Production and biological properties of M-protein of Streptococcus equi.
Abstract: The production of M-protein antigen of Streptococcus equi was studied during in vitro growth in equine blood and in various media. Of 11 S equi strains studied, seven which had initially possessed 0.04 mg or less M-protein per 10 mg of streptococcal cell extract showed an increase in M-protein content after successive culture in heparinised horse blood. Maximum proliferation occurred in Todd-Hewitt (TH) medium with added 0.2 per cent w/v glucose when compared with TH medium alone or TH medium with 2 per cent w/v sucrose, starch, neopeptone or normal horse serum. The M-protein of these strains did not change after the addition of either neopeptone or normal horse serum to TH medium but declined with the addition of sugars. In experiments involving phagocytosis of S equi by equine polymorphs, the percentage of polymorphs which engulfed cocci was higher with a capsule-deficient strain (69.0 +/- 11.6 per cent) than with five typical encapsulated strains (21.1 +/- 7.0 per cent to 30.9 +/- 13.3 per cent). Phagocytosis of five typical strains was greater after growth in a trypsin-containing medium than in medium devoid of trypsin. Trypsin-grown cells took longer to kill mice than did normal cells. It was concluded that M-protein was one of the factors involved in the virulence of S equi.
Publication Date: 1985-03-01 PubMed ID: 4001557
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article explores the production and biological properties of the M-protein of the Streptococcus equi bacterium. The study tested eleven strains in different growth environments, and observed changes in M-protein levels. It concluded the M-protein plays a significant role in the bacterium’s virulence.
M-Protein Production
- The researchers studied the production of the M-protein antigen of Streptococcus equi during in vitro growth in horse blood and several media.
- Out of eleven strains of S equi investigated, seven strains, which had initially possessed 0.04 mg or less M-protein, showed an increase in M-protein content after sequential culture in heparinised horse blood.
- Maximum bacterial proliferation was observed in Todd-Hewitt (TH) medium supplemented with 0.2 per cent w/v glucose, compared to TH medium alone or TH medium with other additives such as sucrose, starch, and neopeptone.
Changes in M-Protein
- There were no changes in the M-protein levels in the strains after adding either neopeptone or normal horse serum to the TH medium.
- However, there was a decrease in M-protein when sugars were added to the medium, suggesting that the presence of sugars might negatively affect the production of M-protein in S equi.
Phagocytosis of Streptococcus equi
- In phagocytosis experiments, a higher percentage of equine polymorphs (types of white blood cells) engaged in the engulfment of cocci (round bacteria) from a capsule-deficient strain versus encapsulated strains. This indicates that the capsule surrounding some bacteria can possibly inhibit the engulfment by white blood cells.
- Phagocytosis of typical strains was increased when grown in a trypsin-containing medium compared to a medium without trypsin. This suggests that trypsin may enhance the susceptibility of the bacteria to being engulfed by white blood cells.
- Cells grown in trypsin took longer to kill mice compared to normal cells, indicating that trypsin might reduce the virulence of the bacteria.
Conclusion
- The study concludes that M-protein is one of the factors involved in the virulence, or disease-causing ability, of Streptococcus equi. This suggests that modulation of M-protein production could potentially be used to control the virulence of this bacterium.
Cite This Article
APA
Srivastava SK, Barnum DA, Prescott JF.
(1985).
Production and biological properties of M-protein of Streptococcus equi.
Res Vet Sci, 38(2), 184-188.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Antigens, Bacterial
- Bacterial Outer Membrane Proteins
- Bacterial Proteins / biosynthesis
- Bacterial Proteins / immunology
- Carrier Proteins
- Culture Media
- Horse Diseases / microbiology
- Horses
- Mice
- Neutrophils / immunology
- Phagocytosis
- Species Specificity
- Streptococcal Infections / microbiology
- Streptococcus / immunology
- Streptococcus / metabolism
- Streptococcus / pathogenicity
- Virulence
Citations
This article has been cited 2 times.- Barnett TC, Scott JR. Differential recognition of surface proteins in Streptococcus pyogenes by two sortase gene homologs. J Bacteriol 2002 Apr;184(8):2181-91.
- Fischetti VA. Streptococcal M protein: molecular design and biological behavior. Clin Microbiol Rev 1989 Jul;2(3):285-314.
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