Detection of antibodies against the Mycoplasma bovis glyceraldehyde-3-phosphate dehydrogenase protein in beef cattle.

Diseases caused by Mycoplasma bovis are an important source of financial losses for beef and dairy cattle producers. Antigenic variation in M. bovis hinders the production of effective vaccines and although there are few vaccines available, they are prepared from bacteria obtained from few isolates potentially limiting their effectiveness. Thus, to develop a vaccine that protects against all M. bovis isolates, it is necessary to use a common antigen that shows less or no antigenic variation. We have isolated the gap gene of M. bovis encoding for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and showed that cattle colonized with M. bovis were able to mount an immune response to GAPDH. Using restriction-fragment length polymorphism (RFLP) of several M. bovis gap genes amplified by PCR, we were able to detect small intragenic variations that allowed us to classify the genes into two groups without changing the antigenic makeup of the proteins. The immune responses detected in cattle combined with the antigenic conservation of the proteins suggest that the M. bovis GAPDH protein could be a potential target for development of a more effective vaccine against all M. bovis isolates.