Vaccination of neonatal calves withMycobacterium bovisBCG induces protection against intranasal challenge with virulentM. bovis

Abstract

SummaryVaccination of neonates with Mycobacterium bovis bacillus Calmette-Guérin (BCG) may be a strategy that overcomes reduced vaccine efficacy associated with exposure to environmental mycobacteria in humans and cattle. Preliminary comparisons indicated that 2-week-old calves produced an immune response to vaccination at least as intense as that observed in adults. Subsequently, five gnotobiotic hysterotomy derived calves aged 1 day were inoculated with BCG and 3 months later were challenged intranasally with virulent M. bovis . The number of tissues with lesions and the pathological extent of these lesions was reduced significantly in vaccinates. Furthermore, lesions were evident in the lung or associated chest lymph nodes of four of five controls but none of five vaccinates. BCG vaccination reduced significantly the level of bacterial colonization. However, lesions in the head associated lymph nodes were observed in three of five BCG-vaccinated cattle. Levels of interferon gamma (IFN-g g g g ) detected by enzyme-linked immunosorbent assay (ELISA) or enzyme-linked immunospot (ELISPOT) in individual vaccinated animals at challenge did not correlate with subsequent resistance and in general immune responses post-challenge were lower in vaccinated calves. Low IL-10 responses were evident but IL-4 was not detected. Responses to ESAT-6 and/or CFP-10 were evident in four of four control calves that had lesions. Two of the BCG vaccinates with lesions did not produce a response to ESAT-6 and CFP-10, indicating that these antigens did not distinguish vaccinated immune animals from vaccinated animals with lesions. Overall, vaccination of neonatal calves with BCG induced significant protection against disease and has potential as a strategy for the reduction of the incidence of bovine tuberculosis.

Vaccination of white-tailed deer (Odocoileus virginianus) with Mycobacterium bovis bacillus Calmette Guerín

“…Vaccination of neonatal calves has been used as a strategy to avoid prior sensitization by saprophytic environmental mycobacteria. Indeed, vaccination of neonatal calves induces a higher level of immunity than that seen in calves vaccinated at 5-6 months of age [44,[51][52][53]. A similar strategy could be feasible for vaccination of captive white-tailed deer, but would be problematic for vaccination of free-ranging white-tailed deer.…”

Immunity and Vaccination against Tuberculosis in Cattle

“…Vaccination of neonatal calves (<1 month of age) induced higher levels of protection than those vaccinated at 6 months of age [42,43]. This may be explained by the high numbers of circulating NK and γδ T cells in young calves which may lead to a robust innate response following vaccination and administration of BCG prior to presensitisation with environmental mycobacteria.…”

Tuberculosis Vaccines and Prevention of Infection

“…Although low M. bovis challenge doses would better mimic natural transmission, to ensure uniform outcome, typical doses involve 2 ϫ 10 3 to 5 ϫ 10 3 CFU given intratracheally. In the majority of studies, protection has been characterized as reductions in M. bovis-induced pathology and bacterial loads rather than prevention or clearance of infection (144,145). Although there is variability within groups, there are reports suggesting that some BCG-vaccinated cattle lacked evidence of disease, even in the case of high-dose M. bovis challenge (146,147).…”