Protective Mucosal Immunity Elicited by Intranasal Dna Vaccination Expressing the Ha1 of Equine-2 Influenza Virus

Abstract

A vaccination trial was performed in mice by intranasal inoculation of DNA vaccines pTOPOKY98#6 and pVAXKY98/11-9 encapsulating with liposome and metastim. DNA vaccines were designed to express HA1 protein from equine-2 influenza virus, A/Eq/Ky/98. After a booster vaccination, each mouse was challenged with a sub-lethal dose (16 HAU) of homologous equine-2 influenza virus. By using a weight loss model, it was found that the vaccinated mice showed less severe disease than the unvaccinated mice. Elevated IgG and IgA levels were recorded in the sera of the vaccinated mice. HA1 was capable of inducing protective immunity against homologous challenge. In the unvaccinated group mice, a maximum of 8.4% weight loss was observed while the observed weight losses were 1.2% and 0.82% for pTOPOKY98#6 and pVAXKY98/11-9 group mice respectively. It was found that dose levels as low as 0.01 ?g DNA/gram body-weight were sufficient to elicit protective immunity.