To clarify whether infection of HIV/SIV mediated through FPRL1 is dependent on CD4 or not, NP-2/CD4/FPRL1 and NP-2/CD4/CCR5 cells were pretreated with serially-diluted anti-CD4 MoAb, NuTH/I, before inoculation. The gene discussed is CD4; the disease is infection.