Figure 4From: A single immunization with HA DNA vaccine by electroporation induces early protection against H5N1 avian influenza virus challenge in mice HI titers in mice immunized once with various dosages of H5N1 virus HA DNA. Blood samples collected on various days were detected for specific antibodies by hemagglutinin inhibition (HI) assay. No HI activity was detectable in non-immunized mice.Back to article page