Effect of Rab27a mutants on granule exocytosis of cytotoxic cells.

(A) Release of cytotoxic granules BLT esterase activity from the activated T cells of a control or from patients 9 (P9) and 37 (P37). Following 4-hour cytotoxic cell incubation in the presence of CD3-coated plates, cell supernatants were collected and assayed using an enzyme-linked immunosorbent assay (ELISA) for serine esterase. The data represent the mean percentage and SD of specific release (test/total release) from triplicate samples. (B) Effect of overexpression of Rab27a mutants on the cytotoxic granule exocytosis of H saimiri CD8⁺ T-cell line. Following overexpression of Rab27a cDNAs, granule exocytosis was measured in the same conditions as in panel A (░). Transfection efficiency for each construct was assessed by FACScan analysis of EGFP expression (□). The results shown are representative of 2 independent experiments with similar results.