Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 4/18/2008
Publication Date: 4/18/2008
Citation: Chen, J., Kathaperumal, K., Mcdonough, S., Akey, B., Huntley, J., Bannantine, J.P., Chang, Y. 2008. Vaccination with rMAP Proteins Induces Protection in a Goat Model Against Infection by Oral Challenge [abstract]. Johne's Disease Integrated Program. p. 16. Interpretive Summary:
Technical Abstract: Four recombinant antigens (85A, 85B, Superoxide dismutase [SOD] and a fusion polypeptide [74F] of Mycobacterium avium subsp paratuberculosis (MAP) were used along with adjuvant dimethydioctadecyl ammonium bromide (DDA) to assess the differential immune responses and protective efficacy in goat against MAP challenge. Twenty five goat kids from Johne’s disease- negative herds were divided into three groups. Group I (8 kids) animals were immunized with the four antigens along with adjuvant DDA. Group II (8 kids) animals were administered with the four antigens without the adjuvant. Group III (9 kids) animals received only the adjuvant. The immunizations were repeated three weeks after the primary immunization and all the animals were challenged three weeks after the booster. All the four antigens induced peak serum antibody response at 6 weeks after the primary vaccination. Significant, antigen specific lymphoproliferation was observed in the vaccinated animals 3 weeks after the booster immunization. This response increased further at 4 weeks after the booster. Similarly, antigen specific IFN-gamma response was found to increase in the vaccinated animals 3 weeks after the booster vaccination. The response was significantly higher for 85A than the other three antigens. CD4+ T cell populations were higher in the vaccinated animals from 6 to 10 weeks after vaccination than the control animals. Again, 85A specific CD4+ T cell populations were found to be significantly higher than 85B, SOD and 74F antigens. At necropsy (32 weeks after challenge), we found that one animal in group I, five animals in group II and all the nine animals in group III were positive for MAP organisms from one or more tissues. In group I, a single animal had MAP (3CFU) isolated from the ileum. In group II, among the five culture positive animals, one animal had 115CFU in mesenteric lymph node and 118 CFU in ileum, whereas the other four animals had only less than 10CFU. In group III control animals, majority of the positive animals had at least 5 tissues positive for MAP with >300 CFU (too many to count). Preliminary data generated in our study indicated that all the four recombinant antigens induced good Th1 response and conferred protection against MAP infection in a goat model.