Submitted to: Annual Conference on Vaccine Research
Publication Type: Abstract Only
Publication Acceptance Date: February 21, 2013
Publication Date: April 22, 2013
Citation: Lin, K., Vincent, A.L., Roth, J.A., Kehrli, Jr., M.E., Lager, K.M., Ramamoorthy, S. 2013. Cross-reactive, linear B cell epitopes of the influenza virus matrix protein 1. In: Proceedings of the 16th Annual Conference on Vaccine Research. April 22-24, Baltimore, Maryland. p. 115. Technical Abstract: Objective: Evaluate antibody responses to the conserved influenza matrix protein. Background: Little is known about the B cell epitopes in conserved internal influenza proteins or their role in viral immunity and immunopathogenesis. Based on epitope information present in the Immune Epitope Database [IEDB] only one out of four matrix 1 protein B cell epitopes of the 2009 pandemic H1N1 (pH1N1) virus was predicted to be conserved(1). In this study we have used in-silico and wet lab methods to validate these findings. Methods: Immunogenic regions and linear B cell epitopes on the influenza matrix 1 protein were predicted by antigenic Index prediction and the IEDB Immune Epitope Database B cell epitope prediction tools. Sequential anti-sera against two pH1N1 strains and four contemporary swine influenza virus strains were raised by experimental infection of piglets with the corresponding viruses. 15-mer synthetic peptides with a 5 amino acid overlap spanning the pH1N1 matrix protein were used to map linear B cell epitopes. Results: Five of the ten immunodominant regions that were identified had strong antibody binding activity (>5 S/N ratio). All regions had broad cross reactivity to the swine H1 virus strains tested. Single amino acid changes in the sequence did not alter cross-reactivity. The Jameson-Wolf Antigenic Index, BiPred and EliPro predicted the five major immunodominant regions accurately, but showed differences in predicting the other regions. Conclusions: Previously unmapped linear B cell epitopes in the influenza matrix protein 1 were identified. While conformational epitopes were not studied, all of the identified linear epitopes were conserved in the virus strains that were tested. Reference: 1.Greenbaum, J.A. et al. Pre-existing immunity against swine-origin H1N1 influenza viruses in the general human population. Proceedings of the National Academy of Sciences of the United States of America 106, 20365-70 (2009).