Immunoinformatic approach for the evaluation of sortase C and E proteins as vaccine targets against caseous lymphadenitis

Abstract

Corynebacterium pseudotuberculosis, a facultative intracellular pathogen, causes caseous lymphadenitis, a disease of veterinary importance in small ruminants. In order to reduce the economic losses caused by the disease, an effective prophylactic measure is necessary. We adopted an immunoinformatic approach to evaluate the immunological profile of sortases C and E. For this, we performed homology analysis, searched for T and B cell epitopes, evaluated immunogenic capacity, toxicity and allergenicity, and the conservation of these epitopes in different C. pseudotuberculosis strains. The tertiary structure of the protein was predicted, and molecular docking analysis with TLR-2 was performed. Physicochemical parameters of the two sortases were also evaluated. Sortases C and E were observed to produce cellular immunity through specific epitopes for T lymphocytes, humoral immunity through epitopes of B lymphocytes, and also exhibited a high binding capacity to toll-like receptor 2. We filtered and selected six sortase C and two sortase E non-toxic and non-allergenic epitopes and confirmed their interaction with the OVAR-N*0201 allele of sheep. Our results indicate that sortase C and E have important epitopes that participate in the course of C. pseudotuberculosis infection and can serve as immunobiological candidates in the prevention of caseous lymphadenitis.