Preferential infection of α4β7⁺ memory CD4⁺ T cells during early acute human immunodeficiency virus type 1 infection

Background. Establishment of persistent human immunodeficiency virus type 1 (HIV-1) reservoirs occurs early in infection, and biomarkers of infected CD4⁺ T cells during acute infection are poorly defined. CD4⁺ T cells expressing the gut homing integrin complex α4β7 are associated with HIV-1 acquisition, and are rapidly depleted from the periphery and gastrointestinal mucosa during acute HIV-1 infection. Methods. Integrated HIV-1 DNA was quantified in peripheral blood mononuclear cells obtained from acutely (Fiebig I–III) and chronically infected individuals by sorting memory CD4⁺ T-cell subsets lacking or expressing high levels of integrin β7 (β7^negative and β7^high, respectively). HIV-1 DNA was also assessed after 8 months of combination antiretroviral therapy (cART) initiated in Fiebig II/III individuals. Activation marker and chemokine receptor expression was determined for β7-defined subsets at acute infection and in uninfected controls. Results. In Fiebig I, memory CD4⁺ T cells harboring integrated HIV-1 DNA were rare in both β7^high and β7^negative subsets, with no significant difference in HIV-1 DNA copies. In Fiebig stages II/III and in chronically infected individuals, β7^high cells were enriched in integrated and total HIV-1 DNA compared to β7^negative cells. During suppressive cART, integrated HIV-1 DNA copies decreased in both β7^negative and β7^high subsets, which did not differ in DNA copies. In Fiebig II/III, integrated HIV-1 DNA in β7^high cells was correlated with their activation. Conclusions. β7^high memory CD4⁺ T cells are preferential targets during early HIV-1 infection, which may be due to the increased activation of these cells.