Identification, immunogenicity, and cross‐reactivity of type IV pilin and pilin‐like proteins from Clostridium difficile

We describe nine pilin or pilin‐like protein genes, for which we introduce a coherent nomenclature, in the C. difficile R20291 genome. The nine predicted pilin or pilin‐like proteins have relatively conserved N‐terminal hydrophobic regions, but diverge at their C‐termini. Analysis of synonymous and nonsynonymous substitutions revealed evidence of diversifying selective pressure in two pilin genes. Six of the nine identified proteins were purified and used to immunize mice. Immunization of mice with each individual protein generated antibody responses that varied in titer and cross‐reactivity, a notable result given the low amino acid sequence identity among the pilins. Further studies in other small mammals mirrored our results in mice. Our results illuminate components of the C. difficile type IV pilus and help identify targets for an anti‐C. difficile vaccine. Type IV pilins of Clostridium difficile: We describe nine type IV pilins or pilin‐like proteins identified in the genome of C. difficile. These proteins have relatively conserved N‐terminal regions, but diverge at the C‐termini. Analysis of synonymous and nonsynonymous substitutions indicates two pilin proteins contain codons under positive selection. Immunization of mice with six of the pilins resulted in generation of antibodies with varying titer and crossreactivity.
Source: FEMS Immunology and Medical Microbiology - Category: Microbiology Authors: Tags: Research Article Source Type: research