The CD8 + Memory Stem T Cell (T SCM ) Subset Is Associated with Improved Prognosis in Chronic HIV-1 Infection

• Published in: Journal of virology Vol. 88; no. 23; pp. 13836 - 13844
• Main Authors: Ribeiro, Susan P., Milush, Jeffrey M., Cunha-Neto, Edecio, Kallas, Esper G., Kalil, Jorge, Somsouk, Ma, Hunt, Peter W., Deeks, Steven G., Nixon, Douglas F., SenGupta, Devi
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01.12.2014
• Subjects: Adult; Antiretroviral Therapy, Highly Active; CD4-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - immunology; Cohort Studies; Cross-Sectional Studies; Female; HIV Infections - drug therapy; HIV Infections - immunology; HIV-1 - immunology; Human immunodeficiency virus 1; Humans; Immunologic Memory; Male; Middle Aged; Pathogenesis and Immunity; Prognosis; Stem Cells - immunology
• ISSN: 0022-538X; 1098-5514; 1098-5514
• DOI: 10.1128/JVI.01948-14

Memory stem T cells (T SCM ) constitute a long-lived, self-renewing lymphocyte population essential for the maintenance of functional immunity. The hallmarks of HIV-1 pathogenesis are CD4 + T cell depletion and abnormal cellular activation. We investigated the impact of HIV-1 infection on the T SCM compartment, as well as any protective role these cells may have in disease progression, by characterizing this subset in a cohort of 113 subjects with various degrees of viral control on and off highly active antiretroviral therapy (HAART). We observed that the frequency of CD8 + T SCM was decreased in all individuals with chronic, untreated HIV-1 infection and that HAART had a restorative effect on this subset. In contrast, natural controllers of HIV-1 had the highest absolute number of CD4 + T SCM cells among all of the infected groups. The frequency of CD4 + T SCM predicted higher CD8 + T SCM frequencies, consistent with a role for the CD4 + subset in helping to maintain CD8 + memory T cells. In addition, T SCM appeared to be progenitors for effector T cells (T EM ), as these two compartments were inversely correlated. Increased frequencies of CD8 + T SCM predicted lower viral loads, higher CD4 + counts, and less CD8 + T cell activation. Finally, we found that T SCM express the mucosal homing integrin α4β7 and can be identified in gut-associated lymphoid tissue (GALT). The frequency of mucosal CD4 + T SCM was inversely correlated with that in the blood, potentially reflecting the ability of these self-renewing cells to migrate to a crucial site of ongoing viral replication and CD4 + T cell depletion. IMPORTANCE HIV-1 infection leads to profound impairment of the immune system. T SCM constitute a recently identified lymphocyte subset with stem cell-like qualities, including the ability to generate other memory T cell subtypes, and are therefore likely to play an important role in controlling viral infection. We investigated the relationship between the size of the CD8 + T SCM compartment and HIV-1 disease progression in a cohort of chronically infected individuals. Our results suggest that HAART restores a normal frequency of CD8 + T SCM and that the natural preservation of this subset in the setting of untreated HIV-1 infection is associated with improved viral control and immunity. Therefore, the CD8 + T SCM population may represent a correlate of protection in chronic HIV-1 infection that is directly relevant to the design of T cell-based vaccines, adoptive immunotherapy approaches, or the pharmacologic induction of T SCM .