Efficacy and immunogenicity of Mycobacterium bovis RD1 against aerosol M. bovis infection in neonatal calves

• Published in: Vaccine Vol. 27; no. 8; pp. 1201 - 1209
• Main Authors: Waters, W Ray, Palmer, Mitchell V, Nonnecke, Brian J, Thacker, Tyler C, Scherer, Charles F Capinos, Estes, D Mark, Hewinson, R Glyn, Vordermeier, H Martin, Barnes, S Whitney, Federe, Glenn C, Walker, John R, Glynne, Richard J, Hsu, Tsungda, Weinrick, Brian, Biermann, Karolin, Larsen, Michelle H, Jacobs Jr, William R
• Format: Journal Article
• Language: English
• Published: 01.02.2009
• Subjects: Mycobacterium bovis
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2008.12.018

An attenuated Mycobacterium bovis RD1 deletion (RD1) mutant of the Ravenel strain was constructed, characterized, and sequenced. This M. bovis RD1 vaccine strain administered to calves at 2 weeks of age provided similar efficacy as M. bovis bacillus Calmette Guerin (BCG) against low dose, aerosol challenge with virulent M. bovis at 3.5 months of age. Approximately 4.5 months after challenge, both RD1- and BCG-vaccinates had reduced tuberculosis (TB)-associated pathology in lungs and lung-associated lymph nodes and M. bovis colonization of tracheobronchial lymph nodes as compared to non-vaccinates. Mean central memory responses elicited by either RD1 or BCG prior to challenge correlated with reduced pathology and bacterial colonization. Neither RD1 or BCG elicited IFN-g responses to rESAT-6:CFP-10 prior to challenge, an emerging tool for modern TB surveillance programs. The RD1 strain may prove useful for bovine TB vaccine programs, particularly if additional mutations are included to improve safety and immunogenicity.