Neutralizing epitopes of lymphocytic choriomeningitis virus are conformational and require both glycosylation and disulfide bonds for expression.
Lymphocytic choriomeningitis virus (Armstrong strain) bears two overlapping epitopes, GP-1A (A) and GP-1D (D), recognized by neutralizing antibodies on the major surface glycoprotein GP-1. Both are discontinuous conformational epitopes that require prior formation of disulfide bridges and addition of N-linked oligosaccharides. Using monoclonal antibodies specific for each of these epitopes, as well as for conformation-independent epitopes, we have investigated the requirements for biosynthesis and folding of the epitopes. The carbohydrate residues themselves do not appear to comprise critical informational components of these epitopes, but are required for proper folding of the nascent glycopeptide chain within the rough endoplasmic reticulum. These epitopes differ in their resistance to denaturation; epitope D is retained when denatured with SDS under nonreducing conditions, whereas epitope A is lost. Monoclonal antibodies to epitope A cross-react with several strains of LCMV. However, epitope D is detected in only a subset of isolates derived from the Armstrong strain of LCMV. By RNA sequence analysis, we have mapped a single amino acid change distinguishing those virions containing epitope D. Acquisition of binding activity of the epitope D-specific monoclonal correlates with a Thr----Ala or Thr----Lys mutation at amino acid 173 of the GP-1 molecule and concomitant disruption of a consensus N-linked glycosylation site.
Wright
K E
KE
Department of Immunology, Research Institute of Scripps Clinic, La Jolla, California 92037.
Salvato
M S
MS
Buchmeier
M J
MJ
D000595:Amino Acid Sequence; D000956:Antigens, Viral / Q000276:immunology*; D003902:Detergents; D004220:Disulfides; D000939:Epitopes; D006031:Glycosylation; D008217:Lymphocytic choriomeningitis virus / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000276:immunology; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D011233:Precipitin Tests; D011487:Protein Conformation; D011489:Protein Denaturation; D011499:Protein Processing, Post-Translational; D013329:Structure-Activity Relationship; D014415:Tunicamycin / Q000494:pharmacology; D014764:Viral Proteins / Q000276:immunology*
D000956:Antigens, Viral; D003902:Detergents; D004220:Disulfides; D000939:Epitopes; D008562:Membrane Glycoproteins; D014764:Viral Proteins; D014415:Tunicamycin