Properties of anti-Lyb-2-mediated B-cell activation and the relationship between Lyb-2 molecules and receptors for B-cell stimulatory factor-1 on murine B lymphocytes.
The murine B-cell differentiation antigen Lyb-2 has been shown to be involved in B-lymphocyte activation and has been postulated by some to be related to a receptor for B-cell stimulatory factor I (BSF-1) (H. Yakura et al., J. Immunol. 137, 1475, 1986). Here we have demonstrated that monoclonal antibody (mAB) to Lyb-2 resembles BSF-1 in its ability to activate small resting B cells and enhancement of surface Ia. Anti-Lyb-2 antibodies bound B cells with very high avidity and were able to induce mobilization of cytosolic-free calcium. Anti-Lyb-2 mAB differs from BSF-1 in that BSF-1 but not anti-Lyb-2 is able to synergize with anti-mu in induction of B-cell proliferation. The relation between Lyb-2 molecules and BSF-1 receptors was tested in assays that measure binding of anti-Lyb-2 or BSF-1 in B cells and were found not to compete with each other. It appears that the two B-cell agonists anti-Lyb-2 and BSF-1 may exert their effects on B cells through different cell surface moieties as well as different intracellular pathways.
Subbarao
B
B
Department of Medical Microbiology and Immunology, University of Kentucky, Lexington 40536.
Morris
J
J
Baluyut
A R
AR
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000502:physiology; D000911:Antibodies, Monoclonal / Q000502:physiology; D000950:Antigens, Ly / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D001666:Binding Sites, Antibody; D002118:Calcium / Q000378:metabolism; D004357:Drug Synergism; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D007075:Immunoglobulin M / Q000276:immunology / Q000502:physiology; D007163:Immunosorbent Techniques; D015847:Interleukin-4; D007378:Interleukins / Q000378:metabolism* / Q000502:physiology; D007399:Interphase; D007424:Intracellular Fluid / Q000378:metabolism; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen / Q000502:physiology*
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D000950:Antigens, Ly; D000949:Histocompatibility Antigens Class II; D007075:Immunoglobulin M; D007378:Interleukins; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen; C044203:anti-IgM; D015847:Interleukin-4; D002118:Calcium