Micci L, Cervasi B, Ende ZS, Iriele RI, Reyes-Aviles E, Vinton C, Else J, Silvestri G, Ansari AA, Villinger F, Pahwa S, Estes JD, Brenchley JM, Paiardini M. Paucity of IL-21-producing CD4(+) T cells is associated with Th17 cell depletion in SIV infection of rhesus macaques.
Blood 2012;
120:3925-35. [PMID:
22990011 PMCID:
PMC3496953 DOI:
10.1182/blood-2012-04-420240]
[Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 08/31/2012] [Indexed: 12/21/2022] Open
Abstract
IL-21 regulates Th17 cell homeostasis, enhances the differentiation of memory B cells and antibody-secreting plasma cells, and promotes the maintenance of CD8(+) T-cell responses. In this study, we investigated the phenotype, function, and frequency of blood and intestinal IL-21-producing cells in nonhuman primates that are hosts of progressive (rhesus macaques [RMs]) and nonprogressive (sooty mangabeys [SMs]) SIV infection. We found that, in both species, memory CD4(+)CD95(+)CCR6(-) T cells are the main IL-21 producers, and that only a small fraction of CD4(+)IL-21(+) T cells produce IL-17. During chronic SIV infection of RMs, CD4(+)IL-21(+) T cells were significantly depleted in both blood and rectal mucosa, with the extent of this depletion correlating with the loss of Th17 cells. Furthermore, treatment with IL-21 increased the in vivo levels of Th17 cells in SIV-infected RMs. In contrast, normal levels of CD4(+)IL-21(+) T cells were found in SIV-infected SMs. Collectively, these data indicate that depletion of IL-21-producing CD4(+) T cells distinguishes progressive from nonprogressive SIV infection of RMs and SMs, and suggest that depletion of CD4(+)IL-21(+) T cells is involved in the preferential loss of Th17 cells that is associated with SIV disease progression. Further preclinical studies of IL-21 as a potential immunotherapeutic agent for HIV infection may be warranted.
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