Characterization of the cellular immune response to Brucella abortus RB51 vaccination and boost in cattle

Abstract

Abstract Brucellosis is a bacterial zoonosis caused by organisms belonging to the genus Brucella. In domestic species (cattle, goats, sheep) brucellosis results in infertility and reproductive loss, while in humans, brucellosis results in a chronic debilitating disease. Worldwide, brucellosis is a significant source of financial loss and a major public health concern. Bovine brucellosis, as caused primarily by Brucella abortus, is an economically important cause of reproductive loss in cattle. While vaccines are available for cattle, safe and effective vaccines for humans (and other domestic species) are not available. Currently, most of the knowledge regarding protective immune responses against Brucella have come from mouse studies. In the work presented our goal was to characterize the T cell subpopulations and effector phenotype of the immune response elicited following vaccination and boost with RB51. In order to accomplish this, we performed ex vivo analysis of peripheral blood mononuclear cells (PBMC) for the expression of surface markers associated with effector (CD45RO− CD62L−/lo CCR7−) and memory phenotypes (TEM: CD45RO+ CD62Llo/intCCR7−and TCM: CD45RO+ CD62L+ CCR7+). Additionally, we performed in vitro recall responses of PBMC and assessed cytokine production and proliferation in response to antigen stimulation. Altogether, the data from these studies will help us understand the protective, cell mediated immune response elicited by vaccination in a natural host for Brucella species.