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Enhancement of Streptococcus faecalis infection and complement depletion in yeast-treated mice
Abstract:
Enhancement of Streptococcus faecalis infection and lowering of the complement level have been demonstrated in mice injected with a heat-treated suspension of baker's yeast (Saccharomyces cerevisiae). The leucocyte response to the infection was not affected. The yeast preparation showed, in vitro, an intense anti-complementary activity on mouse serum and interfered with the microbial killing function of the mouse peritoneal macrophages. No significant stimulation of the growth of S. faecalis in vitro in the presence of the yeast was observed. The enhancement of the infection in mice treated with the yeast seems to be mediated, mainly, by complement depletion.
Insights
Baker's yeast (Saccharomyces cerevisiae) enhances Streptococcus faecalis infections in mice by depleting complement levels. This yeast preparation also inhibits macrophage antimicrobial activity, suggesting a key role for complement in the observed infection enhancement.
Area of Science:
- Immunology
- Microbiology
- Mycology
Background:
- Baker's yeast (Saccharomyces cerevisiae) is commonly used in various applications.
- Streptococcus faecalis is a known pathogen.
- The complement system plays a crucial role in innate immunity and host defense against bacterial infections.
Purpose of the Study:
- To investigate the effect of heat-treated baker's yeast on Streptococcus faecalis infection in a mouse model.
- To elucidate the mechanisms underlying the observed changes in infection susceptibility.
- To assess the impact of yeast on host immune responses, including complement levels and macrophage function.
Main Methods:
- Mice were injected with heat-treated baker's yeast suspension.
- Infection levels of Streptococcus faecalis were monitored.
- Complement levels in mouse serum were measured.
- In vitro assays were performed to assess yeast's effect on serum complement activity and macrophage microbial killing.
- Yeast's effect on S. faecalis growth in vitro was evaluated.
Main Results:
- Baker's yeast administration enhanced Streptococcus faecalis infection in mice.
- A significant decrease in complement levels was observed in yeast-treated mice.
- Yeast preparation exhibited potent anti-complementary activity in vitro.
- The yeast interfered with the microbial killing capacity of mouse peritoneal macrophages.
- No significant in vitro stimulation of S. faecalis growth by yeast was detected.
- Leukocyte response to infection remained unaffected.
Conclusions:
- Heat-treated baker's yeast enhances Streptococcus faecalis infection in mice.
- Complement depletion is the primary mechanism mediating the enhanced infection.
- Yeast's anti-complementary activity and interference with macrophage function contribute to increased susceptibility to infection.