FIG 4.

Infection and interference assay of LacZ-carrying Env-pseudotyped viruses. (A) The Env-pseudotyped viruses of FeLV-A Clone 33, FeLV-A Glasgow-1, FeLV-A (TG35-4), FeLV-B (FeLV-B Gardner-Arnstein), and FeLV TG35-2 were tested for infection in R5 expressing feTHTR1 cells (R5-feTHTR1). (B) The Env-pseudotyped FeLV-B (FeLV-B/Gardner-Arnstein) and FeLV TG35-2 viruses were tested for infection in the R5 cells expressing feline RFC (R5-feRFC) and R5-feRFC cells preinfected with FeLV 33TGE2 (R5-feRFC/33TGE2). The infection units were indicated by log₁₀ of β-galactosidase (LacZ)-positive cells per milliliter of supernatant. Data represent the averages from three independent experiments, with the standard deviations shown.