Development of classical swine fever virus E2-protein based indirect ELISA for detection of antibodies against the virus in pigs.

Classical swine fever (CSF) is an economically important and highly contagious disease of pigs caused by CSF virus, genus Pestivirus. Serological diagnosis of the disease is highly valuable for surveillance and thereby containment of spread of the disease. In this study, we have demonstrated the development of CSFV envelope glycoprotein E2-based indirect ELISA (E2-iELISA) for the detection of CSFV specific antibodies. The full-length E2 protein was expressed in E. coli and the purified protein was used as a coating antigen in indirect ELISA for detecting CSFV specific antibodies in pigs. A panel of 506 pig sera samples was used to validate the ELISA and the results were highly comparable to the results obtained with the commercial antibody detection kit (PrioCHECK CSFV Ab kit). The in-house E2-iELISA demonstrated high diagnostic sensitivity (95.4%) and specificity (95.5%), highlighting its potential application for sero-surveillance or monitoring of the disease in the swine population.

A new blocking ELISA for detection of foot-and-mouth disease non-structural protein (NSP) antibodies in a broad host range.

Large-scale monitoring of foot-and-mouth disease (FMD) in livestock is imperative in an FMD control program. Detection of antibodies against non-structural proteins (NSP) of FMD virus (FMDV) is one of the best tools to estimate the prevalence of past infection; availability of such a well-validated test is therefore essential. Using a FMDV 3B protein-specific monoclonal antibody, we have developed a new NSP antibody blocking ELISA (10H9 bELISA) and validated it on large panels of sera from different susceptible species. The diagnostic sensitivity of the ELISA was 95% with a specificity of 98%, similar to the values found using a commercial kit (PrioCHECK FMD NS test). The 10H9 bELISA can be used in a broad range of FMD susceptible species making it a very useful tool in monitoring the foot-and-mouth disease control programs by detection of virus circulation in the vaccinated populations. KEY POINTS: • A new ELISA for detection of foot and mouth disease (FMD) antibodies. • Diagnostic sensitivity of 95% and specificity of 98%. • Tested with panels of validated sera from broad host range.

Induction of antiviral and cell mediated immune responses significantly reduce viral load in an acute foot-and-mouth disease virus infection in cattle.

Foot-and-mouth disease virus (FMDV) causes a severe infection in ruminant animals. Here we present an in-depth transcriptional analysis of soft-palate tissue from cattle experimentally infected with FMDV. The differentially expressed genes from two Indian cattle (Bos indicus) breeds (Malnad Gidda and Hallikar) and Holstein Friesian (HF) crossbred calves, highlighted the activation of metabolic processes, mitochondrial functions and significant enrichment of innate antiviral immune response pathways in the indigenous calves. The results of RT-qPCR based validation of 12 genes was in alignment with the transcriptome data. The indigenous calves showing lesser virus load, elicited early neutralizing antibodies and IFN-γ immune responses. This study revealed that induction of potent innate antiviral response and cell mediated immunity in indigenous cattle, especially Malnad Gidda, significantly restricted FMDV replication during acute infection. These data highlighting the molecular processes associated with host-pathogen interactions, could aid in the conception of novel strategies to prevent and control FMDV infection in cattle.