Recombinant env-gp85 of HPRS-103 (subgroup J) avian leukosis virus: antigenic characteristics and usefulness as a diagnostic reagent.

We describe the construction of a recombinant baculovirus containing the cloned DNA encoding the gp85 envelope glycoprotein of HPRS-103 (subgroup J) avian leukosis virus fused to the carboxy-terminus of the affinity tag glutathione-S-transferase. The fusion protein was efficiently secreted into the supernatant medium of the infected insect cell culture and could be purified in a single step using immobilized glutathione. An enzyme-linked immunosorbent assay using the recombinant protein was found to be specific and sensitive for detection of HPRS-103 virus-specific antibodies in the sera of infected birds.