Table 2.

Antiviral antibody responses to recombinant H3HA or H5HA antigen after vaccination with H3N2 virus

Coating antigenTreatmentVaccination routeaAntiviral antibody titerb
Serum IgGLung IgGSerum IgALung IgA
H3HALT(R192G)i.n.<250<25<250<25
H3N2i.n.1 × 106 6,40016,0001,600
H3N2 and LT(R192G)i.n.1 × 106 6,40064,00025,600
LT(R192G)s.c.<250<25<250<25
H3N2s.c.256,000<25<250<25
H3N2 and LT(R192G)s.c.1 × 106 1,600<250<25
H5HALT(R192G)i.n.<250<25<250<25
H3N2i.n.16,000100250400
H3N2 and LT(R192G)i.n.64,000400250400
H1N1 and LT(R192G)i.n.64,0001,6001,0001,600
Live H3N2i.n.1,000<25<250<25
LT(R192G)s.c.<250<25<250<25
H3N2s.c.<250<25<250<25
H3N2 and LT(R192G)s.c.<250<25<250<25
  • a Mice received three inoculations at weekly intervals of 20 μg of formalin-inactivated H3N2 (X-31) or H1N1 (A/TW) virus plus 2 μg of LT(R192G) or 2 μg of LT(R192G) alone. Two weeks after the final vaccine boost, five mice from each vaccine and LT(R192G) control group were euthanatized for serum and lung wash collection. Samples pooled from five mice per group were used.

  • b ELISA plates were coated with 2 μg of bromelain-cleaved, purified H3HA or 2 μg of purified rH5HA protein. Titers are expressed as the highest dilution of serum having a mean optical density at 405 nm greater than the mean plus two standard deviations of similarly diluted LT(R192G) control serum.