Effects of concurrent administration of modified live viral vaccines with RB51 on immune responses to RB51

Authors: CRAWFORD, LAUREN - Oak Ridge Institute For Science And Education (ORISE); FALKENBERG, SHOLLIE - Auburn University; Putz, Ellie; Olsen, Steven; Boggiatto, Paola

Submitted to: Frontiers in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/16/2023
Publication Date: 2/16/2023
Citation: Crawford, L., Falkenberg, S., Putz, E.J., Olsen, S.C., Boggiatto, P.M. 2023. Effects of concurrent administration of modified live viral vaccines with RB51 on immune responses to RB51. Frontiers in Veterinary Science. 10. eArticle 1105485. https://doi.org/10.3389/fvets.2023.1105485.
DOI: https://doi.org/10.3389/fvets.2023.1105485

Interpretive Summary: Bovine brucellosis, cause by infection with Brucella abortus, causes reproductive failure in cattle, has a major economic impact to producers, and as a zoonoses, it is a disease of public health concern. In the field, it is common practice for multiple vaccines to be administered at the time of RB51 vaccination. This is termed co-vaccination or concomitant vaccination. Understanding the host immune response, and more specifically, the T cell response to vaccination is critical for the development of vaccine strategies. Our goal was to evaluate the impact the use of co-vaccination with a modified live vaccine may have on the effects of RB51 specific immune responses. We were able to detect and characterize RB51-specific responses in single vaccinates and combo vaccinates and compare their responses directly for alterations elicited by co-vaccination. The work presented here will be of interest to researchers in the field of brucellosis as well as others studying infectious diseases of cattle.

Technical Abstract: Brucella abortus is a gram negative, zoonotic pathogen that can cause abortions and stillbirths in the cattle industry and has contributed to significant economic losses to cow-calf producers. Cell mediated immunity (CMI) is an important component of the immune response associated with protection against Brucella abortus and other intracellular pathogens. Brucellosis and viral modified live vaccines (vMLV) are licensed individually but may be used concurrently under field conditions. The goal of this study was to characterize immune responses to RB51 vaccination and determine the effect of concurrent vaccine administration. Peripheral blood mononuclear cells (PBMC) from non-vaccinated cattle and cattle vaccinated with either Brucella abortus strain RB51, a vMLV or both RB51 and a vMLV vaccine were isolated. The frequency of CD4+, CD8+ and 'd+ T cell populations within PBMC, and the frequency of interferon gamma (IFN-') production within these cell types was characterized via flow-cytometry. Although immune responses were greatest in PBMC from cattle vaccinated with only RB51, cattle vaccinated with both RB51 and vMLV demonstrated strong T cell responses associated with protective immunity. Data suggests a lack of significant biological differences between the groups in protective immune responses. Collectively, our data demonstrated a lack of vaccine interference following concurrent administration of vMLV and RB51. Although concurrent administration of individually licensed vaccines may influence immune responses and contribute to vaccine interference, potential vaccine combinations should be evaluated for biological effects.