Activation of dense human tonsilar B cells. Induction of c-myc gene expression via two distinct signal transduction pathways
| Autor: | White, M. W., Mcconnell, F., Shu, G. L., Morris, D. R., Edward A Clark |
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| Rok vydání: | 1991 |
| Předmět: | |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.146.3.846 |
| Popis: | Antibodies to surface Ig or to the B cell marker CD20 trigger resting human B cells in similar yet distinct ways. Either antibody induces five-fold increases in the expression of the protooncogene, c-myc, as detected with semi-quantitative Northern blot assays. The induction of c-myc mRNA by anti-IgM or anti-CD20 is blocked by inhibitors of protein kinase C (PKC) such as staurosporine and by pretreatment of B cells with phorbol esters to reduce cellular PKC levels. This suggests that PKC is involved in the pathways stimulated by both anti-IgM and anti-CD20. However, anti-CD20, unlike anti-IgM, does not activate significant increases in inositol triphosphate or intracellular-free calcium. Further, anti-CD20-triggered elevation of c-myc mRNA is inhibited by pertussis and cholera toxins, whereas the pathway initiated by anti-IgM if anything is stimulated by pertussis toxin and unchanged by cholera toxin. Further differences in the nature of these two signals were seen when the expression of adhesion/recognition molecules were examined. Anti-IgM consistently induces increased expression of the adhesion molecules CD54 (I-CAM-1) and B7/BB-1 on B cells, but anti-CD20 does not. Yet both anti-CD20 and anti-IgM increase class II MHC, CD18 (LFA-1 beta-chain) and LFA-3 levels. These data suggest that the way in which B cells are activated may influence their surface phenotype and possibly subsequent migration or cell-cell interactions. |
| Databáze: | OpenAIRE |
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