RESUMEN
In the present investigations, gammadelta T cells were isolated from the peripheral blood of oral cancer patients and analyzed for their immunophenotype and cytotoxic potential. Flow-cytometric analysis revealed a dominant population expressing Vgamma9 and Vdelta2 T-cell receptors. In a 4-hr 51Cr-release assay, activated gammadelta T cells showed specific cytotoxicity against Daudi Burkitt's lymphoma cells and fresh oral tumor cells. Cold target competition assays demonstrated that gammadelta T cells recognize a common ligand on Daudi and oral tumor cells. Expression of heat shock protein 60 (hsp60) molecules was detected on the surface of Daudi as well as oral tumor cells by flow cytometry and immunoprecipitation of surface biotinylated cells by anti-hsp60 monoclonal antibody (MAb). Such MAbs brought about a significant inhibition of cytotoxicity of gammadelta T cells against Daudi and oral tumor cells. The results suggest that gammadelta T cells isolated from the peripheral blood of oral cancer patients have the ability to lyse oral tumor cells. The lysis of oral tumor cells occurs via recognition of hsp60 on the surface of oral tumor cells.
Asunto(s)
Carcinoma de Células Escamosas/inmunología , Chaperonina 60/inmunología , Citotoxicidad Inmunológica , Neoplasias de la Boca/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Linfocitos T/inmunología , Anticuerpos Monoclonales , Carcinoma de Células Escamosas/sangre , Carcinoma de Células Escamosas/patología , Línea Celular , Células Cultivadas , Chaperonina 60/análisis , Humanos , Inmunofenotipificación , Células K562 , Neoplasias de la Boca/sangre , Neoplasias de la Boca/patología , Estadificación de Neoplasias , Células Tumorales CultivadasRESUMEN
Frequencies of proliferating and cytotoxic lymphocytes from the peripheral blood and tumour tissue of oral cancer patients and healthy individuals were monitored using limiting dilution analysis. Significantly lower precursor frequencies of proliferating lymphocytes were observed in the peripheral blood and tumour tissue of oral cancer patients. A high frequency of natural killer (NK) cells but low cytotoxic T lymphocytes (CTL) was observed in the peripheral blood compartment of oral cancer patients as compared to healthy individuals. A marked reduction in both NK and CTL frequencies in the tumour tissue compared to the peripheral blood was observed. In the tumour tissues, increased percentages of activated CD4+ lymphocytes as compared to CD8+ lymphocytes were observed. Our results suggest that impaired proliferative and cytotoxic potential of tumour infiltrating lymphocytes may play an important role in the escape of tumour cells from the immune system.