Polymorphism in the LcrV Antigen Enables Immune Escape From the Protection Conferred by an LcrV-Secreting in a Pseudotuberculosis Mouse Model.

Yersinioses caused by , and are significant concerns in human and veterinary health. The link between virulence and the potent LcrV antigen has prompted the latter's selection as a major component of anti- vaccines. Here, we report that (i) the group of species encompassing and produces at least five different clades of LcrV and (ii) vaccination of mice with an LcrV-secreting only protected against strains producing the same LcrV clade as that of used for vaccination. By vaccinating with engineered LcrVs and challenging mice with strains producing either type of LcrV or a LcrV mutated for regions of interest, we highlight key polymorphic residues responsible for the absence of cross-protection. Our results show that an anti-LcrV-based vaccine should contain multiple LcrV clades if protection against the widest possible array of strains is sought.