This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project was designed to evaluate the protective immunogenicity of HIV-1 Envelope (Env) glycoproteins cloned from newly transmitted clade C infections. Based on conserved biological and genetic characteristics we hypothesized that the transmitted Env would induce cross-protective neutralizing antibody responses. We achieved the following research goals during 2008: + Using the the second MJ4-based system that we developed in the previous funding period, we directly cloned a pilot panel of subtype C env genes that were generated in collaboration with Dr. Eric Hunter using a Single-Genome Amplication (SGA) protocol. Development of such a system will provide for our laboratory as well as that of other researchers a relatively high through-put and robust method for screening the a wide array of HIV-1 env genes. + After completing the construction of 40 subtype C HIV molecular clones representing the viral variants from 3 matched Donor/Recipient couples from Dr. Susan Allen's Zambian discordant couple cohort and performing replication assays on the subtype C HIV molecular clones on primary CD4 T cells, we have now analyzed the he replication kinetics of each molecular clone by calculating the Area Under the Curve (AUC) to define the replication phenotype. Our primary observation shows that replication fitness is not the only characteristic associated with the Donor-to-Recipient transmission event. + Completed our evaluation of the replication kinetics of the subtype C HIV molecular clones on primary CD4 T cells and CD4 T cell-dendritic cell co-cultures and following treatment to increase CCR5 expression. Our results indicated that there was no significant increase in replication kinetics due to co-culture conditions or CCR5 expression levels. The significance of this progress is that it provides unique and valuable reagents that are key to understanding the phenotype associated with HIV-1 transmission and the targets for an effective vaccine for protection from HIV-1 infection.