Purification of a syngeneic cross-reactive autotumorolytic factor.

Abstract

An autotumorolytic fraction (ATF) derived from sera of mice bearing spontaneous mammary adenocarcinoma has been purified by sequential chromatography on Sephacryl 200 SF, DEAE Sephacel, hydroxylapatite, and Sephacryl 200 SF. At each stage of the purification, tumorolytic activity was assessed by the ability of the active material to induce lysis of a 2-week-old mammary tumor, and verified by histopathological analysis. Active fractions obtained during the stages of purification were capable of inducing lysis of tumors in both the original donor mice and the syngeneic tumor-bearing mice. Lytic activity was specific only for tumor tissue. This syngeneic crossreactivity of partially purified materials permitted pooling of serum samples for purification purposes. The resultant final preparation of ATF is an homogenous protein fraction, as verified by gradient SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and high-performance liquid chromatography. The molecular weight of active ATF is approximately 50,000 Da, as determined by gradient SDS-PAGE.