Table 2.

Immunization of rhesus monkeys with BPIV3/HPIV3 chimeric recombinants induces resistance to challenge with wild-type HPIV3 28 days later

Immunizing virusaNo. of animalsbMean peak virus titerc following challenge (log10 TCID50/ml ± SE) [Duncan grouping]dSerum HAI antibody titer (mean reciprocal log2 ± SE) for HPIV3 [Duncan grouping] for:
Nasopharyngeal swabeTracheal lavagefOn the day of challenge28 days after challenge
None44.5 ± 0.33 [A]4.5 ± 0.19 [A]<212.0 ± 0.58 [A]
rHPIV362.3 ± 0.14 [B]1.2 ± 0.20 [B]9.5 ± 0.72 [A]11.7 ± 0.21 [A]
rBPIV3-FHHNH 42.5 ± 0.25 [B]1.0 ± 0.48 [B]6.8 ± 0.63 [BC]10.5 ± 0.29 [AB]
rHPIV3-NB 62.3 ± 0.41 [B]1.4 ± 0.08 [B]8.2 ± 0.48 [AB]11.5 ± 0.22 [A]
rHPIV3-FBHNB 43.0 ± 0.14 [B]1.0 ± 0.0 [B]4.5 ± 0.29 [D]9.5 ± 0.87 [B]
BPIV3 Ka62.9 ± 0.26 [B]1.3 ± 0.20 [B]5.5 ± 0.62 [CD]9.3 ± 0.76 [B]
  • a Each previously immunized monkey and nonimmunized controls were challenged with 106TCID50 of HPIV3 JS in a 1-ml inoculum at each site.

  • b The groups with six animals contain four animals each from a previous rhesus study (1).

  • c Mean of peak virus titer for each animal in its group irrespective of sampling day.

  • d Virus titrations were performed on LLC-MK2 cells. The limit of detectability of virus titer was 10 TCID50/ml. Mean viral titers were compared using a Duncan multiple range test (α = 0.05). Within each column, mean titers with different letters are statistically different. Titers indicated with two letters are not significantly different from those indicated with either letter.

  • e Nasopharyngeal swab samples were collected on days 3 to 8 postchallenge.

  • f Tracheal lavage samples were collected on days 4, 6, and 8 postchallenge.