title: HIV-specific CD4 T cells and immune control of viral replication.
abstract: OBJECTIVE
  To understand the role of HIV-specific CD4 T cells in viral control and highlight recent progress in the field.
  
  
  RESULTS
  HIV-specific CD4 T cells show higher functional avidity in elite controllers than in patients with progressive infection. There is an attrition of the HIV-specific CD4 T-cell population in the digestive mucosa of antiretroviral therapy (ART)-treated patients that contrasts with robust responses in individuals with spontaneous viral control. Secretion of the cytokine IL-21, by HIV-specific CD4 T cells, is associated with disease control and enhances the capacity of HIV-specific CD8 T cells to suppress viral replication. Studies of the PD-1, IL-10, and Tim-3 pathways provided insight into mechanisms of HIV-specific CD4 T-cell exhaustion and new evidence that manipulation of these networks may restore immune functions. Robust, polyfunctional CD4 T-cell responses can be elicited with novel HIV and simian immunodeficiency virus (SIV) vaccines.
  
  
  CONCLUSIONS
  These observations show that HIV-specific CD4 T-cell responses are different in elite controllers and individuals with progressive disease. Evidence suggests that HIV-specific CD4 T cells will be an important component of an effective HIV vaccine and significant efforts need to be made to further our understanding of HIV-specific CD4 T-cell functions in different body compartments.
authors.affiliation: Ragon Institute of MGH, MIT and Harvard, Massachusetts General Hospital, Harvard Medical School, USA.
authors.forename: Filippos
authors.initials: F
authors.lastname: Porichis
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Kaufmann
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D015658:HIV Infections / Q000276:immunology* / Q000473:pathology; D020276:HIV Long-Term Survivors; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D014766:Viremia / Q000276:immunology / Q000517:prevention & control