Not all potently neutralizing, vaccine-induced antibodies to Epstein-Barr virus ensure protection of susceptible experimental animals.

Cottontop tamarins have been immunized with a high molecular weight, Epstein-Barr (EB) virus membrane antigen (MA) glycoprotein (gp340) separated by monoclonal antibody immunoaffinity chromatography (MCABgp340). Specific antibody production was monitored by immunofluorescence, a highly sensitive enzyme-linked immunosorbent assay (ELISA), and virus neutralization tests, and was found to reach high titre after 4/5 inoculations. The animals were challenged with a 100% lymphomagenic dose of EB virus but despite possessing powerful neutralizing antibodies were not protected against tumour causation by the virus. This result contrasts with that of earlier experiments in which tamarins with neutralizing antibodies induced by gp340 prepared by a molecular weight-based method (MWgp340) were protected. The reasons for this difference in protection associated with vaccine molecules prepared in different ways are discussed together with the need for parameters other than neutralizing antibody for use in the assessment of subunit immunogens against EB virus.