PRIMARY GENETIC-CHARACTERIZATION OF HIV-1 ISOLATES FROM WHO-SPONSOREDVACCINE EVALUATION SITES BY THE RNASE-A MISMATCH METHOD

We have analyzed by the RNase-A mismatch method 35 isolates from four WHO-sponsored vaccine evaluation sites as a secondary laboratory of th e WHO Network for HIV Isolation and Characterization. The application of an estimator for the establishment of genetic distances based on th e RNase-A digestion patterns in combination with the phylogenetic anal ysis has allowed us to construct a tree with five well defined groups of viruses. Because the clustering with known reference strains, sampl es from Brazil could be grouped as subtype B and the majority of those from Thailand were subtype E. Some of the samples from Uganda were cl assified as subtype D. Isolates from Rwanda and some from Uganda were identified as subtype A viruses. These results coincide with data obta ined by heteroduplex mobility assay and nucleotide sequencing in env r egions. The RNase-A mismatch method combined with phylogenetic analysi s permitted the primary genetic classification of 33 of 35 samples fro m the WHO Network.