Characterization of HIV-1 genotypes and phenotypes involved in mother-to-infant transmission

Objective: Better characterization of HIV-1 isolates transmitted from mother-to-infant has important implications for the development of prevention and treatment strategies because the strategies invoK/ed should be targeted at viral isolates with the properties of the transmitted viruses. To elucidate the genetic and biological properties of HIV-1 transmitted from mother-to-infant we have undertaken a systematic analysis of the genotypic and phenotyptc characteristics of HIV-1 env and accessory genes involved in maternal transmission. Methods: HIV-1 DNA was isolated from infected mother-infant pairs' peripheral blood mononuclear cells (PBMC) followed by PCR amplification of HtV-l envV3 region and accessory gene vifThe PCR amplified fragments were cloned in pGem 3Zf vector and 20 to 30 clones were sequenced from each patient The sequences were analyzed by DNA computer programs. To investigate the biological properties conferred by mother-infant isolates, the V3 region sequences (Bgl II to II) from 3 mother-infant pairs were transferred into a known infectious clone, pNL4-3.The proviraf chimeras were transfected into HeLa cell line to generate virus. Results:The V3 region sequences directly derived from the DNA of the uncultured peripheral Wood mononuclear cells (PBMQ from infected mothers displayed a heterogeneous population. In contrast the infants' sequences were less diverse than those of their mothers. In addition, the sequences from the younger infants' PBMC DNA were more homogeneous than the older infants' sequences. All infants' sequences were different but displayed patterns similar to those as seen in their mothers. The vif sequences from mother-infant pairs are being analyzed In addition, the viruses generated as a resutt of prwra! DNA transfectkx>s (V3 region substitutions) are being used to infectT-tymphocytes and monocyte-macrophe|e lineage cell lines, and primary cells in order to determine the repl-cation efficiency, cell tropism, and cytopathic effects, Conclusion: tn the mother-infant pairs' sequences analyzed, a minor genotype or subtype found m the mothers predominated in their infants. The phenotypes of these variants are betng analyzed.