Passive immunization against oral AIDS virus transmission: An approach to prevent mother-to-infant HIV-1 transmission?

To develop immunoprophylaxis regimens against mother-to-child human immunod eficiency virus type 1 (HIV-1) transmission, we established a simian-human immunodeficiency virus (SHIV) model in neonatal macaques that mimics intrap artum mucosal virus exposure (T.W. Baba, J. Koch, E.S. Mittler et al.: AIDS Res Hum Retroviruses 10:351-357, 1994). We protected four neonates from or al SHIV-vpu(+) challenge by ante- and postpartum treatment with a synergist ic triple combination of immunoglobulin (Ig) G1 human anti-HIV-1 neutralizi ng monoclonal antibodies (mAbs) (T.W. Baba, V. Liska, R. Hofmann-Lehmann et al.: Nature Med 6:200-206, 2000), which recognize the CD4-binding site of Env, a glycosylation-dependent gp120, or a linear gp41 epitope. Two neonate s that received only postpartum mAbs were also protected from oral SHIV-vpu + challenge, indicating that postpartum treatment alone is sufficient. Next , we evaluated a similar mAb combination against SHIV89.6P, which encodes e nv of primary HIV89.6. One of four mAb-treated neonates was protected from infection and two maintained normal CD4(+) T-cell counts. We conclude that the epitopes recognized by the three mAbs are important determinants for ac hieving protection. Combination immunoprophylaxis with synergistic mAbs see ms promising to prevent maternal HIV-1 transmission in humans.