HLA-DRB1 and infection: Understanding the unique interactions between commensal microbe antigens presented by APCs, the MHC II molecules encoded by the DRB1*15:01-DRB5*01:01 haplotype, and Tfh cells may provide valuable insights into how host genetics impact the composition of gut microbial communities in individuals susceptible to enteric infection, compared with those who are resistant to infection.