CCR5 and infection: As isolated human intestinal fetal lamina propria lymphocytes (LPLs) have a limited cell survival in long-term cultures (S7C, Supplementary Information), we have studied intestinal HIV-1 productive infection by carrying out HIV-1 transmission by LPLs in co-culture with target U87.CD4.CCR5 cells (Fig. 4A, schematic representation in Fig. S7E,F, Supplementary Information).