We have demonstrated that T lymphocytes from the spleens of adult guinea pigs sensitized to group A streptococcal antigens are cytotoxic for cultured fetal guinea pig heart cells. Lymphocyte cytotoxicity, measured by 51Cr release from target cells, was stimulated by sensitization in vivo with group A whole cells, cell walls, and purified protoplast membranes emulsified with complete Freund's adjuvant (CFA). Sensitization with group C streptococcal antigens in CFA or CFA alone produced lymphocytes with little or no specific cytotoxic activity. Target cells of cultured fetal skeletal muscle, liver, or skin were relatively refractory to effector cell cytotoxicity. The presence of antigenic determinants on the membranes of cultured myofibers, cross-reacting with group A streptococcal cellular antigens, was confirmed by immunofluorescence. These data are discussed in terms of a model for poststreptococcal rheumatic myocarditis in which cell-mediated autoimmune mechanisms may participate.

The streptococcal group E cell wall polysaccharide antigen was extracted from strain K129 cells with hot trichloroacetic acid and purified. It contained rhamnose and glucose in a 2:1 molar ratio, 2% protein, 1 % phosphorus, and was free of muramic acid and glycerol. No type polysaccharide antigen was present. The reaction of specific group E rabbit antiserum with the polysaccharide was effectively inhibited by D-glucose and f-glucosides such as 1-methyl-f-D-glucose, cellobiose, and gentiobiose. The 1-methyl-aD glucose was one-half as effective as the beta isomer. L-Rhamnose and N-acetyl-D-glucosamine were ineffective. Partial acid hydrolysis of the antigen followed by chromatographic separation of the oligosaccharides resulted in the isolation and analysis of five fractions. These fractions were di-, tri-, and tetrasaccharides. A study of these fractions by chemical analysis, reduction with borohydride, inhibition of the antigen-antibody reaction, release of glucose by f3-glucosidase, and other evidence indicate that 3-D-glucose is the immunodominant sugar in the antigen. A glucose-rhamnose trisaccharide (1:2 molar ratio) was the most effective inhibitor of the precipitin reaction; the glucose was readily released by f3-glucosidase, and one-half of the rhamnose was reduced with borohydride. This trisaccharide is considered to be a repeating unit in the native polysaccharide and probably has the following structure: 0-03-D-glucosyl-(1-2)-O-a-L-rhamnosyl-(1-4)-L-rhamnose. A glucose-rhamnose disaccharide in which the hexose and pentose are linked as in the trisaccharide was an effective inhibitor of the precipitin reaction. Strain K129 cells do not appear to contain a type polysaccharide antigen.

Escherickia coli and Pseudomonas fluorescens followed similar patterns of adaptation to tolerate quaternary ammonium compounds.

The group R streptococcal group antigen has been shown to be a polysaccharide located at the surface of the cell wall of the organism. The antigen was extracted from cell walls in 0.05 N HCI or 5% trichloracetic acid at 100 C, from whole cells at room temperature in 0.85% NaCl or 0.1 M acetate (pH 5.0), and by sonic oscillation. The antigen is largely destroyed when extracted from whole cells in 0.05 N HCI at 100 C. Acetate is recommended for routine extraction. The antigen extracted by sonic treatment was separated into six immunologically active fractions on diethylaminoethyl-Sephadex. The fractions were found to possess a common antigen which exhibited similar properties on immunodiffusion and immunoelectrophoresis. The purified antigen did not react with any other streptococcal group antisera. Adsorption of group R serum with the antigen removed all antibodies against whole cell antigen extracts of R cells. Chemical and enzymatic analysis of three fractions showed that the antigen was composed of D-glucose, D-galactose, rhamnose, and glucosamine. No significant quantities of phosphorus, glycerol, ribitol, or muramic acid were present. Significant inhibition of the quantitative precipitin determination by D-galactose and stachyose indicated that galactose in terminal alpha linkage was the immunodominant hexose in the antigen. D-Glucose and D-glucosamine possessed a partial inhibitory activity. N-acetyl-D-glucosamine and L-rhamnose did not produce significant inhibition. The results indicate that the R antigen is an immunologically specific structure which serves as a reliable means of identification of these streptococci as a serological group. The cells were grown for 17 hr at 37 C in Todd-Hewitt broth (Difco) supplemented with glucose and salts (12), removed from the medium by centrifugation, and, in some cases, washed with distilled water and lyophilized. Growth was estimated by optical density measurements at 550 nm. Lyophilized cells were extracted with either 0.01, 0.05, or 0.2 N HCl (2 mg/ml) at 100 C for 10 min and

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