An exploration of amniotic fluids as a possible source of fetal infection in the feline immunodeficiency virus (FIV)-infected cat model of pediatric aids

The role that amniotic fluid (AF) may play in HIV vertical infection is unresolved. We used the FIV-infected cat model to study this question. We hypothesized that AF may be a source of fetal infection if the virus is present in the fluids. However, virus neutralizing (VN) antibodies in AF may limit vertical transfer. Fetuses were delivered from FIV-infected queens by cesarean section at early and late gestation. AFs were aspirated from intact fetal membranes and tested for viral antigen and RNA and for FIV-specific antibody. Randomlyselected samples were tested for VN activity using a syncytium reduction assay. Neither FIV antigen nor RNA was detected in any AFs. AFs and parallel serum samples from early and late pregnancy were positive for FIV-specific antibody. VN activity was detected in three early-term AFs and a parallel serum, but not late-term AFs. AF appears to play no appreciable role in FIV vertical transmission.