Pyogenes Cells Research Articles

An enzyme-linked immunosorbent assay (ELISA) for quantification of antibodies to Streptococcus mutans surface antigens

An ELISA was developed to quantitate the level of antibodies to various cell surface antigens of the Gram positive bacterium. Streptococcus mutans. Whole cells and purified cell wall components of S. mutans, lipoteichoic acid (LTA) from Streptococcus pyogenes, and dextran T 2000 were employed as coating antigens in this study. Cell walls of S. mutans were purified by mechanical disruption of whole cells followed by differential centrifugation and proteolytic enzyme treatment. Serotype-specific carbohydrate was purified from an autoclaved, lyophilized S. mutans whole cell preparation by column chromatography. LTA was prepared by Sepharose 4B chromatography of a phenol-water extract of S. pyogenes and used for detection of anti-polyglycerophosphate (PGP) antibodies. A rabbit antiserum to S. mutans 6715 (serotype g), which precipitated with purified carbohydrate antigen (RR g), gave good reactions with purified cell walls and whole cells of S. mutans 6715, less activity with RR g and low activity to LTA and dextran when tested by ELISA. Adsorption of this antiserum with whole cells of S. pyogenes resulted in antibody activity with specificity only to the serotype carbohydrate. The specificity of the antibody for homologous coating antigen was RR g > cell wall > whole cells. An antiserum to S. mutans MT573 (serotype e) contained antibody predominantly to LTA, whereas, anti- S. mutans MT703 (serotype e) reacted with both dextran and LTA; however, the activity to LTA was removed by prior adsorption of the antiserum with S. pyogenes cells. This treatment did not alter the antibody activity to dextran. To establish the sensitivity of ELISA, a purified IgG anti-serotype carbohydrate antibody was prepared by adsorption of anti- S, mutans 6715 antiserum with a mutant of S. mutans which lacks serotype carbohydrate followed by adsorption and elution of specific antibodies from S. mutans 6715 whole cells. The minimum level of sensitivity of ELISA was 12.5 ng of IgG anti-serotype carbohydrate.

Parameters affecting the adherence and tissue tropisms of Streptococcus pyogenes.

Virulent M protein-containing strains of Streptococcus pyogenes were found to adhere well to human pharyngeal cells in vitro. In contrast, an avirulent M - strain and an enteropathogenic Escherichia coli strain adhered feebly. When various rat tissues were exposed to mixtures of a virulent S. pyogenes strain and an enteropathogenic E. coli strain, the relative proportions of the two pathogenic strains recovered from mucosal surfaces differed among the sites studied. S. pyogenes cells were found to adhere in higher proportions than enteropathogenic E. coli cells to the mucosal surfaces of rat tongues, whereas on surfaces of the urinary bladder, their affinities were reversed. The data indicate that bacterial adherence is influenced by the specificity of both the bacterial and epithelial surfaces, and they suggest that adherence may influence the tissue tropisms of pathogens. Early stationary-phase cells of S. pyogenes attached better to epithelial cells than did bacteria in other growth phases. The adherence of S. pyogenes cells was impaired by pretreatment with trypsin, wheat germ lipase, Tween 80, Triton X-100, sodium lauryl sulfate, heat at 56 C, anti-group A antiserum, the presence of phospholipids, and preincubation of the epithelial cells with Streptococcus salivarius cell walls. Altering the pH or treatment with ethylenediaminetetraacetic acid had no effect on the ability of S. pyogenes cells to adhere.

Observations on the Mouse Lethal Power and Serology of Corynebacterium pyogenes

Nine strains of Corynebacterium pyogenes grown in Todd-Hewitt broth produced maximum haemolysin titres at 48 hours, when the population was 108 living organisms per ml. The haemolysin resembled the toxin of C. pyogenes in some properties and it was related to the toxin serologically, but it failed to pass through a Seitz EKS filter. A Todd-Hewitt broth culture supernatant was lethal to mice. The lethal power of C. pyogenes for mice was determined by inoculating graded doses of washed organisms. The organisms were more lethal by the intravenous than by the intraperitoneal route, and the survival time decreased as the dose was increased. Precipitin tests using unabsorbed and absorbed sera and extracts of C. pyogenes cells did not reveal qualitative antigenic differences among 50 strains. An antitoxic serum prepared against a single strain neutralized the haemolytic toxin of 50 strains.