[Study of the sensitivity of the L-forms of group A Streptococcus to antibiotics in artificial nutrient media and in human cell cultures].

Sensitivity of L-forms of group A streptococci to 5 antibiotics such as erythromycin, lincomycin, tetracycline, gentamicin and chloramphenicol was studied in an artificial nutrient medium and cell cultures i.e. human fibroblast diploid cells and transplantable human heart cells (Girardi).

[Effect of intraperitoneal administration of Streptococcus group A and its cell fractions on the development of adjuvant arthritis in rats].

The effect produced by the intraperitoneal injection of live and heat-killed group A streptococci, the fractions of their cell walls (both intact and sonicated) and cytoplasm was studied on 450 white rats with experimental adjuvant arthritis (AA). The injection of live streptococci into rats with AA decreased the swelling of joints (by 70-80% in the second half of the experiment), reduced the titers of rheumatoid-like factor (RLF), and inhibited the development of polyarthritis. The use of heat-killed streptococci gave a less pronounced antiarthritic effect, while the fraction of streptococcal cell walls, similarly to live streptococci, decreased the swelling of joints (by 27-64%); at the same time a considerable drop in the titers of RLF was observed in 3 experiments, and the development of polyarthritis was registered in 38% of the test animals and in 62% of the control animals.

[Determination of the cytotoxic action of cell fractions of Streptococcus group A on continuous human heart cells].

The work deals with the study of the cytotoxic action of the fractions of group A streptococcal cells, type 1, on human heart cells in continuous cell cultures, carried out by the method of J. L. Middlebrook and R.

[Erythrocyte and lymphocyte interaction with streptococcal L-forms].

The adsorption of human, sheep and human red blood cells and human lymphocytes on the colonies of streptococci in the L-form has been studied. Th electron-microscopic study of the interaction between human lymphocytes and streptococcal L-forms is suspensions has also been carried out. The red blood cells of all species under study, as well as human lymphocytes, have been found capable of being adsorbed on the colonies of streptococci in the L-form, this adsorption occurring only on the periphery of the colony.

[Interaction of streptococcal L-forms and tissue culture cells].

The interaction between 2 strains of group A streptococci in L-forms and the cells of the continuous cell lines HEp, HeLa, L, GPK and PEK, as well as the cells of primary human and chick embryo cell cultures was studied under conditions of infection with different doses. In most of the cell cultures used in this study L-form of streptococci showed no pronounced cytopathic effect. They could be isolated, when using cell cultures as inoculum, from the cultivated cells of continuous cell lines during the whole period of the cultivation of the infected monolayer (6--7 days), primary human embryo cell culture up to days 8--11 and from chick embryo cell culture up to days 1--3.