Injection of anti-CEA-H-2K^b/ova conjugate induces regression and growth inhibition of palpable tumors grafted in syngeneic mice adoptively transferred with OT-1 splenocytes. (A) Individual tumor growth curves of all five mice treated with the conjugate and five control mice during the first 24 days after tumor graft. Treatment was started on day 8 (arrow), when all ten mice had palpable nodules. Systemic injection of 20 µg conjugate (filled symbols) or anti-CEA F(ab')₂ fragment (empty symbols) was repeated every two days until the end of the experiment. The first three injections were i.v. and the following ones were i.p. (B) Mean values and standard deviations of tumor volumes from four treated and four control mice determined up to day 35. One mouse, which did not respond to treatment as shown in A (black circle), was excluded from the mean value, as was a control mouse which died on day 18, as shown in A (open triangle). On day 35, a Wilcoxon test was performed to compare the tumor volumes, giving P = 0.0209 for treated versus control groups, without including the non-responding tumor, and P = 0.05 when the non-responding mouse was included.