BACULOVIRUS EXPRESSION AND AFFINITY PURIFICATION OF PROTEIN E2 OF CLASSICAL SWINE FEVER VIRUS-STRAIN ALFORT 187/

The genome region encoding the major envelope glycoprotein E2 (gp55) o f the classical swine fever virus (CSFV) strain Alfort/187 was cloned and sequenced. The E2 gene, either with or without additional authenti c 5'-terminal sequences coding for two variants of a putative signal s equence, was used to construct recombinant baculoviruses expressing th e respective glycosylated and nonglycosylated E2 protein in insect cel ls. The signal sequences mediated glycosylation in insect cells, but n o efficient secretion of the protein into the cell culture supernatant was observed. Six histidine residues introduced at the carboxy termin us of E2 allowed purification of E2 protein by Ni2+-chelate affinity c hromatography. The proteins obtained were characterized and their immu nological properties were compared by western blot analysis.