GF109203X, a specific PKC inhibitor, abrogates anti-CD3 antibody-induced upregulation of CD4+ T cell adhesion to B cells.
Antigen-independent adhesion of CD4+ T lymphocytes to Epstein-Barr virus transformed B cells is mainly mediated by LFA-1 (CD11a/CD18) and CD2 molecules. Low-affinity binding of resting T cells can be transiently upregulated by cross-linking of CD3-TCR (T cell receptor) complexes. This inside-out signaling influences integrin (beta 1 and beta 2) adhesion capacity. Studies using the nonspecific inhibitor staurosporine have suggested that this phenomenon is dependent on protein kinase C activation. We found that the upregulation of anti-CD3-activated CD4+ T cell adhesion was inhibited strongly and in a concentration-dependent manner by GF109203X, a compound described as a potent and selective inhibitor of PKC. Comparative studies showed that GF109203X and staurosporine had similar inhibitory effects on the upregulation of activated CD4+ T cell adhesion. However, staurosporine is a nonselective kinase inhibitor. PMA-activated CD4+ T cell adhesion was also inhibited by GF109203X. In contrast, passive enhancement of adhesion by treatment with the CD11a-specific antibody NKI-L16 was unaffected by GF109203X. Taken together, these results show that PKC is involved in upregulating the adhesion of CD4+ T cells to B cells following activation of the former by CD3 cross-linking. PKC-dependent upregulation of CD4+ T cell adhesion to B cells is exclusively LFA-1-dependent, as GF109203X had no additional inhibitory effect on anti-LFA-1 antibody-pretreated T cells activated by the anti-CD3 antibody OKT3 and had no effect on the adhesion of LFA-1(-) CD4+ T cells. Finally, PKC inhibition did not alter CD2-mediated adhesion. This points to a limited participation of CD2 in T-B cell interactions after TCR/CD3 cross-linking.
Hauss
P
P
INSERM U 132, Hôpital Necker Enfants Malades, Paris, France.
Mazerolles
F
F
Hivroz
C
C
Lecomte
O
O
Barbat
C
C
Fischer
A
A
D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001402:B-Lymphocytes / Q000502:physiology*; D017252:CD3 Complex / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology*; D002448:Cell Adhesion; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000502:physiology; D008301:Maleimides / Q000494:pharmacology*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D015854:Up-Regulation
D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D007211:Indoles; D016169:Lymphocyte Function-Associated Antigen-1; D008301:Maleimides; D011493:Protein Kinase C; C070515:bisindolylmaleimide I