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NLM AIDSLINE

IgM secreted by human T lymphoma virus-I-infected and transformed human B cell clones recognize a 66-kilodalton host-encoded protein.




 

J Immunol. 1989 Oct 15;143(8):2501-7. Unique Identifier : AIDSLINE

It has previously been determined that transformed human B cells may be infected by and retain integrated human T cell lymphotropic virus, type I (HTLV-I). Although HTLV-I is primarily associated with transformation of human T lymphocytes, immortalized B cell populations have arisen after cocultivation of normal B cells and irradiated HTLV-I-infected T cells. To test whether HTLV-I infection might be involved in this B cell transformation process, we characterized five independent HTLV-I-infected and -immortalized human B cell clones. All five clones contained clonal HTLV-I integrations, expressed cell surface IgM, and secreted IgM in quantities varying from 0.1 to 4.0 micrograms/ml. Immunoblotting and immunoprecipitation of metabolically labeled cell lysates failed to detect synthesis of HTLV-I gag, env, or tat gene products, and cellular RNA dot blot analysis detected varying levels of HTLV-I gene transcripts in only three of the five clones. The secreted IgM from culture supernatants were affinity purified, and were found to selectively immunoprecipitate an acidic protein (isoelectric point = 5.0) of 66,000 m.w. (p66) from purified radioiodinated HTLV-I virions. This p66 copurified with metabolically labelled HTLV-I-infected B cell IgM from HKA-3 cells. Although HTLV-I RNA transcripts were present at low levels, the absence of HTLV-I proteins in HKA-3 cells made it unlikely that p66 was related to the major HTLV-I envelope glycoprotein, gp62. Anti-idiotypic mAb directed against the IgM produced by one B cell clone (HKA-3), as well as purified HTLV-I virions (containing p66), stimulated HKA-3 cell proliferation. Preincubating the anti-Id antibody or HTLV-I with excess HKA-3 IgM abolished the binding of either to HKA-3 cells. These data suggest that HTLV-I infected cells produce a cellular protein (p66), which is incorporated into and copurifies with HTLV-I virions, and which in at least one case (HKA-3) may act as a mitogenic stimulus, potentially contributing to the HTLV-I mediated transformation process.

Antibodies, Anti-Idiotypic/PHYSIOLOGY Antibodies, Monoclonal/PHYSIOLOGY B-Lymphocytes/IMMUNOLOGY/*METABOLISM/MICROBIOLOGY Blotting, Southern Cell Division Cell Line, Transformed Cell Transformation, Viral Clone Cells/IMMUNOLOGY/METABOLISM/MICROBIOLOGY Epitopes/ANALYSIS Human HTLV-I/*IMMUNOLOGY/METABOLISM/PHYSIOLOGY HTLV-I Infections/*METABOLISM IgM/*BIOSYNTHESIS/IMMUNOLOGY/PHYSIOLOGY Immunoglobulin Idiotypes/IMMUNOLOGY Molecular Weight Support, Non-U.S. Gov't Support, U.S. Gov't, P.H.S. Viral Proteins/*IMMUNOLOGY/METABOLISM Virion/PHYSIOLOGY JOURNAL ARTICLE



 




Information in this article was accurate in January 30, 1990. The state of the art may have changed since the publication date. This material is designed to support, not replace, the relationship that exists between you and your doctor. Always discuss treatment options with a doctor who specializes in treating HIV.