Anti-viral immunity induced by recombinant nucleoprotein of influenza A virus. II. Protection from influenza infection and mechanism of protection

Immunology. 1990 Oct;71(2):202-7.


Protection against influenza A virus infection in mice immunized with recombinant nucleoprotein (rNP) was studied. Nucleoprotein-immune mice were protected against a lethal challenge with A/Puerto Rico/8/34 (A/PR8) virus but showed considerable morbidity before recovery. Local boosting of the immune system with rNP by intranasal immunization improved the protection in NP-immune mice, and the decrease in morbidity after infection was reflected in accelerated clearance of virus from lungs. However, immune, boosted mice also rapidly cleared an antigenically unrelated influenza B virus from their lungs. Mice immunized with rNP precipitated with alhydrogel, that subsequently developed significant resistance to virus infection, failed to generate detectable levels of class I major histocompatibility complex (MHC)-restricted killer cells. Furthermore, B10.A(5R) mice that are non-responders for NP-specific class I killer cells could also be protected by immunization with rNP. In contrast, rNP-immunized mice developed strong proliferative T-cell responses to rNP. These data argue for an important role for helper T cells rather than virus-specific class I cytotoxic T cells in protection against influenza virus infection induced by rNP.

MeSH terms

  • Animals
  • Antigens, Viral / immunology*
  • Influenza A virus / immunology*
  • Influenza Vaccines / immunology*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred Strains
  • Nucleoproteins / immunology*
  • Orthomyxoviridae Infections / immunology
  • Orthomyxoviridae Infections / prevention & control*
  • Recombinant Proteins / immunology
  • T-Lymphocytes, Cytotoxic / immunology


  • Antigens, Viral
  • Influenza Vaccines
  • Nucleoproteins
  • Recombinant Proteins