Characterization of Monoclonal Antibodies against HA Protein of H1N1 Swine Influenza Virus and Protective Efficacy against H1 Viruses in Mice

Abstract

H1N1 swine influenza viruses (SIV) are prevalent in pigs globally, and occasionally emerge in humans, which raises concern about their pandemic threats. To stimulate hemagglutination (HA) of A/Swine/Guangdong/LM/2004 (H1N1) (SW/GD/04) antibody response, eukaryotic expression plasmid pCI-neo-HA was constructed and used as an immunogen to prepare monoclonal antibodies (mAbs). Five mAbs (designed 8C4, 8C6, 9D6, 8A4, and 8B1) against HA protein were obtained and characterized. Western blot showed that the 70 kDa HA protein could be detected by all mAbs in MDCK cells infected with SW/GD/04. Three mAbs—8C4, 8C6, and 9D6—have hemagglutination inhibition (HI) and neutralization test (NT) activities, and 8C6 induces the highest HI and NT titers. The protection efficacy of 8C6 was investigated in BALB/c mice challenged with homologous or heterologous strains of the H1 subtype SIV. The results indicate that mAb 8C6 protected the mice from viral infections, especially the homologous strain, which was clearly demonstrated by the body weight changes and reduction of viral load. Thus, our findings document for the first time that mAb 8C6 might be of potential therapeutic value for H1 subtype SIV infection.

Dendritic Cells TargetingLactobacillus plantarumStrain NC8 with a Surface-Displayed Single-Chain Variable Fragment of CD11c Induce an Antigen-Specific Protective Cellular Immune Response

“…Therefore, it is important to study novel passive immunization approaches to prevent H1N1 influenza A virus infection. For influenza viruses, HA glycoproteins induce neutralizing antibody production and mediate adaptive immune responses (19). Vaccination with a mixture of HAs from different H1N1 influenza A viruses has been shown to be useful for the induction of specific immunity against the viruses represented in the mixture and confer some degree of cross-protection against unrelated influenza virus strains.…”

Sowing the Seeds of a Pandemic? Mammalian Pathogenicity and Transmissibility of H1 Variant Influenza Viruses from the Swine Reservoir

“…With one exception, the variant influenza viruses examined here did not display high virulence in this species, suggesting that although H1v influenza viruses have been undergoing continuous evolution in pigs for many years, their virulence in the mouse model has largely remained unchanged. While mice are limited in their presentation of clinical signs and symptoms of infection, characterization of H1v viruses in this model can provide supportive information for subsequent evaluation of novel vaccine and antiviral formulations against pandemic and potentially pandemic H1 subtype influenza viruses [83,84]. Furthermore, although genetically distinct from North American viruses, Eurasian swine influenza viruses were reported to cause infections ranging from mild to fatal in mice [85,86].…”