In silico design and testing of a multi-epitope camel mastitis vaccine candidate for development.

INTRODUCTION: Camel mastitis caused by a diverse array of pathogenic bacteria including Staphylococcus aureus and Streptococcus agalactiae is responsible for enormous socioeconomic losses in the arid and semi-arid regions of Africa where camels are an invaluable source of livelihood and nutrition. Although S. aureus and S. agalactiae are environmental contaminants, the latter is an infectious zoonotic agent. The development of a safe, efficacious vaccine for camel mastitis is a compelling priority particularly against the backdrop of climate change and antimicrobial resistance.

METHODS: We have sequenced and assembled the genomes of local strains of S. aureus, S. agalactiae, L. lactis, E. faecium and E. gallinarum isolated from milk samples of pastoralists' camel herds in Kenya, analysed the subtracted proteomes for antigenic proteins using VaxiJen and ascertained the allergenicity, subcellular localisation and the number of transmembrane helices of the putative candidates using AllerTOP, PSORTb and DeepTMHMM. Furthermore, B-cell and T-cell epitopes uncovered in the antigenic protein sequences using Bepi-Pred-2.0, NetCTL 1.2 and NetMHCII 2.3 were used to design a potential vaccine candidate that exhibited adequate immunogenicity, stability and flexibility without toxicity and allergenicity.

RESULTS: We have designed and computationally evaluated a multi-epitope camel mastitis vaccine candidate from 20 antigenic S. aureus and S. agalactiae proteins. The candidate exhibits desirable immunogenicity, is non-allergenic and non-toxic, and warrants further experimental investigations.

DISCUSSION: Collectively, we have designed and computationally evaluated a potentially viable camel mastitis vaccine candidate.