Computational and structural analysis of FliC–TLR5 interaction, a key for immunity against Clostridium chauvoei infection

Deciphering intricacies of the immune response to Clostridium chauvoei is critical for developing effective vaccines and therapeutic strategies against blackleg in ruminants. Flagellin (FliC), a key virulence factor, facilitates bacterial motility and acts as a pathogen-associated molecular pattern (PAMP), eliciting host immune responses through Toll-like receptor 5 (TLR5). Building on this, a computational analysis of FliC from diverse C. chauvoei strains was conducted to identify conserved immunogenic regions and assess its interaction with TLR5 in Bos taurus and Ovis aries. Multiple sequence alignment revealed conserved N- and C-terminal domains flanking a hypervariable central region. Immuno-informatic analysis predicted 13 B-cell epitopes, two of which were highly conserved and represent promising candidates for cross-protective vaccine development. Structural models of FliC and TLR5 receptors were predicted and validated for reliability. Subsequent docking and molecular dynamics simulations demonstrated a stronger and more stable interaction between FliC and Bos taurus TLR5, supported by favourable binding energy (−69.85 ± 3.70 kcal/mol), highlighting species-specific immune recognition. These findings establish FliC as a potential subunit vaccine candidate and provide insights into host-specific immune responses, contributing to the development of flagellin based immuno-therapeutics to combat blackleg disease in ruminants.