Effect of protein kinase Cθ on the regulation of L-selectin expression of human γδT cells

Objective To investigate the role of PKCθ signal pathway on regulation of L-selectin (CD62L) expression in human activated γδT cells. Methods Human peripheral blood mononuclear cells (PBMC) were stimulated with Mycobacterium tuberculosis antigen (Mtb-Ag) and cultured for 6-8 d to generate Mtb-Ag activated T cells(MtbAT) as γδT cells enrichment T cell line. The MtbAT were stimulated with PMA or PMA + IMN for 3, 6, 12 and 24 h, respectively, or MtbAT cultured for 8 d were stimulated with Mtb-Ag, or PMA, with or without PKC0 inhibitor Rottlerin for 4 h. After the treated cells stained with fluo-rescent labeled monoclonal antibodies, the expression of CD62L on γδT cells were measured by flow cytome-try (FCM ). Results The expression of CD62L on γδT cells cultured for 6-8 d were 75.0%-87.0%. Decrease of CD62L from the surface of γδT cells by 3 h to 12 h after exposure to PMA (42.3% to 23.5% ), but CD62L expression increased to 53.2% when γδT cells were exposed to PMA for 24 h. The expression of CD62L of γδT cells decreased to 52.1% and 39.3% respectively when γδT cells were exposed to PMA + IMN for 3 h and 6 h. After treated with PMA + IMN for 12 h and 24 h, the expression of CD62L were 52.9% and 35. 3% respectively. The CD62L expression of γδT cells treated with PMA and Rottlerin (47.9%) were higher than that treated with PMA alone (31.8%). After Mtb-Ag restimulated MtbAT for 4 h, the CD62L level of γδT cells decreased from 70.0% to 54.8%, Rottlerin could inhibite Mtb-Ag down regulation CD62L level of γδT cells (63.1%). Conclusion The CD62L expression of γδT cells could be ingibited partly by the inhibitor of PKCθ signal pathway may regulate L-selectin (CD62L) expression of activated human γδT cells. Key words: L-selectin;  γδT lymphocytes;  Protein kinase C