Integrative reanalysis of public intracellular and vaccine-challenge transcriptomes, informed by single-cell and metabolomic atlases, refines antigen prioritisation for next-generation veterinary Brucella vaccines

Abstract

Brucellosis is the most widespread bacterial zoonosis and a leading cause of abortion and infertility in cattle, sheep, goats and pigs. The live vaccines licensed for livestock (B. abortus S19 and RB51, B. melitensis Rev.1) give incomplete protection, retain residual virulence and induce antibodies that are indistinguishable from those of field infection, and no human vaccine is licensed. Antigen discovery for safer subunit and mRNA alternatives has proceeded one candidate at a time, so it remains unclear which immunogenic proteins are abundant in the intracellular niche that protective immunity must recognise. We reanalysed four public data layers: dual RNA-sequencing of intracellular B. abortus and infected murine macrophages (GSE100914), splenic transcriptomes from vaccinated and challenged mice (GSE254248), and single-cell (PRJCA054635) and metabolomic (ST003696, ST003692) atlases. Intracellular residence induced 704 genes and repressed 249, enriching translation functions 2.9-fold. Omp28/BP26 was the second most abundant intracellular transcript (35,652 TPM; log2FC 4.25), whereas the lipoproteins omp16, omp10 and omp19 were 116-637-fold less abundant. Vaccination left a germinal-centre and TCF1+ memory imprint rather than an effector-cytokine signature. A composite score combining abundance, induction and surface exposure reorders the candidate panel, placing Omp28/BP26 and omp2b above current candidates and defining concrete priorities for veterinary vaccine development.