| Abstract: | Individual specific antigenic rubella virus (RV) structural proteins are required for accurate serological diagnosis of acute and congenital rubella infections as well as rubella immune status. The RV envelope glycoprotein E1 is the major target antigen and plays an important role in viral-specific immune responses. The native virion is difficult to produce in large quantities and the protein subunits are also difficult to isolate without loss of antigenicity. The production of a soluble RV E1 (designated E1ΔTm) using the baculovirus-insect cell expression system is described. In contrast to wild-type RV E1, the genetically engineered E1ΔTm protein lacks a transmembrane anchor. It behaved as a secretory protein and was secreted abundantly from insect cells. Pulse-chase studies were used to examine the synthesis, glycosylation, and secretion of E1ΔTm by the insect cells. The secreted E1ΔTm protein was purified from serum-free medium by onestep immunochromatography. The purified E1ΔTm protein retained full antigenicity and may be a convenient source of E1 protein for use in diagnostic assay and rubella vaccine development. |
