During human T-cell lymphotropic virus type 1 (HTLV)-1 and HTLV-2 infections with CCLs and CCRs, Tax1 and Tax2 may increase innate immunity in the extracellular environment, which may play a major role in regulating innate immunity during co-infection with HIV/ HTLV and inhibiting CCR5/HIV-1 [51]. Here, CNTN2 is linked to coinfection.