Background Sheep pulmonary adenocarcinoma (OPA) is a contagious lung cancer of sheep caused by the Jaagsiekte retrovirus (JSRV). OPA typically has a serious economic impact worldwide. A vaccine has yet to be developed, even though the disease has been globally spread, along with its complications. This study aimed to construct an effective multi-epitopes vaccine against JSRV eliciting B and T lymphocytes using immunoinformatics tools. Results The designed vaccine was composed of 499 amino acids. Before the vaccine was computationally validated, all critical parameters were taken into consideration; including antigenicity, allergenicity, toxicity, and stability. The physiochemical properties of the vaccine displayed an isoelectric point of 9.88. According to the Instability Index (II), the vaccine was stable at 28.28. The vaccine scored 56.51 on the aliphatic index and -0.731 on the GRAVY, indicating that the vaccine was hydrophilic. The RaptorX server was used to predict the vaccine's tertiary structure, the GalaxyWEB server refined the structure, and the Ramachandran plot and the ProSA-web server validated the vaccine's tertiary structure. Protein-sol and the SOLPro servers showed the solubility of the vaccine. Moreover, the high mobile regions in the vaccine’s structure were reduced and the vaccine’s stability was improved by disulfide engineering. Also, the vaccine construct was docked with an ovine MHC-1 allele and showed efficient binding energy. Immune simulation remarkably showed high levels of immunoglobulins, T lymphocytes, and INF-γ secretions. The molecular dynamic simulation provided the stability of the constructed vaccine. Finally, the vaccine was back-transcribed into a DNA sequence and cloned into a pET-30a ( +) vector to affirm the potency of translation and microbial expression. Conclusion A novel multi-epitopes vaccine construct against JSRV, was formed from B and T lymphocytes epitopes, and was produced with potential protection. This study might help in controlling and eradicating OPA.

Background: Human papillomavirus 16 (HPV16) is a small non-enveloped DNA virus is belonging to Papillomaviridae. It usually causes warts and about 60% of cancer diseases. HPV16 genome consists of double-stranded cDNA of six early and two late proteins. This study attempted to design safe and efficient multi epitopes vaccine from structural proteins (L1 and L2) by using various immunoinformatic databases. The results demonstrated that the predicted vaccine comprised of 408aa and validated in terms of antigenicity, allergenicity, toxicity and stability by putting all critical parameters into consideration. The physiochemical properties displayed isoelectric point (pl) of 10.37. The instability index (II) was 33.6 categorizing vaccine as stable. The aliphatic index was 63.24 and the GRAVY was −0.652 demonstrating the hydrophilicity of the vaccine. Vaccine structures were predicted, refined and validated. Stability of the vaccine was assessed through Ramachandan plot and further assessed by ProSA server. Vaccine solubility was higher than the solubility of E. coli proteins indicating that the vaccine was soluble. Disulfide engineering increased the vaccine stability by substituting the unstable residues with cysteine residues. Vaccine-TLR4 receptor docking resulted in attractive binding energy of –1274.1 kcal/mol and –1450.4kcal/mol for chain A and chain B of the receptor respectively. Reverse transcription of the vaccine protein into a DNA sequence was performed and cloned into a pET30a (+) vector to confirm the clonability of the sequence during microbial expression. Taken together, the vaccine potentially induced immune responses and thus was suitable as a vaccine to combat HPV16 disease. Nonetheless, the efficiency of vaccines must be approved by in vitro and in vivo immunological analysis.