Effect of fetal bovine serum and heat-inactivated fetal bovine serum on microbial cell wall-induced expression of procoagulant activity by equine and canine mononuclear cells in vitro.

This research article explores how fetal bovine serum (FBS) and heat-inactivated FBS (HI-FBS) affect the response of equine and canine mononuclear cells to substances deemed foreign by the immune system. The results suggest that FBS increases the activity of cells that promote blood clotting, but this effect is not seen when the FBS is heat-inactivated. Meanwhile, the presence of HI-FBS seems to boost the sensitivity of these cells to bacterial and yeast cell wall components.

Research Methodology

• The study utilized mononuclear cells from 18 horses and 3 dogs.
• These cells were incubated with different concentrations of FBS, HI-FBS, lipopolysaccharide (LPS, a component of bacterial cell walls), zymosan (a component of yeast cell walls), polymyxin B (an antibiotic), and anti-LPS-binding protein monoclonal antibody or combinations of these constituents.
• A 1 stage recalcification assay, a lab test used to assess coagulation, was used to measure procoagulant activity.

Key Findings

• FBS added to the cells’ media notably enhanced their procoagulant activity, with 1% and 10% FBS stimulating equine and canine cells, respectively.
• The simultaneous presence of FBS and polymyxin B did not lessen this impact, indicating that this stimulation was not due to LPS contamination.
• Introduction of HI-FBS to the media did not stimulate the cells’ procoagulant activity, and it also amplified the sensitivity of equine cells to LPS.
• This heightened LPS sensitivity dropped by 40% under the influence of a monoclonal antibody targeting the human version of LPS-binding protein.
• Higher concentration of HI-FBS enhanced the procoagulant activity of canine cells when induced by LPS or zymosan.

Conclusion

• The production of procoagulant activity in equine and canine mononuclear cells was notably increased by the addition of FBS, while heat inactivation of FBS removed this effect.
• Heat inactivation, however, did not nullify the function of serum proteins involved in enhancing the activity of cells treated with LPS and zymosan.
• The findings suggest HI-FBS can be used as a source of serum proteins that enhance the sensitivity of mononuclear cells to bacterial and yeast cell wall components.