Table 1.

Pulmonary clearance and phagocytic cell counts following mucosal immunization with OMP26 and challenge by homologous and nonhomologous NTHI strains

Rat groupbSampleMeanH. influenzae recovered 4 h postchallenge (log10 CFU)a ± SEM (% clearance)Total no. of cells (106) in BAL (mean ± SEM)
NTHI-INTHI-IINTHI-INTHI-II
NonimmuneBAL7.01 ± 0.116.28 ± 0.0715.9 ± 1.117.5 ± 3.0
Lung7.76 ± 0.056.69 ± 0.05
OMP26 immunizedBAL6.15 ± 0.15 (87)c 5.15 ± 0.16 (93)c 26.1 ± 1.1c 28.2 ± 1.6c
Lung6.81 ± 0.17 (89)c 6.01 ± 0.19 (80)c
  • a Values for rats challenged for 4 h with live bacteria from either NTHI-I or NTHI-II strains on day 21 after IPP immunization with 10 μg of OMP26. All rats received an i.t. boost (10 μg) on day 14. Nonimmune rats were a combination of sham-treated and untreated animals, with no difference in response observed between animals. The concentration of live bacteria in the challenge inoculum (as determined by plating of serial dilutions) was 10.38 (log10) CFU per ml for NTHI-I and 10.17 (log10) CFU per ml for NTHI-II.

  • b n = 4 per group for challenge with NTHI-I; n = 4 for nonimmune and n = 6 for OMP26-immunized groups for challenge with NTHI-II.

  • c P < 0.005 compared to nonimmune group.