Neutralizing antibodies and complement-mediated, antibody-dependent enhancement (C'-ADE) of human immunodeficiency virus infection in its vertical transmission.

Abstract

Mother-to-child transmission is a major route for the spread of human immunodeficiency virus (HIV) worldwide. Our understanding of its mechanisms and parameters is still limited. Among the factors possibly involved in virus passage determination are the level and quality of antiviral humoral response. Anti-HIV-1/Lai neutralizing activity in sera from 35 mother-infant pairs (in which 13 transmission cases occurred) was investigated, as was the complement-mediated antibody-dependent enhancement capacity of the same sera. Neutralization titers of 640 or more were found only in four mothers of uninfected children, but this result was not significant. No significant link was obtained with the occurrence of complement-mediated, antibody-dependent enhancement. As suggested by a synthesis of the literature, vertical transmission of HIV is probably the result of multiple active and/or stochastic parameters in the mother, the fetal structures, and the viral population. The precise definition of cellular mechanisms involved in in utero infection would help to better define which immune activity in the mother should be more carefully considered.