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Influence of the thymus and the normal microflora on the plasma fibronectin concentration in mice
1Institute of Microbiology, Semmelweis University Medical School, Budapest. Hungary.
Abstract:
The plasma fibronectin (pFN) concentration (cc) of untreated genetically or artificially athymic mice, or treated with TP-4 (thymus hormone sequence analog synthetic preparation) showed no significant difference from their euthymic or untreated controls. In contrast, the pFN cc in mice with different microbiological state showed significant alterations; the highest level occurred in conventional mice and the lower level in germfree mice was increased by bacterial monocontamination. The alternation from SPF into conventional state in nude mice also resulted in the increase of the pFN cc. Based on these and earlier results, it was assumed that the pFN cc is independent from the presence or absence of the thymus, but it depends on the actual microbiological state of the macroorganism.
Insights
Plasma fibronectin levels are unaffected by thymus presence but significantly altered by the microbiological state. Conventional mice have higher levels than germfree mice, which increase with bacterial exposure.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- Plasma fibronectin (pFN) is a crucial protein in immune responses and tissue repair.
- The influence of the thymus and the microbiome on pFN levels is not fully understood.
Purpose of the Study:
- To investigate the impact of thymus absence (athymic mice) and varying microbiological states on plasma fibronectin concentration (pFN cc).
- To determine if pFN cc is dependent on the thymus or the host's microbiome.
Main Methods:
- Assessed pFN cc in genetically or artificially athymic mice and euthymic controls.
- Evaluated pFN cc in mice with different microbiological states: germfree, conventional, and specific pathogen-free (SPF).
- Administered TP-4 (thymus hormone sequence analog synthetic preparation) and bacterial monocontamination to assess effects on pFN cc.
Main Results:
- No significant difference in pFN cc was observed between athymic and euthymic mice, regardless of TP-4 treatment.
- Significant alterations in pFN cc were found based on microbiological status, with conventional mice showing the highest levels and germfree mice the lowest.
- Bacterial monocontamination increased pFN cc in germfree mice, and transitioning nude mice from SPF to a conventional state also elevated pFN cc.
Conclusions:
- Plasma fibronectin concentration is independent of the presence or absence of the thymus.
- Plasma fibronectin concentration is significantly influenced by the host's microbiological state.
- The microbiome plays a critical role in regulating plasma fibronectin levels in mammals.