Transmembrane signaling through CD80 (B7-1) induces growth arrest and cell spreading of human B lymphocytes accompanied by protein tyrosine phosphorylation.
We addressed the issue of the role for CD80 (B7-1) expressed on human B cells in transmembrane signaling. Cross-linking of CD80 on B lymphoma Raji cells induced tyrosine phosphorylation in 160-, 120-, 55-, 46- and 44-kDa proteins, which was inhibited by genistein. CD80-mediated signaling resulted in the inhibition of DNA replication of B cells and induced the changes in morphology like macrophages or fibroblasts. This cell spreading was inhibited by the pre-treatment of the cells with genistein. These results suggest that the CD80 antigen is involved in transmembrane outside-in signaling in B cells and its biological effects appear to be mediated by tyrosine kinases.
Hirokawa
M
M
Department of Internal Medicine III, Akita University School of Medicine, Japan.
Kuroki
J
J
Kitabayashi
A
A
Miura
A B
AB
D001402:B-Lymphocytes / Q000166:cytology* / Q000187:drug effects*; D018122:B7-1 Antigen / Q000494:pharmacology*; D002051:Burkitt Lymphoma; D002455:Cell Division / Q000276:immunology; D002465:Cell Movement / Q000187:drug effects / Q000276:immunology*; D006801:Humans; D010766:Phosphorylation / Q000187:drug effects; D011506:Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism*
D018122:B7-1 Antigen; D011506:Proteins; D014443:Tyrosine