Human leukocyte antigen class II gene diversity tunes antibody repertoires to common pathogens
Allelic diversity of HLA class II genes may help maintain humoral immunity against infectious diseases. We investigated the relative contribution of specific HLA class II alleles, haplotypes and genotypes on the variation of antibody responses to a variety of common pathogens in a cohort of 800 adults representing the general Arab population. We found that classical HLA class II gene heterozygosity confers a selective advantage. Moreover, we demonstrated that multiple HLA class II alleles play a synergistic role in shaping the antibody repertoire. Interestingly, associations of HLA-DRB1 genotypes with specific antigens were identified. Our findings suggest that HLA class II gene polymorphisms confer specific humoral immunity against common pathogens, which may have contributed to the genetic diversity of HLA class II loci during hominine evolution.