CD4 and infection: Therefore, the Leronlimab-induced increase in CCR5+CD4+ T cell targets did not exacerbate ongoing SIV replication; rather, the binding of Leronlimab to the CCR5 co-receptor used for viral entry protected these cells from infection and greatly diminished ongoing SIV replication, resulting in minimal plasma viremia during the period of complete CCR5 RO.