Objective—To determine whether maternally derived antibodies interfere with the mucosal immune response following intranasal (IN) vaccination of newborn calves with a multivalent modified-live virus vaccine.
Design—Randomized controlled clinical trial.
Animals—23 newborn Holstein bull calves.
Procedures—Calves received colostrum and were assigned to group A (unvaccinated control calves), group B (IN vaccination on day 0), or group C (IN vaccination on days 0 and 35). Serum and nasal secretion sample (NSS) titers of antibodies specific for bovine herpesvirus 1, bovine viral diarrhea virus 1, and bovine viral diarrhea virus 2; WBC counts; and NSS interferon concentrations were determined up to day 77.
Results—Calves had high serum titers of maternally derived antibodies specific for vaccine virus antigens on day 0. High IgA and low IgG titers were detected in NSSs on day 0; NSS titers of IgA decreased by day 5. Group B and C NSS IgA titers were significantly higher than those of group A on days 10 through 35; group C IgA titers increased after the second vaccination. Serum antibody titers decreased at a similar rate among groups of calves. Interferons were not detected in NSSs, and calves did not develop leukopenia.
Conclusions and Clinical Relevance—IN vaccination of newborn calves with high concentrations of virus-neutralizing antibodies increased NSS IgA titers but did not change serum antibody titers. Revaccination of group C calves on day 35 induced IgA production. Intranasal vaccination with a modified-live virus vaccine was effective in calves that had maternally derived antibodies.
To compare immune responses induced by 2 commercially available vaccines with a bovine herpesvirus type 1 (BHV1) component following intranasal (IN) administration to colostrum-fed calves.
90 male Holstein calves (ages, 5 to 14 days).
In a randomized complete block design, each calf received 2 mL (1 mL/nostril) of vaccine A (n = 30), vaccine B (30), or saline (0.9% NaCl) solution (30) on day 0. Blood samples were collected for determination of serum anti-BHV1 IgG titer, and nasal fluid (NF) samples were collected for determination of interferon (IFN)-α and IFN-γ concentrations and for secretory IgA titers against BHV1, Mannheimia haemolytica, and Pasteurella multocida at predetermined times for 42 days after vaccination.
All calves were seropositive for anti-BHV1 IgG, and the mean anti-BHV1 IgG titer did not differ significantly among the 3 groups at any time. Both vaccines induced significant transient increases in NF IFN-α and IFN-γ concentrations. On day 5, mean IFN-α concentration and the proportion of calves with detectable IFN-α concentrations for the vaccine A group were significantly greater than those for the vaccine B and control groups. On day 42, the mean NF anti–P multocida IgA titers for both vaccine groups were significantly greater than that of the control group.
CONCLUSIONS AND CLINICAL RELEVANCE
Both vaccines induced innate and acquired immune responses in calves with colostral antibodies. The magnitude of the IFN-α response and proportion of calves with detectable IFN-α differed between the 2 vaccine groups. Both vaccines appeared to enhance the IgA response against P multocida.