Sheep-erythrocyte-capping by human T-lymphocytes. Pharmacological inhibition by phenothiazine drugs.
In our previous studies it was found that E-rosette dissociation and sheep-erythrocyte capping were active processes involving the cytoskeleton. These cellular functions are now shown to be very sensitive to phenothiazine-drugs whose activities can be differentiated as follows: trifluoperazine greater than chlorpromazine greater than sulfoxide derivatives, suggesting a role for calmodulin-mediated events. These findings are in contradiction to prior reports pointing to the inefficacy of chlorpromazine to inhibit slow kinetic capping. However, no co-capping of trifluoperazine fluorescence (as a probe of calmodulin) and sheep erythrocytes could be observed. No requirement in extracellular calcium was evident for E-rosette formation and dissociation.
D000328:Adult; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002147:Calmodulin / Q000502:physiology; D004912:Erythrocytes / Q000276:immunology*; D006801:Humans; D007152:Immunologic Capping / Q000187:drug effects*; D010640:Phenothiazines / Q000494:pharmacology*; D012397:Rosette Formation; D012756:Sheep; D013601:T-Lymphocytes / Q000276:immunology*
D002147:Calmodulin; D010640:Phenothiazines; D002118:Calcium