CD4 and HIV infectious disease: Data obtained from these ex vivo models highlighted that enteric pathogenic and commensal bacteria-reactive CD4 T cells are normal components of the gut CD4 T cell repertoire.8–11 Furthermore, commensal enteric bacteria, including species of Gram-negative bacteria that are increased in abundance in PWH, drive LP CD4 T cell activation and proliferation and increase productive HIV infection and CD4 T cell death in vitro.