Deep sequencing reveals an association between HIV-1 subtype C mutations in gp41 MPER epitopes and mother-to-child transmission

Abstract

Methods Pyrosequences of HIV-1 subtype-C gp41 heptad repeatregion 2 (HR2), MPER, and membrane-spanning domain (MSD) were generated from 2,000 plasma viral copies/subject from four mothers who transmitted via breast feeding (TM) and four non-transmitting mothers (NTM) in a matched case control study. A bioinformatic pipeline with rigorous quality controls generated ~50,000 quality pyrosequences/subject and provided 25-fold coverage of input virus populations. Population genetic algorithms clustered pyrosequences at 3% genetic distance to study biodiversity using rarefaction/Chao1. Frequency distribution of cluster sizes defined population structure. Consensus sequences constructed from bioclusters for each subject were aligned to an HIV-1 subtype-C consensus sequence to determine number and frequency of nonsynonymous substitutions at each position and to identify mutations by HIV Molecular Immunology Database. Groups were compared using paired t-test.