Effect of CRCL immunizing dose on mean tumor volume of challenged mice. BALB/c mice (n = 4 per group) were immunized with increasing quantities (5-50 μg) of 12B1-derived CRCL, or with saline on days - 14 and - 7, and were challenged in the opposite groin with 12B1 leukemia cells on day 0. Tumors were measured and volumes calculated once tumors were palpable. Mean tumor volumes for days 17 to 23 are shown. Representative data from 1 of 2 experiments are shown. Error bars represent SEM.