Memory B cells: a proposed new immunological correlate for protective efficacy of Japanese encephalitis vaccine

Abstract

Evaluation of: Larena M, Prow NA, Hall RA, Petrovsky N, Lobigs M. JE-ADVAX Vaccine protection against Japanese encephalitis virus mediated by memory B cells in the absence of CD8+ T cells and pre-exposure neutralizing antibody. J. Virol. 87(8), 4395–4402 (2013).Japanese encephalitis (JE) virus requires dissemination within the host via the circulation for disease development. Thus, a serum-neutralizing antibody is an effective factor to protect against disease. Current licensed JE vaccines induce neutralizing antibodies and titers of 1:10 or higher are the recommended immunological correlate of protection. In this paper, the authors demonstrated, using a highly susceptible knockout mouse model, that memory B cells are required for disease protection and that detectable neutralizing antibodies at the time of challenge are dispensable. The authors proposes that the extent of memory B cells would be an alternative and better immunological correlate for evaluating the efficacy of JE vaccine candidates in clinical trials.