Pilins of Bacteroides nodosus: molecular basis of serotypic variation and relationships to other bacterial pilins

Pili of Bacteroides nodosus , the causative organisms of ovine footrot, are the major host-protective immunogen in current footrot vaccines. In vaccination trials, purified pili alone provide excellent protection against homologous serotypic challenge. Pilus-based protection is, however, confined within each serogroup, necessitating the inclusion of representatives from all major serogroups of B. nodosus in broad-spectrum vaccines. To define the sites and basis of antigenic variation in B. nodosus pilins and to determine the regions essential for the structural integrity, amino acid sequences of pilins from members of eight major serogroups of B. nodosus have been compared with each other and with pilins from other bacterial species.