Objective: To observe the expression of Fas receptor and ligand in human laryngocarcinoma cell line, Hep-2 and to investigate the possible mechanism of immune escape through Fas/FasL pathway in Hep-2 cell.
Method: The mRNA and protein expressions of Fas and FasL in Hep-2 cell were analyzed by RT-PCR and flow cytometry (FCM). Growth curve of Jurkat cell was drawer based on the results of MMT, and apoptosis of Jurkat cell were determined by FCM and Hoechst 33342 staining after coculturing with Hep-2 cell.
Result: The expressions of Fas and FasL in Hep-2 cell line were evaluated by flow cytometry and the mean fluorescence intensity were (32.91 +/- 5.6) and (25.57 +/- 7.1) respectively. After coincubation with Hep-2 cell (1 X 10(9)/L), the apoptosis rates of Jurkat cells were (38.95 +/- 0.11) % and (13.28 +/- 0.14) %, with planting concentration at 1 x 10(8)/L and 5 x 10 (8)/L respectively. In contrast, the apoptosis rate of Jurkat cultured separately was (7.53 +/- 0.17)%. The proliferation of Jurkat cell was obviously inhibited after coculture. However, the apoptosis rate was significantly decreased after adding neutralizing antibody of FasL.
Conclusion: Laryngocarcinoma cell could induce apoptosis of T lymphocytes through Fas-FasL system, thus it provided a potential mechanism to escape from immune surveillance of host.