Fig 1.
ELISA was used to determine the titer of IgG-pcAb.
In brief, 96-well plates were pre-coated with 56601 or 56606. The concentration of purified rabbit-raised antibodies was adjusted to 20 mg/ml and then added to the well by a two-fold serial dilution (210 to 227). The OD450 was then determined. Data were presented as the mean from two separate experiments, each individually conducted in triplicate.
Table 1.
Leptospiral agglutinating activity of antisera
Fig 2.
Survival of hamsters with acute leptospirosis treated with IgG-pcAb.
(A) Efficacy of IgG-pcAb (16, 8, 4, 2, 1and 0.5 mg/kg) for treating acute homologous (56601) leptospirosis. (B) Efficacy of IgG-pcAb (16 and 8 mg/kg) for treating acute heterologous (56606) leptospirosis. Survival differences between study groups were compared using the log-rank test. *P<0.05, **P<0.01 and ***P<0.001 vs. the control group.
Fig 3.
Survival of hamsters treated in the late leptospirosis.
Efficacy of IgG-pcAb (16 mg/kg), antibiotic (doxycycline, 5mg/kg) and combination (pcAb plus antibiotic) were evaluated in treating acute and late homologous (56601) leptospirosis. Survival differences between study groups were compared using the log-rank test. *P<0.05 vs. the control group.
Fig 4.
Histopathology and scores of kidney, liver and lung after infection with Leptospira interrogans serogroup Lai (56601) or Autumnalis (56606).
(A) Histopathology scores of the kidney, liver and lung in hamsters. The data represent the mean histopathology scores for the two groups of hamsters. Statistical analysis of results for infected controls (n = 8) and pcAb group (n = 8) was performed using the Wilcoxon rank sum test. *p < 0.05. (B) Tukey-Kramer pair-wise comparisons with the control. (C) Histopathology of the kidney (a, d), liver (b, d), and lung (c, f) of infected controls (a, b, c) and the pcAb group (d, e, f) after infection with leptospira in hamsters. These representative photographs were selected from hamsters infected 56601 or 56606.
Fig 5.
56601 (A) and 56606 (B) burden of primary organs (kidney, liver and lung) as determined by qPCR. The results are presented as the number of genome equivalents per μg kidney, liver and lung DNA with a scatter dot plot. Each dot represents a positive sample of organs. The results were presented as the mean from two separate experiments, each individually conducted in triplicate.