The early B lineage antigen BP-1 and the transformation-associated antigen 6C3 are on the same molecule.
Biochemical similarities and cellular distribution patterns of the early B lineage-specific BP-1 alloantigen and the B lineage transformation-associated 6C3 Ag prompted this comparative study of the reactivities of the BP-1 and 6C3 mAb. Both Ag were found to be expressed on the same cells in normal tissues, and on the same cell lines when a large panel was analyzed. The Ag are both phosphorylated and have identical m.w., which may vary in different cell types because of differences in glycosylation. Immunoprecipitation of pre-B cell lysates with the BP-1 antibody removed the 6C3-reactive molecules and vice versa. However, the 6C3 antibody did not inhibit binding of the BP-1 antibody to viable cells and, in fact, enhanced immunofluorescence staining was observed when both antibodies were added together. These results indicate that the BP-1 and 6C3 antibodies react with different epitopes on the same molecule that is expressed in relatively low levels on normal early B lineage cells, and in relatively high levels on most neoplastic pre-B cells, pre-B cells in long term bone marrow cultures and certain stromal cell lines.
Wu
Q
Q
Division of Developmental and Clinical Immunology, University of Alabama, Birmingham 35294.
Tidmarsh
G F
GF
Welch
P A
PA
Pierce
J H
JH
Weissman
I L
IL
Cooper
M D
MD
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000937:Antigen-Antibody Reactions; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology* / Q000302:isolation & purification; D000957:Antigens, Viral, Tumor / Q000276:immunology*; D002460:Cell Line; D005260:Female; D006412:Hematopoietic Stem Cells / Q000276:immunology; D008221:Lymphoid Tissue / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D010750:Phosphoproteins / Q000276:immunology / Q000302:isolation & purification; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000944:Antigens, Differentiation, B-Lymphocyte; D000957:Antigens, Viral, Tumor; D010750:Phosphoproteins; C050155:antigen gp 160(6C3)