CELLULAR IMMUNE FACTORS ASSOCIATED WITH MOTHER-TO-INFANT TRANSMISSIONOF HIV

Objective: To study a possible correlate of protection in mother-to-in fant transmission of HIV infection. In particular, to determine whethe r lack of HIV-specific T-helper (TH) function as indicated by HIV and non-HIV antigen-stimulated interleukin (IL)-2 production of mother and /or newborn peripheral blood leukocytes (PBL) is associated with mothe r-to-infant transmission of HIV. Methods: PBL from 21 HIV-seropositive pregnant women and 23 cord blood leukocytes (CBL) from their offsprin g were studied for in vitro TH function by IL-2 production in response to HIV and non-HIV antigens. Polymerase chain reaction (PCR) and vira l culture assays were performed to determine HIV infection of the infa nts. Results: PBL from 10 out of 21 (48%) mothers and from eight out o f 23 (35%) CBL samples responded to two or more out of five synthetic gp160 envelope (env) peptides. Three of the 23 (13%) offspring were sh own to be HIV-infected by PCR and/or viral culture on follow-up. All t hree infected infants were from a subset whose CBL did not exhibit env -specific TH immunity. Conclusion: Our results demonstrate that fetal T cells can be primed to HIV env determinants in utero, suggest that H IV-specific TH immunity may be protective in newborns, and provide a p ossible means for identifying newborns who are at risk for HIV infecti on.