Endogenous expression of delta on the surface of WEHI-231. Characterization of its expression and signaling properties.
WEHI-231 is a murine B cell lymphoma that has been used extensively as a model for the immature stage B cell and its functional response to Ag receptor cross-linking as a model for immature B cell tolerance. This cell line expresses sIgM, CD5, and FcR gamma, but lacks the B cell-specific isoform of CD45 (B220). This study demonstrates for the first time that WEHI-231, in contrast to classically defined immature B cells, expresses delta on its surface. Analysis of delta on WEHI-231 revealed structural differences with respect to that on BAL-17 or primary splenic B cells. Although the m.w. of delta on the latter two B cell populations was similar, delta on WEHI-231 manifested a marked increase in its apparent m.w. deduced by SDS-PAGE. This difference was found to be due primarily to differential N-linked glycosylation. Signal transduction through the endogenous sIgD on WEHI-231 was investigated. In contrast to cross-linking of sIgM, cross-linking of the endogenous surface IgD on WEHI-231 was unable to generate a negative growth response in these cells. This inability may be due to uncoupling from normal surface Ig signaling pathways. The signaling properties of the endogenous sIgD on WEHI-231 differ from that on primary B cells and other sIgD-expressing cell lines. Whereas sIgD on splenic B lymphocytes or the mature B cell line BAL-17 is coupled to inositol phospholipid hydrolysis and calcium mobilization, cross-linking of sIgD on WEHI-231 failed to elicit these events, although induced changes in tyrosine phosphorylation were observed. Thus, endogenous expression of surface IgD on WEHI-231 is inconsistent with its representing the classically defined immature stage B cell. The structural and signaling differences associated with delta on these cells suggest the potential for developmentally regulated delta function and model for study of sIgD signal transduction.
Haggerty
H G
HG
Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia 19104.
Wechsler
R J
RJ
Lentz
V M
VM
Monroe
J G
JG
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D000954:Antigens, Surface / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology*; D002118:Calcium / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D007072:Immunoglobulin D / Q000032:analysis* / Q000737:chemistry; D016393:Lymphoma, B-Cell / Q000276:immunology* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D010716:Phosphatidylinositols / Q000378:metabolism; D010766:Phosphorylation; D011947:Receptors, Antigen, B-Cell / Q000032:analysis* / Q000737:chemistry; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
D000888:Antibodies, Anti-Idiotypic; D000954:Antigens, Surface; D007072:Immunoglobulin D; D010716:Phosphatidylinositols; D011947:Receptors, Antigen, B-Cell; C039951:anti-IgD; D002118:Calcium