Synthesis and processing of a 22-26K murine cytomegalovirus glycoprotein recognized by a neutralizing monoclonal antibody.

A 22-26K glycoprotein (gp24) of the murine cytomegalovirus (MCMV) virion was immunoprecipitated by a monoclonal antibody (MAb) 6A1.21A that neutralized MCMV infectivity only in the presence of complement. Pulse-chase experiments demonstrated that gp24, which contained only N-linked, complex-type oligosaccharides, was processed from an 18.4K high-mannose precursor (gp18.4). Analyses by two-dimensional (nonreducing/reducing) gel electrophoresis have shown that both gp18.4 and gp24 are present as disulfide-linked complexes, and rapid oligomerization of the 18.4K precursor is an early step in the processing pathway of gp24. Finally, we demonstrated that gp24 belongs to the "late" class of MCMV proteins.