Downregulation of beta adrenergic receptor expression on B cells by activation of early signals in alloantigen-induced immune response.
Previously we described a decrease in beta-adrenergic receptor expression in B lymphocytes as a consequence of in vivo alloimmunization. This decrease correlates with the highest response of alloantibody production by B cells. In the present report we examined the participation of intracellular signals elicited after alloimmune stimulation. We showed that in vitro stimulation of B cells with mitomycin C-treated allogenic cells induced a reduction in the number of beta-adrenoceptors. This downregulation correlated to changes in basal and in isoproterenol-stimulated intracellular cAMP levels. We found that calcium mobilization and protein kinase C activation triggered after direct allogenic stimulation and/or by the action of T cell-soluble factors induced the reduction in beta-adrenoceptor sites. These findings could be of interest to understand the neuroendocrine mechanisms involved in the regulation of B cell activation.
Genaro
A M
AM
Cátedra de Farmacología, Universidad de Buenos Aires and Centro de Estudios Farmacológicos y Botánicos (CEFYBO-CONICET), Buenos Aires, Argentina. genaro@cefybo.edu.ar
Cremaschi
G A
GA
Gorelik
G
G
Sterin-Borda
L
L
Borda
E S
ES
D000818:Animals; D001402:B-Lymphocytes / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism*; D002118:Calcium / Q000502:physiology; D002474:Cell-Free System / Q000276:immunology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D015536:Down-Regulation / Q000276:immunology*; D005260:Female; D007518:Isoantibodies / Q000096:biosynthesis; D007519:Isoantigens / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D011493:Protein Kinase C / Q000502:physiology; D011943:Receptors, Adrenergic, beta / Q000096:biosynthesis* / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology*; D012995:Solubility; D013601:T-Lymphocytes / Q000378:metabolism
D017077:Culture Media, Conditioned; D007518:Isoantibodies; D007519:Isoantigens; D011943:Receptors, Adrenergic, beta; D011493:Protein Kinase C; D002118:Calcium