HIV-1-specific mucosal IgA in a cohort of HIV-1-resistant Kenyan sex workers

Objectives: Most HIV-1 transmission is sexual; therefore, immune responses in the genital mucosa may be important in mediating protection against HIV infection. This study examined HIV-1-specific mucosal IgA in a cohort of HI V-1-resistant Kenyan female sex workers. Methods: HIV-1-specific immune responses were compared in HIV-1-resistant a nd HIV-1-infected sex workers, and in lower risk uninfected women. Cervical and vaginal samples from each group were tested for HIV-1-specific IgA and Ige by enzyme immunoassay. Systemic T-helper lymphocyte cell responses to HIV-1 envelope peptide epitopes were assayed using an interleukin 2 bioassa y. HIV-1 risk-taking behaviours were assessed using standardized questionna ires. Results: HIV-1-specific IgA was present in the genital tract of 16 out of 2 1 (76%) HIV-1-resistant sex workers, five out of 19 (26%) infected women, a nd three out of 28 (11%) lower risk women (P < 0.0001). Among lower risk wo men, the presence of HIV-1-specific IgA was associated with HIV-1 risk-taki ng behaviour. Systemic T-helper lymphocyte responses to HIV-1 envelope pept ides were present in 11 out of 20 (55%) HIV-7-resistant women, four out of 18 (22%) infected women, and one out of 25 (4%) lower risk women (P < 0.001 ). T-helper lymphocyte responses did not correlate with the presence or tit re of virus-specific mucosal IgA in any study group. Conclusions: HIV-1-specific IgA is present in the genital tract of most HIV -1-resistant Kenyan sex workers, and of a minority of tower risk uninfected women, where it is associated with risk-taking behaviour. These data sugge st a role for mucosal HIV-1-specific IgA responses in HIV-1 resistance, ind ependent of host cellular responses. (C) 1999 Lippincott Williams & Wilkins .