Detection of HTLV-1 antigens by the sera of the infected rabbits. Sera from each rabbit infected with the HTLV-1 molecular clones were collected at weeks 0, 5, and 15 and reacted with Western blot strips carrying HTLV-1 antigens. All sera were negative in Western blot at week 0 (data not shown) but reacted with the p24 and p19 Gag proteins by weeks 5 and 15 from infection. The rgp46 refers to the recombinant peptide from the HTLV envelope protein; ns stands for a nonspecific HTLV-1 protein.