Vaccination of Cattle withMycobacterium bovisCulture Filtrate Proteins and Interleukin-2 for Protection against Bovine Tuberculosis

Open Access
Publisher Website
Google Scholar
Abstract
In this study vaccines prepared from culture filtrate proteins (CFP) ofMycobacterium bovisand interleukin-2 (IL-2) were tested in cattle for their capacity to stimulate immune responses and to protect against an intratracheal challenge with virulentM. bovis. Nine groups of cattle were vaccinated with combinations of different doses of CFP and bovine IL-2 mixed with a monophosphoryl lipid A (MPL) adjuvant. An additional group was vaccinated withM. bovisBCG. Immune responses in CFP–IL-2-vaccinated animals differed from those seen in BCG-vaccinated animals by inducing high antigen-specific antibody responses and low levels of gamma interferon and IL-2 released from purified protein derivative-stimulated whole-blood cultures. In a concurrent experiment, additional animals were added to the high-dose CFP–IL-2, MPL control, and BCG groups and these expanded groups of animals were challenged intratracheally with virulentM. bovis. Although the lung lesion scores were significantly lower for both the CFP–IL-2-and BCG-vaccinated groups compared to the MPL control group, the overall level of protection was greatest for the BCG-vaccinated animals. There were more animals with extrathoracic spread of disease in the CFP–IL-2 group than in the other groups. While vaccination of cattle withM. bovisCFP gave an encouraging reduction in tuberculous lesions and did not induce a delayed-type hypersensitivity response to PPD, future CFP vaccines must prevent any extrathoracic spread of disease.