Fangchinoline specifically reduces the incorporation of HIV-1 Env into nascent virus particles.

(A) 293T cells were co-transfected with pSG3^ΔEnv and an envelope expressing plasmid. At 3 hours post-transfection, the cell supernatant was removed, and fresh medium with test compounds (IDV, 1 µM; fangchinoline, 1.3–10 µM) was added. At 48 hours after transfection, the infectivity of the virions produced by the co-transfected cells was determined in the TZM-b1 assay. (B) 293T cells were transfected with pNL4-3. At 3 hours post-transfection, the cell supernatant was removed, and fresh medium with indicated concentration of fangchinoline was added. At 48 hours after transfection, the content of Env in the HIV-1 particles produced by the pNL4-3 transfected 293T cells was analyzed by Western blot. (C) 293T cells were cotransfected with pSG3^Δenv and pVpack-VSV-G. At 48 hours after transfection, the content of VSV-G in the pseudotyped HIV-1 particles produced in the presence or absence of fangchinoline was analyzed by Western blot.