INTERFERON-γ MESSENGER RNA LEVEL IN PERIPHERAL BLOOD MONONUCLEAR CELLS OF NAIVE BOVINES AFTER FOOT-AND-MOUTH DISEASE VIRUS VACCINATION AND CHALLENGE

The study evaluated the antibody response and interferon-gamma (IFN-gamma) messenger ribonucleic acid (mRNA) expression levels in naive bovine calves from a Foot-and-Mouth Disease virus (FMDV) potency test. Peripheral blood mononuclear cells (PBMCs) were separated from blood samples and total RNA was extracted. Two step quantitative (Real time-polymerase chain reaction (RT-PCR) method was used for measurement of IFN-gamma specific mRNA. Plasma samples were screened to detect anti-non structural proteins (NSP) antibodies for FMDV in 3AB NSP antibody enzyme linked immunosorbent assay (ELISA). Plasma samples were found free for anti-NSP antibodies for FMDV in vaccinated bovine calves as evaluated in 3AB NSP antibody ELISA test. Increase in mRNA expression level of IFN-gamma after 15 days post vaccination (DPV) was found unequivocally in all five vaccinated calves (more than two-fold increase in 4 out of 5 calves). Liquid phase blocking ELISA (LPBE) test results also revealed highest humoral antibody response on 15 DPV. Monovalent FMDV vaccination elicited highest antibody titre on 15 DPV in correlation with elevated IFN-gamma mRNA level. Humoral and cellular immunity both play important role in protection against FMDV. The study will help in further understanding the role played by both the humoral and cellular immune response against FMDV.