Interleukin-21 and T follicular helper cells in HIV infection: research focus and future perspectives.
Interleukin (IL)-21 is a member of the γ chain-receptor cytokine family along with IL-2, IL-4, IL-7, IL-9, and IL-15. The effects of IL-21 are pleiotropic, owing to the broad cellular distribution of the IL-21 receptor. IL-21 is secreted by activated CD4 T cells and natural killer T cells. Within CD4 T cells, its secretion is restricted mainly to T follicular helper (Tfh) cells and Th17 cells to a lesser extent. Our research focus has been on the role of IL-21 and more recently of Tfh in immunopathogenesis of HIV infection. This review focuses on first the influence of IL-21 in regulation of T cell, B cell, and NK cell responses and its immunotherapeutic potential in viral infections and as a vaccine adjuvant. Second, we discuss the pivotal role of Tfh in generation of antibody responses in HIV-infected persons in studies using influenza vaccines as a probe. Lastly, we review data supporting ability of HIV to infect Tfh and the role of these cells as reservoirs for HIV and their contribution to viral persistence.
Department of Microbiology and Immunology, University of Miami Miller School of Medicine, 1580 NW 10th Avenue, BCRI 712, Miami, FL, 33136, USA.
Suresh
S
Pallikkuth
Savita
S
Pahwa
D000375:Aging / Q000276:immunology; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D003602:Cytotoxicity, Immunologic; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology* / Q000378:metabolism*; D015497:HIV-1 / Q000276:immunology; D006801:Humans; D056724:Immunity, Humoral; D007155:Immunologic Factors / Q000008:administration & dosage / Q000378:metabolism / Q000627:therapeutic use; D007378:Interleukins / Q000008:administration & dosage / Q000378:metabolism* / Q000627:therapeutic use; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology* / Q000378:metabolism*; D000098546:Interleukin-21
D007155:Immunologic Factors; D007378:Interleukins; D000098546:Interleukin-21