265 Changes in Cytokine concentrations among Bos indicus and Bos indicus-influenced cattle after vaccination with a combination or individual modified live viral vaccine.

Abstract Combination modified live viral (MLV) vaccines have previously been reported to cause damage to the integrity of the corpus luteum and negatively affect estrous cyclicity and reproductive success in cattle, but when cows were vaccinated with a MLV that contained only Bovine Viral Diarrhea Virus (BVDV) no abnormal cycles were observed. Among animals that had an abnormal cycle after vaccination with a MLV specific proinflammatory cytokines were increased. The objective of this study was to determine changes in cytokine populations post-vaccination among animals vaccinated with a combination MLV vaccine, a MLV vaccine for Infectious Bovine Rhinotracheitis (IBR) only, a combination killed vaccine, or not vaccinated. Brahman and F1 Brahman cattle having normal estrous cycles were administered PGF2α to regress the corpus lutea on d-3. Animals (d0) were immunized with one of four treatments: 1) combination MLV containing both BVDV and IBR (BVDV+IBR; n=5), 2) MLV containing only IBR (IBR; n=5), 3) killed combination viral vaccine containing both BVDV and IBR (IVV; n=5), or 4) sterile saline (CON; n=3). Blood samples were collected via venipuncture on d-3, 0, 3, 5, 11, 18, 21, 28, 34, 48, and 62 and plasma was isolated from each sample. All plasma samples were evaluated for IFN-γ, IL-1α, IL-1β, IL-4, IL-6, IL-8, IL-10, IL-17A, MIP-1α, MIP-1β, IL-36RA, IP-10, MCP-1, TNF-α, and VEGFA concentrations using the MILLIPLEX Bovine Cytokine/Chemokine Magnetic Bead Panel. Differences in cytokine concentrations between treatments were analyzed as repeated measures using PROC MIXED procedure in SAS (v9.4) with treatment, time, and treatment by time included in the experimental model. There was an effect of treatment on IL-1α, (P= 0.002), IL-1β (P< 0.0001), IL-4 (P< 0.0001), IL-6 (P= 0.01), IL-10 (P< 0.0001), IL-17A (P= 0.005), IP-10 (P= 0.0002), MCP-1 (P= 0.0008), MIP-1α (P< 0.001), and TNF-α (P= 0.003). Specifically, IL-1α was decreased in all vaccinated animals compared to CON; IL-1β was increased in BVDV+IBR compared to all other treatments; IL-10, IP-10, and MCP-1 were decreased in BVDV+IBR compared to all other treatments; IL-4 and IL-6 increased in IVV compared to all other treatments; and TNF-α decreased in both BVDV+IBR and IVV compared to both CON and IBR. Overall, treatment had a significant effect on cytokine concentrations following vaccination and may lead to a better understanding on why certain vaccines negatively impact reproductive success. USDA is an equal opportunity provider and employer.