Acquisition of direct antiviral effector functions by CMV-specific CD4 T lymphocytes with cellular maturation

Immunology Laboratory, Human Immunology Section, Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
Journal of Experimental Medicine (Impact Factor: 12.52). 01/2007; 203(13):2865-77. DOI: 10.1084/jem.20052246
Source: PubMed


The role of CD4+ T cells in the control of persistent viral infections beyond the provision of cognate help remains unclear. We used polychromatic flow cytometry to evaluate the production of the cytokines interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-2, the chemokine macrophage inflammatory protein (MIP)-1beta, and surface mobilization of the degranulation marker CD107a by CD4+ T cells in response to stimulation with cytomegalovirus (CMV)-specific major histocompatibility complex class II peptide epitopes. Surface expression of CD45RO, CD27, and CD57 on responding cells was used to classify CD4+ T cell maturation. The functional profile of virus-specific CD4+ T cells in chronic CMV infection was unique compared with that observed in other viral infections. Salient features of this profile were: (a) the simultaneous production of MIP-1beta, TNF-alpha, and IFN-gamma in the absence of IL-2; and (b) direct cytolytic activity associated with surface mobilization of CD107a and intracellular expression of perforin and granzymes. This polyfunctional profile was associated with a terminally differentiated phenotype that was not characterized by a distinct clonotypic composition. Thus, mature CMV-specific CD4+ T cells exhibit distinct functional properties reminiscent of antiviral CD8+ T lymphocytes.

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Available from: Joseph P Casazza, Oct 04, 2015
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    • "MHC class II restricted CD4 effectors with cytolytic potential have been described since the late 1970s [3] and while early reports confined this activity to in vitro stimulated CD4 effectors [4]–[6], recent data underscores this cell type as an important mediator of viral clearance (reviewed in [7]–[9]). Cytolytic CD4 T cells (CD4 CTL) have been identified in humans with chronic infections such as Epstein-Barr Virus [10], cytomegalovirus [11] and Human Immunodeficiency Virus [12], suggesting prolonged exposure to antigen induces a terminally differentiated effector capable of cytotoxic activity. CD4 CTL have also been described during acute viral infections such as influenza [13], [14], LCMV [15], and ectromelia virus [16]. "
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    ABSTRACT: Cytolytic CD4 T cells (CD4 CTL) have been identified in vivo in response to viral infections; however, the factors necessary for driving the cytolytic phenotype have not been fully elucidated. Our previously published work suggests IL-2 may be the master regulator of perforin-mediated cytotoxicity in CD4 effectors. To further dissect the role of IL-2 in CD4 CTL generation, T cell receptor transgenic mice deficient in the ability to produce IL-2 or the high affinity IL-2 receptor (IL-2Rα, CD25) were used. Increasing concentrations of IL-2 were necessary to drive perforin (Prf) expression and maximal cytotoxicity. Granzyme B (GrB) expression and killing correlated with STAT5 activation and CD25 expression in vitro, suggesting that signaling through the high affinity IL-2R is critical for full cytotoxicity. IL-2 signaling was also necessary in vivo for inducing the Th1 phenotype and IFN-γ expression in CD4 T cells during influenza A (IAV) infection. In addition, GrB expression, as measured by mean fluorescent intensity, was decreased in CD25 deficient cells; however, the frequency of CD4 cells expressing GrB was unchanged. Similarly, analysis of cytolytic markers such as CD107a/b and Eomesodermin indicate high IL-2Rα expression is not necessary to drive the CD4 CTL phenotype during IAV infection. Thus, inflammatory signals induced by viral infection may overcome the need for strong IL-2 signals in driving cytotoxicity in CD4 cells.
    PLoS ONE 02/2014; 9(2):e89010. DOI:10.1371/journal.pone.0089010 · 3.23 Impact Factor
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    • "Of particular interest, Th1 cells expressed transcripts corresponding to KLRK1/NKG2D, an activating receptor typically expressed on cytotoxic NK cells and CD8+ T-cells [99]. The acquisition of cytotoxic antiviral function was previously reported for CMV-specific cells [100], which exhibit indeed a Th1 polarization profile [30] and are protected from infection [32,33,36]. The acquisition of cytotoxic antiviral functions may contribute to the intrinsic HIV resistance in Th1 cells thus, explaining the expansion of Th1 cells in HIV-infected subjects [31]. "
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    ABSTRACT: We previously demonstrated that primary Th1Th17 cells are highly permissive to HIV-1, whereas Th1 cells are relatively resistant. Molecular mechanisms underlying these differences remain unknown. Exposure to replication competent and single-round VSV-G pseudotyped HIV strains provide evidence that superior HIV replication in Th1Th17 vs. Th1 cells was regulated by mechanisms located at entry and post-entry levels. Genome-wide transcriptional profiling identified transcripts upregulated (n = 264) and downregulated (n = 235) in Th1Th17 vs. Th1 cells (p-value < 0.05; fold change cut-off 1.3). Gene Set Enrichment Analysis revealed pathways enriched in Th1Th17 (nuclear receptors, trafficking, p38/MAPK, NF-kappaB, p53/Ras, IL-23) vs. Th1 cells (proteasome, interferon alpha/beta). Differentially expressed genes were classified into biological categories using Gene Ontology. Th1Th17 cells expressed typical Th17 markers (IL-17A/F, IL-22, CCL20, RORC, IL-26, IL-23R, CCR6) and transcripts functionally linked to regulating cell trafficking (CEACAM1, MCAM), activation (CD28, CD40LG, TNFSF13B, TNFSF25, PTPN13, MAP3K4, LTB, CTSH), transcription (PPARgamma, RUNX1, ATF5, ARNTL), apoptosis (FASLG), and HIV infection (CXCR6, FURIN). Differential expression of CXCR6, PPARgamma, ARNTL, PTPN13, MAP3K4, CTSH, SERPINB6, PTK2, and ISG20 was validated by RT-PCR, flow cytometry and/or confocal microscopy. The nuclear receptor PPARgamma was preferentially expressed by Th1Th17 cells. PPARgamma RNA interference significantly increased HIV replication at levels post-entry and prior HIV-DNA integration. Finally, the activation of PPARgamma pathway via the agonist Rosiglitazone induced the nuclear translocation of PPARgamma and a robust inhibition of viral replication. Thus, transcriptional profiling in Th1Th17 vs. Th1 cells demonstrated that HIV permissiveness is associated with a superior state of cellular activation and limited antiviral properties and identified PPARgamma as an intrinsic negative regulator of viral replication. Therefore, triggering PPARgamma pathway via non-toxic agonists may contribute to limiting covert HIV replication and disease progression during antiretroviral treatment.
    Retrovirology 12/2013; 10(1):160. DOI:10.1186/1742-4690-10-160 · 4.19 Impact Factor
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    • "In HIV-infected persons, the proportion of CMV-Sp cells within CD4 T cells can be higher than healthy controls [20,21]. This maybe because large proportions of CMV-Sp-CD4 T cells are also CD57+ [20,22] and are less likely to be infected by HIV [23]. However, in advanced HIV-infection, CMV-Sp-CD4 T cells are more likely to be absent in those with lower CD4 T cell count, especially with a CD4 T cell count of <50 cells/µL [24,25]. "
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    ABSTRACT: Restoration of Cytomegalovirus-specific-CD4 T cell (CMV-Sp-CD4) responses partly accounts for the reduction of CMV-disease with antiretroviral-therapy (ART), but CMV-Sp-CD4 may also drive immune activation and immunosenescence. This study characterized the dynamics of CMV-Sp-CD4 after ART initiation and explored associations with CD4 T cell recovery as well as frequency of naïve CD4 T cells at week 96. Fifty HIV-infected, ART-naïve Thai adults with CD4 T cell count ≤350cells/µL and starting ART were evaluated over 96 weeks ( identifier NCT01296373). CMV-Sp-CD4 was detected by co-expression of CD25/CD134 by flow cytometry after CMV-antigen stimulation. All subjects were CMV sero-positive, 4 had quantifiable CMV-DNA (range 2.3-3.9 log10 copies/mL) at baseline but none had clinically apparent CMV-disease. Baseline CMV-Sp-CD4 response was positive in 40 subjects. Those with CD4 T cell count <100cells/µL were less likely to have positive baseline CMV-Sp-CD4 response (P=0.003). Positive baseline CMV-Sp-CD4 response was associated with reduced odds of quantifiable CMV-DNA (P=0.022). Mean CD4 T cell increase at week 96 was 213 cells/µL. This was associated positively with baseline HIV-VL (P=0.001) and negatively with age (P=0.003). The frequency of CMV-Sp-CD4 increased at week 4 (P=0.008), then declined. Those with lower baseline CMV-Sp-CD4 (P=0.009) or CDC category C (P<0.001) had greater increases in CMV-Sp-CD4 at week 4. At week 96, CD4 T cell count was positively (P<0.001) and the frequency of CMV-Sp-CD4 was negatively (P=0.001) associated with the percentage of naïve CD4 T cells. Increases in CMV-Sp-CD4 with ART occurred early and were greater in those with more advanced immunodeficiency. The frequency of CMV-Sp-CD4 was associated with reduced naïve CD4 T cells, a marker associated with immunosenescence.
    PLoS ONE 10/2013; 8(10):e77479. DOI:10.1371/journal.pone.0077479 · 3.23 Impact Factor
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