A Multi-Epitope-Based Dna Vaccine Confers Cross-Protection Against Influenza a H1n1 and H3n2 Viruses Publisher

Summary: Could a DNA vaccine protect across flu strains? In animals, conserved flu epitopes induced immunity and prevented deaths; human benefit is unknown. #Influenza #Vaccines

Barkhordari K ; Rezaei F ; Salimi V ; Sadeghi K ; Moghadam M A ; Bagheri H ; Pourjabali M ; Karimi M ; Fotouhi O ; Azad T M
Source: Iranian Journal of Microbiology Published:2026

Abstract

Background and Objectives: Influenza A virus remains a major global health concern because antigenic drift reduces the long-term efficacy of current vaccines. This study evaluated a multi-epitope DNA vaccine targeting conserved regions of hemagglutinin (HA) and polymerase acidic (PA) proteins from influenza A/H1N1 and A/H3N2 viruses. Materials and Methods: Conserved B-cell, CD4+ T-cell, and CD8+ T-cell epitopes were identified using immunoinformatic tools and linked to β-defensin-2 in the pcDNA3.1(+) vector. Protein expression was confirmed in HEK293 cells. BALB/c mice were immunized intramuscularly and challenged with lethal doses of H1N1 or H3N2 viruses. Humoral and cellular immune responses, lung viral loads, histopathology, and clinical outcomes were assessed. Results: Vaccinated mice exhibited undetectable or markedly reduced lung viral loads (1,000-10,000-fold; p<0.01), significantly decreased pulmonary lesions, and milder clinical manifestations than controls. Vaccination induced significant CD4+ (p=0.041) and CD8+ (p=0.038) T-cell responses in bronchoalveolar lavage fluid, accompanied by increased interferon-γ and interleukin-4 production, indicating balanced cellular and humoral immunity. Complete protection against mortality was observed following viral challenge. Conclusion: This multi-epitope DNA vaccine elicited cross-protective immunity against influenza A/H1N1 and A/H3N2 by targeting conserved HA and PA epitopes, supporting its potential as a candidate for universal influenza vaccine development. Copyright © 2026 The Authors.