Development of REC1: A Reverse Vaccinology-Derived Multi-Epitope Vaccine Candidate Against Brucellosis

Background/Objectives: Brucellosis is a widespread intracellular zoonosis that continues to impose substantial public-health and economic burdens in endemic regions. No human brucellosis vaccine has yet been approved, and most existing multi-epitope candidates rely solely on computational predictions, without population-specific human leukocyte antigen (HLA) optimization or in vivo epitope validation. REC1 is therefore an early-stage, proof-of-concept, human-oriented multi-epitope candidate, with epitopes screened against high-frequency HLA alleles in the Chinese population. This study developed a multi-epitope vaccine candidate, REC1, using an integrated reverse-vaccinology workflow.

Methods

We predicted Major Histocompatibility Complex (MHC) I and II epitopes against high-frequency HLA alleles representative of the Chinese population (AFND). Population coverage of the final incorporated epitope set was estimated with the IEDB Population Coverage tool under Hardy-Weinberg equilibrium, while paired HLA-DQ heterodimers, which the tool cannot model, were evaluated independently from Chinese DQA1-DQB1 haplotype frequencies. Epitopes supported by in vivo immunoreactivity were then assembled into the modular REC1 construct, which we characterized in silico for physicochemical properties, structural architecture, and simulated immune responses.