Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/15/2010
Publication Date: 12/6/2010
Citation: Barnhill, A.E., Bannantine, J.P., Chang, Y., Osman, M., Bayles, D.O., Stabel, J.R. 2010. Immunologic responses to Mycobacterium avium subsp. paratuberculosis protein cocktail vaccines in a mouse model. In: Proceedings of Conference of Research Workers in Animal Diseases, December 6-8, 2010, Chicago, Illinois. p. 15. Interpretive Summary:
Technical Abstract: Johne’s disease is a chronic granulomatous enteritis characterized by severe diarrhea, wasting and a decline in milk production caused by the bacterium Mycobacterium avium subsp. paratuberculois (MAP). The vaccine currently on the market has some limitations including a severe injection site reaction and cross-reactivity with the tuberculosis test. Our goal is to identify candidates for a better Johne’s vaccine. Four MAP proteins were arrayed in 4 cocktails of 3 proteins each and then injected subcutaneously in 6-week-old Balb/c mice. MAP proteins were chosen based on IFN-gamma responses and antigenicity. This was followed by a boost 3 weeks later and IP challenge with live MAP 2 weeks after the final boost. Serum and tissues were collected 3 months later for analysis. Splenocyte culture supernatants were harvested for measurement of cytokine secretion and cells were harvested for flow cytometric analyses. All MAP protein vaccinate groups significantly reduced the recovery of live MAP from the ileum, while cocktails 2 and 3 showed a trend towards decreasing colonization in the liver. No significant differences were seen in mesenteric lymph node or spleen. Stimulation of splenocytes with a whole cell sonicate of MAP upregulated IFN-g and IL-23 secretion in all treatment groups, regardless of vaccination. Interestingly, IL-4 was moderately downregulated for vaccinates compared to control infected mice. An increase in total CD25 expression was noted for 3 of the 4 protein vaccinate groups upon stimulation of splenocytes with MAP, with this effect becoming more significant within CD4CD25 and CD8CD25 subpopulations. Vaccination with cocktails of MAP proteins affected the host immune response after MAP challenge and decreased the amount of organisms in some tissues. Further analysis of these and other MAP proteins are still needed.