Immune phenotype is differentially affected by changing the type of bovine respiratory disease vaccine administered at revaccination in beef heifers

Abstract

During preconditioning, modified-live vaccines are frequently administered to beef calves before weaning. In this study, we began to characterize the immune phenotype of calves that received a modified-live vaccination at 3-4 months of age and then either received the same modified-live or an inactivated vaccine upon arrival at the feedlot (weaning) and 28 days post-arrival (booster). Innate and adaptive immune measures were assessed before revaccination and 14 and 28 days post. Heifers that received three doses of the modified-live vaccine exhibited a relatively balanced immune response based on increases in mean cytokine concentrations (IL-17, IL-21) and total immunoglobulin-G (IgG) and subsets IgG1 and IgG2, which are related to both arms of the adaptive immune system. Conversely, heifers that received one dose of modified live and two doses of the inactivated vaccine had a more robust neutrophil chemotactic response and greater serum-neutralizing antibody titers, resulting in an enhanced innate immune and a skewed proinflammatory response. These results indicate that the revaccination protocol used after initial vaccination with a modified-live vaccine differentially influences the immune phenotype of beef calves, with three doses of modified live inducing potentially immune homeostasis and a combination of modified live and inactivated vaccines inducing a skewed immune phenotype. However, more research is needed to determine the protective efficacy of these vaccination protocols against disease.

Keywords: bovine respiratory disease; cattle; cytokines; immunoglobulins; serum-neutralizing titers; vaccine.

Figure 1

Effect of vaccine treatment on percentage of neutrophils (A), percentage of lymphocytes (B) and the ratio of neutrophils to lymphocytes (C) at 14 and 28 days post-revaccination (PRv) and post-booster (PB), n = 28 heifers. Data are expressed as means ± standard error of the mean. Means with * between treatments within a day differ at p < 0.05. Treatment × Day = p = 0.001 for Neutrophil %, p = 0.003 for Lymphocyte %, p = 0.003 for Neutrophil to Lymphocyte ratio.

Figure 2

Effect of vaccine treatment by day on serum neutralization antibody titers for Parainfluenza 3 (A) at 14 and 28 days post-revaccination (PRv) and post-booster (PB) Treatment × Day interactive = p < 0.0001. No effect of vaccine treatment by day was found for serum neutralizing antibody titers for Infectious Bovine Rhinotracheitis (B), Bovine Viral Diarrhea Virus type 1a (C), 1b (D) or 2 (E), or Bovine Respiratory Syncytial Virus (F). Data are expressed as means ± standard error of the mean. Means between treatments within a day with * differ at p < 0.05.

Figure 3

Effect of vaccine treatment by day on serum concentrations (ng/mL) of immunoglobulin G1 (A), immunoglobulins G2 (B), and total immunoglobulin G (C) and the ratio of Immunoglobulin G1:Immunoglobulin G2 ratio (D) at 14 and 28 days post-revaccination (PRv) and post-booster (PB), n = 28 heifers. Data are expressed as means ± standard error of the mean. Means with * between treatments within a day differ at p < 0.05 and means with # differ at p < 0.10. Treatment × Day = p < 0.0001 for IgG1, p < 0.05 for IgG2, p = 0.002 for Total IgG, and p > 0.65 for the Ratio of IgG1 to IgG2.