ABSTRACT
Many human solid tumors are infiltrated by mononuclear cells which are mostly localized in the tumor stroma or in tissues immediately surrounding the tumor. The lymphoid component of these infiltrates consists almost entirely of T and B lymphocytes, while natural killer cells are infrequently found among tumor-infiltrating lymphocytes. Many human solid tumors are infiltrated by mononuclear cells which are mostly localized in the tumor stroma or in tissues immediately surrounding the tumor. The molecular basis of tumor-induced immunosuppression appears to involve several distinct mechanisms. A variety of other soluble factors produced in the tumor microenvironment are likely to profoundly affect tumor growth and its interactions with immune effector cells. The ability of the tumor to downregulate or cause deletion of T cells positive for the T cell receptor complex Vß2 genes from the T cell repertoire is another example of tumor-mediated modulation of effector cells.
