Veterinary Research Forum

Abstract The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus is the causative agent of the emerging zoonotic respiratory disease. One of the most important prerequisites for combating emerging diseases is the development of vaccines within a short period of time. In this study, antigen-irradiated, inactivated SARS-CoV-2 viruses and the disaccharide trehalose were used to enhance immune responses in the Syrian hamster. The SARS-CoV-2 virus was isolated from tracheal swabs, confirmed by Real-Time Polymerase Chain Reaction (RT-PCR), and propagated on Vero cells. For inactivation, it was irradiated with 14.00 kGy gamma radiation. Evaluation of the antigenic properties of the spike protein subunit S1 showed that the antigens were intact after gamma irradiation. The gamma-irradiated and formalin-treated viruses were used to immunize hamsters in four vaccine formulations. Neutralizing antibodies increased significantly in all vaccinated groups three weeks after the second and third vaccinations. The concentration of secretory immunoglobulin A in the irradiated vaccine plus trehalose increased significantly in nasal lavage and nasopharyngeal-associated lymphoid tissue fluids three weeks after the second and third vaccinations. The lymphocyte proliferation test in the spleen showed a significant increase in all vaccinated hamsters, but the increase was greater in irradiated vaccine plus trehalose and irradiated vaccine plus alum. We can recommend the irradiated inactivated vaccine SARS-CoV-2 plus trehalose (intra-nasal) and another irradiated inactivated vaccine SARS-CoV-2 plus alum (subcutaneous) as safe vaccines against coronavirus disease of 2019 (COVID-19), which can stimulate mucosal, humeral, and cellular immunities. However, the protectivity of the vaccine against COVID-19 in vaccinated hamsters must be investigated in a challenge test to assess the potency and efficiency of vaccine.

Abstract Bovine Leukemia Virus (BLV) is an oncogenic retrovirus of the genus Deltaretrovirus. The genome of BLV encodes a cluster of 10 mature microRNAs (miRNAs). Considering the importance of miRNAs in regulating gene expression, it seems that each of the miRNAs of BLV plays a vital role in the process of pathogenesis and tumorigenesis of the virus. First, sequences of each of the miRNAs of BLV were selected and downloaded from the miRBase database. The sequences were then investigated using TargetScan and miRWalk to identify target genes of each of the mature miRNAs of the virus. Second, the expression levels of the two miRNAs with the highest number of target genes in B lymphocytes and lymphoid tissues were evaluated using qPCR and were compared between cattle with different forms of BLV infection: PL form was compared to ‎aleukemic (AL) form (Group 1) and BLV+ with normal lymph nodes were compared to lymphosarcoma form (Group 2). We identified a total of 1595 target genes of the micro RNAs. The miRNAs with the highest target genes included miR-B4-3p with 760 and B2-5p with 102 target genes. In the second phase, miRNA expression in BLV-infected animals was investigated. The Fold Change (FC) values for miR-B4-3p and miR-B2-5p in group 1 were 22 and 67, respectively. In the second group, the FCs for miR-B4-3p and miR-B2-5p were 47 and 133, respectively. The expression was significantly higher in persistent lymphocytosis (PL) cattle in group one and lymphosarcoma cattle in group two.