Comparison of Concomitant and Sinecomitant Tumor Immunity

Concomitant immunity has been observed in syngeneic rats (Lewis) harboring a progressively growing methylcholanthrene-induced tumor, and in mice (C3H) with spontaneous mammary tumors. Such immunity, as determined by the growth of a challenge of tumor cells from the immunizing tumor, was equivalent to that found in animals whose primary tumors had been removed prior to challenge (sinecomitant immunity). Partial or complete removal of the primary tumor subsequent to challenge failed to alter immunity.