Immunological response of mice to the bovine respiratory syncytial virus fusion glycoprotein expressed in recombinant baculovirus infected insect cells

Abstract

Bovine respiratory syncytial virus (BRSV) is a major cause of respiratory disease in calves. The BRSV genome encodes two major glycoproteins, G and F, which are the major targets for the host antibody response. We have expressed the F glycoprotein in insect cells (Sf9) using a recombinant baculovirus vector. A comparison of the F protein expressed in mammalian and insect cells by SDS-PAGE showed that only part of the baculovirus-produced protein was soluble and processed like the native protein. The antigenicity of the soluble form of the F protein expressed in insect cells was identical to that of the F protein expressed in mammalian cells. Immunization with the F protein expressed in insect cells induced neutralizing antibodies in mice. This antigenic preparation adjuvanted with Quil-A produced an increased neutralizing antibody titer and induced protection.

Expression-System-Dependent Modulation of HIV-1 Envelope Glycoprotein Antigenicity and Immunogenicity

“…Mammalian cell-expressed gp120 contained the expected proportions of complex and high-mannose glycans, implying that the purification process did not impose any dramatic bias in the selection of glycan types on the different glycoprotein forms. It has been reported that insect cell-expressed material may have reduced numbers of glycans due to sequon skipping11; 12. Reduced numbers of glycans would be expected to modify the antigenicity of a highly-glycosylated protein, and might also influence immunogenicity.…”

“…High-mannose glycans occur more frequently in the conserved regions, whereas those attached to variable loops, being more exposed to the glycosylation machinery of the Golgi, are more frequently processed into complex glycans6; 9. Conversely, in wild-type insect cell systems glycosylation is restricted to paucimannosidic structures10 and the degree of sequon occupancy may be lower11; 12.…”