Distribution of epitopes within the amino acid sequence of the Epstein-Barr virus major envelope glycoprotein, gp340, recognized by hyperimmune rabbit sera.

Epstein-Barr virus (EBV) is a major human pathogen for which the development of an effective vaccine remains an important goal. Rabbits were immunized with one of a set of 10 fusion proteins representing protein fragments from the EBV receptor-binding ligand and candidate subunit vaccine gp340. Sera from recipients of fragments from the amino-terminal half of the polypeptide chain bound gp340 in Western blot assays and ELISA but were not virus-neutralizing. The fine epitope specificity of these sera, and of EBV-neutralizing rabbit sera raised against whole EBV and gp340-containing immune-stimulating complexes, were assessed in a peptide ELISA. All but two of these sera bound peptides located between positions 236 and 327 in the 907 amino acids of the gp340 polypeptide chain. Among these it was possible to identify regions containing candidate virus-neutralizing B cell epitopes. The use of a gp340 fusion protein affinity column to isolate antibodies from EBV-neutralizing rabbit sera specific for this region suggests the presence of both continuous and discontinuous B cell epitopes with potential roles in EBV neutralization.