PERSISTENCE OF MULTIPLE MATERNAL GENOTYPES OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-I IN INFANTS INFECTED BY VERTICAL TRANSMISSION

The extent of nucleotide variation within the HIV-1 env hypervariable domains serves as a marker of virus genotypes within infected individu als and as a means to track transmission of the virus between individu als. We analyzed env V1 and V2 sequences in longitudinal samples from two HIV-1-infected mothers, each with three children infected by mater nal transmission of the virus. Sequences in samples that were obtained from two infants at 2 d and 4 wk after birth displayed more variation in V1 and V2 than maternal samples obtained at the same times. Multip le HIV-1 genotypes were identified in each mother. In each family, mul tiple maternal HIV-1 genotypes were transmitted to the infants. Specif ic amino acid residues in the hypervariable domains were conserved wit hin sequences from each family producing a family-specific amino acid signature pattern in V1 and V2. Viruses that were highly related to ma ternal viruses in signature pattern persisted for as long as 4 yr in t he older children. Results support a model of transmission involving m ultiple HIV-1 genotypes with development of genetic variation from dif ferential outgrowth and accumulation of genetic changes within each in dividual.