Identification of vaccine candidate peptides and harvesting epitopes of Brucella melitensis

Abstract

Brucella spp. is a facultative intracellular bacteria that is considered a Class B Select Agent and the available human vaccines are ineffective in producing immunological memory. Adaptive immune responses are crucial to the control of Brucella, as previous studies have shown that the acute response is CD8+ T cell mediated. Also, there are no defined immunogenic epitopes for any Brucella, and this is a critical hole in our understanding of how to control this bacterial infection. BALB/c mouse Class I alleles, H2Kd and H2Dd, were used in RankPep, a peptide prediction algorithm, to predict Class I Brucella peptides. After analysis of the data generated from each individual Brucella ORF, a group of peptides were chosen as probable high affinity binders. These peptides were synthesized and then tested in a competitive MHC binding assay. Pooled peptide vaccinations and subsequent quantification of immune activation by intracellular cytokine staining is a high‐throughput method for investigating the roles of large numbers of predicted Class I peptides. Preliminary results demonstrate that 22.5% of the predicted peptides are naturally presented during Brucella melitensis infection of BALB/c mice. These data present an important first step in the development of a multivalent peptide vaccine that will protect against brucellosis. Supported by NIH 1R01AI073558‐01A1 and GLRCE 1U54AI057153.