PT - JOURNAL ARTICLE AU - Woo, Edward Y. AU - Yeh, Heidi AU - Chu, Christina S. AU - Schlienger, Katia AU - Carroll, Richard G. AU - Riley, James L. AU - Kaiser, Larry R. AU - June, Carl H. TI - Cutting Edge: Regulatory T Cells from Lung Cancer Patients Directly Inhibit Autologous T Cell Proliferation AID - 10.4049/jimmunol.168.9.4272 DP - 2002 May 01 TA - The Journal of Immunology PG - 4272--4276 VI - 168 IP - 9 4099 - http://www.jimmunol.org/content/168/9/4272.short 4100 - http://www.jimmunol.org/content/168/9/4272.full SO - J. Immunol.2002 May 01; 168 AB - Active suppression by T regulatory cells plays an important role in the down-regulation of T cell responses to foreign and self-Ags. Thus far, the potential role of CD4+CD25+ T cells in human tumors has not been reported. In this work we show that lung tumors contain large numbers of these cells and that they have constitutive high-level expression of CD152 (CTLA-4). Furthermore, the CD4+CD25+ T cells mediate potent inhibition of autologous T cell proliferation. Finally, regulatory T cells from patient tumors failed to inhibit the proliferation of allogeneic T cells. Together these results suggest that the CD4+CD25+ T cells found in lung tumors selectively inhibit the host immune response and therefore could contribute to the progression of lung cancer.