Submitted to: Infection and Immunity
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/6/2005
Publication Date: 10/1/2005
Citation: Huntley, J.F., Stabel, J.R., Paustian, M., Reinhardt, T.A., Bannantine, J.P. 2005. Expression Library Immunization Confers Protection against Mycobacterium avium subsp. paratuberculosis Infection. Infection and Immunity. 73(10):6877-6884. Interpretive Summary: Johne's disease is a chronic, debilitating intestinal disorder in cattle characterized by diarrhea, reduced feed intake, weight loss and death. Cattle usually become infected as young calves by ingesting feces containing the causative bacteria. However, symptoms of disease do not usually present themselves until the animals reach 3 to 5 years of age or even older. During this time the animal is infected and may be shedding the organism in its feces without showing any clinical signs of disease. In addition to reduced production by these animals through reduced milk production, they also present a potential infective threat to the rest of the herd. Johne's disease is difficult to diagnose and therefore to control. There is one commercial vaccine available for use in the US. However, the vaccine does not prevent infection it merely reduces signs of clinical disease and fecal shedding of the bacterium. The present study was designed to find genes that may be protective against infection and could be considered as vaccine candidates.
Technical Abstract: Paratuberculosis (Johne's disease) is a chronic granulomatous infection of cattle, caused by the intracellular bacterium, Mycobacterium avium subsp. paratuberculosis, for which there is no effective vaccine. In an effort to identify protective M. avium subsp. paratuberculosis sequences, a genomic DNA expression library was generated and subdivided into pools of clones. Eleven of the clone pools were evaluated to determine DNA vaccine efficacy by immunizing mice via gene gun delivery and challenging with live, virulent M. avium subsp. paratuberculosis. Four clone pools demonstrated a significant (P < 0.05) of M. avium subsp. paratuberculosis infection in mice when compared to other clone pools and nonvaccinated, infected control mice. This study demonstrates that M. avium subsp. paratuberculosis DNA sequences, when delivered by a gene gun, can protect mice against paratuberculosis infection.