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Production of L-forms of Streptococcus pyogenes and their antitumor effects
Abstract:
Unstable L-forms of Streptococcus 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 to 40 subcultures, two 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 Meth-A ascites tumor. On the other hand, the L-form of C-512, which has no antitumor effect, produced no effect on the tumor growth. Using two different transplantable tumors, the antitumor properties of th L-form of Su were investigated by comparing them with protoplast and cell wall fraction derived from the Su strain. In ascites tumors, the L-form treatment showed visible effects, while the cell wall produced no inhibitory effect. On the contrary, 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.
Insights
Stable Streptococcus pyogenes L-forms were isolated and tested for antitumor effects. The Su L-form demonstrated significant antitumor activity in mice, prolonging lifespan in ascites tumor models.
Area of Science:
- Microbiology
- Immunology
- Biochemistry
Background:
- Streptococcus pyogenes L-forms are unstable bacterial variants.
- Isolation of L-forms from certain serotypes (3 and 4) has been challenging.
- Investigating L-form properties for therapeutic potential is of interest.
Purpose of the Study:
- To effectively isolate stable L-forms of Streptococcus pyogenes.
- To evaluate the antitumor effects of isolated L-forms.
- To compare the efficacy of L-forms with parent strains and cellular components.
Main Methods:
- Induction of protoplasts using muralysin and cultivation on penicillin-G gradient plates for L-form isolation.
- Subculturing to achieve stable L-form strains in fluid medium without serum or penicillin.
- In vivo studies using Meth-A ascites tumor and other transplantable tumors in mice to assess antitumor activity.
Main Results:
- Stable L-forms were successfully isolated from Streptococcus pyogenes serotypes 3 and 4.
- The Su L-form strain exhibited significant antitumor effects, prolonging survival in mice with ascites tumors.
- The C-512 L-form strain showed no antitumor activity.
- L-forms demonstrated antitumor activity comparable to protoplasts in both ascites and solid tumors.
Conclusions:
- Stable Streptococcus pyogenes L-forms can be effectively isolated using specific culture techniques.
- The Su L-form possesses notable antitumor properties, particularly against ascites tumors.
- L-forms and their derived protoplasts show comparable antitumor activities, suggesting potential therapeutic applications.