The suppression of mitogen- and alloantigen-stimulated peripheral blood lymphocytes by cultured human T lymphocytes
Maca, R.D.; Bonnard, G.D.; Herberman, R.B.
Journal of Immunology 123(1): 246-251
1979
ISSN/ISBN: 0022-1767 PMID: 156232 Document Number: 148499
Cultured T into nuclear protein was then quantitated at the end of the culture period and compared to the control 3HTdR uptake values. The addition of CTC significantly suppressed thymidine incorporation in the mitogen- and alloantigen-stimulated cultures. This suppressed thymidine uptake was not due to competitive inhibition by cold thymidine released into the culture medium by the CTC. This suppressor activity was not due to a crowding effect of the added CTC or to the depletion of nutrients from the culture medium by metabolizing CTC. CTC autologous to the responding normal lymphocytes were as effective in suppressing the mitogen and alloantigen responses as allogeneic CTC; the observed suppression by CTC could not be explained by the cytotoxicity by alloantigen-sensitized or polyclonal-activated CTC. Viable and irradiated CTC were equally effective in suppressing the Con A response. In the response to allogeneic cells, irradiating the CTC completely abrogated the suppressor effect. This model system is good for studying suppressor activity of human T lymphocytes that are not contaminated by other types of cells with suppressor potential, such as monocytes. This system should provide a means to evaluate ways by which this T cell suppressor activity can be modulated.