Effect of ectopic CXCR4 expression on infection with glycosylation mutants. AH927 cells expressing low level endogenous CXCR4 (endog.) or enhanced levels of either feline CXCR4 (+feline) or human CXCR4 (+human), in conjunction with feline CD134 (feCD134), CRD1 of fCD134 in the context of hCD134 (CRD1), or vector-only control (Control), were infected with HIV(FIV) pseudotypes bearing the GL8 or CPG41 Envs. 72 hours post-infection luciferase activity was assayed. Each point represents the mean +/- SE of triplicate samples.