Soluble expression of OmpA from Haemophilus parasuis in Escherichia coli and its protective effects in the mouse model of infection.

Haemophilus parasols causes contagious porcine Glasser's disease leading to severe losses in the swine industry. In this study, we established an efficient Escherichia coli-based system for the expression of H. parasols major outer-membrane protein (MOMP) that has been known as a good vaccine candidate against Glasser's disease. Use of an E. coli-derived pelB leader sequence made it possible to produce recombinant MOMP (rMOMP) as the soluble forms without an additional refolding process. Using two different animal models, it was evaluated that the rMOMP was capable of inducing a significant immune response and providing protection against H. parasols infection.