Assembly of CCR5 with gp120 inhibits the HIV infectivity specifically in T cells

For the entry of R5 human immunodeficiency virus type 1 (HIV-1) into target cells, CCR5 functions as a coreceptor following the binding of the envelope glycoprotein gp120 to the receptor CD4. While CD4 is known to be strongly downregulated after infection, the fate of CCR5 post-infection remains unclear. We investigated the surface expression of CCR5 on PM1/CCR5 cells following infection with HIV-1_JR-FL. Flow cytometry using anti-CCR5 MAb (T21/8 and 2D7) revealed that CCR5 was not downregulated on the surface of infected cells. Notably, CCR5 was found to be coassembled with HIV-1 Gag at the viral budding sites. A specific subset of CCR5, designated as CCR5^A, which is recognized by T21/8 but not 2D7, was significantly colocalized with gp120 on the cell surface. Virions incorporating CCR5 were immunoprecipitated using T21/8 MAb but not with 2D7 Mab, indicating that CCR5^A was incorporated into progeny virions. The efficiency of CCR5^A incorporation into virions was positively correlated with the level of CCR5 expression on the cell surface. Moreover, incorporation efficiency was approximately 83-fold higher in CD4⁺ T cells than in adherent CCR5⁺ cells. Furthermore, the incorporation of CCR5^A into HIV-1_JR-FL virions resulted in a 25% decrease in viral infectivity. These findings suggest that CCR5^A may have a detrimental effect during the late stage of the HIV-1 replication cycle.