Human Toll-like receptor activation by pathogenic Arcobacter species

Area of Science:

• Immunology
• Microbiology
• Bacteriology

Background:

• Rising human infections by Arcobacter spp. necessitate understanding their virulence mechanisms.
• Arcobacter butzleri's ability to induce proinflammatory cytokines in macrophages is known, but the underlying mechanism remains unclear.
• Investigating the innate immune response to pathogenic Arcobacter spp. is crucial.

Purpose of the Study:

• To investigate the human innate immune response triggered by pathogenic Arcobacter species.
• To study the activation of human Toll-like receptors (TLRs) by different Arcobacter species.
• To explore the correlation between TLR activation and Arcobacter pathogenicity.

Main Methods:

• Assessing the activation of human Toll-like receptors (TLRs) by various Arcobacter species.
• Utilizing motility assays and electron microscopy to analyze flagella presence and structure.
• Performing flagellin amino acid sequence alignment to compare TLR5 recognition sites.

Main Results:

• Arcobacter skirrowii activated all tested TLRs, while A. cryaerophilus activated TLR1/2, TLR4, and TLR2/6.
• Arcobacter butzleri showed minimal TLR activation (TLR2/6 and TLR1/2).
• Only A. skirrowii's flagellum activated TLR5, attributed to greater amino acid similarity with Salmonella flagellin for TLR5 recognition.

Conclusions:

• TLR activation by Arcobacter species is species-specific.
• A potential correlation exists between the pattern of TLR activation and the pathogenicity of Arcobacter species.
• Understanding TLR activation pathways provides insights into Arcobacter virulence and host immune response.