its activities. We also show that the same technique can identify memory-like emission episodes in the flaring emission in soft gamma-ray repeaters (SGRs), which are believed to be Galactic, highly magnetized neutron stars named magnetars. Such a phenomenon challenges the standard black hole central engine models for GRBs, and suggest a common physical mechanism behind GRBs and SGRs, which points toward a magnetar central engine of GRBs.

  3. CENTRAL ENGINE MEMORY OF GAMMA-RAY BURSTS AND SOFT GAMMA-RAY REPEATERS

    SciTech Connect

    Zhang, Bin-Bin; Castro-Tirado, Alberto J.; Zhang, Bing

    2016-04-01

    Gamma-ray bursts (GRBs) are bursts of γ-rays generated from relativistic jets launched from catastrophic events such as massive star core collapse or binary compact star coalescence. Previous studies suggested that GRB emission is erratic, with no noticeable memory in the central engine. Here we report a discovery that similar light curve patterns exist within individual bursts for at least some GRBs. Applying the Dynamic Time Warping method, we show that similarity of light curve patterns between pulses of a single burst or between the light curves of a GRB and its X-ray flare can be identified. This suggests that the central engine of at least some GRBs carries “memory” of its activities. We also show that the same technique can identify memory-like emission episodes in the flaring emission in soft gamma-ray repeaters (SGRs), which are believed to be Galactic, highly magnetized neutron stars named magnetars. Such a phenomenon challenges the standard black hole central engine models for GRBs, and suggest a common physical mechanism behind GRBs and SGRs, which points toward a magnetar central engine of GRBs.

  4. Tyrosine kinase activity of CD4-associated p56lck may not be required for CD4-dependent T-cell activation.

    PubMed Central

    Collins, T L; Burakoff, S J

    1993-01-01

    The lymphoid-specific tyrosine kinase p56lck (Lck) is critical for the development and activation of T lymphocytes, and Lck kinase activity has been implicated in both T-cell antigen receptor/CD3- and CD4-mediated signaling. CD4-dependent T-cell activation has been demonstrated to be dependent upon the association of CD4 with Lck. To examine the role of the kinase activity of Lck in CD4-dependent T-cell activation, we have generated several kinase-deficient mutants of Lck. When transfected into CD4+ murine T-cell hybridoma cells, these mutants cause approximately 90% diminution in CD4-associated Lck kinase activity. Specifically, upon CD4 crosslinking there is decreased Lck autophosphorylation and decreased phosphorylation of an exogenous substrate. When CD4 is crosslinked to the T-cell antigen receptor-CD3 complex, decreased phosphorylation of associated substrates is also observed. In spite of this striking inhibition of Lck kinase function, cells expressing the kinase-deficient mutants demonstrate normal or enhanced CD4-dependent antigen responsiveness. These data demonstrate that the level of Lck kinase activity does not correlate with its CD4-associated function and suggest that the kinase activity of Lck may not be required for CD4-mediated signaling. Images Fig. 1 Fig. 2 Fig. 3 PMID:7505449

  5. Establishment and Maintenance of the Human Naïve CD4+ T-Cell Compartment

    PubMed Central

    Silva, Susana L.; Sousa, Ana E.

    2016-01-01

    The naïve CD4+ T-cell compartment is considered essential to guarantee immune competence throughout life. Its replenishment with naïve cells with broad diverse receptor repertoire, albeit with reduced self-reactivity, is ensured by the thymus. Nevertheless, cumulative data support a major requirement of post-thymic proliferation both for the establishment of the human peripheral naïve compartment during the accelerated somatic growth of childhood, as well as for its lifelong maintenance. Additionally, a dynamic equilibrium is operating at the cell level to fine-tune the T-cell receptor threshold to activation and survival cues, in order to counteract the continuous naïve cell loss by death or conversion into memory/effector cells. The main players in these processes are low-affinity self-peptide/MHC and cytokines, particularly IL-7. Moreover, although naïve CD4+ T-cells are usually seen as a homogeneous population regarding stage of maturation and cell differentiation, increasing evidence points to a variety of phenotypic and functional subsets with distinct homeostatic requirements. The paradigm of cells committed to a distinct lineage in the thymus are the naïve regulatory T-cells, but other functional subpopulations have been identified based on their time span after thymic egress, phenotypic markers, such as CD31, or cytokine production, namely IL-8. Understanding the regulation of these processes is of utmost importance to promote immune reconstitution in several clinical settings, namely transplantation, persistent infections, and aging. In this mini review, we provide an overview of the mechanisms underlying human naïve CD4+ T-cell homeostasis, combining clinical data, experimental studies, and modeling approaches. PMID:27843891

  6. Memory

    MedlinePlus

    ... it has to decide what is worth remembering. Memory is the process of storing and then remembering this information. There are different types of memory. Short-term memory stores information for a few ...

  7. CD4 Variability in Malawi: Implications for Use of a CD4 Threshold of 500 Cells/mm3 Versus Universal Eligibility for Antiretroviral Therapy

    PubMed Central

    Schooley, Alan L.; Kamudumuli, Pocha Samuel; Vangala, Sitaram; Tseng, Chi-hong; Soko, Chifundo; Parent, Julie; Phiri, Khumbo; Jahn, Andreas; Namarika, Dan; Hoffman, Risa M.

    2016-01-01

    Background. Given the uncertainty about the ability of a single CD4 count to accurately classify a patient as antiretroviral therapy (ART) eligible, we sought to understand the extent to which CD4 variability results in misclassification at a CD4 threshold of 500 cells/mm3. Methods. We performed a prospective study of CD4 variability in Malawian human immunodeficiency virus-infected, ART-naive, World Health Organization (WHO) stage 1 or 2, nonpregnant adults. CD4 counts were performed daily for 8 days. We fit a Bayesian linear mixed-effects model of log-transformed CD4 cell counts to the data. We used Monte Carlo approximations to estimate misclassification rates for different observed values of CD4. The misclassification rate was calculated based on the conditional probability of true CD4 given the geometric mean of observed CD4 measurements. Results. Fifty patients were enrolled from 2 sites. The median age was 33.5 years (interquartile range, 27.5–40.0) and 34 (68%) were female. Misclassification rates were <1% when the observed CD4 counts were ≤250 or ≥750 cells/mm3. Rates of misclassification were high at observed CD4 counts between 350 and 650 cells/mm3, particularly when a single measurement was used (up to 46.7%). Conclusions. Our data show that ART eligibility based on a single CD4 count results in highest risk of misclassification when observed CD4 counts are in the range of 350–650 cells/mm3. Given the benefits of early ART, countries should weigh the costs and complexity of CD4 testing using a 500 cell/mm3 threshold against the cost savings and public health benefits of universal eligibility. PMID:27704028

  8. Influence of clitoria ternatea extracts on memory and central cholinergic activity in rats.

    PubMed

    Taranalli, A D; Cheeramkuzhy, T C

    2000-01-01

    Clitoria ternatea , commonly known as Shankpushpi, is widely used in the traditional Indian system of medicine as a brain tonic and is believed to promote memory and intelligence. We examined the effectiveness of alcoholic extracts of aerial and root parts of C. ternatea at 300 and 500 mg/kg doses orally in rats in attenuating electroshock-induced amnesia. Extracts at 300 mg/kg dose produced significant memory retention, and the root parts were found to be more effective. In order to delineate the possible mechanism through which C. ternatea elicits the anti-amnesic effects, we studied its influence on central cholinergic activity by estimating the acetylcholine content of the whole brain and acetylcholinesterase activity at different regions of the rat brain, viz., cerebral cortex, midbrain, medulla oblongata and cerebellum. Our results suggest that C. ternatea extracts increase rat brain acetylcholine content and acetyl cholinesterase a ctivity in a similar fashion to the standard cerebro protective drug Pyritinol.

  9. Successful immunotherapy induces previously unidentified allergen-specific CD4+ T-cell subsets.

    PubMed

    Ryan, John F; Hovde, Rachel; Glanville, Jacob; Lyu, Shu-Chen; Ji, Xuhuai; Gupta, Sheena; Tibshirani, Robert J; Jay, David C; Boyd, Scott D; Chinthrajah, R Sharon; Davis, Mark M; Galli, Stephen J; Maecker, Holden T; Nadeau, Kari C

    2016-03-01

    Allergen immunotherapy can desensitize even subjects with potentially lethal allergies, but the changes induced in T cells that underpin successful immunotherapy remain poorly understood. In a cohort of peanut-allergic participants, we used allergen-specific T-cell sorting and single-cell gene expression to trace the transcriptional "roadmap" of individual CD4+ T cells throughout immunotherapy. We found that successful immunotherapy induces allergen-specific CD4+ T cells to expand and shift toward an "anergic" Th2 T-cell phenotype largely absent in both pretreatment participants and healthy controls. These findings show that sustained success, even after immunotherapy is withdrawn, is associated with the induction, expansion, and maintenance of immunotherapy-specific memory and naive T-cell phenotypes as early as 3 mo into immunotherapy. These results suggest an approach for immune monitoring participants undergoing immunotherapy to predict the success of future treatment and could have implications for immunotherapy targets in other diseases like cancer, autoimmune disease, and transplantation.

  10. Successful immunotherapy induces previously unidentified allergen-specific CD4+ T-cell subsets

    PubMed Central

    Ryan, John F.; Hovde, Rachel; Glanville, Jacob; Lyu, Shu-Chen; Ji, Xuhuai; Gupta, Sheena; Tibshirani, Robert J.; Jay, David C.; Boyd, Scott D.; Chinthrajah, R. Sharon; Davis, Mark M.; Galli, Stephen J.; Maecker, Holden T.; Nadeau, Kari C.

    2016-01-01

    Allergen immunotherapy can desensitize even subjects with potentially lethal allergies, but the changes induced in T cells that underpin successful immunotherapy remain poorly understood. In a cohort of peanut-allergic participants, we used allergen-specific T-cell sorting and single-cell gene expression to trace the transcriptional “roadmap” of individual CD4+ T cells throughout immunotherapy. We found that successful immunotherapy induces allergen-specific CD4+ T cells to expand and shift toward an “anergic” Th2 T-cell phenotype largely absent in both pretreatment participants and healthy controls. These findings show that sustained success, even after immunotherapy is withdrawn, is associated with the induction, expansion, and maintenance of immunotherapy-specific memory and naive T-cell phenotypes as early as 3 mo into immunotherapy. These results suggest an approach for immune monitoring participants undergoing immunotherapy to predict the success of future treatment and could have implications for immunotherapy targets in other diseases like cancer, autoimmune disease, and transplantation. PMID:26811452

  11. Putative alpha-helical structures in the human immunodeficiency virus type 1 Vpu protein and CD4 are involved in binding and degradation of the CD4 molecule.

    PubMed Central

    Tiganos, E; Yao, X J; Friborg, J; Daniel, N; Cohen, E A

    1997-01-01

    The human immunodeficiency virus type 1 (HIV-1) vpu gene encodes a 16-kDa class I integral membrane phosphoprotein with an N-terminal membrane-spanning region and a C-terminal cytoplasmic domain. In the cytoplasmic domain, two amphipathic alpha-helices joined by a flexible turn containing two phosphoacceptor sites have been predicted. Previous studies have shown that Vpu downregulates CD4 molecules by inducing their specific degradation in the endoplasmic reticulum. Phosphorylation of serine residues 52 and 56, present within the cytoplasmic domain of the Vpu protein, has been shown to be essential to this Vpu function. However, the contribution of these two phosphoacceptor sites in the mechanism of CD4 degradation remains undefined. Interestingly, a specific interaction between Vpu and CD4 was recently demonstrated in coimmunoprecipitation experiments. Binding of Vpu was shown to be necessary but not sufficient to mediate CD4 degradation, indicating that interaction between Vpu and CD4 represents an early step critical in triggering a process leading to CD4 degradation. To delineate the sequence(s) and/or structural determinant(s) involved in this Vpu-CD4 interaction and in the Vpu-mediated CD4 degradation, we performed a mutational analysis of the cytoplasmic domain of CD4 and Vpu. Coimmunoprecipitation experiments reveal that disruption of the putative alpha-helical structure in the membrane-proximal cytoplasmic domain of CD4 affects the binding to Vpu, suggesting that this structure may act as an interface for the CD4-Vpu interaction that mediates CD4 degradation. Vpu proteins containing mutations in either or both of the phosphoacceptor sites (Ser52 or/and Ser56) were inactive in regard to CD4 degradation yet retained the capacity to interact with the cytoplasmic domain of CD4. In an attempt to define the minimal region responsible for this interaction, we tested a panel of mutations which were designed to affect the integrity of the putative alpha

  12. Affinity maturation of human CD4 by yeast surface display and crystal structure of a CD4–HLA-DR1 complex

    PubMed Central

    Wang, Xin Xiang; Li, Yili; Yin, Yiyuan; Mo, Min; Wang, Qian; Gao, Wei; Wang, Lili; Mariuzza, Roy A.

    2011-01-01

    Helper T-cell activation generally requires the coreceptor CD4, which binds MHC class II molecules. A remarkable feature of the CD4–MHC class II interaction is its exceptionally low affinity, which ranges from KD = ∼200 μM to >2 mM. Investigating the biological role of the much lower affinity of this interaction than those of other cell–cell recognition molecules will require CD4 mutants with enhanced binding to MHC class II for testing in models of T-cell development. To this end, we used in vitro-directed evolution to increase the affinity of human CD4 for HLA-DR1. A mutant CD4 library was displayed on the surface of yeast and selected using HLA-DR1 tetramers or monomers, resulting in isolation of a CD4 clone containing 11 mutations. Reversion mutagenesis showed that most of the affinity increase derived from just two substitutions, Gln40Tyr and Thr45Trp. A CD4 variant bearing these mutations bound HLA-DR1 with KD = 8.8 μM, compared with >400 μM for wild-type CD4. To understand the basis for improved affinity, we determined the structure of this CD4 variant in complex with HLA-DR1 to 2.4 Å resolution. The structure provides an atomic-level description of the CD4-binding site on MHC class II and reveals how CD4 recognizes highly polymorphic HLA-DR, -DP, and -DQ molecules by targeting invariant residues in their α2 and β2 domains. In addition, the CD4 mutants reported here constitute unique tools for probing the influence of CD4 affinity on T-cell activation and development. PMID:21900604

  13. Endogenous factors enhance HIV infection of tissue naive CD4 T cells by stimulating high molecular mass APOBEC3G complex formation.

    PubMed

    Kreisberg, Jason F; Yonemoto, Wes; Greene, Warner C

    2006-04-17

    Human immunodeficiency virus (HIV) can infect resting CD4 T cells residing in lymphoid tissues but not those circulating in peripheral blood. The molecular mechanisms producing this difference remain unknown. We explored the potential role of the tissue microenvironment and its influence on the action of the antiviral factor APOBEC3G (A3G) in regulating permissivity to HIV infection. We found that endogenous IL-2 and -15 play a key role in rendering resident naive CD4 T cells susceptible to HIV infection. Infection of memory CD4 T cells also requires endogenous soluble factors, but not IL-2 or -15. A3G is found in a high molecular mass complex in HIV infection-permissive, tissue-resident naive CD4 T cells but resides in a low molecular mass form in nonpermissive, blood-derived naive CD4 T cells. Upon treatment with endogenous soluble factors, these cells become permissive for HIV infection, as low molecular mass A3G is induced to assemble into high molecular mass complexes. These findings suggest that in lymphoid tissues, endogenous soluble factors, likely including IL-2 and -15 and others, stimulate the formation of high molecular mass A3G complexes in tissue-resident naive CD4 T cells, thereby relieving the potent postentry restriction block for HIV infection conferred by low molecular mass A3G.

  14. Cytomegalovirus-Associated CD4(+) CD28(null) Cells in NKG2D-Dependent Glomerular Endothelial Injury and Kidney Allograft Dysfunction.

    PubMed

    Shabir, S; Smith, H; Kaul, B; Pachnio, A; Jham, S; Kuravi, S; Ball, S; Chand, S; Moss, P; Harper, L; Borrows, R

    2016-04-01

    Emerging data suggest that expansion of a circulating population of atypical, cytotoxic CD4(+) T cells lacking costimulatory CD28 (CD4(+) CD28(null) cells) is associated with latent cytomegalovirus (CMV) infection. The purpose of the current study was to increase the understanding of the relevance of these cells in 100 unselected kidney transplant recipients followed prospectively for a median of 54 months. Multicolor flow cytometry of peripheral blood mononuclear cells before transplantation and serially posttransplantation was undertaken. CD4(+) CD28(null) cells were found predominantly in CMV-seropositive patients and expanded in the posttransplantation period. These cells were predominantly effector-memory phenotype and expressed markers of endothelial homing (CX3CR1) and cytotoxicity (NKG2D and perforin). Isolated CD4(+) CD27(-) CD28(null) cells proliferated in response to peripheral blood mononuclear cells previously exposed to CMV-derived (but not HLA-derived) antigens and following such priming incubation with glomerular endothelium resulted in signs of endothelial damage and apoptosis (release of fractalkine and von Willebrand factor; increased caspase 3 expression). This effect was mitigated by NKG2D-blocking antibody. Increased CD4(+) CD28(null) cell frequencies were associated with delayed graft function and lower estimated glomerular filtration rate at end follow-up. This study suggests an important role for this atypical cytotoxic CD4(+) CD28(null) cell subset in kidney transplantation and points to strategies that may minimize the impact on clinical outcomes.

  15. New candidates for CD4 T cell pathogenicity in experimental neuroinflammation and multiple sclerosis.

    PubMed

    Hoppmann, Nicola; Graetz, Christiane; Paterka, Magdalena; Poisa-Beiro, Laura; Larochelle, Catherine; Hasan, Maruf; Lill, Christina M; Zipp, Frauke; Siffrin, Volker

    2015-04-01

    Multiple sclerosis is a chronic autoimmune demyelinating disease of the central nervous system, which is thought to be triggered by environmental factors in genetically susceptible individuals leading to activation of autoreactive T lymphocytes. Large multi-centre genome-wide association studies have identified multiple genetic risk loci in multiple sclerosis. In this study, we investigated T cell transcriptomic changes in experimental autoimmune encephalomyelitis, an animal model for multiple sclerosis. We correlated these findings with the multiple sclerosis risk genes postulated by the most recent Immunochip analysis and found that multiple sclerosis susceptibility genes were significantly regulated in experimental autoimmune encephalomyelitis. Our data indicate that nine distinct genes associated with multiple sclerosis risk, Bach2, Il2ra, Irf8, Mertk, Odf3b, Plek, Rgs1, Slc30a7 and Thada, can be confirmed to be differentially regulated in pathogenic CD4(+) T cells. During the effector phase within the inflamed CNS, CD4(+) T cells undergo comprehensive transformation and we identified key transcription factors and signalling networks involved in this process. The transformation was linked to metabolic changes with the involvement of liver X receptor/retinoid X receptor signalling and cholesterol biosynthesis, which might control the T cell effector function in the central nervous system. Thus, our study confirms the involvement of multiple sclerosis risk genes in the pathophysiology of the animal model and sheds light on additional disease-relevant inflammatory networks.

  16. Memory.

    ERIC Educational Resources Information Center

    McKean, Kevin

    1983-01-01

    Discusses current research (including that involving amnesiacs and snails) into the nature of the memory process, differentiating between and providing examples of "fact" memory and "skill" memory. Suggests that three brain parts (thalamus, fornix, mammilary body) are involved in the memory process. (JN)

  17. Role of CD4+, CD8+ and double negative T-cells in the protection of SCID/beige mice against respiratory challenge with Rhodococcus equi.

    PubMed Central

    Ross, T L; Balson, G A; Miners, J S; Smith, G D; Shewen, P E; Prescott, J F; Yager, J A

    1996-01-01

    To evaluate the contributions of T-lymphocyte subsets in pulmonary immunity against Rhodococcus equi, C.B-17 SCID/beige mice were adoptively transferred with splenic lymphocytes from congenic BALB/c mice previously infected with R. equi. Spleen cells were enriched for either CD4+ or CD8+ populations before inoculation, Flow cytometry showed that each enriched population contained less than 0.5% cross contamination. Groups of adoptively transferred SCID/beige mice were sacrificed 6 and 13 d after intranasal infection with R. equi. Bacterial clearance was measured in the lungs, liver and spleen. Lesion development was assessed by gross and histopathological score and the fate of transferred cells assessed by flow cytometry and by immunohistochemistry. SCID/beige mice receiving either CD4+ or CD8+ T-cells were able to clear the infection better than control mice. On d 6 post-infection, bacterial numbers were significantly lower in the lungs of CD4+ transferred mice as compared to CD8+ mice. By d 13, both groups had cleared R. equi from all organs. CD4+ cells were however identified in the lung and spleen of CD8+ recipients at d 13 making conclusions about the role of CD8+ cells in R. equi clearance impossible. By contrast, no significant increases in CD8+ lymphocytes were observed in the organs of CD4+ recipients. All mice developed suppurative bronchopneumonia but lesions were most severe in the CD4+ group. Immunohistochemistry and flow cytometry confirmed that CD4+ and CD8+ cells had migrated to the lungs of adoptively transferred mice. Serum antibody against R, equi was not detected by ELISA in the recipients. SCID/beige mice receiving CD4-CD8- cells were unable to clear R. equi. The study supports the suggestion that CD4+ cells have a central role in R. equi clearance in mice. Images Figure 2. Figure 5. PMID:8809381

  18. How Word Reading Skill Impacts Text Memory: The Centrality Deficit and How Domain Knowledge Can Compensate

    PubMed Central

    Miller, Amanda C.; Keenan, Janice M.

    2010-01-01

    We examined text memory in children with word reading deficits to determine how these difficulties impact representations of text meaning. We show that even though children with poor word decoding recall more central than peripheral information, they show a significantly bigger deficit relative to controls on central than on peripheral information. We call this the centrality deficit and argue that it is the consequence of insufficient cognitive resources for connecting ideas together due to these children's resources being diverted from comprehension to word decoding. We investigated a possible compensatory mechanism for making these connections. Because a text representation is a synthesis of text information and a reader's prior knowledge, we hypothesized that having knowledge of the passage topic might reduce or eliminate the centrality deficit. Our results support this knowledge compensation hypothesis: the centrality deficit was evident when poor readers did not have prior knowledge, but was eliminated when they did. This presents an exciting avenue to pursue for possible remediation of reading comprehension in children with word identification difficulties. PMID:19475514

  19. Identification of homing receptors that mediate the recruitment of CD4 T cells to the genital tract following intravaginal infection with Chlamydia trachomatis.

    PubMed Central

    Kelly, K A; Rank, R G

    1997-01-01

    Murine genital infection induced with the mouse pneumonitis biovar of Chlamydia trachomatis (MoPn) elicits a short-lived protective immunity mediated primarily by Th1 CD4 cells. To understand the development of local cell-mediated immunity against C. trachomatis infection, we investigated the mechanism(s) which mediates CD4 lymphocyte migration to the genital mucosa by identifying molecules that could support this process. We found that primarily CD4 cells were recruited to the genital tract (GT) during primary and challenge MoPn infection. Peak levels were found 21 days after primary inoculation (15.4% +/- 2.7%) and 7 days (31.3% +/- 8.5%) after challenge but diminished after resolution of infection. The CD4 cells appeared to be recruited to the GT in response to infection since these cells expressed the profile of activated, or memory, cells. We also observed up-regulation of homing receptors containing LFA-1 (CD11a) and alpha4 (CD49d) on GT CD4 cells over the course of infection. Furthermore, the mucosal homing receptor chain, beta7, but not the peripheral homing receptor chain beta1 (CD29), was detected on GT CD4 cells. MoPn-infected GT tissue expressed the endothelial cell ligands vascular cell adhesion molecule 1 (VCAM-1), intracellular adhesion molecule 1 (ICAM-1), and mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1), which correspond to the homing receptors on GT CD4 cells. Interestingly, VCAM-1 and MAdCAM-1 were not expressed in the GTs of uninfected mice but were temporarily induced following infection, indicating that expression of endothelial ligands in the GT are regulated by chlamydial infection. These data suggest that recruitment of CD4 cells to the GT is mediated through LFA-1:ICAM-1 and alpha4beta7:MAdCAM-1-VCAM-1 interactions. PMID:9393816

  20. Chimpanzees Immunized with Recombinant Soluble CD4 Develop Anti-Self CD4 Antibody Responses with Anti-Human Immunodeficiency Virus Activity

    NASA Astrophysics Data System (ADS)

    Watanabe, Mamoru; Boyson, Jonathan E.; Lord, Carol I.; Letvin, Norman L.

    1992-06-01

    In view of the efficiency with which human immunodeficiency virus replication can be blocked in vitro with anti-CD4 antibodies, the elicitation of an anti-CD4 antibody response through active immunization might represent a useful therapeutic strategy for AIDS. Here we demonstrate that immunization of chimpanzees with recombinant soluble human CD4 elicited an anti-CD4 antibody response. The elicited antibody bound self CD4 on digitonin-treated but not freshly isolated lymphocytes. Nevertheless, this antibody blocked human immunodeficiency virus replication in chimpanzee and human lymphocytes. These observations suggest that immunization with recombinant soluble CD4 from human immunodeficiency virus-infected humans may be feasible and therapeutically beneficial.

  1. Functional aortic stiffness: role of CD4(+) T lymphocytes.

    PubMed

    Majeed, Beenish A; Eberson, Lance S; Tawinwung, Supannikar; Larmonier, Nicolas; Secomb, Timothy W; Larson, Douglas F

    2015-01-01

    The immune system is suggested to be essential in vascular remodeling and stiffening. To study the dependence upon lymphocytes in vascular stiffening, we compared an angiotensin II-model of vascular stiffening in normal C57BL/6J mice with lymphocyte-deficient RAG 1(-/-) mice and additionally characterized the component of vascular stiffness due to vasoconstriction vs. vascular remodeling. Chronic angiotensin II increased aortic pulse wave velocity, effective wall stiffness, and effective Young's modulus in C57BL/6J mice by three-fold but caused no change in the RAG 1(-/-) mice. These functional measurements were supported by aortic morphometric analysis. Adoptive transfer of CD4(+) T helper lymphocytes restored the angiotensin II-mediated aortic stiffening in the RAG 1(-/-) mice. In order to account for the hydraulic vs. material effects of angiotensin II on pulse wave velocity, subcutaneous osmotic pumps were removed after 21 days of angiotensin II-infusion in the WT mice to achieve normotensive values. The pulse wave velocity (PWV) decreased from three- to two-fold above baseline values up to 7 days following pump removal. This study supports the pivotal role of the CD4(+) T-lymphocytes in angiotensin II-mediated vascular stiffening and that angiotensin II-mediated aortic stiffening is due to the additive effect of active vascular smooth muscle vasoconstriction and vascular remodeling.

  2. Human immunodeficiency virus type 1 Nef-induced down-modulation of CD4 is due to rapid internalization and degradation of surface CD4.

    PubMed Central

    Rhee, S S; Marsh, J W

    1994-01-01

    Human immunodeficiency virus type 1 (HIV-1) Nef is a myristylated protein with a relative molecular mass of 27 kDa, is localized to the cytoplasmic surfaces of cellular membranes, and has been reported to down-modulate CD4 in human T cells. To understand the mechanism of HIV-1 Nef-mediated down-modulation of cell surface CD4, we expressed Nef protein in human T-cell line VB. Expression of HIV-1 Nef protein down-modulated surface CD4 molecules. In pulse-chase experiments, CD4 molecules in Nef-expressing cells were synthesized at normal levels. However, the bulk of newly synthesized CD4 protein was degraded with a half-life of approximately 6 h, compared with the 24-h half-life in control cells. This Nef-induced acceleration of CD4 turnover was inhibited by lysosomotropic agents NH4Cl and chloroquine as well as by the protease inhibitor leupeptin. Surface CD4 biotinylation experiments demonstrated that CD4 molecules in Nef-expressing T cells are transported to the plasma membrane with normal kinetics but are then rapidly internalized. Therefore, HIV-1 Nef-induced down-modulation of CD4 is due to rapid internalization of surface CD4 and subsequent degradation by an acid-dependent process, potentially lysosomal. Additionally, in a Nef-expressing cell, we find accelerated dissociation of the T-cell tyrosine kinase p56lck and CD4 but only after the complex reaches the plasma membrane. This implies that HIV-1 Nef protein might play a role in triggering a series of T-cell activation-like events, which contribute to p56lck dissociation and internalization of surface CD4 molecules. Images PMID:8035515

  3. Lung Angiogenesis Requires CD4+Forkhead Homeobox Protein-3+ Regulatory T Cells

    PubMed Central

    D’Alessio, Franco R.; Zhong, Qiong; Jenkins, John; Moldobaeva, Aigul

    2015-01-01

    Angiogenesis in ischemic organs is modulated by immune cells. Systemic neovascularization of the ischemic lung requires macrophages, with chemokines playing a central role in new vessel growth. Because regulatory T (Treg) cells modulate tumor-induced neovascularization, we questioned whether this CD4+ lymphocyte subset impacts blood vessel growth during ischemia. In a model of left lung ischemia, an increase in CD4+ CD25+ forkhead homeobox protein-3 (Foxp3)+ cells was observed 3–5 days after the onset of ischemia in wild-type C57Bl/6 mice. Using transgenic mice where Foxp3+ Treg cells can be depleted with diphtheria toxin (DT; Foxp3DTR), we unexpectedly found that Foxp3+ Treg depletion led to markedly reduced lung angiogenesis (90% reduction from Foxp3gfp controls). Adoptive transfer studies using CD4+ CD25+ splenocytes from congenic CD45.1 mice into Foxp3+ Treg–depleted mice showed an almost complete recovery of the angiogenic phenotype (80% of Foxp3gfp controls). A survey of lung gene expression of angiogenic (lipopolysaccharide-induced CXC chemokine [LIX], IL-6, IL-17) and angiostatic (IFN-γ, transforming growth factor-β, IL-10) cytokines showed Treg-dependent differences only in LIX (CXCL5) and IL-6. Protein confirmation demonstrated a significant reduction in LIX in Treg-deficient mice compared with controls 5 days after the onset of ischemia. Phenotyping other inflammatory cells in the lung by multicolor flow cytometry demonstrated a significantly reduced number of macrophages (major histocombatibility complex class II [MHCII]int, CD11C+) in Treg-deficient lungs compared with Treg-sufficient lungs. Treg cells are essential for maximal systemic angiogenesis after pulmonary ischemia. One likely mechanism responsible for the decrease in angiogenesis in Treg-depleted mice was the decline in the essential CXC chemokine, LIX. PMID:25275926

  4. IL-10 within the CNS is necessary for CD4+ T cells to mediate neuroprotection

    PubMed Central

    Xin, Junping; Wainwright, Derek A.; Mesnard, Nichole A.; Serpe, Craig J.; Sanders, Virginia M.; Jones, Kathryn J.

    2010-01-01

    We have previously shown that immunodeficient mice exhibit significant facial motoneuron (FMN) loss compared to wild-type (WT) mice after a facial nerve axotomy. Interleukin-10 (IL-10) is known as a regulatory cytokine that plays an important role in maintaining the anti-inflammatory environment within the central nervous system (CNS). IL-10 is produced by a number of different cells, including Th2 cells, and may exert an anti-apoptotic action on neurons directly. In the present study, the role of IL-10 in mediating neuroprotection following a facial nerve axotomy model in Rag2- and IL-10-deficient mice was investigated. Results indicate that IL-10 is neuroprotective, but only in the presence of CD4+ T cells that are not the requisite source of IL-10. In addition, using real-time PCR analysis of laser microdissected brainstem sections, results show that IL-10 mRNA is constitutively expressed in the facial nucleus and that a transient, significant reduction of IL-10 mRNA occurs following axotomy under immunodeficient conditions. Dual labeling immunofluorescence data show, unexpectedly, that the IL-10 receptor (IL-10R) is constitutively expressed by facial motoneurons, but is selectively induced in astrocytes within the facial nucleus after axotomy. Thus, a non-CD4+ T cell source of IL-10 is necessary for modulating both glial and neuronal events that mediate neuroprotection of injured motoneurons, but only with the cooperation of CD4+ T cells, providing an avenue of novel investigation into therapeutic approaches to prevent or reverse motoneuron diseases, such as amyotrophic lateral sclerosis (ALS). PMID:20723599

  5. CD4+ and CD8+ T-Cell Responses to Latent Antigen EBNA-1 and Lytic Antigen BZLF-1 during Persistent Lymphocryptovirus Infection of Rhesus Macaques

    PubMed Central

    Leskowitz, R. M.; Zhou, X. Y.; Villinger, F.; Fogg, M. H.; Kaur, A.; Lieberman, P. M.; Wang, F.

    2013-01-01

    Epstein-Barr virus (EBV) infection leads to lifelong viral persistence through its latency in B cells. EBV-specific T cells control reactivations and prevent the development of EBV-associated malignancies in most healthy carriers, but infection can sometimes cause chronic disease and malignant transformation. Epstein-Barr nuclear antigen 1 (EBNA-1) is the only viral protein consistently expressed during all forms of latency and in all EBV-associated malignancies and is a promising target for a therapeutic vaccine. Here, we studied the EBNA-1-specific immune response using the EBV-homologous rhesus lymphocryptovirus (rhLCV) infection in rhesus macaques. We assessed the frequency, phenotype, and cytokine production profiles of rhLCV EBNA-1 (rhEBNA-1)-specific T cells in 15 rhesus macaques and compared them to the lytic antigen of rhLCV BZLF-1 (rhBZLF-1). We were able to detect rhEBNA-1-specific CD4+ and/or CD8+ T cells in 14 of the 15 animals screened. In comparison, all 15 animals had detectable rhBZLF-1 responses. Most peptide-specific CD4+ T cells exhibited a resting phenotype of central memory (TCM), while peptide-specific CD8+ T cells showed a more activated phenotype, belonging mainly to the effector cell subset. By comparing our results to the human EBV immune response, we demonstrate that the rhLCV model is a valid system for studying chronic EBV infection and for the preclinical development of therapeutic vaccines. PMID:23698300

  6. Impact of Distinct Poxvirus Infections on the Specificities and Functionalities of CD4+ T Cell Responses

    PubMed Central

    Siciliano, Nicholas A.; Hersperger, Adam R.; Lacuanan, Aimee M.; Xu, Ren-Huan; Sidney, John; Sette, Alessandro; Sigal, Luis J.

    2014-01-01

    ABSTRACT The factors that determine CD4+ T cell (TCD4+) specificities, functional capacity, and memory persistence in response to complex pathogens remain unclear. We explored these parameters in the C57BL/6 mouse through comparison of two highly related (>92% homology) poxviruses: ectromelia virus (ECTV), a natural mouse pathogen, and vaccinia virus (VACV), a heterologous virus that nevertheless elicits potent immune responses. In addition to elucidating several previously unidentified major histocompatibility complex class II (MHC-II)-restricted epitopes, we observed many qualitative and quantitative differences between the TCD4+ repertoires, including responses not elicited by VACV despite complete sequence conservation. In addition, we observed functional heterogeneity between ECTV- and VACV-specific TCD4+ at both a global and individual epitope level, particularly greater expression of the cytolytic marker CD107a from TCD4+ following ECTV infection. Most striking were differences during the late memory phase where, in contrast to ECTV, VACV infection failed to elicit measurable epitope-specific TCD4+ as determined by intracellular cytokine staining. These findings illustrate the strong influence of epitope-extrinsic factors on TCD4+ responses and memory. IMPORTANCE Much of our understanding concerning host-pathogen relationships in the context of poxvirus infections stems from studies of VACV in mice. However, VACV is not a natural mouse pathogen, and therefore, the relevance of results obtained using this model may be limited. Here, we explored the MHC class II-restricted TCD4+ repertoire induced by mousepox (ECTV) infection and the functional profile of the responding epitope-specific TCD4+, comparing these results to those induced by VACV infection under matched conditions. Despite a high degree of homology between the two viruses, we observed distinct specificity and functional profiles of TCD4+ responses at both acute and memory time points, with VACV

  7. Comparison of CD4 cell count by a simple enzyme-linked immunosorbent assay using the TRAx CD4 test kit and by flow cytometry and hematology.

    PubMed Central

    Paxton, H; Pins, M; Denton, G; McGonigle, A D; Meisner, P S; Phair, J P

    1995-01-01

    Measurement of CD4 T-lymphocyte levels is clinically useful in monitoring immune status in a number of conditions, including human immunodeficiency virus (HIV) infection, in which the absolute CD4 count is used to guide therapy. The absolute CD4 count is obtained by multiplying the results of the leukocyte count and the differential with a hematology cell counter and the percentage of CD4+ T lymphocytes determined by flow cytometry. These techniques require expensive, complex instrumentation, and interlaboratory results are difficult to standardize and reproduce. The rapid growth of HIV infection worldwide has increased the need for more-reproducible and cost-effective methods for CD4 T-cell monitoring. The TRAx CD4 test kit is based on a novel adaptation of conventional enzyme-linked immunosorbent assay (ELISA) and permits the simple quantitation of total CD4 protein from whole-blood lysates. In this study, the relationship between total CD4 protein measured in units per milliliter (TRAx) and in cells per microliter (flow cytometry and hematology) was defined in a multisite clinical study using linear regression analysis. Data from 230 HIV-seronegative and 321 HIV-seropositive specimens were used to calibrate the TRAx assay recombinant CD4 standards and controls in equivalent CD4 T lymphocytes per microliter (cells per microliter). The calibration of the TRAx CD4 assay in cells per microliter was validated with a second group of specimens from 17 healthy volunteers and 20 HIV-seropositive patients which were collected and tested under strictly controlled conditions intended to minimize the effects of specimen aging on the results of the reference method. These data were also used to estimate the variability of absolute CD4 count by cytometric methods as well as the precision of the TRAx CD4 result after it was calibrated in cells per microliter. Overall, correlations between the two methods ranged from 0.87 to 0.95. Additional studies demonstrated that the

  8. Inhibition of Nef- and phorbol ester-induced CD4 degradation by macrolide antibiotics.

    PubMed Central

    Luo, T; Anderson, S J; Garcia, J V

    1996-01-01

    Human immunodeficiency virus type 1 (HIV-1) is the causative agent of AIDS. The simian immunodeficiency virus (SIV) causes a similar syndrome in macaques. The product of the nef gene of SIV has been shown to be important for virus replication and disease progression in vivo. In vitro, both SIV and HIV Nef downregulate surface expression of CD4 and accelerate total CD4 turnover. The mechanism by which Nef downregulates CD4 has not been established. A current model suggests that Nef enhances cell surface CD4 endocytosis and degradation in lysosomes. However, this was recently challenged when CD4 was found to accumulate in early endosomes of cells expressing Nef. Because inhibition of Nef function might halt virus replication and disease progression, we tested two macrolide antibiotics for their ability to inhibit Nef function. Concanamycin B (ConB) and bafilomycin A1 (BFLA1) are specific inhibitors of acidification of cell endosomes and lysosomes and, unlike other inhibitors, do not affect transport. Although ConB (25 nM) and BFLA1 (100 nM) blocked phorbol myristate acetate- and Nef-induced CD4 degradation in human monocyte U937 cells, CD4 surface expression was not recovered. Instead, CD4 accumulated in lysosomes. To determine if Nef is directly responsible for CD4 degradation or if they bind to each other in a manner similar to Vpu, transcripts of human CD4 and HIV-1 nef were cotranslated in vitro. Our results indicate that under our experimental conditions, Nef does not affect CD4 stability and does not associate with CD4 in this in vitro system. Our data suggest that (i) CD4 downregulation by Nef results in degradation of CD4 in lysosomes, (ii) inhibition of CD4 degradation by macrolide antibiotics does not restore surface expression, and (iii) the inhibition of CD4 expression by Nef appears to be indirect and is likely to involve cellular factors. PMID:8627671

  9. CD4 Lymphocyte Decline and Survival in Human Immunodeficiency Virus Infection

    DTIC Science & Technology

    1992-01-01

    assess the association of CD4 cell decline (half-life), race, age, gender, initial CD4-cell count, and treatment (anti- Pneumocystis carinii pneumonia ...with a median interval of 2.65 mo between tests. (AZT), anti-Pneumnocystis cariniI pneumonia (PCP) prophy- The decline of CD4 cell count over time for

  10. Quaternary contact in the initial interaction of CD4 with the HIV-1 envelope trimer.

    PubMed

    Liu, Qingbo; Acharya, Priyamvada; Dolan, Michael A; Zhang, Peng; Guzzo, Christina; Lu, Jacky; Kwon, Alice; Gururani, Deepali; Miao, Huiyi; Bylund, Tatsiana; Chuang, Gwo-Yu; Druz, Aliaksandr; Zhou, Tongqing; Rice, William J; Wigge, Christoph; Carragher, Bridget; Potter, Clinton S; Kwong, Peter D; Lusso, Paolo

    2017-04-01

    Binding of the gp120 envelope (Env) glycoprotein to the CD4 receptor is the first step in the HIV-1 infectious cycle. Although the CD4-binding site has been extensively characterized, the initial receptor interaction has been difficult to study because of major CD4-induced structural rearrangements. Here we used cryogenic electron microscopy (cryo-EM) to visualize the initial contact of CD4 with the HIV-1 Env trimer at 6.8-Å resolution. A single CD4 molecule is embraced by a quaternary HIV-1-Env surface formed by coalescence of the previously defined CD4-contact region with a second CD4-binding site (CD4-BS2) in the inner domain of a neighboring gp120 protomer. Disruption of CD4-BS2 destabilized CD4-trimer interaction and abrogated HIV-1 infectivity by preventing the acquisition of coreceptor-binding competence. A corresponding reduction in HIV-1 infectivity occurred after the mutation of CD4 residues that interact with CD4-BS2. Our results document the critical role of quaternary interactions in the initial HIV-Env-receptor contact, with implications for treatment and vaccine design.

  11. Inhibition of HIV replication by pokeweed antiviral protein targeted to CD4+ cells by monoclonal antibodies

    NASA Astrophysics Data System (ADS)

    Zarling, Joyce M.; Moran, Patricia A.; Haffar, Omar; Sias, Joan; Richman, Douglas D.; Spina, Celsa A.; Myers, Dorothea E.; Kuebelbeck, Virginia; Ledbetter, Jeffrey A.; Uckun, Fatih M.

    1990-09-01

    FUNCTIONAL impairment and selective depletion of CD4+ T cells, the hallmark of AIDS, are at least partly caused by human immunodeficiency virus (HIV-1) type 1 binding to the CD4 molecule and infecting CD4+ cells1,2. It may, therefore, be of therapeutic value to target an antiviral agent to CD4+ cells to prevent infection and to inhibit HIV-1 production in patients' CD4+ cells which contain proviral DNA3,4. We report here that HIV-1 replication in normal primary CD4+ T cells can be inhibited by pokeweed antiviral protein, a plant protein of relative molecular mass 30,000 (ref. 5), which inhibits replication of certain plant RNA viruses6-8, and of herpes simplex virus, poliovirus and influenza virus9-11. Targeting pokeweed antiviral protein to CD4+ T cells by conjugating it to monoclonal antibodies reactive with CDS, CD7 or CD4 expressed on CD4+ cells, increased its anti-HIV potency up to 1,000-fold. HIV-1 replication is inhibited at picomolar concentrations of conjugates of pokeweed antiviral protein and monoclonal antibodies, which do not inhibit proliferation of normal CD4+ T cells or CD4-dependent responses. These conjugates inhibit HIV-1 protein synthesis and also strongly inhibit HIV-1 production in activated CD4+ T cells from infected patients.

  12. Decreased percentage of CD4+Foxp3+TGF-β+ and increased percentage of CD4+IL-17+ cells in bronchoalveolar lavage of asthmatics

    PubMed Central

    2014-01-01

    Background Asthma is a chronic inflammatory disorder of the airways with the proven role of Th2 cells in its pathogenesis. The role and characteristic of different subsets of CD4+ cells is much less known. Aim The aim of the study was to analyze the incidence of different subsets of CD4+ T cells, in particular different subsets of CD4+ cells with the co-expression of different cytokines. Methods Twenty five stable asthmatic and twelve age-matched control subjects were recruited to the study. Bronchoscopy and bronchoalveolar lavage (BAL) were performed in all study subjects. CD4+ T cells were isolated from BAL fluid by positive magnetic selection. After stimulation simultaneous expression of TGF-β, FoxP3, CD25, IFN-γ, IL-4, TNF-α (set 1); IL-10, FoxP3, CD25, IFN-γ, IL-4, MIP-1β (set 2); IL-17A, IL-8, IFN-γ, IL-4, MIP-1β (set 3) were measured by flow cytometry. Results The percentage of CD4+ cells co-expressing Foxp3 and TGF-β (CD4+Foxp3+TGF-β+ cells) was significantly lower (P = 0.03), whereas the percentage of CD4+IL-17+ cells (P = 0.008), CD4+IL-17+ IFN-γ+ cells (P = 0.047) and CD4+IL-4+ cells (P = 0.01) were significantly increased in asthmatics compared with that seen in healthy subjects. A significantly higher percentage of CD4+Foxp3+ cells from asthma patients expressed IFN-γ (P = 0.01), IL-4 (P = 0.004) and CD25 (P = 0.04), whereas the percentage of CD4+IL-10+ cells expressing Foxp3 was significantly decreased in asthmatics (P = 0.03). FEV1% predicted correlated negatively with the percentage of CD4+IL-17+ cells (r = -0.33; P = 0.046) and positively with CD4+Foxp3+TGF-β+ cells (r = 0.43; P = 0.01). Conclusions Our results suggest that in the airways of chronic asthma patients there is an imbalance between increased numbers of CD4+IL-17+ cells and Th2 cells and decreased number of CD4+Foxp3+TGF-β+. PMID:25132806

  13. Control of inflammatory heart disease by CD4+ T cells.

    PubMed

    Barin, Jobert G; Čiháková, Daniela

    2013-05-01

    This review focuses on autoimmune myocarditis and its sequela, inflammatory dilated cardiomyopathy (DCMI), and the inflammatory and immune mechanisms underlying the pathogenesis of these diseases. Several mouse models of myocarditis and DCMI have improved our knowledge of the pathogenesis of these diseases, informing more general problems of cardiac remodeling and heart failure. CD4(+) T cells are critical in driving the pathogenesis of myocarditis. We discuss in detail the role of T helper cell subtypes in the pathogenesis of myocarditis, the biology of T cell-derived effector cytokines, and the participation of other leukocytic effectors in mediating disease pathophysiology. We discuss interactions between these subsets in both suppressive and collaborative fashions. These findings indicate that cardiac inflammatory disease, and autoimmunity in general, may be more diverse in divergent effector mechanisms than has previously been appreciated.

  14. Postarrest stalling rather than crawling favors CD8(+) over CD4(+) T-cell migration across the blood-brain barrier under flow in vitro.

    PubMed

    Rudolph, Henriette; Klopstein, Armelle; Gruber, Isabelle; Blatti, Claudia; Lyck, Ruth; Engelhardt, Britta

    2016-09-01

    Although CD8(+) T cells have been implied in the pathogenesis of multiple sclerosis (MS), the molecular mechanisms mediating CD8(+) T-cell migration across the blood-brain barrier (BBB) into the central nervous system (CNS) are ill defined. Using in vitro live cell imaging, we directly compared the multistep extravasation of activated CD4(+) and CD8(+) T cells across primary mouse brain microvascular endothelial cells (pMBMECs) as a model for the BBB under physiological flow. Significantly higher numbers of CD8(+) than CD4(+) T cells arrested on pMBMECs under noninflammatory and inflammatory conditions. While CD4(+) T cells polarized and crawled prior to their diapedesis, the majority of CD8(+) T cells stalled and readily crossed the pMBMEC monolayer preferentially via a transcellular route. T-cell arrest and crawling were independent of G-protein-coupled receptor signaling. Rather, absence of endothelial ICAM-1 and ICAM-2 abolished increased arrest of CD8(+) over CD4(+) T cells and abrogated T-cell crawling, leading to the efficient reduction of CD4(+) , but to a lesser degree of CD8(+) , T-cell diapedesis across ICAM-1(null) /ICAM-2(-/-) pMBMECs. Thus, cellular and molecular mechanisms mediating the multistep extravasation of activated CD8(+) T cells across the BBB are distinguishable from those involved for CD4(+) T cells.

  15. Macrophage entry mediated by HIV Envs from brain and lymphoid tissues is determined by the capacity to use low CD4 levels and overall efficiency of fusion

    SciTech Connect

    Thomas, Elaine R.; Dunfee, Rebecca L.; Stanton, Jennifer; Bogdan, Derek; Taylor, Joann; Kunstman, Kevin; Bell, Jeanne E.; Wolinsky, Steven M.; Gabuzda, Dana . E-mail: dana_gabuzda@dfci.harvard.edu

    2007-03-30

    HIV infects macrophages and microglia in the central nervous system (CNS), which express lower levels of CD4 than CD4+ T cells in peripheral blood. To investigate mechanisms of HIV neurotropism, full-length env genes were cloned from autopsy brain and lymphoid tissues from 4 AIDS patients with HIV-associated dementia (HAD). Characterization of 55 functional Env clones demonstrated that Envs with reduced dependence on CD4 for fusion and viral entry are more frequent in brain compared to lymphoid tissue. Envs that mediated efficient entry into macrophages were frequent in brain but were also present in lymphoid tissue. For most Envs, entry into macrophages correlated with overall fusion activity at all levels of CD4 and CCR5. gp160 nucleotide sequences were compartmentalized in brain versus lymphoid tissue within each patient. Proline at position 308 in the V3 loop of gp120 was associated with brain compartmentalization in 3 patients, but mutagenesis studies suggested that P308 alone does not contribute to reduced CD4 dependence or macrophage-tropism. These results suggest that HIV adaptation to replicate in the CNS selects for Envs with reduced CD4 dependence and increased fusion activity. Macrophage-tropic Envs are frequent in brain but are also present in lymphoid tissues of AIDS patients with HAD, and entry into macrophages in the CNS and other tissues is dependent on the ability to use low receptor levels and overall efficiency of fusion.

  16. Structural Basis for Species Selectivity in the HIV-1 gp120-CD4 Interaction: Restoring Affinity to gp120 in Murine CD4 Mimetic Peptides

    PubMed Central

    Kassler, Kristin; Meier, Julia; Eichler, Jutta; Sticht, Heinrich

    2011-01-01

    The first step of HIV-1 infection involves interaction between the viral glycoprotein gp120 and the human cellular receptor CD4. Inhibition of the gp120-CD4 interaction represents an attractive strategy to block HIV-1 infection. In an attempt to explore the known lack of affinity of murine CD4 to gp120, we have investigated peptides presenting the putative gp120-binding site of murine CD4 (mCD4). Molecular modeling indicates that mCD4 protein cannot bind gp120 due to steric clashes, while the larger conformational flexibility of mCD4 peptides allows an interaction. This finding is confirmed by experimental binding assays, which also evidenced specificity of the peptide-gp120 interaction. Molecular dynamics simulations indicate that the mCD4-peptide stably interacts with gp120 via an intermolecular β-sheet, while an important salt-bridge formed by a C-terminal lysine is lost. Fixation of the C-terminus by introducing a disulfide bridge between the N- and C-termini of the peptide significantly enhanced the affinity to gp120. PMID:22312332

  17. Macrophage IL-12p70 Signaling Prevents HSV-1–Induced CNS Autoimmunity Triggered by Autoaggressive CD4+ Tregs

    PubMed Central

    Mott, Kevin R.; Gate, David; Zandian, Mandana; Allen, Sariah J.; Rajasagi, Naveen Kumar; van Rooijen, Nico; Chen, Shuang; Arditi, Moshe; Rouse, Barry T.; Flavell, Richard A.; Town, Terrence; Ghiasi, Homayon

    2011-01-01

    Purpose. CD4+CD25+FoxP3+ naturally occurring regulatory T cells (Tregs) maintain self-tolerance and function to suppress overly exuberant immune responses. However, it is unclear whether innate immune cells modulate Treg function. Here the authors examined the role of innate immunity in lymphomyeloid homeostasis. Methods. The involvement of B cells, dendritic cells (DCs), macrophages, natural killer (NK) cells, and T cells in central nervous system (CNS) demyelination in different strains of mice infected ocularly with herpes simplex virus type 1 (HSV-1) was investigated. Results. The authors found that depletion of macrophages, but not DCs, B cells, NK cells, CD4+ T cells, or CD8+ T cells, induced CNS demyelination irrespective of virus or mouse strain. As with macrophage depletion, mice deficient in interleukin (IL)-12p35 or IL-12p40 showed CNS demyelination after HSV-1 infection, whereas demyelination was undetectable in HSV-1–infected, IL-23p19–deficient, or Epstein-Barr virus–induced gene 3-deficient mice. Demyelination could be rescued in macrophage-depleted mice after the injection of IL-12p70 DNA and in IL-12p35−/− or IL-12p40−/− mice after injection with IL-12p35 or IL-12p40 DNA or with recombinant viruses expressing IL-12p35 or IL-12p40. Using FoxP3-, CD4-, CD8-, or CD25-depletion and gene-deficient mouse approaches, the authors demonstrated that HSV-1–induced demyelination was blocked in the absence of CD4, CD25, or FoxP3 in macrophage-depleted mice. Flow cytometry showed an elevation of CD4+CD25+FoxP3+ T cells in the spleens of infected macrophage-depleted mice, and adoptive transfer of CD4+CD25+ T cells to infected macrophage-depleted severe combined immunodeficient mice induced CNS demyelination. Conclusions. The authors demonstrated that macrophage IL-12p70 signaling plays an important role in maintaining immune homeostasis in the CNS by preventing the development of autoaggressive CD4+ Tregs. PMID:21220560

  18. Myd88 Initiates Early Innate Immune Responses and Promotes CD4 T Cells during Coronavirus Encephalomyelitis

    PubMed Central

    Butchi, Niranjan; Kapil, Parul; Puntambekar, Shweta; Stohlman, Stephen A.; Hinton, David R.

    2015-01-01

    ABSTRACT Myd88 signaling is critical to the control of numerous central nervous system (CNS) infections by promoting both innate and adaptive immune responses. Nevertheless, the extent to which Myd88 regulates type I interferon (IFN) versus proinflammatory factors and T cell function, as well as the anatomical site of action, varies extensively with the pathogen. CNS infection by neurotropic coronavirus with replication confined to the brain and spinal cord induces protective IFN-α/β via Myd88-independent activation of melanoma differentiation-associated gene 5 (MDA5). However, a contribution of Myd88-dependent signals to CNS pathogenesis has not been assessed. Infected Myd88−/− mice failed to control virus, exhibited enhanced clinical disease coincident with increased demyelination, and succumbed to infection within 3 weeks. The induction of IFN-α/β, as well as of proinflammatory cytokines and chemokines, was impaired early during infection. However, defects in both IFN-α/β and select proinflammatory factors were rapidly overcome prior to T cell recruitment. Myd88 deficiency also specifically blunted myeloid and CD4 T cell recruitment into the CNS without affecting CD8 T cells. Moreover, CD4 T cells but not CD8 T cells were impaired in IFN-γ production. Ineffective virus control indeed correlated most prominently with reduced antiviral IFN-γ in the CNS of Myd88−/− mice. The results demonstrate a crucial role for Myd88 both in early induction of innate immune responses during coronavirus-induced encephalomyelitis and in specifically promoting protective CD4 T cell activation. In the absence of these responses, functional CD8 T cells are insufficient to control viral spread within the CNS, resulting in severe demyelination. IMPORTANCE During central nervous system (CNS) infections, signaling through the adaptor protein Myd88 promotes both innate and adaptive immune responses. The extent to which Myd88 regulates antiviral type I IFN, proinflammatory

  19. Analysis of recombinant human tumour necrosis factor-alpha-induced CD4 expression on human eosinophils.

    PubMed Central

    Hossain, M; Okubo, Y; Horie, S; Sekiguchi, M

    1996-01-01

    We examined the hypothesis that one of the pro-inflammatory cytokines, tumour necrosis factor-alpha (TNF-alpha), could induce expression of the adhesion molecule CD4 on human eosinophils. We further examined the effector function of CD4 and the mechanisms regulating CD4 expression. Human eosinophils were cultured with various concentrations of recombinant human TNF-alpha (rhTNF-alpha) with or without various drugs for 24 hr. After culture, eosinophils were stained for CD4 using a monoclonal antibody and then analysed by flow cytometry. Eosinophil-derived neurotoxin (EDN) release as eosinophil degranulation was examined by cross-linking of CD4 on eosinophils. The rhTNF-alpha induced CD4 expression on human eosinophils in a dose- and time-dependent fashion; rhTNF-alpha-induced CD4 expression was significantly inhibited by 10(-6) M cycloheximide, 10(-8) M dexamethasone, or 10(-6) M herbimycin A. Recombinant human interferon-gamma inhibited rhTNF-alpha-induced CD4 expression in a dose-dependent manner. However, cross-linking of CD4 on eosinophils did not evoke EDN release, suggesting that newly expressed CD4 molecules on human eosinophils do not play any role in triggering degranulation. Our data indicate that TNF-alpha-induced CD4 expression on human eosinophils is dependent on protein synthesis and may be dependent on tyrosine kinase activity. PMID:8690465

  20. Molecular cloning and characterization of CD4 in an aquatic mammal, the white whale Delphinapterus leucas.

    PubMed

    Romano, T A; Ridgway, S H; Felten, D L; Quaranta, V

    1999-05-01

    Given the importance of the cell surface recognition protein, CD4, in immune function, the cloning and characterization of CD4 at the molecular level from an odontocete cetacean, the white whale (Delphinapterus leucas), was carried out. Whale CD4 cDNA contains 2662 base pairs and translates into a protein containing 455 amino acids. Whale CD4 shares 64% and 51% identity with the human and mouse CD4 protein, respectively, and is organized in a similar manner. Unlike human and mouse, however, the cytoplasmic domain, which is highly conserved, contains amino acid substitutions unique to whale. Moreover, only one of the seven potential N-linked glycosylation sites present in whale is shared with human and mouse. Evolutionarily, the whale CD4 sequence is most similar to pig and structurally similar to dog and cat, in that all lack the cysteine pair in the V2 domain. These differences suggest that CD4 may have a different secondary structure in these species, which may affect binding of class II and subsequent T-cell activation, as well as binding of viral pathogens. Interestingly, as a group, species with these CD4 characteristics all have high constitutive expression of class II molecules on T lymphocytes, suggesting potential uniqueness in the interaction of CD4, class II molecules, and the immune response. Molecular characterization of CD4 in an aquatic mammal provides information on the CD4 molecule itself and may provide insight into adaptive evolutionary changes of the immune system.

  1. Disappearance of CD4 lymphocyte circadian cycles after autologous bone marrow transplantation.

    PubMed

    Martini, E; Gorin, N C; Gastal, C; Doinel, C; Roquin, H; Najman, A; Salmon, C

    1988-01-01

    Circadian variations are observed in CD4 lymphocyte count in healthy people. Samples taken of the basal value occurring around 08.00 hr and peak value at midnight made it possible to define the range of cyclic variations. Movement of lymphocytes seems important in accounting for the observed circadian variations. CD4 circadian cycle amplitudes were investigated in 12 patients with autologous bone marrow transplantation. Cycle abnormalities were observed in 7 patients. Two of them had a normal CD4 lymphocyte count. It was therefore possible for functional abnormalities in CD4 lymphocytes to be detected in patients with a normal CD4 count. Because of these results, we are of the opinion that the evaluation of CD4 lymphocyte cycle might be a more sensitive test than the absolute CD4 count itself.

  2. Expression of the CD4 gene requires a Myb transcription factor.

    PubMed Central

    Siu, G; Wurster, A L; Lipsick, J S; Hedrick, S M

    1992-01-01

    We have analyzed the control of developmental expression of the CD4 gene, which encodes an important recognition molecule and differentiation antigen on T cells. We have determined that the CD4 promoter alone functions at high levels in the CD4+ CD8- mature T cell but not at the early CD4+ CD8+ stage of T-cell development. In addition, the CD4 promoter functions only in T lymphocytes; thus, the stage and tissue specificity of the CD4 gene is mediated in part by its promoter. We have determined that a Myb transcription factor binds to the CD4 promoter and is critical for full promoter function. Thus, Myb plays an important role in the expression of T-cell-specific developmentally regulated genes. Images PMID:1347906

  3. Antigen-specific CD4{sup +} effector T cells: Analysis of factors regulating clonal expansion and cytokine production

    SciTech Connect

    Ohnuki, Kazunobu; Watanabe, Yuri; Takahashi, Yusuke; Kobayashi, Sakiko; Watanabe, Shiho; Ogawa, Shuhei; Kotani, Motoko; Kozono, Haruo; Tanabe, Kazunari; Abe, Ryo

    2009-03-20

    In order to fully understand T cell-mediated immunity, the mechanisms that regulate clonal expansion and cytokine production by CD4{sup +} antigen-specific effector T cells in response to a wide range of antigenic stimulation needs clarification. For this purpose, panels of antigen-specific CD4{sup +} T cell clones with different thresholds for antigen-induced proliferation were generated by repeated stimulation with high- or low-dose antigen. Differences in antigen sensitivities did not correlate with expression of TCR, CD4, adhesion or costimulatory molecules. There was no significant difference in antigen-dependent cytokine production by TG40 cells transfected with TCR obtained from either high- or low-dose-responding T cell clones, suggesting that the affinity of TCRs for their ligands is not primary determinant of T cell antigen reactivity. The proliferative responses of all T cell clones to both peptide stimulation and to TCR{beta} crosslinking revealed parallel dose-response curves. These results suggest that the TCR signal strength of effector T cells and threshold of antigen reactivity is determined by an intrinsic property, such as the TCR signalosome and/or intracellular signaling machinery. Finally, the antigen responses of high- and low-peptide-responding T cell clones reveal that clonal expansion and cytokine production of effector T cells occur independently of antigen concentration. Based on these results, the mechanisms underlying selection of high 'avidity' effector and memory T cells in response to pathogen are discussed.

  4. Induction of CD4(+) and CD8(+) anti-tumor effector T cell responses by bacteria mediated tumor therapy.

    PubMed

    Stern, Christian; Kasnitz, Nadine; Kocijancic, Dino; Trittel, Stephanie; Riese, Peggy; Guzman, Carlos A; Leschner, Sara; Weiss, Siegfried

    2015-10-15

    Facultative anaerobic bacteria like E. coli can colonize solid tumors often resulting in tumor growth retardation or even clearance. Little mechanistic knowledge is available for this phenomenon which is however crucial for optimization and further implementation in the clinic. Here, we show that intravenous injections with E. coli TOP10 can induce clearance of CT26 tumors in BALB/c mice. Importantly, re-challenging mice which had cleared tumors showed that clearance was due to a specific immune reaction. Accordingly, lymphopenic mice never showed tumor clearance after infection. Depletion experiments revealed that during induction phase, CD8(+) T cells are the sole effectors responsible for tumor clearance while in the memory phase CD8(+) and CD4(+) T cells were involved. This was confirmed by adoptive transfer. CD4(+) and CD8(+) T cells could reject newly set tumors while CD8(+) T cells could even reject established tumors. Detailed analysis of adoptively transferred CD4(+) T cells during tumor challenge revealed expression of granzyme B, FasL, TNF-α and IFN-γ in such T cells that might be involved in the anti-tumor activity. Our findings should pave the way for further optimization steps of this promising therapy.

  5. In vivo dendritic cell targeting cellular vaccine induces CD4+ Tfh cell-dependent antibody against influenza virus

    PubMed Central

    Yamasaki, Satoru; Shimizu, Kanako; Kometani, Kohei; Sakurai, Maki; Kawamura, Masami; Fujii, Shin-ichiro

    2016-01-01

    An induction of long-term cellular and humoral immunity is for the goal of vaccines, but the combination of antigens and adjuvant remain unclear. Here, we show, using a cellular vaccine carrying foreign protein antigen plus iNKT cell glycolipid antigen, designated as artificial adjuvant vector cells (aAVCs), that mature XCR1− DCs in situ elicit not only ordinal antigen-specific CD4+T cells, but also CD4+ Tfh and germinal center, resulted in inducing long-term antibody production. As a mechanism for leading the long-term antibody production by aAVC, memory CD4+ Tfh cells but not iNKTfh cells played an important role in a Bcl6 dependent manner. To develop it for influenza infection, we established influenza hemagglutinin-carrying aAVC (aAVC-HA) and found that all the mice vaccinated with aAVC-HA were protected from life-threatening influenza infection. Thus, the in vivo DC targeting therapy by aAVC would be useful for protection against viral infection. PMID:27739478

  6. CD4+ T-cell-independent mechanisms suppress reactivation of latent tuberculosis in a macaque model of HIV coinfection.

    PubMed

    Foreman, Taylor W; Mehra, Smriti; LoBato, Denae N; Malek, Adel; Alvarez, Xavier; Golden, Nadia A; Bucşan, Allison N; Didier, Peter J; Doyle-Meyers, Lara A; Russell-Lodrigue, Kasi E; Roy, Chad J; Blanchard, James; Kuroda, Marcelo J; Lackner, Andrew A; Chan, John; Khader, Shabaana A; Jacobs, William R; Kaushal, Deepak

    2016-09-20

    The synergy between Mycobacterium tuberculosis (Mtb) and HIV in coinfected patients has profoundly impacted global mortality because of tuberculosis (TB) and AIDS. HIV significantly increases rates of reactivation of latent TB infection (LTBI) to active disease, with the decline in CD4(+) T cells believed to be the major causality. In this study, nonhuman primates were coinfected with Mtb and simian immunodeficiency virus (SIV), recapitulating human coinfection. A majority of animals exhibited rapid reactivation of Mtb replication, progressing to disseminated TB and increased SIV-associated pathology. Although a severe loss of pulmonary CD4(+) T cells was observed in all coinfected macaques, a subpopulation of the animals was still able to prevent reactivation and maintain LTBI. Investigation of pulmonary immune responses and pathology in this cohort demonstrated that increased CD8(+) memory T-cell proliferation, higher granzyme B production, and expanded B-cell follicles correlated with protection from reactivation. Our findings reveal mechanisms that control SIV- and TB-associated pathology. These CD4-independent protective immune responses warrant further studies in HIV coinfected humans able to control their TB infection. Moreover, these findings will provide insight into natural immunity to Mtb and will guide development of novel vaccine strategies and immunotherapies.

  7. Risk factors, CD4 long-term evolution and mortality of HIV-infected patients who persistently maintain low CD4 counts, despite virological response to HAART.

    PubMed

    Pacheco, Yolanda M; Jarrín, Inmaculada; Del Amo, Julia; Moreno, Santiago; Iribarren, José A; Viciana, Pompeyo; Parra, Jorge; Gomez-Sirvent, Juan L; Gutierrez, Félix; Blanco, José R; Vidal, Francesc; Leal, Manuel

    2009-11-01

    A proportion of HIV-patients does not normally restore their CD4 counts despite virological response to HAART. Those whose CD4 counts persistently remain closed to the critical threshold for opportunistic infections deserve special interest. To study the risk factors, the long-term CD4 counts evolution, and the risk of death of patients who persistently maintain low CD4 counts, despite virological response to HAART, within a multicenter, hospital-based cohort study. A total of 147 patients were selected from CoRIS-MD and classified into a "Low-Group" or a "High-Group", depending on their CD4 counts after two-years of effective HAART (threshold 250 cells/microL). Associated risk factors were analysed by logistic regression, the CD4 dynamics were evaluated over a total period of 7.70 years (IQR, 6.70-9.00), and mortality was estimated by Cox proportional hazard. A total of 40 patients (27%) were classified into the "Low-Group". The odds ratio for this group increased with age, being 4.56 (2.23-9.33) for over 40, and was also higher among IDU, 3.63 (1.04-12.68). Six years thereafter, among these patients, only a 30% exceeded 350 CD4 cells/microL and a 12% exceeded 500 CD4 cells/microL. Furthermore, the "Low-Group" had a death rate of 2.42 per 100 persons/year (95%CI, 1.01-5.81), although once adjusted by age the estimates were no longer significant [4.14 (0.87-19.72)]. Our results suggest that those HIV patients who have not overcome the critical threshold of 250 CD4 cells/microL after a two years period of virologically effective HAART do persist with the aforementioned failure of CD4 restoration for a much longer time.

  8. Cytomegalovirus Infection Leads to Development of High Frequencies of Cytotoxic Virus-Specific CD4+ T Cells Targeted to Vascular Endothelium

    PubMed Central

    Begum, Jusnara; Lal, Neeraj; Zuo, Jianmin; Beggs, Andrew; Moss, Paul

    2016-01-01

    Cytomegalovirus (CMV) infection elicits a very strong and sustained intravascular T cell immune response which may contribute towards development of accelerated immune senescence and vascular disease in older people. Virus-specific CD8+ T cell responses have been investigated extensively through the use of HLA-peptide tetramers but much less is known regarding CMV-specific CD4+ T cells. We used a range of HLA class II-peptide tetramers to investigate the phenotypic and transcriptional profile of CMV-specific CD4+ T cells within healthy donors. We show that such cells comprise an average of 0.45% of the CD4+ T cell pool and can reach up to 24% in some individuals (range 0.01–24%). CMV-specific CD4+ T cells display a highly differentiated effector memory phenotype and express a range of cytokines, dominated by dual TNF-α and IFN-γ expression, although substantial populations which express IL-4 were seen in some donors. Microarray analysis and phenotypic expression revealed a profile of unique features. These include the expression of CX3CR1, which would direct cells towards fractalkine on activated endothelium, and the β2-adrenergic receptor, which could permit rapid response to stress. CMV-specific CD4+ T cells display an intense cytotoxic profile with high level expression of granzyme B and perforin, a pattern which increases further during aging. In addition CMV-specific CD4+ T cells demonstrate strong cytotoxic activity against antigen-loaded target cells when isolated directly ex vivo. PD-1 expression is present on 47% of cells but both the intensity and distribution of the inhibitory receptor is reduced in older people. These findings reveal the marked accumulation and unique phenotype of CMV-specific CD4+ T cells and indicate how such T cells may contribute to the vascular complications associated with CMV in older people. PMID:27606804

  9. Early Induction of Interleukin-10 Limits Antigen-Specific CD4+ T Cell Expansion, Function, and Secondary Recall Responses during Persistent Phagosomal Infection

    PubMed Central

    Singh, Abinav Kumar

    2014-01-01

    Diverse pathogens have evolved to survive and replicate in the endosomes or phagosomes of the host cells and establish persistent infection. Ehrlichiae are Gram-negative, intracellular bacteria that are transmitted by ticks. Ehrlichiae reside in the endosomes of the host phagocytic or endothelial cells and establish persistent infection in their vertebrate reservoir hosts. CD4+ T cells play a critical role in protection against phagosomal infections. In the present study, we investigated the expansion, maintenance, and functional status of antigen-specific CD4+ T cells during persistent Ehrlichia muris infection in wild-type and interleukin-10 (IL-10)-deficient mice. Our study indicated that early induction of IL-10 led to reduced inflammatory responses and impaired bacterial clearance during persistent Ehrlichia infection. Notably, we demonstrated that the functional production of gamma interferon (IFN-γ) by antigen-specific CD4+ T cells maintained during a persistent phagosomal infection progressively deteriorates. The functional loss of IFN-γ production by antigen-specific CD4+ T cells was reversed in the absence of IL-10. Furthermore, we demonstrated that transient blockade of IL-10 receptor during the T cell priming phase early in infection was sufficient to enhance the magnitude and the functional capacity of antigen-specific effector and memory CD4+ T cells, which translated into an enhanced recall response. Our findings provide new insights into the functional status of antigen-specific CD4+ T cells maintained during persistent phagosomal infection. The study supports the concept that a better understanding of the factors that influence the priming and differentiation of CD4+ T cells may provide a basis to induce a protective immune response against persistent infections. PMID:25024370

  10. Membrane expression of NK receptors CD160 and CD158k contributes to delineate a unique CD4+ T-lymphocyte subset in normal and mycosis fungoides skin.

    PubMed

    Sako, Nouhoum; Schiavon, Valérie; Bounfour, Touda; Dessirier, Valérie; Ortonne, Nicolas; Olive, Daniel; Ram-Wolff, Caroline; Michel, Laurence; Sicard, Hélène; Marie-Cardine, Anne; Bagot, Martine; Bensussan, Armand; Schmitt, Christian

    2014-10-01

    CD160 is a GPI-anchored Ig-like receptor identified by the BY55 mAb on human circulating CD56dim+ NK cells and TCRγδ lymphocytes. In addition, while most intestinal T lymphocytes express it, only a minor circulating CD4+ or CD8+ T lymphocyte subset is CD160+. Here we describe a population of CD4+ CD160+ human blood T lymphocytes of circulating cutaneous T cells. These rare T lymphocytes represent 2.1 ± 1.9% of the circulating CD3+ CD4+ T cells, coexpress CD8αα, CD244, and perforin but lack CD28 expression, a phenotype corresponding to effector memory cytotoxic T-lymphocytes. Functional studies further confirmed their cytotoxic potential. These cells lack αEβ7 integrin and CCR7 expression but do express skin-addressing molecules CLA, and CCR4. In normal human skin, CD4+ CD160+ cells represent 34.6 ± 14.7% of the CD4+ T lymphocytes extracted by collagenase treatment. These T cells coexpress CLA (81 ± 13.6%), CCR4 (62.3 ± 15.9%), and some CD8αα (19.6 ± 13%) or CCR7 (24.4 ± 11.7%) expression. Cutaneous T-cell lymphoma cells express the natural killer receptor KIR3DL2 (CD158k) used as a tumor marker. Not only we confirmed the expression of this marker in the blood and/or skin of mycosis fungoides patients but we also show for the first time CD158k expression (often associated with CD160) on cutaneous CD4+ T cells from healthy individuals (25.3 ± 15%). Therefore, CD4+ CD160+ T cells expressing CD158k might represent specialized cutaneous lymphocytes devoted to immune surveillance, from which could originate cutaneous T-cell lymphomas such as mycosis fungoides.

  11. The spleen CD4+ T cell response to blood-stage Plasmodium chabaudi malaria develops in two phases characterized by different properties.

    PubMed

    Muxel, Sandra Marcia; Freitas do Rosário, Ana Paula; Zago, Cláudia Augusta; Castillo-Méndez, Sheyla Inés; Sardinha, Luiz Roberto; Rodriguez-Málaga, Sérgio Marcelo; Câmara, Niels Olsen Saraiva; Álvarez, José Maria; Lima, Maria Regina D'Império

    2011-01-01

    The pivotal role of spleen CD4(+) T cells in the development of both malaria pathogenesis and protective immunity makes necessary a profound comprehension of the mechanisms involved in their activation and regulation during Plasmodium infection. Herein, we examined in detail the behaviour of non-conventional and conventional splenic CD4(+) T cells during P. chabaudi malaria. We took advantage of the fact that a great proportion of CD4(+) T cells generated in CD1d(-/-) mice are I-A(b)-restricted (conventional cells), while their counterparts in I-A(b-/-) mice are restricted by CD1d and other class IB major histocompatibility complex (MHC) molecules (non-conventional cells). We found that conventional CD4(+) T cells are the main protagonists of the immune response to infection, which develops in two consecutive phases concomitant with acute and chronic parasitaemias. The early phase of the conventional CD4(+) T cell response is intense and short lasting, rapidly providing large amounts of proinflammatory cytokines and helping follicular and marginal zone B cells to secrete polyclonal immunoglobulin. Both TNF-α and IFN-γ production depend mostly on conventional CD4(+) T cells. IFN-γ is produced simultaneously by non-conventional and conventional CD4(+) T cells. The early phase of the response finishes after a week of infection, with the elimination of a large proportion of CD4(+) T cells, which then gives opportunity to the development of acquired immunity. Unexpectedly, the major contribution of CD1d-restricted CD4(+) T cells occurs at the beginning of the second phase of the response, but not earlier, helping both IFN-γ and parasite-specific antibody production. We concluded that conventional CD4(+) T cells have a central role from the onset of P. chabaudi malaria, acting in parallel with non-conventional CD4(+) T cells as a link between innate and acquired immunity. This study contributes to the understanding of malaria immunology and opens a perspective for

  12. Common clonal origin of central and resident memory T cells following skin immunization

    PubMed Central

    Gaide, Olivier; Emerson, Ryan O.; Jiang, Xiaodong; Gulati, Nicholas; Nizza, Suzanne; Desmarais, Cindy; Robins, Harlan; Krueger, James G.; Clark, Rachael A.; Kupper, Thomas S.

    2015-01-01

    Central memory T (TCM) cells in lymph nodes (LN) and resident memory T (TRM) cells in peripheral tissues play distinct roles in protective immunity1-5. Both are generated after primary infections, but the clonal origin of TRM and TCM cells is unclear. To address this question, mice were immunized through the skin with either a protein antigen, a chemical hapten, or a non-replicating poxvirus. We then analyzed antigen activated T cells from different tissues using high-throughput sequencing (HTS) of the gene (Tcrbv) encoding T cell receptor gene β chain CDR3 region to simultaneously track thousands of unique T cells6. For every abundant TRM clone generated in the skin, an abundant TCM clone bearing the identical TCR was present in lymph nodes (LN). Thus antigen reactive skin TRM and LN TCM clones were derived from a common naive T cell precursor after skin immunization, generating overlapping TCR repertoires. Although they bore the same TCR, TRM mediated rapid contact hypersensitivity (CHS)7 responses in mice, whereas TCM mediated delayed and attenuated responses. Studies in human subjects confirmed the generation of skin TRM in allergic contact dermatitis. Thus, immunization through skin simultaneously generates skin TRM and LN TCM in similar numbers from the same naïve T cells. PMID:25962122

  13. Bcl6 and Maf cooperate to instruct human follicular helper CD4 T cell differentiation.

    PubMed

    Kroenke, Mark A; Eto, Danelle; Locci, Michela; Cho, Michael; Davidson, Terence; Haddad, Elias K; Crotty, Shane

    2012-04-15

    Follicular helper CD4 T (Tfh) cells provide B cells with signals that are important for the generation of high-affinity Abs and immunological memory and, therefore, are critical for the protective immunity elicited by most human vaccines. Transcriptional regulators of human Tfh cell differentiation are poorly understood. In this article, we demonstrate that Bcl6 controls specific gene modules for human Tfh cell differentiation. The introduction of Bcl6 expression in primary human CD4 T cells resulted in the regulation of a core set of migration genes that enable trafficking to germinal centers: CXCR4, CXCR5, CCR7, and EBI2. Bcl6 expression also induced a module of protein expression critical for T-B interactions, including SAP, CD40L, PD-1, ICOS, and CXCL13. This constitutes direct evidence for Bcl6 control of most of these functions and includes three genes known to be loci of severe human genetic immunodeficiencies (CD40L, SH2D1A, and ICOS). Introduction of Bcl6 did not alter the expression of IL-21 or IL-4, the primary cytokines of human Tfh cells. We show in this article that introduction of Maf (c-Maf) does induce the capacity to express IL-21. Surprisingly, Maf also induced CXCR5 expression. Coexpression of Bcl6 and Maf revealed that Bcl6 and Maf cooperate in the induction of CXCR4, PD-1, and ICOS. Altogether, these findings reveal that Bcl6 and Maf collaborate to orchestrate a suite of genes that define core characteristics of human Tfh cell biology.

  14. CD4+ T-cell subsets in inflammatory diseases: beyond the Th1/Th2 paradigm

    PubMed Central

    Hirahara, Kiyoshi

    2016-01-01

    CD4+ T cells are crucial for directing appropriate immune responses during host defense and for the pathogenesis of inflammatory diseases. In addition to the classical biphasic model of differentiation of T-helper 1 (Th1) and Th2 cells, unexpected increases in the numbers of CD4+ T-cell subsets, including Th17, Th9, T follicular-helper (Tfh) and T-regulatory (Treg) cells, have been recognized. In the present review, we focus on how these various T-helper cell subsets contribute to the pathogenesis of immune-mediated inflammatory diseases. In particular, we focus on multiple sclerosis, psoriasis and asthma as typical model diseases in which multiple T-helper cell subsets have recently been suggested to play a role. We will also discuss various unique sub-populations of T-helper cells that have been identified. First, we will introduce the heterogeneous T-helper cell subsets, which are classified by their simultaneous expression of multiple key transcription factors. We will also introduce different kinds of memory-type Th2 cells, which are involved in the pathogenesis of chronic type-2 immune-related diseases. Finally, we will discuss the molecular mechanisms underlying the generation of the plasticity and heterogeneity of T-helper cell subsets. The latest progress in the study of T-helper cell subsets has forced us to reconsider the etiology of immune-mediated inflammatory diseases beyond the model based on the Th1/Th2 balance. To this end, we propose another model—the pathogenic T-helper population disease-induction model—as a possible mechanism for the induction and/or persistence of immune-mediated inflammatory diseases. PMID:26874355

  15. CD4 T-helper cell cytokine phenotypes and antibody response following tetanus toxoid booster immunization.

    PubMed

    Livingston, Kimberly A; Jiang, Xiaowen; Stephensen, Charles B

    2013-04-30

    Routine methods for enumerating antigen-specific T-helper cells may not identify low-frequency phenotypes such as Th2 cells. We compared methods of evaluating such responses to identify tetanus toxoid- (TT) specific Th1, Th2, Th17 and IL10(+) cells. Eight healthy subjects were given a TT booster vaccination. Blood was drawn before, 3, 7, 14, and 28days after vaccination and peripheral blood mononuclear cells (PBMC) were cultured for 7days with TT, negative control (diluent), and a positive control (Staphylococcus enterotoxin B [SEB]). Activation markers (CD25 and CD69) were measured after 44h (n=8), cytokines in supernatant after 3 and 7days, and intracellular cytokine staining (ICS) of proliferated cells (identified by dye dilution) after 7days (n=6). Vaccination increased TT-specific expression of CD25 and CD69 on CD3(+)CD4(+) lymphocytes, and TT-specific proliferation at 7, 14 and 28days post vaccination. Vaccination induced TT-specific Th1 (IFN-γ, TNF-α, and IL-2) Th2 (IL-13, IL-5, and IL-4), Th17 (IL-17A) and IL-10(+) cells as measured by ICS. TT-specific Th1 cells were the most abundant (12-15% of all TT-specific CD4(+) T-cells) while IL10(+) (1.8%) Th17 (1.1%) and Th2 cells (0.2-0.6%) were less abundant. TT-specific cytokine concentrations in PBMC supernatants followed the same pattern where a TT-specific IL-9 response was also seen. In conclusion, TT booster vaccination induced a broad T-helper cell response. This method of evaluating cytokine phenotypes may be useful in examining the impact of nutrition and environmental conditions on the plasticity of T-helper cell memory responses.

  16. Lymphoid tissue inducer cells: architects of CD4 immune responses in mice and men.

    PubMed

    Kim, M-Y; Kim, K-S; McConnell, F; Lane, P

    2009-07-01

    In this review, we summarize the current understanding of the multiple functions of the mouse lymphoid tissue inducer (LTi) cells in: (i) the development of organized lymphoid tissue, (ii) the generation and maintenance of CD4-dependent immunity in adult lymphoid tissues; and (iii) the regulation of central tolerance in thymus. By contrast with mouse LTi cells, which have been well described, the human equivalent is only just beginning to be characterized. Human LTi-like cells expressing interleukin (IL)-22 have been identified recently and found to differentiate into natural killer (NK) cells. The relationship of LTi cells to NK cells is discussed in the light of several studies reporting a close relationship in the mouse between LTi cells and transcription factor retinoid-related orphan receptor gammat-dependent IL-22 producing NK cells in the gut. We also outline our data suggesting that these cells are present in adult human lymphoid tissues.

  17. Interleukin-2-Dependent Allergen-Specific Tissue-Resident Memory Cells Drive Asthma.

    PubMed

    Hondowicz, Brian D; An, Dowon; Schenkel, Jason M; Kim, Karen S; Steach, Holly R; Krishnamurty, Akshay T; Keitany, Gladys J; Garza, Esteban N; Fraser, Kathryn A; Moon, James J; Altemeier, William A; Masopust, David; Pepper, Marion

    2016-01-19

    Exposure to inhaled allergens generates T helper 2 (Th2) CD4(+) T cells that contribute to episodes of inflammation associated with asthma. Little is known about allergen-specific Th2 memory cells and their contribution to airway inflammation. We generated reagents to understand how endogenous CD4(+) T cells specific for a house dust mite (HDM) allergen form and function. After allergen exposure, HDM-specific memory cells persisted as central memory cells in the lymphoid organs and tissue-resident memory cells in the lung. Experimental blockade of lymphocyte migration demonstrated that lung-resident cells were sufficient to induce airway hyper-responsiveness, which depended upon CD4(+) T cells. Investigation into the differentiation of pathogenic Trm cells revealed that interleukin-2 (IL-2) signaling was required for residency and directed a program of tissue homing migrational cues. These studies thus identify IL-2-dependent resident Th2 memory cells as drivers of lung allergic responses.

  18. TGF-β receptor maintains CD4 T helper cell identity during chronic viral infections

    PubMed Central

    Lewis, Gavin M.; Wehrens, Ellen J.; Labarta-Bajo, Lara; Streeck, Hendrik; Zuniga, Elina I.

    2016-01-01

    Suppression of CD8 and CD4 T cells is a hallmark in chronic viral infections, including hepatitis C and HIV. While multiple pathways are known to inhibit CD8 T cells, the host molecules that restrict CD4 T cell responses are less understood. Here, we used inducible and CD4 T cell–specific deletion of the gene encoding the TGF-β receptor during chronic lymphocytic choriomeningitis virus infection in mice, and determined that TGF-β signaling restricted proliferation and terminal differentiation of antiviral CD4 T cells. TGF-β signaling also inhibited a cytotoxic program that includes granzymes and perforin expression at both early and late stages of infection in vivo and repressed the transcription factor eomesodermin. Overexpression of eomesodermin was sufficient to recapitulate in great part the phenotype of TGF-β receptor–deficient CD4 T cells, while SMAD4 was necessary for CD4 T cell accumulation and differentiation. TGF-β signaling also restricted accumulation and differentiation of CD4 T cells and reduced the expression of cytotoxic molecules in mice and humans infected with other persistent viruses. These data uncovered an eomesodermin-driven CD4 T cell program that is continuously suppressed by TGF-β signaling. During chronic viral infection, this program limits CD4 T cell responses while maintaining CD4 T helper cell identity. PMID:27599295

  19. Crystal structure of HIV-1 primary receptor CD4 in complex with a potent antiviral antibody.

    PubMed

    Freeman, Michael M; Seaman, Michael S; Rits-Volloch, Sophia; Hong, Xinguo; Kao, Chia-Ying; Ho, David D; Chen, Bing

    2010-12-08

    Ibalizumab is a humanized, anti-CD4 monoclonal antibody. It potently blocks HIV-1 infection and targets an epitope in the second domain of CD4 without interfering with immune functions mediated by interaction of CD4 with major histocompatibility complex (MHC) class II molecules. We report here the crystal structure of ibalizumab Fab fragment in complex with the first two domains (D1-D2) of CD4 at 2.2 Å resolution. Ibalizumab grips CD4 primarily by the BC-loop (residues 121-125) of D2, sitting on the opposite side of gp120 and MHC-II binding sites. No major conformational change in CD4 accompanies binding to ibalizumab. Both monovalent and bivalent forms of ibalizumab effectively block viral infection, suggesting that it does not need to crosslink CD4 to exert antiviral activity. While gp120-induced structural rearrangements in CD4 are probably minimal, CD4 structural rigidity is dispensable for ibalizumab inhibition. These results could guide CD4-based immunogen design and lead to a better understanding of HIV-1 entry.

  20. Crystal structure of HIV-1 primary receptor CD4 in complex with a potent antiviral antibody

    PubMed Central

    Freeman, Michael M.; Seaman, Michael S.; Rits-Volloch, Sophia; Hong, Xinguo; Kao, Chia-Ying; Ho, David D.; Chen, Bing

    2010-01-01

    Summary Ibalizumab is a humanized, anti-CD4 monoclonal antibody. It potently blocks HIV-1 infection and targets an epitope in the second domain of CD4 without interfering with immune functions mediated by interaction of CD4 with major histocompatibility complex (MHC) class II molecules. We report here the crystal structure of ibalizumab Fab fragment in complex with the first two domains (D1-D2) of CD4 at 2.2 Å resolution. Ibalizumab grips CD4 primarily by the BC-loop (residues 121-125) of D2, sitting on the opposite side of gp120 and MHC-II binding sites. No major conformational change in CD4 accompanies binding to ibalizumab. Both monovalent and bivalent forms of ibalizumab effectively block viral infection, suggesting that it does not need to crosslink CD4 to exert antiviral activity. While gp120-induced structural rearrangements in CD4 are probably minimal, CD4 structural rigidity is dispensable for ibalizumab inhibition. These results could guide CD4-based immunogen design and lead to a better understanding of HIV-1 entry. PMID:21134642

  1. Serum iron, Folate, Ferritin and CD4 Count in HIV Seropositive Women.

    PubMed

    Kharb, Simmi; Kumawat, Manjulata; Lallar, Meenakshi; Ghalaut, P S; Nanda, Smiti

    2017-03-01

    HIV infects cluster of differentiation 4 (CD4) T-lymphocytes, monocytes and macrophages resulting in decreased number and function of CD4 cells, changes that affect both cell mediated and humoral immunity. Hematological abnormalities are a common complication of human immune virus (HIV) infection and these abnormalities increase as the disease advances. Anemia is the most common haematological abnormality in HIV seropositive patients and its incidence is strongly associated with the progression of the disease. The aim of present study was to assess the haematological profile of HIV seropositive women and compare them with CD4 count. Two hundred seropositive females (age 18-25 years) attending antiretroviral therapy clinic were selected. Routine gynaecological and haematological investigations were carried out, study samples were drawn and serum iron, folate and ferritin were analysed by chemiluminiscence and CD4 count was determined by using flow-cytometry. Anemia was prevalent in seropositive women especially in those with low CD4 levels. Serum folate and ferritin levels were significantly lower in females with lower CD4 levels. Serum iron levels were higher at low CD4 levels. The mean CD4 count in HIV seropositive anaemic women were lower as compared to non anaemics suggesting that anaemia improves with higher CD4 cell counts. Plasma folate and ferritin levels are sensitive predictor of anaemia in early HIV infections and these patients should have a regular monitoring of their folate and ferritin levels especially with lower CD4 levels.

  2. DC-SIGN Increases the Affinity of HIV-1 Envelope Glycoprotein Interaction with CD4

    PubMed Central

    Hijazi, Karolin; Wang, Yufei; Scala, Carlo; Jeffs, Simon; Longstaff, Colin; Stieh, Daniel; Haggarty, Beth; Vanham, Guido; Schols, Dominique; Balzarini, Jan; Jones, Ian M.; Hoxie, James; Shattock, Robin; Kelly, Charles G.

    2011-01-01

    Mannose-binding C-type lectin receptors, expressed on Langerhans cells and subepithelial dendritic cells (DCs) of cervico-vaginal tissues, play an important role in HIV-1 capture and subsequent dissemination to lymph nodes. DC-SIGN has been implicated in both productive infection of DCs and the DC-mediated trans infection of CD4+ T cells that occurs in the absence of replication. However, the molecular events that underlie this efficient transmission have not been fully defined. In this study, we have examined the effect of the extracellular domains of DC-SIGN and Langerin on the stability of the interaction of the HIV-1 envelope glycoprotein with CD4 and also on replication in permissive cells. Surface plasmon resonance analysis showed that DC-SIGN increases the binding affinity of trimeric gp140 envelope glycoproteins to CD4. In contrast, Langerin had no effect on the stability of the gp140:CD4 complex. In vitro infection experiments to compare DC-SIGN enhancement of CD4-dependent and CD4-independent strains demonstrated significantly lower enhancement of the CD4-independent strain. In addition DC-SIGN increased the relative rate of infection of the CD4-dependent strain but had no effect on the CD4-independent strain. DC-SIGN binding to the HIV envelope protein effectively increases exposure of the CD4 binding site, which in turn contributes to enhancement of infection. PMID:22163292

  3. Factors associated with CD4 lymphocyte counts in HIV-negative Senegalese individuals

    PubMed Central

    Mair, C; Hawes, S E; Agne, H D; Sow, P S; N'doye, I; Manhart, L E; Fu, P L; Gottlieb, G S; Kiviat, N B

    2008-01-01

    CD4+ lymphocytes are a primary target of the human immunodeficiency virus (HIV), and CD4 counts are one of the factors used to measure disease progression in HIV-positive individuals. CD4 counts vary in uninfected individuals and across populations due to a variety of demographic, environmental, immunological and genetic factors that probably persist throughout the course of HIV infection. This study sought to determine reference levels and identify factors that influence lymphocyte counts in 681 HIV-uninfected adults in Senegal, where residents are exposed to a variety of infectious diseases and other conditions that may affect CD4 counts. Lymphocyte counts were assessed in commercial sex workers, symptomatic men and women presenting to the University of Dakar infectious disease clinic for out-patient care and women seeking family planning services. CD4 and CD3 lymphocyte counts differed between the four study groups (P < 0·01). Men had the lowest mean CD4 count (711·6 cells/μl), while commercial sex workers had the highest levels (966·0 cells/μl). After adjustment for age and other behavioural and clinical factors, the difference in CD4 counts between the three groups of women did not remain. However, both gender and smoking were associated independently with CD4 counts, as men maintained lower mean CD4 counts (β = −156·4 cells/μl, P < 0·01) and smokers had higher mean CD4 counts (β = 124·0 cells/μl, P < 0·01) than non-smokers in multivariable analyses. This study is the first to explore factors that may influence CD4 levels in Senegal and to estimate baseline CD4 levels among HIV-negatives, information that may guide clinicians in interpreting CD4 counts. PMID:18190600

  4. Stabilization of HIV-1 gp120-CD4 Receptor Complex through Targeted Interchain Disulfide Exchange*

    PubMed Central

    Cerutti, Nichole; Mendelow, Barry V.; Napier, Grant B.; Papathanasopoulos, Maria A.; Killick, Mark; Khati, Makobetsa; Stevens, Wendy; Capovilla, Alexio

    2010-01-01

    HIV-1 enters cells via interaction between the trimeric envelope (Env) glycoprotein gp120/gp41 and the host cell surface receptor molecule CD4. The requirement of CD4 for viral entry has rationalized the development of recombinant CD4-based proteins as competitive viral attachment inhibitors and immunotherapeutic agents. In this study, we describe a novel recombinant CD4 protein designed to bind gp120 through a targeted disulfide-exchange mechanism. According to structural models of the gp120-CD4 receptor complex, substitution of Ser60 on the CD4 domain 1 α-helix with Cys positions a thiol in proximity of the gp120 V1/V2 loop disulfide (Cys126–Cys196), satisfying the stereochemical and geometric conditions for redox exchange between CD4 Cys60 and gp120 Cys126, and the consequent formation of an interchain disulfide bond. In this study, we provide experimental evidence for this effect by describing the expression, purification, refolding, receptor binding and antiviral activity analysis of a recombinant two-domain CD4 variant containing the S60C mutation (2dCD4-S60C). We show that 2dCD4-S60C binds HIV-1 gp120 with a significantly higher affinity than wild-type protein under conditions that facilitate disulfide exchange and that this translates into a corresponding increase in the efficacy of CD4-mediated viral entry inhibition. We propose that targeted redox exchange between conserved gp120 disulfides and nucleophilic moieties positioned strategically on CD4 (or CD4-like scaffolds) conceptualizes a new strategy in the development of high affinity HIV-1 Env ligands, with important implications for therapy and vaccine development. More generally, this chalcogen substitution approach provides a general means of stabilizing receptor-ligand complexes where the structural and biophysical conditions for disulfide exchange are satisfied. PMID:20538591

  5. Conformational Rearrangement Within the Soluble Domains of the CD4 Receptor is Ligand-Specific

    SciTech Connect

    Ashish,F.; Juncadella, I.; Garg, R.; Boone, C.; Anguita, J.; Krueger, J.

    2008-01-01

    Ligand binding induces shape changes within the four modular ectodomains (D1-D4) of the CD4 receptor, an important receptor in immune signaling. Small angle x-ray scattering (SAXS) on both a two-domain and a four-domain construct of the soluble CD4 (sCD4) is consistent with known crystal structures demonstrating a bilobal and a semi-extended tetralobal Z conformation in solution, respectively. Detection of conformational changes within sCD4 as a result of ligand binding was followed by SAXS on sCD4 bound to two different glycoprotein ligands: the tick saliva immunosuppressor Salp15 and the HIV-1 envelope protein gp120. Ab initio modeling of these data showed that both Salp15 and gp120 bind to the D1 domain of sCD4 and yet induce drastically different structural rearrangements. Upon binding, Salp15 primarily distorts the characteristic lobal architecture of the sCD4 without significantly altering the semi-extended shape of the sCD4 receptor. In sharp contrast, the interaction of gp120 with sCD4 induces a shape change within sCD4 that can be described as a Z-to-U bi-fold closure of the four domains across its flexible D2-D3 linker. Placement of known crystal structures within the boundaries of the SAXS-derived models suggests that the ligand-induced shape changes could be a result of conformational changes within this D2-D3 linker. Functionally, the observed shape changes in CD4 receptor causes dissociation of lymphocyte kinase from the cytoplasmic domain of Salp15-bound CD4 and facilitates an interaction between the exposed V3 loops of CD4-bound gp120 molecule to the extracellular loops of its co-receptor, a step essential for HIV-1 viral entry.

  6. Processing and Memory of Central versus Peripheral Information as a Function of Reading Goals: Evidence from Eye-Movements

    ERIC Educational Resources Information Center

    Yeari, Menahem; van den Broek, Paul; Oudega, Marja

    2015-01-01

    The present study examined the effect of reading goals on the processing and memory of central and peripheral textual information. Using eye-tracking methodology, we compared the effect of four common reading goals--entertainment, presentation, studying for a close-ended (multiple-choice) questions test, and studying for an open-ended questions…

  7. Expansion of PD-1-positive effector CD4 T cells in an experimental model of SLE: contribution to the self-organized criticality theory.

    PubMed

    Miyazaki, Yumi; Tsumiyama, Ken; Yamane, Takashi; Ito, Mitsuhiro; Shiozawa, Shunichi

    2013-04-18

    We have developed a systems biology concept to explain the origin of systemic autoimmunity. From our studies of systemic lupus erythematosus (SLE) we have concluded that this disease is the inevitable consequence of over-stimulating the host's immune system by repeated exposure to antigen to levels that surpass a critical threshold, which we term the system's "self-organized criticality". We observed that overstimulation of CD4 T cells in mice led to the development of autoantibody-inducing CD4 T cells (aiCD4 T) capable of generating various autoantibodies and pathological lesions identical to those observed in SLE. We show here that this is accompanied by the significant expansion of a novel population of effector T cells characterized by expression of programmed death-1 (PD-1)-positive, CD27(low), CD127(low), CCR7(low) and CD44(high)CD62L(low) markers, as well as increased production of IL-2 and IL-6. In addition, repeated immunization caused the expansion of CD8 T cells into fully-matured cytotoxic T lymphocytes (CTL) that express Ly6C(high)CD122(high) effector and memory markers. Thus, overstimulation with antigen leads to the expansion of a novel effector CD4 T cell population that expresses an unusual memory marker, PD-1, and that may contribute to the pathogenesis of SLE.

  8. Impaired humoral immunity in X-linked lymphoproliferative disease is associated with defective IL-10 production by CD4+ T cells

    PubMed Central

    Ma, Cindy S.; Hare, Nathan J.; Nichols, Kim E.; Dupré, Loic; Andolfi, Grazia; Roncarolo, Maria-Grazia; Adelstein, Stephen; Hodgkin, Philip D.; Tangye, Stuart G.

    2005-01-01

    X-linked lymphoproliferative disease (XLP) is an often-fatal immunodeficiency characterized by hypogammaglobulinemia, fulminant infectious mononucleosis, and/or lymphoma. The genetic lesion in XLP, SH2D1A, encodes the adaptor protein SAP (signaling lymphocytic activation molecule–associated [SLAM-associated] protein); however, the mechanism(s) by which mutations in SH2D1A causes hypogammaglobulinemia is unknown. Our analysis of 14 XLP patients revealed normal B cell development but a marked reduction in the number of memory B cells. The few memory cells detected were IgM+, revealing deficient isotype switching in vivo. However, XLP B cells underwent proliferation and differentiation in vitro as efficiently as control B cells, which indicates that the block in differentiation in vivo is B cell extrinsic. This possibility is supported by the finding that XLP CD4+ T cells did not efficiently differentiate into IL-10+ effector cells or provide optimal B cell help in vitro. Importantly, the B cell help provided by SAP-deficient CD4+ T cells was improved by provision of exogenous IL-10 or ectopic expression of SAP, which resulted in increased IL-10 production by T cells. XLP CD4+ T cells also failed to efficiently upregulate expression of inducible costimulator (ICOS), a potent inducer of IL-10 production by CD4+ T cells. Thus, insufficient IL-10 production may contribute to hypogammaglobulinemia in XLP. This finding suggests new strategies for treating this immunodeficiency. PMID:15761493

  9. Chromosomal localisation of the CD4cre transgene in B6·Cg-Tg(Cd4-cre)1Cwi mice.

    PubMed

    Westendorf, Kerstin; Durek, Pawel; Ayew, Samia; Mashreghi, Mir-Farzin; Radbruch, Andreas

    2016-09-01

    The B6·Cg-Tg(Cd4-cre)1Cwi line expresses CRE recombinase under the control of the promoter and regulatory elements of the Cd4 gene. Here we show that CRE recombinase expression reduces the number and frequencies of CD4 positive subsets in a dose-dependent manner and localize the integration site of the transgenic construct to position 60335693-60341285 (qD) of chromosome 3. The insert contains at least 15 complete sequential copies of the transgenic construct. Based on this information we describe a novel PCR assay for genetic typing of transgenic mice.

  10. Bystander CD4+ T lymphocytes survive in HIV-infected human lymphoid tissue

    NASA Technical Reports Server (NTRS)

    Grivel, Jean-Charles; Biancotto, Angelique; Ito, Yoshinori; Lima, Rosangela G.; Margolis, Leonid B.

    2003-01-01

    HIV infection is associated with depletion of CD4(+) T cells. The mechanisms of this phenomenon remain to be understood. In particular, it remains controversial whether and to what extent uninfected ("bystander") CD4(+) T cells die in HIV-infected individuals. We address this question using a system of human lymphoid tissue ex vivo. Tissue blocks were inoculated with HIV-1. After productive infection was established, they were treated with the reverse transcriptase inhibitor nevirapine to protect from infection those CD4(+) T cells that had not yet been infected. These CD4(+) T cells residing in HIV-infected tissue are by definition bystanders. Our results demonstrate that after nevirapine application the number of bystander CD4(+) T cells is conserved. Thus, in the context of HIV-infected human lymphoid tissue, productive HIV infection kills infected cells but is not sufficient to cause the death of a significant number of uninfected CD4(+) T cells.

  11. INTIMATE PARTNER VIOLENCE IS ASSOCIATED WITH INCREASED CD4+ T-CELL ACTIVATION AMONG HIV-NEGATIVE HIGH-RISK WOMEN

    PubMed Central

    Kalokhe, Ameeta S.; Ibegbu, Chris C.; Kaur, Surinder P.; Amara, Rama R.; Kelley, Mary E.; del Rio, Carlos; Stephenson, Rob

    2016-01-01

    Background Biological pathways mediating the link between intimate partner violence (IPV) and increased HIV risk remain unexplored. We hypothesized that IPV-induced stress negatively affects HIV systemic immune defenses and aimed to evaluate whether IPV was associated with immune profiles linked to HIV susceptibility: CD4 activation and diminished regulatory T-cell (Treg) frequency. Methods Seventy-five HIV-negative high-risk women were surveyed regarding their IPV experience. They provided blood, urine, and (if present) genital ulcer samples for cortisol, immune assays, and STI testing. Using flow cytometry, we assessed activated CD4+ T-cell (%HLA-DR+/CD38+) and Treg (%CD4+CD25+FoxP3+) frequencies and phenotyping. Nonparametric tests evaluated the association between IPV and immune outcomes. Multivariate regression explored confounding and moderation of the IPV-CD4 activation pathway. Results Lifetime IPV was associated with increased CD4+ activation (r = 0.331, P = 0.004), a shift in CD4+ phenotype from naïve to effector memory (r = 0.343, P = 0.003), and a decrease in naive (%HLA-DR+/CD45RA−) Treg frequency (r = −0.337, P = 0.003). Experiencing IPV over the past year had similar trends. After controlling for sexual IPV, lifetime physical and psychological abuse remained significantly associated with CD4+ activation (P = 0.004 and P = 0.033, respectively). After controlling for race (the only covariate linked to activation), the lifetime IPV-CD4 activation association remained significant (P = 0.012). Alcohol use and depression were identified as potential pathway moderators. Conclusion Our data is the first to suggest an immune link between IPV and HIV, and may help explain differences at the individual level in HIV susceptibility and response to biological HIV prevention strategies. The association of psychological and physical abuse with CD4 activation independent of sexual abuse further supports the existence of a stress-induced immune pathway. PMID

  12. In Vivo Binding and Retention of CD4-Specific DARPin 57.2 in Macaques

    PubMed Central

    Pugach, Pavel; Krarup, Anders; Gettie, Agegnehu; Kuroda, Marcelo; Blanchard, James; Piatak, Michael; Lifson, Jeffrey D.; Trkola, Alexandra; Robbiani, Melissa

    2010-01-01

    Background The recently described Designed Ankyrin Repeat Protein (DARPin) technology can produce highly selective ligands to a variety of biological targets at a low production cost. Methodology/Principal Findings To investigate the in vivo use of DARPins for future application to novel anti-HIV strategies, we identified potent CD4-specific DARPins that recognize rhesus CD4 and followed the fate of intravenously injected CD4-specific DARPin 57.2 in rhesus macaques. The human CD4-specific DARPin 57.2 bound macaque CD4+ cells and exhibited potent inhibitory activity against SIV infection in vitro. DARPin 57.2 or the control E3_5 DARPin was injected into rhesus macaques and the fate of cell-free and cell-bound CD4-specific DARPin was evaluated. DARPin-bound CD4+ cells were detected in the peripheral blood as early as 30 minutes after the injection, decreasing within 6 hours and being almost undetectable within 24 hours. The amount of DARPin bound was dependent on the amount of DARPin injected. CD4-specific DARPin was also detected on CD4+ cells in the lymph nodes within 30 minutes, which persisted with similar kinetics to blood. More extensive analysis using blood revealed that DARPin 57.2 bound to all CD4+ cell types (T cells, monocytes, dendritic cells) in vivo and in vitro with the amount of binding directly proportional to the amount of CD4 on the cell surface. Cell-free DARPins were also detected in the plasma, but were rapidly cleared from circulation. Conclusions/Significance We demonstrated that the CD4-specific DARPin can rapidly and selectively bind its target cells in vivo, warranting further studies on possible clinical use of the DARPin technology. PMID:20805996

  13. H + CD4 abstraction reaction dynamics: product energy partitioning.

    PubMed

    Hu, Wenfang; Lendvay, György; Troya, Diego; Schatz, George C; Camden, Jon P; Bechtel, Hans A; Brown, Davida J A; Martin, Marion R; Zare, Richard N

    2006-03-09

    This paper presents experimental and theoretical studies of the product energy partitioning associated with the H + CD4 (nu = 0) --> HD + CD3 reaction for the collision energy range 0.5-3.0 eV. The theoretical results are based on quasiclassical trajectories from (1) first principles direct dynamics calculations (B3LYP/6-31G), (2) an empirical surface developed by Espinosa-García [J. Chem. Phys. 2002, 116, 10664] (EG), and (3) two semiempirical surfaces (MSINDO and reparametrized MSINDO). We find that most of the energy appears in product translation at energies just above the reactive threshold; however, HD vibration and rotation become quite important at energies above 1 eV, each accounting for over 20% of the available energy above 1.5 eV, according to the B3LYP calculations. The barrier on the B3LYP surface, though being later than that on EG, predicts significantly higher HD vibrational excitation than EG. This deviation is contradictory to what would be expected on the basis of the Polanyi rules and derives from modest differences in the potential energy surfaces. The CD3 internal energy is generally quite low, and we present detailed rotational state distributions which show that the CD3 rotational distribution is largely independent of collision energy in the 0.75-1.95 eV range. The most populated rotational levels are N = 5 and 6 on B3LYP, with most of that excitation being associated with motion about the C2 axes, rather than C3 axis, of the CD3 product, in good agreement with the experimental results. Through our extensive studies in this and previous work concerning the scattering dynamics, we conclude that B3LYP/6-31G provides the best available description of the overall dynamics for the title reaction at relatively high collision energies.

  14. TNF-α blockade induces IL-10 expression in human CD4+ T cells

    NASA Astrophysics Data System (ADS)

    Evans, Hayley G.; Roostalu, Urmas; Walter, Gina J.; Gullick, Nicola J.; Frederiksen, Klaus S.; Roberts, Ceri A.; Sumner, Jonathan; Baeten, Dominique L.; Gerwien, Jens G.; Cope, Andrew P.; Geissmann, Frederic; Kirkham, Bruce W.; Taams, Leonie S.

    2014-02-01

    IL-17+ CD4+ T (Th17) cells contribute to the pathogenesis of several human inflammatory diseases. Here we demonstrate that TNF inhibitor (TNFi) drugs induce the anti-inflammatory cytokine IL-10 in CD4+ T cells including IL-17+ CD4+ T cells. TNFi-mediated induction of IL-10 in IL-17+ CD4+ T cells is Treg-/Foxp3-independent, requires IL-10 and is overcome by IL-1β. TNFi-exposed IL-17+ CD4+ T cells are molecularly and functionally distinct, with a unique gene signature characterized by expression of IL10 and IKZF3 (encoding Aiolos). We show that Aiolos binds conserved regions in the IL10 locus in IL-17+ CD4+ T cells. Furthermore, IKZF3 and IL10 expression levels correlate in primary CD4+ T cells and Aiolos overexpression is sufficient to drive IL10 in these cells. Our data demonstrate that TNF-α blockade induces IL-10 in CD4+ T cells including Th17 cells and suggest a role for the transcription factor Aiolos in the regulation of IL-10 in CD4+ T cells.

  15. ESTABLISHING MEAN CD4+ T CELL VALUES AMONG HEALTHY JAVANESE ADULTS IN INDONESIA.

    PubMed

    Prasetyo, Afiono Agung; Zaini, Khilyat Ulin Nur

    2015-07-01

    The objective of this study was to establish mean CD4+ T cell values among healthy Javanese adults in Indonesia. Two hundred forty-one healthy adults (119 women and 122 men), aged 18-65 years, were enrolled in the study. CD4+ T cells were analyzed by immunophenotyping. The mean absolute CD4+ T cell count was 753.3 ± 270.3 cells/µl (median = 725.0 cells/µl) and the mean CD4+ T cell percentage was 32.6 ± 7.7%, (median = 31.0%). Women had a slightly higher mean absolute CD4+ T cell count and CD4+ T cell percentage (779.1 ± 271.0 cells/ µl; 33.4 ± 8.2%) than men (728.2 ± 268.3 cells/µl; 31.8 ± 7.1%), but the differences were not statistically significant (p = 0.126, p = 0.216, respectively). The mean absolute CD4+ T cell varied significantly by age group (p = 0.002). Sixty-one point seven percent of men studied (37/60) had a CD4+ T cell count less than 500 cells/µl (OR 1.8; 95% CI = 1.001-3.300). Absolute CD4+ T cell counts among Javanese Indonesians varied significantly by age.

  16. Clinical Evaluation of the BD FACSPresto™ Near-Patient CD4 Counter in Kenya

    PubMed Central

    Angira, Francis; Akoth, Benta; Omolo, Paul; Opollo, Valarie; Bornheimer, Scott; Judge, Kevin; Tilahun, Henok; Lu, Beverly; Omana-Zapata, Imelda; Zeh, Clement

    2016-01-01

    Background The BD FACSPresto™ Near-Patient CD4 Counter was developed to expand HIV/AIDS management in resource-limited settings. It measures absolute CD4 counts (AbsCD4), percent CD4 (%CD4), and hemoglobin (Hb) from a single drop of capillary or venous blood in approximately 23 minutes, with throughput of 10 samples per hour. We assessed the performance of the BD FACSPresto system, evaluating accuracy, stability, linearity, precision, and reference intervals using capillary and venous blood at KEMRI/CDC HIV-research laboratory, Kisumu, Kenya, and precision and linearity at BD Biosciences, California, USA. Methods For accuracy, venous samples were tested using the BD FACSCalibur™ instrument with BD Tritest™ CD3/CD4/CD45 reagent, BD Trucount™ tubes, and BD Multiset™ software for AbsCD4 and %CD4, and the Sysmex™ KX-21N for Hb. Stability studies evaluated duration of staining (18–120-minute incubation), and effects of venous blood storage <6–24 hours post-draw. A normal cohort was tested for reference intervals. Precision covered multiple days, operators, and instruments. Linearity required mixing two pools of samples, to obtain evenly spaced concentrations for AbsCD4, total lymphocytes, and Hb. Results AbsCD4 and %CD4 venous/capillary (N = 189/ N = 162) accuracy results gave Deming regression slopes within 0.97–1.03 and R2 ≥0.96. For Hb, Deming regression results were R2 ≥0.94 and slope ≥0.94 for both venous and capillary samples. Stability varied within 10% 2 hours after staining and for venous blood stored less than 24 hours. Reference intervals results showed that gender—but not age—differences were statistically significant (p<0.05). Precision results had <3.5% coefficient of variation for AbsCD4, %CD4, and Hb, except for low AbsCD4 samples (<6.8%). Linearity was 42–4,897 cells/μL for AbsCD4, 182–11,704 cells/μL for total lymphocytes, and 2–24 g/dL for Hb. Conclusions The BD FACSPresto system provides accurate, precise clinical

  17. Enhanced HIV-1 neutralization by a CD4-VH3-IgG1 fusion protein

    SciTech Connect

    Meyuhas, Ronit; Noy, Hava; Fishman, Sigal; Margalit, Alon; Montefiori, David C.; Gross, Gideon

    2009-08-21

    HIV-1 gp120 is an alleged B cell superantigen, binding certain VH3+ human antibodies. We reasoned that a CD4-VH3 fusion protein could possess higher affinity for gp120 and improved HIV-1 inhibitory capacity. To test this we produced several human IgG1 immunoligands harboring VH3. Unlike VH3-IgG1 or VH3-CD4-IgG1, CD4-VH3-IgG1 bound gp120 considerably stronger than CD4-IgG1. CD4-VH3-IgG1 exhibited {approx}1.5-2.5-fold increase in neutralization of two T-cell laboratory-adapted strains when compared to CD4-IgG1. CD4-VH3-IgG1 improved neutralization of 7/10 clade B primary isolates or pseudoviruses, exceeding 20-fold for JR-FL and 13-fold for Ba-L. It enhanced neutralization of 4/8 clade C viruses, and had negligible effect on 1/4 clade A pseudoviruses. We attribute this improvement to possible pairing of VH3 with CD4 D1 and stabilization of an Ig Fv-like structure, rather than to superantigen interactions. These novel findings support the current notion that CD4 fusion proteins can act as better HIV-1 entry inhibitors with potential clinical implications.

  18. Protection conferred by heterologous vaccination against tuberculosis is dependent on the ratio of CD4(+) /CD4(+)  Foxp3(+) cells.

    PubMed

    Fedatto, Paola Fernanda; Sérgio, Cássia Alves; Paula, Marina Oliveira e; Gembre, Ana Flávia; Franco, Luís Henrique; Wowk, Pryscilla Fanini; Ramos, Simone Gusmão; Horn, Cynthia; Marchal, Gilles; Turato, Walter Miguel; Silva, Célio Lopes; da Fonseca, Denise Morais; Bonato, Vânia Luiza Deperon

    2012-11-01

    CD4(+) Foxp3(+) regulatory T cells inhibit the production of interferon-γ, which is the major mediator of protection against Mycobacterium tuberculosis infection. In this study, we evaluated whether the protection conferred by three different vaccines against tuberculosis was associated with the number of spleen and lung regulatory T cells. We observed that after homologous immunization with the 65 000 molecular weight heat-shock protein (hsp 65) DNA vaccine, there was a significantly higher number of spleen CD4(+) Foxp3(+) cells compared with non-immunized mice. Heterologous immunization using bacillus Calmette-Guérin (BCG) to prime and DNA-hsp 65 to boost (BCG/DNA-hsp 65) or BCG to prime and culture filtrate proteins (CFP)-CpG to boost (BCG/CFP-CpG) induced a significantly higher ratio of spleen CD4(+) /CD4(+) Foxp3(+) cells compared with non-immunized mice. In addition, the protection conferred by either the BCG/DNA-hsp 65 or the BCG/CFP-CpG vaccines was significant compared with the DNA-hsp 65 vaccine. Despite the higher ratio of spleen CD4(+) /CD4(+) Foxp3(+) cells found in BCG/DNA-hsp 65-immunized or BCG/CFP-CpG-immunized mice, the lungs of both groups of mice were better preserved than those of DNA-hsp 65-immunized mice. These results confirm the protective efficacy of BCG/DNA-hsp 65 and BCG/CFP-CpG heterologous prime-boost vaccines and the DNA-hsp 65 homologous vaccine. Additionally, the prime-boost regimens assayed here represent a promising strategy for the development of new vaccines to protect against tuberculosis because they probably induce a proper ratio of CD4(+) and regulatory (CD4(+) Foxp3(+) ) cells during the immunization regimen. In this study, this ratio was associated with a reduced number of regulatory cells and no injury to the lungs.

  19. CD4+ primary T cells expressing HCV-core protein upregulate Foxp3 and IL-10, suppressing CD4 and CD8 T cells.

    PubMed

    Fernandez-Ponce, Cecilia; Dominguez-Villar, Margarita; Aguado, Enrique; Garcia-Cozar, Francisco

    2014-01-01

    Adaptive T cell responses are critical for controlling HCV infection. While there is clinical evidence of a relevant role for regulatory T cells in chronic HCV-infected patients, based on their increased number and function; mechanisms underlying such a phenomena are still poorly understood. Accumulating evidence suggests that proteins from Hepatitis C virus can suppress host immune responses. We and others have shown that HCV is present in CD4+ lymphocytes from chronically infected patients and that HCV-core protein induces a state of unresponsiveness in the CD4+ tumor cell line Jurkat. Here we show that CD4+ primary T cells lentivirally transduced with HCV-core, not only acquire an anergic phenotype but also inhibit IL-2 production and proliferation of bystander CD4+ or CD8+ T cells in response to anti-CD3 plus anti-CD28 stimulation. Core-transduced CD4+ T cells show a phenotype characterized by an increased basal secretion of the regulatory cytokine IL-10, a decreased IFN-γ production upon stimulation, as well as expression of regulatory T cell markers, CTLA-4, and Foxp3. A significant induction of CD4+CD25+CD127(low)PD-1(high)TIM-3(high) regulatory T cells with an exhausted phenotype was also observed. Moreover, CCR7 expression decreased in HCV-core expressing CD4+ T cells explaining their sequestration in inflamed tissues such as the infected liver. This work provides a new perspective on de novo generation of regulatory CD4+ T cells in the periphery, induced by the expression of a single viral protein.

  20. TSCOT+ thymic epithelial cell-mediated sensitive CD4 tolerance by direct presentation.

    PubMed

    Ahn, Sejin; Lee, Gwanghee; Yang, Soo Jung; Lee, Deokjae; Lee, Seunghyuk; Shin, Hyo Sun; Kim, Min Cheol; Lee, Kee Nyung; Palmer, Douglas C; Theoret, Marc R; Jenkinson, Eric J; Anderson, Graham; Restifo, Nicholas P; Kim, Moon Gyo

    2008-08-05

    Although much effort has been directed at dissecting the mechanisms of central tolerance, the role of thymic stromal cells remains elusive. In order to further characterize this event, we developed a mouse model restricting LacZ to thymic stromal cotransporter (TSCOT)-expressing thymic stromal cells (TDLacZ). The thymus of this mouse contains approximately 4,300 TSCOT+ cells, each expressing several thousand molecules of the LacZ antigen. TSCOT+ cells express the cortical marker CDR1, CD40, CD80, CD54, and major histocompatibility complex class II (MHCII). When examining endogenous responses directed against LacZ, we observed significant tolerance. This was evidenced in a diverse T cell repertoire as measured by both a CD4 T cell proliferation assay and an antigen-specific antibody isotype analysis. This tolerance process was at least partially independent of Autoimmune Regulatory Element gene expression. When TDLacZ mice were crossed to a novel CD4 T cell receptor (TCR) transgenic reactive against LacZ (BgII), there was a complete deletion of double-positive thymocytes. Fetal thymic reaggregate culture of CD45- and UEA-depleted thymic stromal cells from TDLacZ and sorted TCR-bearing thymocytes excluded the possibility of cross presentation by thymic dendritic cells and medullary epithelial cells for the deletion. Overall, these results demonstrate that the introduction of a neoantigen into TSCOT-expressing cells can efficiently establish complete tolerance and suggest a possible application for the deletion of antigen-specific T cells by antigen introduction into TSCOT+ cells.

  1. The development of prospective memory in young schoolchildren: the impact of ongoing task absorption, cue salience, and cue centrality.

    PubMed

    Kliegel, Matthias; Mahy, Caitlin E V; Voigt, Babett; Henry, Julie D; Rendell, Peter G; Aberle, Ingo

    2013-12-01

    This study presents evidence that 9- and 10-year-old children outperform 6- and 7-year-old children on a measure of event-based prospective memory and that retrieval-based factors systematically influence performance and age differences. All experiments revealed significant age effects in prospective memory even after controlling for ongoing task performance. In addition, the provision of a less absorbing ongoing task (Experiment 1), higher cue salience (Experiment 2), and cues appearing in the center of attention (Experiment 3) were each associated with better performance. Of particular developmental importance was an age by cue centrality (in or outside of the center of attention) interaction that emerged in Experiment 3. Thus, age effects were restricted to prospective memory cues appearing outside of the center of attention, suggesting that the development of prospective memory across early school years may be modulated by whether a cue requires overt monitoring beyond the immediate attentional context. Because whether a cue is in or outside of the center of attention might determine the amount of executive control needed in a prospective memory task, findings suggest that developing executive control resources may drive prospective memory development across primary school age.

  2. CD4 and CD8 T cells mediate distinct lethal meningoencephalitis in mice challenged with Tacaribe arenavirus.

    PubMed

    Ireland, Derek Dc; Tami, Cecilia; Pedras-Vasconcelos, Joao; Verthelyi, Daniela

    2017-01-01

    Neonates are at increased risk of viral encephalopathies that can result in neurological dysfunction, seizures, permanent disability and even death. The neurological damage results from the combined effect of the virus and the immune response it elicits, thus finding tools to facilitate viral clearance from central nervous system (CNS) while minimizing neuron damage remains a critical challenge. Neonatal mice inoculated intraperitoneally with Tacaribe virus (TCRV) develop seizures, hindlimb paralysis and death within 15 days of inoculation. TCRV localizes to the CNS within days of challenge, primarily infecting astrocytes in the cerebellum and brain stem. We show that infection leads to inflammation, T cell and monocyte infiltration into the cerebellar parenchyma, apoptosis of astrocytes, neuronal degeneration and loss of Purkinje cells. Infiltrating antigen-specific T cells fail to clear the virus but drive the disease, as T-cell-deficient CD3ɛ KO mice survive TCRV infection with minimal inflammation or clinical manifestations despite no difference in CNS viral loads in comparison with T-cell sufficient mice. CD8+ T cells drive the pathology, which even in the absence of CD4+ T-cell help, infiltrate the parenchyma and mediate the apoptotic loss of cerebellar astrocytes, neurodegeneration and loss of Purkinje cells resulting in loss of balance, paralysis and death. CD4+ T cells are also pathogenic inducing gliosis and inflammation in the cerebellum and cerebrum that are associated with wasting and death several weeks after CD4+ T-cell transfer. These data demonstrate distinct pathogenic effects of CD4+ and CD8+ T cells and identify them as possible therapeutic targets.

  3. CD4 and CD8 T cells mediate distinct lethal meningoencephalitis in mice challenged with Tacaribe arenavirus

    PubMed Central

    Ireland, Derek DC; Tami, Cecilia; Pedras-Vasconcelos, Joao; Verthelyi, Daniela

    2017-01-01

    Neonates are at increased risk of viral encephalopathies that can result in neurological dysfunction, seizures, permanent disability and even death. The neurological damage results from the combined effect of the virus and the immune response it elicits, thus finding tools to facilitate viral clearance from central nervous system (CNS) while minimizing neuron damage remains a critical challenge. Neonatal mice inoculated intraperitoneally with Tacaribe virus (TCRV) develop seizures, hindlimb paralysis and death within 15 days of inoculation. TCRV localizes to the CNS within days of challenge, primarily infecting astrocytes in the cerebellum and brain stem. We show that infection leads to inflammation, T cell and monocyte infiltration into the cerebellar parenchyma, apoptosis of astrocytes, neuronal degeneration and loss of Purkinje cells. Infiltrating antigen-specific T cells fail to clear the virus but drive the disease, as T-cell-deficient CD3ɛ KO mice survive TCRV infection with minimal inflammation or clinical manifestations despite no difference in CNS viral loads in comparison with T-cell sufficient mice. CD8+ T cells drive the pathology, which even in the absence of CD4+ T-cell help, infiltrate the parenchyma and mediate the apoptotic loss of cerebellar astrocytes, neurodegeneration and loss of Purkinje cells resulting in loss of balance, paralysis and death. CD4+ T cells are also pathogenic inducing gliosis and inflammation in the cerebellum and cerebrum that are associated with wasting and death several weeks after CD4+ T-cell transfer. These data demonstrate distinct pathogenic effects of CD4+ and CD8+ T cells and identify them as possible therapeutic targets. PMID:27569560

  4. Antigen-Presenting Human γδ T Cells Promote Intestinal CD4(+) T Cell Expression of IL-22 and Mucosal Release of Calprotectin.

    PubMed

    Tyler, Christopher J; McCarthy, Neil E; Lindsay, James O; Stagg, Andrew J; Moser, Bernhard; Eberl, Matthias

    2017-03-22

    The cytokine IL-22 plays a critical role in mucosal barrier defense, but the mechanisms that promote IL-22 expression in the human intestine remain poorly understood. As human microbe-responsive Vγ9/Vδ2 T cells are abundant in the gut and recognize microbiota-associated metabolites, we assessed their potential to induce IL-22 expression by intestinal CD4(+) T cells. Vγ9/Vδ2 T cells with characteristics of APCs were generated from human blood and intestinal organ cultures, then cocultured with naive and memory CD4(+) T cells obtained from human blood or the colon. The potency of blood and intestinal γδ T-APCs was compared with that of monocytes and dendritic cells, by assessing CD4(+) T cell phenotypes and proliferation as well as cytokine and transcription factor profiles. Vγ9/Vδ2 T cells in human blood, colon, and terminal ileum acquired APC functions upon microbial activation in the presence of microenvironmental signals including IL-15, and were capable of polarizing both blood and colonic CD4(+) T cells toward distinct effector fates. Unlike monocytes or dendritic cells, gut-homing γδ T-APCs employed an IL-6 independent mechanism to stimulate CD4(+) T cell expression of IL-22 without upregulating IL-17. In human intestinal organ cultures, microbial activation of Vγ9/Vδ2 T cells promoted mucosal secretion of IL-22 and ICOSL/TNF-α-dependent release of the IL-22 inducible antimicrobial protein calprotectin without modulating IL-17 expression. In conclusion, human γδ T-APCs stimulate CD4(+) T cell responses distinct from those induced by myeloid APCs to promote local barrier defense via mucosal release of IL-22 and calprotectin. Targeting of γδ T-APC functions may lead to the development of novel gut-directed immunotherapies and vaccines.

  5. CD4 T Follicular Helper Cells and HIV Infection: Friends or Enemies?

    PubMed Central

    Moukambi, Félicien; Rodrigues, Vasco; Fortier, Yasmina; Rabezanahary, Henintsoa; Borde, Chloé; Krust, Bernard; Andreani, Guadalupe; Silvestre, Ricardo; Petrovas, Constantinos; Laforge, Mireille; Estaquier, Jérôme

    2017-01-01

    Follicular T helper (Tfh) cells, a subset of CD4 T lymphocytes, are essential for memory B cell activation, survival, and differentiation and assist B cells in the production of antigen-specific antibodies. Work performed in recent years pointed out the importance of Tfh cells in the context of HIV and SIV infections. The importance of tissue distribution of Tfh is also an important point since their frequency differs between peripheral blood and lymph nodes compared to the spleen, the primary organ for B cell activation, and differentiation. Our recent observations indicated an early and profound loss of splenic Tfh cells. The role of transcriptional activator and repressor factors that control Tfh differentiation is also discussed in the context of HIV/SIV infection. Because Tfh cells are important for B cell differentiation and antibody production, accelerating the Tfh responses early during HIV/SIV infection could be promising as novel immunotherapeutic approach or alternative vaccine strategies. However, because Tfh cells are infected during the HIV/SIV infection and represent a reservoir, this may interfere with HIV vaccine strategy. Thus, Tfh represent the good and bad guys during HIV infection. PMID:28265271

  6. Follicular Helper CD4+ T Cells in Human Neuroautoimmune Diseases and Their Animal Models.

    PubMed

    Fan, Xueli; Lin, Chenhong; Han, Jinming; Jiang, Xinmei; Zhu, Jie; Jin, Tao

    2015-01-01

    Follicular helper CD4(+) T (TFH) cells play a fundamental role in humoral immunity deriving from their ability to provide help for germinal center (GC) formation, B cell differentiation into plasma cells and memory cells, and antibody production in secondary lymphoid tissues. TFH cells can be identified by a combination of markers, including the chemokine receptor CXCR5, costimulatory molecules ICOS and PD-1, transcription repressor Bcl-6, and cytokine IL-21. It is difficult and impossible to get access to secondary lymphoid tissues in humans, so studies are usually performed with human peripheral blood samples as circulating counterparts of tissue TFH cells. A balance of TFH cell generation and function is critical for protective antibody response, whereas overactivation of TFH cells or overexpression of TFH-associated molecules may result in autoimmune diseases. Emerging data have shown that TFH cells and TFH-associated molecules may be involved in the pathogenesis of neuroautoimmune diseases including multiple sclerosis (MS), neuromyelitis optica (NMO)/neuromyelitis optica spectrum disorders (NMOSD), and myasthenia gravis (MG). This review summarizes the features of TFH cells, including their development, function, and roles as well as TFH-associated molecules in neuroautoimmune diseases and their animal models.

  7. Trichloroethylene activates CD4+ T cells: potential role in an autoimmune response.

    PubMed

    Gilbert, K M; Griffin, J M; Pumford, N R

    1999-11-01

    Trichloroethylene is an industrial solvent and has become a major environmental contaminant. Autoimmune-prone MRL +/+ mice were treated for up to 22 weeks with trichloroethylene in the drinking water (0, 2.5, and 5.0 mg/mL) in order to study the immunoregulatory effects of this environmental toxicant. After only 4 weeks of treatment, trichloroethylene was shown to promote the expansion of CD4+ T cells that expressed a memory/activation phenotype (i.e., CD44hi CD45RBlo) and secreted high levels of IFN-gamma, but not IL-4. In addition, trichloroethylene treatment accelerated the development of an autoimmune response in the MRL +/+ mice as evidenced by an earlier appearance of antinuclear antibodies and increased levels of total IgG2a. MRL +/+ mice treated with trichloroethylene for 22 weeks also contained antibodies specific for trichloroethylene adducts, suggesting the activation of trichloroethylene-specific T cells. The results suggest that trichloroethylene can stimulate antigen nonspecific as well as specific T cells that are capable of promoting autoimmunity in genetically predisposed individuals.

  8. Working Memory in the Classroom: An Inside Look at the Central Executive.

    PubMed

    Barker, Lauren A

    2016-01-01

    This article provides a review of working memory and its application to educational settings. A discussion of the varying definitions of working memory is presented. Special attention is given to the various multidisciplinary professionals who work with students with working memory deficits, and their unique understanding of the construct. Definitions and theories of working memory are briefly summarized and provide the foundation for understanding practical applications of working memory to assessment and intervention. Although definitions and models of working memory abound, there is limited consensus regarding universally accepted definitions and models. Current research indicates that developing new models of working memory may be an appropriate paradigm shift at this time. The integration of individual practitioner's knowledge regarding academic achievement, working memory and processing speed could provide a foundation for the future development of new working memory models. Future directions for research should aim to explain how tasks and behaviors are supported by the substrates of the cortico-striatal and the cerebro-cerebellar systems. Translation of neurobiological information into educational contexts will be helpful to inform all practitioners' knowledge of working memory constructs. It will also allow for universally accepted definitions and models of working memory to arise and facilitate more effective collaboration between disciplines working in educational setting.

  9. Association of p56lck with the cytoplasmic domain of CD4 modulates HIV-1 expression.

    PubMed Central

    Tremblay, M; Meloche, S; Gratton, S; Wainberg, M A; Sékaly, R P

    1994-01-01

    To investigate the role played by the cytoplasmic domain of the CD4 glycoprotein in the process of HIV infection, we have transfected two CD4-negative human T cell lines with cDNAs encoding the full-length CD4 and a truncated form of the molecule, lacking most of the cytoplasmic domain. Levels of viral replication were significantly higher in cells carrying the truncated version of CD4, in comparison with cells expressing the full-length CD4, as measured by the percentage of cells expressing viral p24 protein and the number of infectious particles released into culture supernatants. The extent of viral entry and reverse transcription was similar in each case, as monitored by an enzymatic test and quantitative PCR. Quantitative differences at RNA and protein levels were responsible for changes in viral production. To further characterize the mechanisms responsible for decreased rates of HIV replication in CD4-expressing cells we have treated the different cell lines, very early after HIV infection, with azidothymidine and soluble CD4, two antiviral agents that inhibit replication of HIV at different stages in the virus replicative cycle. Results from these experiments indicate that a cellular signal is mediated by the CD4 molecule, which negatively regulates the expression of viral DNA already present in such cells. This signal would be initiated following oligomerization of the CD4 molecule by the virus itself. Results from experiments with a CD4 construct containing mutations of the cysteine residues which are responsible for association of CD4 with p56lck demonstrate that p56lck is implicated in the transduction of the signal negatively regulating HIV replication. Images PMID:8112293

  10. Soluble CD4 antigen reactivity in intravenous immunoglobulin preparations: is it specific?

    PubMed Central

    Perosa, F; Rizzi, R; Pulpito, V; Dammacco, F

    1995-01-01

    Soluble CD4 antigen (sCD4) was measured in seven commercially available intravenous immunoglobulin preparations (IVIg) by means of a double determinant immunoassay (DDIA), whereby two MoAbs recognizing two distinct and spatially distant epitopes on CD4 were used to capture and detect the antigen, respectively. Preincubation of six out of seven IVIg, which were found to be apparently positive for sCD4, with mouse- and bovine-derived serum or purified immunoglobulins completely neutralized DDIA reactivity for sCD4. The inhibition was specific since it was not or only partially observed when IVIg were mixed with whole serum or purified IgG from rabbit. Extensive absorption of six IVIg on insolubilized mouse IgG (mIgG) resulted in a complete loss of reactivity. Eluted human anti-mouse antibodies (HAMA) from any of the IVIg displayed a dose-dependent binding in a DDIA, though its extent varied from one preparation to another. Western blot analysis showed that HAMA from all IVIg contained no component with a molecular weight identical with or close to that of recombinant CD4. Purified mIgG markedly influenced the sCD4 reactivity of two IVIg (Sandoglobulin and Globuman I.V.) when sCD4 was measured with a purchased 'CD4-specific Test Kit', thus suggesting that HAMA can exceed the absorbing capacity of the sample diluent. Taken as a whole, these data indicate that sCD4-based DDIA signal is mostly, if not completely, generated by the presence of human immunoglobulin with anti-mouse immunoglobulin reactivity, thus casting doubts on the actual occurrence of sCD4 in IVIg. Images Fig. 4 PMID:7813106

  11. Immunological predictors of CD4+ T cell decline in antiretroviral treatment interruptions

    PubMed Central

    Seoane, Elena; Resino, Salvador; Moreno, Santiago; de Quiros, Juan Carlos Lopez Bernaldo; Moreno, Ana; Rubio, Rafael; Gonzalez-García, Juan; Arribas, José Ramón; Pulido, Federico; Muñoz-Fernández, Ma Ángeles

    2008-01-01

    Background The common response to stopping anti-HIV treatment is an increase of HIV-RNA load and decrease in CD4+, but not all the patients have similar responses to this therapeutic strategy. The aim was to identify predictive markers of CD4+ cell count declines to < 350/μL in CD4-guided antiretroviral treatment interruptions. Methods 27 HIV-infected patients participated in a prospective multicenter study in with a 24 month follow-up. Patients on stable highly active antiretroviral therapy (HAART), with CD4+ count > 600/μL, and HIV-RNA < 50 copies/ml for at least 6 months were offered the option to discontinue antiretroviral therapy. The main outcome was a decline in CD4+ cell count to < 350/μL. Results After 24 months of follow-up, 16 of 27 (59%) patients (who discontinued therapy) experienced declines in CD4+ cell count to < 350/μL. Patients with a CD4+ nadir of < 200 cells/μL had a greater risk of restarting therapy during the follow-up (RR (CI95%): 3.37 (1.07; 10.36)). Interestingly, lymphoproliferative responses to Mycobacterium tuberculosis purified protein derivative (PPD) below 10000 c.p.m. at baseline (4.77 (1.07; 21.12)), IL-4 production above 100 pg/mL at baseline (5.95 (1.76; 20.07)) in PBMC cultured with PPD, and increased IL-4 production of PBMC with p24 antigen at baseline (1.25 (1.01; 1.55)) were associated to declines in CD4+ cell count to < 350/μL. Conclusion Both the number (CD4+ nadir) and the functional activity of CD4+ (lymphoproliferative response to PPD) predict the CD4+ decrease associated with discontinuation of ART in patients with controlled viremia. PMID:18302775

  12. A Low Peripheral Blood CD4/CD8 Ratio Is Associated with Pulmonary Emphysema in HIV

    PubMed Central

    Attia, Engi F.; Akgün, Kathleen M.; Soo Hoo, Guy W.; Freiberg, Matthew S.; Butt, Adeel A.; Wongtrakool, Cherry; Goetz, Matthew Bidwell; Brown, Sheldon T.; Graber, Christopher J.; Huang, Laurence; Crothers, Kristina

    2017-01-01

    Objectives The prevalence of emphysema is higher among HIV-infected (HIV+) individuals compared to HIV-uninfected persons. While greater tobacco use contributes, HIV-related effects on immunity likely confer additional risk. Low peripheral blood CD4+ to CD8+ T-lymphocyte (CD4/CD8) ratio may reflect chronic inflammation in HIV and may be a marker of chronic lung disease in this population. Therefore, we sought to determine whether the CD4/CD8 ratio was associated with chronic obstructive pulmonary disease (COPD), particularly the emphysema subtype, in a cohort of HIV+ subjects. Methods We performed a cross-sectional analysis of 190 HIV+ subjects enrolled in the Examinations of HIV Associated Lung Emphysema (EXHALE) study. Subjects underwent baseline laboratory assessments, pulmonary function testing and chest computed tomography (CT) analyzed for emphysema severity and distribution. We determined the association between CD4/CD8 ratio and emphysema, and the association between CD4/CD8 ratio and pulmonary function markers of COPD. Results Mild or greater emphysema (>10% lung involvement) was present in 31% of subjects. Low CD4/CD8 ratio was associated with >10% emphysema in multivariable models, adjusting for risk factors including smoking, current and nadir CD4 count and HIV RNA level. Those with CD4/CD8 ratio <0.4 had 6.3 (1.1–39) times the odds of >10% emphysema compared to those with a ratio >1.0 in fully adjusted models. A low CD4/CD8 ratio was also associated with reduced diffusion capacity (DLCO). Conclusions A low CD4/CD8 ratio was associated with emphysema and low DLCO in HIV+ subjects, independent of other risk factors and clinical markers of HIV. The CD4/CD8 ratio may be a useful, clinically available, marker for risk of emphysema in HIV+ subjects in the antiretroviral therapy (ART) era. PMID:28122034

  13. The Transcription Factor Hobit Identifies Human Cytotoxic CD4+ T Cells

    PubMed Central

    Oja, Anna E.; Vieira Braga, Felipe A.; Remmerswaal, Ester B. M.; Kragten, Natasja A. M.; Hertoghs, Kirsten M. L.; Zuo, Jianmin; Moss, Paul A.; van Lier, René A. W.; van Gisbergen, Klaas P. J. M.; Hombrink, Pleun

    2017-01-01

    The T cell lineage is commonly divided into CD4-expressing helper T cells that polarize immune responses through cytokine secretion and CD8-expressing cytotoxic T cells that eliminate infected target cells by virtue of the release of cytotoxic molecules. Recently, a population of CD4+ T cells that conforms to the phenotype of cytotoxic CD8+ T cells has received increased recognition. These cytotoxic CD4+ T cells display constitutive expression of granzyme B and perforin at the protein level and mediate HLA class II-dependent killing of target cells. In humans, this cytotoxic profile is found within the human cytomegalovirus (hCMV)-specific, but not within the influenza- or Epstein–Barr virus-specific CD4+ T cell populations, suggesting that, in particular, hCMV infection induces the formation of cytotoxic CD4+ T cells. We have previously described that the transcription factor Homolog of Blimp-1 in T cells (Hobit) is specifically upregulated in CD45RA+ effector CD8+ T cells that arise after hCMV infection. Here, we describe the expression pattern of Hobit in human CD4+ T cells. We found Hobit expression in cytotoxic CD4+ T cells and accumulation of Hobit+ CD4+ T cells after primary hCMV infection. The Hobit+ CD4+ T cells displayed highly overlapping characteristics with Hobit+ CD8+ T cells, including the expression of cytotoxic molecules, T-bet, and CX3CR1. Interestingly, γδ+ T cells that arise after hCMV infection also upregulate Hobit expression and display a similar effector phenotype as cytotoxic CD4+ and CD8+ T cells. These findings suggest a shared differentiation pathway in CD4+, CD8+, and γδ+ T cells that may involve Hobit-driven acquisition of long-lived cytotoxic effector function. PMID:28392788

  14. HIV-1 Vpr accelerates viral replication during acute infection by exploitation of proliferating CD4+ T cells in vivo.

    PubMed

    Sato, Kei; Misawa, Naoko; Iwami, Shingo; Satou, Yorifumi; Matsuoka, Masao; Ishizaka, Yukihito; Ito, Mamoru; Aihara, Kazuyuki; An, Dong Sung; Koyanagi, Yoshio

    2013-01-01

    The precise role of viral protein R (Vpr), an HIV-1-encoded protein, during HIV-1 infection and its contribution to the development of AIDS remain unclear. Previous reports have shown that Vpr has the ability to cause G2 cell cycle arrest and apoptosis in HIV-1-infected cells in vitro. In addition, vpr is highly conserved in transmitted/founder HIV-1s and in all primate lentiviruses, which are evolutionarily related to HIV-1. Although these findings suggest an important role of Vpr in HIV-1 pathogenesis, its direct evidence in vivo has not been shown. Here, by using a human hematopoietic stem cell-transplanted humanized mouse model, we demonstrated that Vpr causes G2 cell cycle arrest and apoptosis predominantly in proliferating CCR5(+) CD4(+) T cells, which mainly consist of regulatory CD4(+) T cells (Tregs), resulting in Treg depletion and enhanced virus production during acute infection. The Vpr-dependent enhancement of virus replication and Treg depletion is observed in CCR5-tropic but not CXCR4-tropic HIV-1-infected mice, suggesting that these effects are dependent on the coreceptor usage by HIV-1. Immune activation was observed in CCR5-tropic wild-type but not in vpr-deficient HIV-1-infected humanized mice. When humanized mice were treated with denileukin diftitox (DD), to deplete Tregs, DD-treated humanized mice showed massive activation/proliferation of memory T cells compared to the untreated group. This activation/proliferation enhanced CCR5 expression in memory CD4(+) T cells and rendered them more susceptible to CCR5-tropic wild-type HIV-1 infection than to vpr-deficient virus. Taken together, these results suggest that Vpr takes advantage of proliferating CCR5(+) CD4(+) T cells for enhancing viremia of CCR5-tropic HIV-1. Because Tregs exist in a higher cycling state than other T cell subsets, Tregs appear to be more vulnerable to exploitation by Vpr during acute HIV-1 infection.

  15. CD4 T Follicular Helper and Regulatory Cell Dynamics and Function in HIV Infection

    PubMed Central

    Miles, Brodie; Miller, Shannon M.; Connick, Elizabeth

    2016-01-01

    T follicular helper cells (TFH) are a specialized subset of CD4 T cells that reside in B cell follicles and promote B cell maturation into plasma cells and long-lived memory B cells. During chronic infection prior to the development of AIDS, HIV-1 (HIV) replication is largely concentrated in TFH. Paradoxically, TFH numbers are increased in early and midstages of disease, thereby promoting HIV replication and disease progression. Despite increased TFH numbers, numerous defects in humoral immunity are detected in HIV-infected individuals, including dysregulation of B cell maturation, impaired somatic hypermutation, and low quality of antibody production despite hypergammaglobulinemia. Clinically, these defects are manifested by increased vulnerability to bacterial infections and impaired vaccine responses, neither of which is fully reversed by antiretroviral therapy (ART). Deficits in TFH function, including reduced HIV-specific IL-21 production and low levels of co-stimulatory receptor expression, have been linked to these immune impairments. Impairments in TFH likely contribute as well to the ability of HIV to persist and evade humoral immunity, particularly the inability to develop broadly neutralizing antibodies. In addition to direct infection of TFH, other mechanisms that have been linked to TFH deficits in HIV infection include upregulation of PD-L1 on germinal center B cells and augmented follicular regulatory T cell responses. Challenges to development of strategies to enhance TFH function in HIV infection include lack of an established phenotype for memory TFH as well as limited understanding of the relationship between peripheral TFH and lymphoid tissue TFH. Interventions to augment TFH function in HIV-infected individuals could enhance immune reconstitution during ART and potentially augment cure strategies. PMID:28082992

  16. CD4/CD8 ratio and CD8 counts predict CD4 response in HIV-1-infected drug naive and in patients on cART

    PubMed Central

    Sauter, Rafael; Huang, Ruizhu; Ledergerber, Bruno; Battegay, Manuel; Bernasconi, Enos; Cavassini, Matthias; Furrer, Hansjakob; Hoffmann, Matthias; Rougemont, Mathieu; Günthard, Huldrych F; Held, Leonhard

    2016-01-01

    Abstract Plasma HIV viral load is related to declining CD4 lymphocytes. The extent to which CD8 cells, in addition to RNA viral load, predict the depletion of CD4 cells is not well characterized so far. We examine if CD8 cell count is a prognostic factor for CD4 cell counts during an HIV infection. A longitudinal analysis is conducted using data from the Swiss HIV cohort study collected between January 2000 and October 2014. Linear mixed regression models were applied to observations from HIV-1-infected treatment naive patients (NAIVE) and cART-treated patients to predict the short-term evolution of CD4 cell counts. For each subgroup, it was quantified to which extent CD8 cell counts or CD4/CD8 ratios are prognostic factors for disease progression. In both subgroups, 2500 NAIVE and 8902 cART patients, past CD4 cells are positively (P < 0.0001) and past viral load is negatively (P < 0.0001) associated with the outcome. Including additionally past CD8 cell counts improves the fit significantly (P < 0.0001) and increases the marginal explained variation 31.7% to 40.7% for the NAIVE and from 44.1% to 50.7% for the cART group. The past CD4/CD8 ratio (instead of the past CD8 level) is positively associated with the outcome, increasing the explained variation further to 41.8% for NAIVE and 51.9% for cART. PMID:27759638

  17. Selective culling of high avidity antigen-specific CD4+ T cells after virulent Salmonella infection.

    PubMed

    Ertelt, James M; Johanns, Tanner M; Mysz, Margaret A; Nanton, Minelva R; Rowe, Jared H; Aguilera, Marijo N; Way, Sing Sing

    2011-12-01

    Typhoid fever is a persistent infection caused by host-adapted Salmonella strains adept at circumventing immune-mediated host defences. Given the importance of T cells in protection, the culling of activated CD4+ T cells after primary infection has been proposed as a potential immune evasion strategy used by this pathogen. We demonstrate that the purging of activated antigen-specific CD4+ T cells after virulent Salmonella infection requires SPI-2 encoded virulence determinants, and is not restricted only to cells with specificity to Salmonella-expressed antigens, but extends to CD4+ T cells primed to expand by co-infection with recombinant Listeria monocytogenes. Unexpectedly, however, the loss of activated CD4+ T cells during Salmonella infection demonstrated using a monoclonal population of adoptively transferred CD4+ T cells was not reproduced among the endogenous repertoire of antigen-specific CD4+ T cells identified with MHC class II tetramer. Analysis of T-cell receptor variable segment usage revealed the selective loss and reciprocal enrichment of defined CD4+ T-cell subsets after Salmonella co-infection that is associated with the purging of antigen-specific cells with the highest intensity of tetramer staining. Hence, virulent Salmonella triggers the selective culling of high avidity activated CD4+ T-cell subsets, which re-shapes the repertoire of antigen-specific T cells that persist later after infection.

  18. The differentiation and protective function of cytolytic CD4 T cells in influenza infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    CD4 T cells that recognize peptide antigen in the context of Class II MHC can differentiate into various subsets that are characterized by their helper functions. However, increasing evidence indicates that CD4 cells with direct cytolytic activity play a role in chronic, as well as, acute infections...

  19. Genetic determinism in the relationship between human CD4+ and CD8+ T lymphocyte populations?

    PubMed

    Ahmadi, K R; Hall, M A; Norman, P; Vaughan, R W; Snieder, H; Spector, T D; Lanchbury, J S

    2001-11-01

    The adaptive immune system in mammals acts in a coordinated manner to eliminate environmentally derived pathogens. Humans, mice and rats show within species variation in the levels and ratios of their peripheral CD4+ and CD8+ T cells and to a significant degree this variation is under the control of polymorphic genes. Whether genes act separately to specify CD4+ and CD8+ subpopulation levels or whether CD8+ variation is controlled through gene and environmental action on CD4+ cells or vice versa, is not known. We use a quantitative modelling approach in identical and non-identical female human twins to delineate the lines of control which act upon and between CD4+ and CD8+ subsets. The major findings of the study are: (1) genetic variation controls CD8+ T cell levels through two major routes-the first is via an effect on CD4+ T cells which accounts for the observed co-variation between CD4+ and CD8+ T cells, the second is through direct action on CD8+ T cell levels. (2) No evidence of a gene effect from CD8+ T cells on CD4+ cells is observed. Our findings have implications for the evolution of the complex defence system of which CD4+ and CD8+ T cells are a crucial part and encourage further work towards locating common pleiotropic quantitative trait loci responsible for variation in numbers of T cells.

  20. Itk Signals Promote Neuroinflammation by Regulating CD4+ T-Cell Activation and Trafficking

    PubMed Central

    Kannan, Arun K.; Kim, Do-Geun

    2015-01-01

    Here we demonstrate that interleukin-2-inducible T-cell kinase (Itk) signaling in cluster of differentiation 4-positive (CD4+) T cells promotes experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis (MS). We show that Itk−/− mice exhibit reduced disease severity, and transfer of Itk−/− CD4+ T cells into T cell-deficient recipients results in lower disease severity. We observed a significant reduction of CD4+ T cells in the CNS of Itk−/− mice or recipients of Itk−/− CD4+ T cells during EAE, which is consistent with attenuated disease. Itk−/− CD4+ T cells exhibit defective response to myelin antigen stimulation attributable to displacement of filamentous actin from the CD4+ coreceptor. This results in inadequate transmigration of Itk−/− CD4+ T cells into the CNS and across brain endothelial barriers in vitro. Finally, Itk−/− CD4+ T cells show significant reduction in production of T-helper 1 (Th1) and Th17 cytokines and exhibit skewed T effector/T regulatory cell ratios. These results indicate that signaling by Itk promotes autoimmunity and CNS inflammation, suggesting that it may be a viable target for treatment of MS. PMID:25568116

  1. Human CD4−8− T cells are a distinctive immunoregulatory subset

    PubMed Central

    Huang, Mei-Chuan; Patel, Kalpesh; Taub, Dennis D.; Longo, Dan L.; Goetzl, Edward J.

    2010-01-01

    Human CD4−8− T cells are a minor subset quantitatively but potentially important in immunity because they are predominantly distributed at body surfaces, and their number and activities increase in autoimmune diseases and decrease with aging. Distinguishing characteristics of CD4−8− T cells are found to include a unique profile of cytokines, including Serpin E1, which is not generated by other T cells, MIF, and TGF-β. At 2–5% of the total in mixtures with CD4 + CD8 T cells, CD4−8− T cells enhance the generation of IFN-γ and IL-17 by up to 12- and 5-fold, respectively, without contributing either cytokine or affecting cytokine production by NK/NKT cells. CD4−8− T cell-derived MIF is their major enhancer and TGFβ their principal inhibitor of CD4 and CD8 T cell cytokine production. Decreases in CD4−8− T cell effects may diminish protective immunity in aging, whereas increases may augment the severity of autoimmune diseases.—Huang, M.-C., Patel, K., Taub, D. D., Longo, D. L., Goetzl, E. J. Human CD4−8− T cells are a distinctive immunoregulatory subset. PMID:20154266

  2. Key role for CD4 T cells during mixed antibody mediated rejection of renal allografts

    PubMed Central

    Gaughan, A.; Wang, J.; Pelletier, R.P.; Nadasdy, T.; Brodsky, S.; Roy, S.; Lodder, M.; Bobek, D.; Mofatt-Bruce, S.; Fairchild, R.L.; Henry, M.L.; Hadley, G.A.

    2014-01-01

    We utilized mouse models to elucidate the immunologic mechanisms of functional graft loss during mixed antibody mediated rejection of renal allografts (mixed AMR), in which humoral and cellular responses to the graft occur concomitantly. Although the majority of T cells in the graft at the time of rejection were CD8 T cells with only a minor population of CD4 T cells, depletion of CD4 but not CD8 cells prevented acute graft loss during mixed AMR. CD4 depletion eliminated anti-donor alloantibodies and conferred protection from destruction of renal allografts. ELISPOT revealed that CD4 T effectors responded to donor alloantigens by both the direct and indirect pathways of allorecognition. In transfer studies, CD4 T effectors primed to donor alloantigens were highly effective at promoting acute graft dysfunction, and exhibited the attributes of effector T cells. Laser capture microdissection and confirmatory immunostaining studies revealed that CD4 T cells infiltrating the graft produced effector molecules with graft destructive potential. Bioluminescent imaging confirmed that CD4 T effectors traffic to the graft site in immune replete hosts. These data document that host CD4 T cells can promote acute dysfunction of renal allografts by directly mediating graft injury in addition to facilitating anti-donor alloantibody responses. PMID:24410909

  3. Role of LAP+CD4+ T cells in the tumor microenvironment of colorectal cancer

    PubMed Central

    Zhong, Wu; Jiang, Zhi-Yuan; Zhang, Lei; Huang, Jia-Hao; Wang, Shi-Jun; Liao, Cun; Cai, Bin; Chen, Li-Sheng; Zhang, Sen; Guo, Yun; Cao, Yun-Fei; Gao, Feng

    2017-01-01

    AIM To investigate the abundance and potential functions of LAP+CD4+ T cells in colorectal cancer (CRC). METHODS Proportions of LAP+CD4+ T cells were examined in peripheral blood and tumor/paratumor tissues of CRC patients and healthy controls using flow cytometry. Expression of phenotypic markers such as forkhead box (Fox)p3, cytotoxic T-lymphocyte-associated protein (CTLA)-4, chemokine CC receptor (CCR)4 and CCR5 was measured using flow cytometry. LAP-CD4+ and LAP+CD4+ T cells were isolated using a magnetic cell-sorting system and cell purity was analyzed by flow cytometry. Real-time quantitative polymerase chain reaction was used to measure expression of cytokines interleukin (IL)-10 and transforming growth factor (TGF)-β. RESULTS The proportion of LAP+CD4+ T cells was significantly higher in peripheral blood from patients (9.44% ± 3.18%) than healthy controls (1.49% ± 1.00%, P < 0.001). Among patients, the proportion of LAP+CD4+ T cells was significantly higher in tumor tissues (11.76% ± 3.74%) compared with paratumor tissues (3.87% ± 1.64%, P < 0.001). We also observed positive correlations between the proportion of LAP+CD4+ T cells and TNM stage (P < 0.001), distant metastasis (P < 0.001) and serum level of carcinoembryonic antigen (P < 0.05). Magnetic-activated cell sorting gave an overall enrichment of LAP+CD4+ T cells (95.02% ± 2.87%), which was similar for LAP-CD4+ T cells (94.75% ± 2.76%). In contrast to LAP-CD4+ T cells, LAP+CD4+ T cells showed lower Foxp3 expression but significantly higher levels of CTLA-4, CCR4 and CCR5 (P < 0.01). LAP+CD4+ T cells expressed significantly larger amounts of IL-10 and TGF-β but lower levels of IL-2, IL-4, IL-17 and interferon-γ, compared with LAP-CD4+ T cells. CONCLUSION LAP+CD4+ T cells accumulated in the tumor microenvironment of CRC patients and were involved in immune evasion mediated by IL-10 and TGF-β. PMID:28210081

  4. Working memory capacity and the functional connectome - insights from resting-state fMRI and voxelwise centrality mapping.

    PubMed

    Markett, Sebastian; Reuter, Martin; Heeren, Behrend; Lachmann, Bernd; Weber, Bernd; Montag, Christian

    2017-02-28

    The functional connectome represents a comprehensive network map of functional connectivity throughout the human brain. To date, the relationship between the organization of functional connectivity and cognitive performance measures is still poorly understood. In the present study we use resting-state functional magnetic resonance imaging (fMRI) data to explore the link between the functional connectome and working memory capacity in an individual differences design. Working memory capacity, which refers to the maximum amount of context information that an individual can retain in the absence of external stimulation, was assessed outside the MRI scanner and estimated based on behavioral data from a change detection task. Resting-state time series were analyzed by means of voxelwise degree and eigenvector centrality mapping, which are data-driven network analytic approaches for the characterization of functional connectivity. We found working memory capacity to be inversely correlated with both centrality in the right intraparietal sulcus. Exploratory analyses revealed that this relationship was putatively driven by an increase in negative connectivity strength of the structure. This resting-state connectivity finding fits previous task based activation studies that have shown that this area responds to manipulations of working memory load.

  5. HIV-1 Vpu targets cell surface markers CD4 and BST-2 through distinct mechanisms

    PubMed Central

    Andrew, Amy; Strebel, Klaus

    2010-01-01

    Vpu is a small integral membrane protein encoded by HIV-1 and some SIV isolates. The protein is known to induce degradation of the viral receptor molecule CD4 and to enhance the release of newly formed virions from the cell surface. Vpu accomplishes these two functions through two distinct mechanisms. In the case of CD4, Vpu acts as a molecular adaptor to connect CD4 to an E3 ubiquitin ligase complex resulting in CD4 degradation by cellular proteasomes. This requires signals located in Vpu's cytoplasmic domain. Enhancement of virus release on the other hand involves the neutralization of a cellular host factor, BST-2 (also known as CD317, HM1.24, or tetherin) and requires Vpu's TM domain. The current review discusses recent advances on the role of Vpu in controlling degradation of CD4 and in regulating virus release. PMID:20858517

  6. Immunogold detection of CD3 and CD4 antigens in patients with Mycosis fungoides.

    PubMed

    Grzanka, A A; Placek, W; Grzanka, A

    2006-01-01

    In this study, we analyzed the distribution of CD3 and CD4 antigens at the ultrastructural level in tissue samples from mycosis fungoides patients using double-immunogold labeling. We observed clusters composed of CD3 and CD4 antigens on the plasma membrane and intracellular. There were also clusters only of one type of the antigen and we could observe more often CD4 than CD3. Labeling of CD3 and CD4 was not found in control cells incubated with non-immune serum. In conclusion, our ultrastructural studies not only visualized pattern distribution and relationship between CD3 and CD4 antigens but might also suggest that the type and form of distribution provides new clues to their possible translocation in mycosis fungoides cells.

  7. Tissue adaptation of regulatory and intraepithelial CD4+ T cells controls gut inflammation

    PubMed Central

    Sujino, Tomohisa; London, Mariya; Hoytema van Konijnenburg, David P.; Rendon, Tomiko; Buch, Thorsten; Silva, Hernandez M.; Lafaille, Juan J.; Reis, Bernardo S.; Mucida, Daniel

    2016-01-01

    Foxp3+ regulatory T cells in peripheral tissues (pTregs) are instrumental in limiting inflammatory responses to non-self antigens. Within the intestine, pTregs are located primarily in the lamina propria, while intraepithelial CD4+ T cells (CD4IELs), which also exhibit anti-inflammatory properties and depend on similar environmental cues, reside in the epithelium. Using intravital microscopy, we show distinct cell dynamics of intestinal Tregs and CD4IELs. Upon migration to the epithelium, Tregs lose Foxp3 and convert to CD4IELs in a microbiota-dependent fashion, an effect attributed to the loss of the transcription factor ThPOK. Finally, we demonstrate that pTregs and CD4IELs perform complementary roles in the regulation of intestinal inflammation. These results reveal intra-tissue specialization of anti-inflammatory T cells shaped by discrete niches of the intestine. PMID:27256884

  8. Role of glutamate receptors of central and basolateral amygdala nuclei on retrieval and reconsolidation of taste aversive memory.

    PubMed

    Garcia-Delatorre, Paola; Pérez-Sánchez, Consuelo; Guzmán-Ramos, Kioko; Bermúdez-Rattoni, Federico

    2014-05-01

    There are a number of experiments showing an important involvement of amygdala N-methyl-d-aspartate (NMDA) glutamate receptors on consolidation of conditioned taste aversion (CTA) memory. Interestingly, recent evidence has shown that α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors are particularly involved in CTA retrieval. Memory reconsolidation has been proposed as a destabilization and re-stabilization process induced by memory reactivation. We have recently suggested that reconsolidation could be enabled in the absence of retrieval. Hence, we decided to analyze the participation of AMPA and NMDA receptors of the central (CeA) and basolateral amygdala (BLA) in CTA memory retrieval and reconsolidation. To do so, we tested whether administrations of an AMPA receptor blocker (NBQX) or an NMDA receptor blocker (APV) 15 min before a second acquisition trial could have effects on taste aversion. We found that administration of NBQX in the BLA blocked retrieval, whereas APV blocked reconsolidation in the BLA, and consolidation in the CeA. When we administered both NBQX and APV into the BLA before the second acquisition trial, results showed impairment of both retrieval and reconsolidation. These results further support the idea that reconsolidation is independent of retrieval, since retrieval blockade in the BLA did not impair memory reconsolidation. These results suggest that glutamate receptors have different participation on retrieval and reconsolidation of CTA and further support the hypothesis that these two processes could be independent.

  9. Central noradrenergic depletion by DSP-4 prevents stress-induced memory impairments in the object recognition task.

    PubMed

    Scullion, G A; Kendall, D A; Sunter, D; Marsden, C A; Pardon, M-C

    2009-12-01

    Environmental stress produces adverse affects on memory in humans and rodents. Increased noradrenergic neurotransmission is a major component of the response to stress and noradrenaline (NA) plays an important role in modulating processes involved in learning and memory. The present study investigated the effect of NA depletion on stress-induced changes on memory performance in the mouse. Central NA depletion was induced using the selective neurotoxin N-(2-chloroethyl)-N-ethyl-2 bromobenzylamine (DSP-4) and verified by high performance liquid chromatography (HPLC). A novel cage stress procedure involving exposure to a new clean cage for 1 h per day, 4 days per week for 4 weeks, was used to produce stress-induced memory deficits measured using the object recognition task. 50 mg/kg DSP-4 produced large and sustained reductions in NA levels in the frontal cortex and hippocampus measured 24 h, 1 week and 5 weeks after treatment. Four weeks of exposure to novel cage stress induced a memory deficit in the object recognition task which was prevented by DSP-4 pre-treatment (50 mg/kg 1 week before the commencement of stress).These findings indicate that chronic environmental stress adversely affects recognition memory and that this effect is, in part, mediated by the noradrenergic stress response. The implication of these findings is that drugs targeting the noradrenergic system to reduce over-activity may be beneficial in the treatment of stress-related mental disorders such as post-traumatic stress disorder or anxiety in which memory is affected.

  10. NKG2C/E Marks the Unique Cytotoxic CD4 T Cell Subset, ThCTL, Generated by Influenza Infection.

    PubMed

    Marshall, Nikki B; Vong, Allen M; Devarajan, Priyadharshini; Brauner, Matthew D; Kuang, Yi; Nayar, Ribhu; Schutten, Elizabeth A; Castonguay, Catherine H; Berg, Leslie J; Nutt, Stephen L; Swain, Susan L

    2017-02-01

    CD4 T cells can differentiate into multiple effector subsets, including ThCTL that mediate MHC class II-restricted cytotoxicity. Although CD4 T cell-mediated cytotoxicity has been reported in multiple viral infections, their characteristics and the factors regulating their generation are unclear, in part due to a lack of a signature marker. We show in this article that, in mice, NKG2C/E identifies the ThCTL that develop in the lung during influenza A virus infection. ThCTL express the NKG2X/CD94 complex, in particular the NKG2C/E isoforms. NKG2C/E(+) ThCTL are part of the lung CD4 effector population, and they mediate influenza A virus-specific cytotoxic activity. The phenotype of NKG2C/E(+) ThCTL indicates they are highly activated effectors expressing high levels of binding to P-selectin, T-bet, and Blimp-1, and that more of them secrete IFN-γ and readily degranulate than non-ThCTL. ThCTL also express more cytotoxicity-associated genes including perforin and granzymes, and fewer genes associated with recirculation and memory. They are found only at the site of infection and not in other peripheral sites. These data suggest ThCTL are marked by the expression of NKG2C/E and represent a unique CD4 effector population specialized for cytotoxicity.

  11. CD4+ T cell vaccination overcomes defective cross-presentation of fungal antigens in a mouse model of chronic granulomatous disease

    PubMed Central

    Luca, Antonella De; Iannitti, Rossana G.; Bozza, Silvia; Beau, Remi; Casagrande, Andrea; D’Angelo, Carmen; Moretti, Silvia; Cunha, Cristina; Giovannini, Gloria; Massi-Benedetti, Cristina; Carvalho, Agostinho; Boon, Louis; Latgé, Jean-Paul; Romani, Luigina

    2012-01-01

    Aspergillus fumigatus is a model fungal pathogen and a common cause of infection in individuals with the primary immunodeficiency chronic granulomatous disease (CGD). Although primarily considered a deficiency of innate immunity, CGD is also linked to dysfunctional T cell reactivity. Both CD4+ and CD8+ T cells mediate vaccine-induced protection from experimental aspergillosis, but the molecular mechanisms leading to the generation of protective immunity and whether these mechanisms are dysregulated in individuals with CGD have not been determined. Here, we show that activation of either T cell subset in a mouse model of CGD is contingent upon the nature of the fungal vaccine, the involvement of distinct innate receptor signaling pathways, and the mode of antigen routing and presentation in DCs. Aspergillus conidia activated CD8+ T cells upon sorting to the Rab14+ endosomal compartment required for alternative MHC class I presentation. Cross-priming of CD8+ T cells failed to occur in mice with CGD due to defective DC endosomal alkalinization and autophagy. However, long-lasting antifungal protection and disease control were successfully achieved upon vaccination with purified fungal antigens that activated CD4+ T cells through the endosome/lysosome pathway. Our study thus indicates that distinct intracellular pathways are exploited for the priming of CD4+ and CD8+ T cells to A. fumigatus and suggests that CD4+ T cell vaccination may be able to overcome defective antifungal CD8+ T cell memory in individuals with CGD. PMID:22523066

  12. The 17D-204 Vaccine Strain-Induced Protection against Virulent Yellow Fever Virus Is Mediated by Humoral Immunity and CD4+ but not CD8+ T Cells

    PubMed Central

    Lam, L. K. Metthew; Klimstra, William B.

    2016-01-01

    A gold standard of antiviral vaccination has been the safe and effective live-attenuated 17D-based yellow fever virus (YFV) vaccines. Among more than 500 million vaccinee