PRODUCTION OF L-FORMS OF STREPTOCOCCUS-PYOGENES AND THEIR ANTI-TUMOR EFFECTS

  • 1 January 1980
    • journal article
    • research article
    • Vol. 50  (5) , 383-388
Abstract
Unstable L-forms of S. pyogenes were effectively isolated when protoplasts induced by muralysin were cultivated on a gradient plate containing penicillin-G. By this method, L-forms were obtained from the strains of serotype 3 and 4, from which they had been considered to be difficult to obtain. After 30-40 subcultures, 2 L-form strains (L-forms of Su and C-512) were successfully transferred into fluid medium without serum and penicillin. The antitumor effects of these stable L-forms were compared with these parent cocci. Treatment of the L-form of Su, which has antitumor effect, showed a considerable prolongation of life span in mice inoculated with [mouse methylcholanthrene-induced fibrosarcoma] Meth-A ascites tumor cells. The L-form of C-512, which has no antitumor effect, produced no effect on the tumor growth. Using 2 different transplantable tumors, the antitumor properties of the L-form of Su were investigated by comparing them with protoplast and cell wall fraction derived from the Su strain. In ascites tumors [mouse Ehrlich carcinoma cells], the L-form treatment showed visible effects; the cell wall produced no inhibitory effect. In solid tumors the antitumor effects obtained by the administration of the cell wall were never improved by the L-form. In both types of tumor, L-form showed antitumor activities similar to protoplast.