Stimulation of transplanted 3-methylcholanthrene-induced sarcomas in mice by specific immune ahd by normal serum.

Serum from Bl x C3H mice carrying syngeneic, progressively growing, highly immunogenic 3-methylcholanthrene-induced tumors when admixed with the specific tumor and inoculated into immunologically crippled syngeneic recipients, stimulated growth as compared with serum from control normal mice. It appears that this acceleration of tumor growth is an immune effect since it is not present when a non-immunogenic (spontaneous tissue culture) tumor is used; and the active factor can be absorbed from the serum by the specific tumor but not by an immunologically unrelated tumor. Normal serum per se also stimulated tumor growth, but to a smaller extent.