In silico discovery of epitopes of gag and env proteins for the development of a multi-epitope vaccine candidate against Maedi Visna Virus using reverse vaccinology approach.

Maedi Visna Virus (MVV) causes a chronic viral disease in sheep. Since there is no specific therapeutic drug that targets MVV, development of a vaccine against the MVV is inevitable. This study aimed to analyze the gag and env proteins as vaccine candidate proteins and to identify epitopes in these proteins. In addition, it was aimed to construct a multi-epitope vaccine candidate. According to the obtained results, the gag protein was detected to be more conserved and had a higher antigenicity value. Also, the number of alpha helix in the secondary structure was higher and transmembrane helices were not detected. Although many B cell and MHC-I/II epitopes were predicted, only 19 of them were detected to have the properties of antigenic, non-allergenic, non-toxic, soluble, and non-hemolytic. Of these epitopes, five were remarkable due to having the highest antigenicity value. However, the final multi-epitope vaccine was constructed with 19 epitopes. A strong affinity was shown between the final multi-epitope vaccine and TLR-2/4. In conclusion, the gag protein was a better antigen. However, both proteins had epitopes with high antigenicity value. Also, the final multi-epitope vaccine construct had a potential to be used as a peptide vaccine due to its immuno-informatics results.

Molecular prevalence and genetic diversity of Hepatozoon spp. in stray cats of Izmir, Türkiye.

Hepatozoon spp. are an apicomplexan protozoan parasites that infect vertebrates including mammals, marsupials, birds, reptiles, and amphibians. Among Hepatozoon species, H. canis and H. felis are causative agents of hepatozoonosis in dogs and cats, respectively and have veterinary importance. This study aimed to determine the prevalence of Hepatozoon spp. in stray cats living in Izmir and investigate genetic diversity among positive samples. To achieve this aim, the prevalence of Hepatozoon spp. 18S rRNA gene was screened by PCR in DNA samples extracted from blood samples of stray cats (n = 1012). Then, Hepatozoon-positive samples were sequenced and the generated data were used for species identification, phylogenetic and haplotype analyses. According to the results, among the samples screened, 2.37 % (24/1012) of them were found to be Hepatozoon-positive, and of these positive samples, 18 (18/24; 75 %) were successfully sequenced. BLAST and phylogenetic analyses revealed that all of these samples were H. felis. Also, phylogenetic analysis showed that H. felis samples were genotype I. Within H. felis samples isolated from cats living in different countries/regions, 9 haplotypes were detected and among these haplotypes, H-1 was found to be prevalent (n = 20 H. felis isolates). In conclusion, this study showed that the prevalence of Hepatozoon spp. was low in stray cats analyzed. Also, H. felis genotype I was predominant in comparison to other Hepatozoon species.