Fig 8. Non-adjuvanted recombinant novirhabdoviruses induce a neutralizing immune response against HA A/PR/8/34 in BALB/c mice.

A) Schedule of immunization and B) groups of BALB/c mice (n = 8) six-week old were immunized subcutaneously with 30 μg of purified recombinant novirhabdoviruses three times at two week interval. Mice sera were taken at day -3, day 21 and day 49. At day 59, mice were challenged with a lethal dose of 5x10⁴ PFU of influenza A/PR/8/34 virus. Course of the infection was monitor daily for two weeks. C) Seroneutralization antibody assay against influenza HA A/PR/8/34. Heat-inactivated sera of immunized mice at day 49 were used to evaluate the amount of serum neutralization antibodies against influenza virus. Titers are expressed as reciprocals of the highest antibody dilution at which cytopathic effects appeared. Bars represent the mean titer of 8 animals in each group.