IFN-γcontributestorejectionof transplantabletumors andinhibitionof methylcholanthrene(MCA)-induced carcinogene-sis,however,by different mechanisms.In most tumor transplantation models,tumor rejectionrequires IFN-γexpressionby host but not tumor cells.IFN-γproduced by either CD4+or CD8+Tcells acts on non-hematopoetic tumor stromacells and,directly orindirectly,induces angiostasis.This prevents rapidtumor burden and allows residual tumor cellstobe eliminated.In some models,IFN-γalso …