The Order of Prime-Boost Vaccination of Neonatal Calves with <i>Mycobacterium bovis</i> BCG and a DNA Vaccine Encoding Mycobacterial Proteins Hsp65, Hsp70, and Apa Is Not Critical for Enhancing Protection against Bovine Tuberculosis

Abstract

Priming neonatal calves at birth with a Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccine and boosting with a DNA vaccine consisting of plasmids encoding mycobacterial antigens Hsp65, Hsp70, and Apa or the reverse prime-boost sequence induced similar levels of protection against experimental challenge with Mycobacterium bovis. When M. bovis was isolated from a thoracic lymph node following challenge, the two groups of calves given the prime-boost regimen had significantly lower numbers of M. bovis isolates than those vaccinated with BCG alone. These observations suggest that the exact sequence of administration of a prime-boost vaccination regimen in a neonatal animal model is not critical to the development of immunity.