Table 1.

Immunity correlates with serum treponemicidal activity and TROMP aggregation

Rabbit serum (n)Immune statusaTEbOM fracture-face observationsTotal no. of particles/μm2% Aggregationc
Group A (17)Susceptible≤1:1245416.5 ± 5.6
Group B (17)Partial1:16204118.9 ± 6.5
Group C (16)Complete1:128207988.6 ± 5.4d
NormalSusceptible0214813.4 ± 4.2
ImmuneComplete1:128205353.9 ± 7.8d
  • a Immune status of infected, treated, and challenged rabbits. Susceptible, dark-field microscopy-positive lesions and disseminated infection; partial, dark-field microscopy-negative lesions and no disseminated infection; complete, no lesions or disseminated infection.

  • b The TE was determined as the final serum dilution which immobilized ≥50% of a treponemal suspension incubated for 16 h in the presence of complement.

  • c Percent aggregation (mean ± standard error) was determined from the number of aggregates consisting of two or more particles and the total number of particles counted.

  • d P < 0.0001, compared with the results for the susceptible animals and normal control animals.