TABLE 2.

Immunogenicity and protective efficacy of HPIV3/EboGP and HPIV3/EboGP-NP in guinea pigs

Immunizing virus (no. of animals)Response to immunization (reciprocal log2 ± SE)aResponse to challenge with EV (mean ± SE)b
Antibodies to HPIV3 (HAI)Antibodies to EV (ELISA)EV antigen in blood (ELISA, reciprocal log2), day 7EV titer in blood, (PFU/ml, reciprocal log10), day 7Mortality, %Antibodies to EV (ELISA, reciprocal log2)
Day 0Day 28Day 0Day 28Day 7Day 22
HPIV3 (9)<2.07.7 ± 0.2<7.6<7.613.9 ± 0.36.7 ± 0.2c100<7.6dNDe
HPIV3/EboGP (10)<2.06.6 ± 0.1<7.613.6 ± 0.0<4.3<1.0014.2 ± 0.316.0 ± 0.3
HPIV3/EboGP-NP (9)<2.07.3 ± 0.2<7.613.9 ± 0.2<4.3<1.0014.1 ± 0.317.2 ± 0.3
  • a Animals were immunized on day 0 with a single intranasal inoculation of 105.3 PFU of the indicated virus. Reciprocal log2 of serum endpoint dilutions are indicated.

  • b Animals were challenged on day 28 (day 0 of the challenge) with 103 PFU of EV administered intraperitoneally.

  • c For the animals that had EV titers in blood exceeding 7.2 × 107 PFU/ml, that value was assigned for calculation of the mean.

  • d Antibody levels were below the detection limit in all animals except for a single animal (animal 7), in which a titer of EV-specific antibodies at the level of 1:1,280 was detected.

  • e ND, not determined. The animals in this group developed EV infection and died on days 8 to 10 postchallenge.