[Bacterial pathogen associated molecular pattern and superantigens indirectly induce the accelerated death of bovine...

Area of Science:

• Immunology
• Cell Biology

Background:

• Pathogen-associated molecular patterns (PAMPs) and bacterial superantigens are known to affect mononuclear cells (MNC) and macrophages.
• The impact of PAMPs, specifically non-methylated CpG motifs, on neutrophilic granulocytes (PMN) has received less attention.

Purpose of the Study:

• To investigate the direct and indirect effects of PAMPs and the superantigen SEA on the survival rate of bovine PMN.
• To determine if CpG motifs, LPS, and SEA influence PMN viability alone or in combination with MNC or macrophages.

Main Methods:

• Exposure of pure bovine PMN to various PAMPs (CpG motifs, GpC motif, LPS) and SEA.
• Co-culture experiments involving PMN with MNC or in vitro generated macrophages (MdM).
• Assessment of PMN viability following stimulation with single agents or combinations thereof, comparing autologous and allogeneic settings.

Main Results:

• Pure PMN viability was not affected by CpG motifs, GpC motif, LPS, or SEA alone.
• In the presence of MNC or MdM, these stimuli induced accelerated PMN death.
• Combinations of CpG motifs with LPS or SEA showed additive or supra-additive effects, reducing PMN viability to 28-36% in MNC/PMN co-cultures.
• Both the stimulated MNC/MdM population and the individual state of PMN influenced the extent of PMN death.

Conclusions:

• CpG motifs, other PAMPs, and superantigens indirectly reduce the viability of bovine neutrophilic granulocytes.
• These interactions diminish the functional capacity of PMN, a crucial effector cell population.
• The combined action of PAMPs and superantigens with MNC/macrophages significantly impacts PMN survival.