Simultaneous infection with gammaherpes and influenza viruses enhances the host immune defense.

We have studied the impact of simultaneous infection of mice with murine gammaherpesvirus (MHV) and influenza A virus (IAV) on the immune response and pathogenesis of both infections. After a persistent MHV-68 herpesviral infection had been established, the same mice were super-infected with IAV. Individual parameters of MHV infection (viral DNA detection in organs and blood) and numbers of leukocytes in lungs and spleens were determined.

Virus-neutralizing antibody response of mice to consecutive infection with human and avian influenza A viruses.

In this work we simulated in a mouse model a naturally occurring situation of humans, who overcame an infection with epidemic strains of influenza A, and were subsequently exposed to avian influenza A viruses (IAV). The antibody response to avian IAV in mice previously infected with human IAV was analyzed. We used two avian IAV (A/Duck/Czechoslovakia/1956 (H4N6) and the attenuated virus rA/Viet Nam/1203-2004 (H5N1)) as well as two human IAV isolates (virus A/Mississippi/1/1985 (H3N2) of medium virulence and A/Puerto Rico/8/1934 (H1N1) of high virulence).

Two distinct regions of HA2 glycopolypeptide of influenza virus hemagglutinin elicit cross-protective immunity against influenza.

Unlabelled: Currently, a new trend in development of vaccines against influenza with broader spectrum of efficacy is focused on conserved antigens of influenza virus. The HA2 glycopolypeptide (HA2 gp) is one of conserved antigens, potentially suitable as immunogens inducing cross-protection against influenza. We selected two distinct domains of HA2 gp originating from influenza A virus (IAV) of H3 subtype for induction of antiviral immune response: the ectodomain (EHA2) comprising aa 23-185 and the fusion peptide (FP) comprising N-terminal aa 1-38.

Heterosubtypic protection against influenza A induced by adenylate cyclase toxoids delivering conserved HA2 subunit of hemagglutinin.

The protective efficacy of currently available influenza vaccines is restricted to vaccine strains and their close antigenic variants. A new strategy to obtain cross-protection against influenza is based on conserved antigens of influenza A viruses (IAV), which are able to elicit a protective immune response. Here we describe a vaccination approach involving the conserved stem part of hemagglutinin, the HA2 subunit, shared by different HA subtypes of IAV.