Species‐dependent antigenicity of the 34‐kDa glycoprotein found on the membrane of various primate lymphocytes transformed by human t‐cell leukemia virus type‐I (HTLV‐I) and simian T‐cell leukemia virus (STLV‐I)

Abstract Sixteen monoclonal antibodies (MAbs) against TA34 antigen found on the surface of human T‐cell leukemia virus type‐I (HTLV‐I) infected cells were prepared. These MAbs and one previously prepared anti‐TA34 MAb (TAG34) recognized 34‐kDa peptide not only in HTLV‐I‐infected cells, but also in cells infected with simian T‐cell leukemia virus (STLV‐I), which is analogous in antigenicity and gene structure to HTLV‐I. Radioimmuno‐precipitation (RIP) tests with the MAbs showed that TA34 antigen had at least 3 overlapping epitope groups. The antigenicities of the TA34 antigens of HTLV‐I‐infected cells derived from various primates were investigated by immunofluorescence staining using 9 anti‐TA34 MAbs. Cells from humans, apes and Old World monkeys reacted with all these antibodies, whereas cells from New World monkeys were stained by most of the antibodies, but little if at all by the remaining 2 (5A8 and TAG34). Similar results were obtained with various primate cells infected with STLV‐I. All 17 MAbs used recognized a 22‐kDa peptide in HTLV‐I‐infected cells cultured in the presence of tunicamycin. When incubated with 1% 2‐mercaptoethanol at ph 7.2 at 37°C, TA34 antigen lost its reactivity with TAG34, suggesting that the antigen has an intramolecular S‐S bond. Twenty sera of adult T‐cell leukemia (ATL) patients did not react with TA34 antigen in RIP tests.