Submitted to: Bovine Practitioner Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/29/2011
Publication Date: 9/1/2011
Citation: Pires, A.F., Hoar, B.R., Sischo, W.M., Olsen, S.C. 2011. Serological response to administration of Brucella abortus strain RB51 vaccine in beef and dairy heifers, using needle-free and standard needle-based injection systems. Bovine Practitioner Journal. 45(2):1-6. Interpretive Summary: Brucella abortus is a disease that causes abortion and associated economic losses in infected cattle herds. The National Brucellosis Eradication program has nearly eradicated B. abortus from cattle within the U.S., but its persistence in wildlife reservoirs pose a risk reintroduction. Needle-free vaccination systems may be safer than needle vaccination and may target cells which induce more protective immune responses. In this pilot study, we evaluated immunologic responses to brucellosis vaccination delivered via needle or needle-free systems in heifers. Our data suggest this needle-free delivery induces similar antibody responses after vaccination and does induce some cell-mediated immunity as measured by gamma interferon production. Identification of a safer and more economic method of brucellosis vaccination would benefit both producers and regulatory personnel. If needle-free vaccination induced more protective immune responses, this would be of benefit in protecting cattle herds against brucellosis, and assist the National Brucellosis Eradication Program.
Technical Abstract: The purpose of this study was to compare immunologic responses of heifers vaccinated with 10**10 colony-forming units (CFU) of Brucella abortus strain RB51 (SRB51) by standard needle-and-syringe system or a needle-free injection system. Heifers were randomly assigned to control and vaccination groups. Humoral immune responses were evaluated at 0 and 30 days after vaccination and in vitro interferon production was evaluated at day 90. Administration method did not affect serologic responses to SRB51 at day 30 (P>0.05). Gamma interferon production at day 90 did not differ between the sham and vaccinated groups or between vaccinated groups. Our data demonstrate that antibody responses of heifers after SRB51 vaccination are similar for needle-free and standard needle-and-syringe delivery. Needle-free injection system may be an alternative to standard needle injection although additional challenge studies need to be done to fully evaluate the efficacy of needle-free vaccination in protecting against brucellosis.