To evaluate the in vitro cytotoxic effects of human cord blood T lymphocytes sensitized with carcino embryonic antigen (CEA) expressing HSP60 under thermal stress on human cancer cells of the Hela type.
Human umbilical cord blood mononuclear cells (T lymphocytes and monocytes) were collected, the ratio of monocyte to T lymphocyte was made to 1:10. They were incubated in five separated tissue culture flasks (5 ml cell suspension in each flask) with CEA in a dose 0.5mg/ml and 30 U/ml for 12 days at 37oC and 5% CO2, during which, four of the three culture flasks were exposed to different thermal stress degrees, 37oC, 40oC, 41oC, and 42oC for one hour a day, the other one was not subjected to heat as a negative control. The HSP60 level was measured by ELISA, and T cell cytotoxicity against Hela cancer cells was estimated by lactate dehydrogenase release.
HSP60 was found at higher levels in cell suspension exposed to 40 oC and 41 oC (15.4±0.4 and 16.1±0.2 ng/ml respectively) and there was a clear decline in HSP60 level for the cell suspension exposed to 42oC (2.8±0.3 ng/ml). The T cell proliferation increased dramatically and the highest proliferation rate was elicited at day six of incubation with exposure 40 oC and 41 oC when the monocyte-T cell ratio declined to 1:35±2 and 1:30±2 respectively. T cell mediated cytotoxicity to Hela target cell was found at its maximum. The maximum cytotoxicity percentage mediated by T cells was observed with T cells exposed to 40oC, there was a slight reduction in the T cells cytotoxicity percentage for those exposed to 41oC but there was no significant difference and they possessed an extremely higher anti tumor activity than those subjected to 37, & 42oC.
This study shows that in vetro addition of the heat during sensitization of cord blood T cell to cancer associated antigen (CEA) in the range of 40oC to 41oC C has induced both the antigen induced sensitization of T cell and their cytotoxicity against target cancer cells of the Hela type. (Rawal Med J 2011;36:53-56).
CEA, T cell sensitization, HSP60, thermal stress cytotoxicity, T cell cytotoxixicty.