Evaluation of antigenicity of the recombinant E2 glycoprotein of Classical Swine Fever Virus

PEREDA,A.; MIQUET,J.; TABOGA,O.; PICCONE,M

Bariloche

Congreso; XXXIX Annual Meeting SAIB; 2003

Classical swine fever (CSF) is a highly contagious disease that affects pigs, causing great economic losses. Argentina uses a lapinized Chinese isolate for vaccination and the vaccinated animals cannot be differentiated by serology from those infected. Obviously, a vaccine that allows the discrimination between vaccinated and infected pigs is essential to eradicate this disease. CSF virus genome consists on a molecule of RNA of positive polarity with a single open reading frame coding for a polyprotein flanked by highly conserved non-coding regions. This polyprotein is processed by viral and cellular proteases to generate structural and nonstructural proteins. The infection with the CSFV stimulates the production of antibodies against the proteins E2, Erns and NS3. Nevertheless, only E2 induces the production of neutralizing antibodies in pigs. This fact reveals that a vaccine based on E2 would allow to discriminate those animals vaccinated from those infected. The purpose of this work was the expression of the protein E2 in procariotic and eucariotic systems to be used either as a vaccine or as a diagnostic reagent. The genomic region that codes for the E2 glycoprotein was amplified by RT-PCR and cloned in vectors for expression in E. coli BL21 and in the system baculovirus / insect cells. Both vectors incorporate a 6 histidine residues (His6) in the NH3 terminal end of the E2 to allow the purification. In tests of western-blot, purified proteins were revealed with Mab against CSFV E2, Mab anti-His6 and with serum from infected and non infected pigs.