Detection of HTLV-1 antigens by the sera of the infected macaques. Sera from each macaque exposed to the HTLV-1 molecular clones were collected at weeks 0, 2, 4, 8, and 11 and reacted with Western blot strips carrying HTLV-1 antigens. Macaque P062 and M985, which were exposed only to uninfected 729 B cells as control, did not seroconvert (A). None of the 12KO-inoculated macaques seroconverted to HTLV-1 antigens (B). All animals inoculated with the HBZKO either fully seroconverted (animals P068 and P069) or partially seroconverted (PM902 and M900) to HTLV-1 antigens (C); full seroconversion was observed only in animal P0011 inoculated with the 30KO virus (D).