TUMOR-SPECIFIC TRANSPLANTATION RESISTANCE IN MICE AFTER TREATMENT OF INITIAL TUMORS WITH STREPTOCOCCUS-THERMOPHILUS

Antitumor activity observed by treatment with Streptococcus thermophil us was further investigated. The mice cured from fibrosarcoma by treat ment with heat-killed preparation of S. thermophilus, when challenged with fibrosarcoma failed to take up the tumor. However, these cured mi ce when challenged with sarcoma-180 or Ehrlich ascites carcinoma, did not show significant changes in tumor take and/or survival compared to their respective controls. Similarly, mice cured from sarcoma-180 wer e challenged with fibrosarcoma, sarcoma-180 or Ehrlich ascites carcino ma. Though there was no change in the mean survival time (MST) of the dying mice regarding sarcoma-180 or Ehrlich ascites carcinoma, there w as 50 and 30% increase in the number of mice that showed total regress ion respectively over controls. However, there was no difference in th e growth rate of fibrosarcoma. Similar observations were made with mic e cured from Ehrlich ascites carcinoma, challenged with these tumors. These findings thus suggest that the antitumor response was tumor-spec ific and that tumor-associated antigens may have a role in imparting t his specificity. Bacterial treatment non-specifically augmented this p rimary response.