Detection of HIV-1 p24 and precursor proteins p55 and p41 by Western blotting using an HIV1 p24 Polyclonal Antibody (Product # PA1-4951). Lane 1: Extract of MT4 cells. Lane2: Extract of MT4 cells infected with HIV-1(LAI strain). The antiserum was diluted 1:2,500. The upper bands are precursors of p55 of p24 and the processed intermediate proteins.