title: Recipient polyclonal B cell activation and immunoglobulin production induced by priming with a retroviral superantigen.
abstract: The superantigen vSAG-7 (or MIs 1a) is a membrane glycoprotein encoded by the endogenous retrovirus mouse mammary tumor virus 7 (MMTV-7) and is highly stimulatory for V beta 6/CD4+ T cells. Priming of adult MMTV-7-negative mice with vSAG-7-expressing cells initially results in the activation of the peripheral V beta 6/CD4+ T cell compartment and is followed by T cell tolerance to the superantigen. During the course of tolerance induction the number of recipient B lymphocytes increases in the lymph nodes, but not the spleen, of vSAG-7-primed recipients. These B cells also express increased levels of class II MHC and present passively acquired superantigen. In this study we asked if these effects on the host B cell compartment are followed by the production of immunoglobulin. Priming of MMTV-7-negative BALB/c or CB.17 mice with vSAG-7-expressing cells from DBA/2 mice induced increases of both IgM and IgG2a in the serum. Use of Igh congenic CB.17 (IgMb) mice as recipients of the vSAG-7-presenting cells from DBA/2 (IgMa) donors indicated that the IgM and IgG produced were entirely of host origin. Priming with vSAG-7 also amplified (four- to fivefold) the antibody-producing cell response induced to a suboptimal dose of sheep RBC. Priming with purified B cells from vSAG-7 donors resulted in recipient V beta 6/CD4+ T cell activation and increased numbers of recipient B cells in the lymph nodes, but did not induce immunoglobulin production. In contrast, priming with purified CD8+ T cells resulted in increased quantities of serum IgM but not vSAG-7-reactive T cell activation or increased numbers of recipient B cells in the lymph nodes. These results indicate that the T cell activation and increased B cell number with upregulated class II MHC expression initially observed following vSAG-7 priming of adult MMTV-7-negative recipients are not linked to the induction of the recipient-derived immunoglobulin production.
authors.affiliation: Department of Urology, Cleveland Clinic Foundation, Ohio 44195, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Modlin
authors.forename: N A
authors.initials: NA
authors.lastname: Muruve
authors.forename: D
authors.initials: D
authors.lastname: Stanko
authors.forename: M J
authors.initials: MJ
authors.lastname: Caulfield
authors.forename: R L
authors.initials: RL
authors.lastname: Fairchild
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis; D000956:Antigens, Viral / Q000494:pharmacology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D007075:Immunoglobulin M / Q000096:biosynthesis; D007136:Immunoglobulins / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D008324:Mammary Tumor Virus, Mouse / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D018089:Superantigens / Q000494:pharmacology*
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D007075:Immunoglobulin M; D007136:Immunoglobulins; D008562:Membrane Glycoproteins; C095378:Mtv-7 superantigen, Mouse mammary tumor virus; D018089:Superantigens