Article: article from journal or magazin.
New infectious mammary tumor virus superantigen with V beta-specificity identical to staphylococcal enterotoxin B (SEB).
European Journal of Immunology
Only few infectious mouse mammary tumor viruses (MMTV) have been characterized which induce a potent superantigen response in vivo. Here we describe the characterization of an MMTV which was isolated from milk of the highly mammary tumor-prone SHN mouse strain. Exposure of newborn mice to milk-borne MMTV (SHN) results in a very slow deletion of V beta 7, 8.1, 8.2 and 8.3 expressing peripheral T cells. Subcutaneous injection of adult mice with this virus induces a rapid and strong stimulation of all four affected V beta-subsets in vivo. Besides the strong T cell effect we observed an early proliferation and activation of the local B cell pool leading to the initial secretion of IgM followed by preferential secretion of IgG2a by day 6. Sequence comparison of the polymorphic C terminus with known open reading frames revealed high homology to the endogenous provirus Mtv-RCS. This is the first report of a virus having a complete overlap in V beta-specificity with a bacterial superantigen stimulating as many as 35% of the whole CD4+ T cell repertoire including V beta 8.2.
Amino Acid Sequence, Animals, Antigens, Viral/immunology, B-Lymphocytes/immunology, Base Sequence, Enterotoxins/immunology, Female, Mammary Tumor Virus, Mouse/immunology, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Milk/immunology, Milk/microbiology, Molecular Sequence Data, Receptors, Antigen, T-Cell, alpha-beta/immunology, Retroviridae Infections/immunology, Superantigens/immunology, T-Lymphocytes/immunology, Tumor Virus Infections/immunology
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