Sequence diversity in the pe_pgrs genes of Mycobacterium tuberculosis is independent of human T cell recognition.

ABSTRACT The Mycobacterium tuberculosis genome includes the large family of pe_pgrs genes, whose functions are unknown. Because of precedents in other pathogens in which gene families showing high sequence variation are involved in antigenic variation, a similar role has been proposed for the pe_pgrs genes. However, the impact of immune selection on pe_pgrs genes has not been examined. Here, we sequenced 27 pe_pgrs genes in 94 clinical strains from five phylogenetic lineages of the M. tuberculosis complex (MTBC). We found that pe_pgrs genes were overall more diverse than the remainder of the MTBC genome, but individual members of the family varied widely in their nucleotide diversity and in…