Spontaneous and antigen-induced chemokine production in exposed but uninfected partners of HIV type 1-infected individuals in North India

Exposure to human immunodeficiency virus (HIV)-1 does not inevitably result in infection and resistance to HIV-1 infection is observed in different categories of at-risk individuals. In this study, the role of β-chemokines and α-chemokine in providing resistance to HIV-1 infection was evaluated in a group of 25 HIV-exposed but uninfected (EU) partners of HIV-1-infected individuals. We studied the levels of regulated on activation, normal T expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1α, MIP-1β, and stromal cell-derived factor (SDF)-1α in culture supernatants of peripheral blood mononuclear cells (PBMCs) after stimulation with HIV gag p24 antigen and phytohemagglutinin (PHA). Higher gag-specific β-chemokine responses were seen in EU individuals and HIV-positive controls when compared with healthy controls (HC). No significant difference was observed in PHA-specific β-chemokine production between these three groups. Moreover, a spontaneous production of all the three β-chemokines by unstimulated PBMCs was observed in EU individuals and HIV-positive controls. No significant difference was observed in α-chemokine (SDF-1) levels between the three groups after p24 and PHA stimulation. We conclude that in our cohort of EU individuals, β-chemokines-mediated resistance against HIV might be present. Since β-chemokines are produced mainly by activated T cells, our results suggest that enhanced chemokine production might be due to exposure to HIV in these individuals.