Cervicovaginal secretory antibodies to human immunodeficiency virus type 1 (HIV-1) that block viral transcytosis through tight epithelial barriers in highly exposed HIV-1-seronegative African women.

ABSTRACT

Antibodies to human immunodeficiency virus (HIV) of the IgA, IgG, and IgM isotypes and high levels of the HIV suppressive beta-chemokine RANTES (regulated on activation, normally T cell expressed and secreted) were found in the cervicovaginal secretions (CVSs) of 7.5% of 342 multiply and repeatedly exposed African HIV-seronegative female sex workers. The antibodies are part of a local compartmentalized secretory immune response to HIV, since they are present in vaginal fluids that are free of contaminating semen. Cervicovaginal antibodies showed a reproducible pattern of reactivity restricted to gp160 and p24. Locally produced anti-env antibodies exhibit reactivity toward the neutralizing ELDKWA epitope of gp41. Study results show that antibodies purified from CVSs block the transcytosis of cell-associated HIV through a tight epithelial monolayer in vitro. These findings suggest that genital resistance to HIV may involve HIV-specific cervicovaginal antibody responses in a minority of highly exposed HIV-seronegative women in association with other protecting factors, such as local production of HIV-suppressive chemokines.