The Action of an Lyb2.1-Specific Monoclonal Antibody in Soluble or Immobilized Form on Resting and Activated B Cells

Abstract

Lyb2, a 45,000 dalton glycoprotein differentiation antigen is present on all murine B lymphocytes (Sato and Boyse, 1976, Tung et al., 1977). The Lyb2.1 allele is present on B cells of many different inbred strains of mice including DBA/₂ and CBA/_J, and absent on many others including C57BL/_6J and CBA/_N. A monoclonal antibody specific for Lyb2 has been shown to inhibit the T cell dependent in vitro responses of B cells to sheep erythrocytes (SRC) (Yakura et al., 1981). Another monoclonal antibody specific for the Lyb2.1 allele has been found to have the same properties. In addition this monoclonal antibody changes the morphology of B cells to blasts and induces proliferation of activated B cells expressing the proper Lyb2 allele (Subbarao and Mosier, 1983). Only a subset of B cells appears to be involved since B cell- deficient CBA/_N × DBA/₂ F1 male cells do not show these effects while the corresponding normal female cells do. These findings have suggested that Lyb2 is a membrane glycoprotein that participates in murine B cell activation, maybe even as a receptor for B cell growth factors.