Local antitumor activity of a primary and an anamnestic response to a syngeneic guinea pig hepatoma

After intradermal (id) injection, the line 10 hepatoma grew progressively in nonimmune guinea pigs, wereas the line 1 hepatoma grew for approximately 2 wk, developed central necrosis, ulcerated, and regressed. Growth of the line 10 hepatoma was suppressed when line 10 hepatoma cells were mixed with antigenically distinct line 1 hepatoma cells before id injection into syngeneic strain 2 guinea pigs. Mixture of line 10 with irradiated line 1 or viable strain 2 embryo cells did not inhibit tumor growth. Preimmunization of recipients to line 1 cells abrogated the suppression of tumor growth from mixtures of line 1 and line 10.