PASSIVE-IMMUNIZATION OF NEWBORN RHESUS MACAQUES PREVENTS ORAL SIMIAN IMMUNODEFICIENCY VIRUS-INFECTION

To determine if passively acquired antiviral antibodies modulate virus transmission and disease progression in human pediatric AIDS, the pot ential of pre- and postexposure passive immunization with hyperimmune serum to prevent oral simian immunodeficiency virus (SIV) infection or disease progression in newborn rhesus macaques was tested. Untreated neonates became infected after oral SIV inoculation and had high virem ia, and most animals developed fatal AIDS within 3 months. In contrast , SIV hyperimmune serum given subcutaneously prior to oral SIV inocula tion protected 6 newborns against infection. When this SIV hyperimmune serum was given to 3 newborns 3 weeks after oral SIV inoculation, vir emia was not reduced, and all 3 infants died within 3 months of age du e to AIDS and immune-complex disease. These results suggest that passi vely acquired antihuman immunodeficiency virus (HIV) IgG may decrease perinatal HIV transmission. However, anti-HIV IgG may not impart thera peutic benefit to infants with established HIV infection.