FIG. 1.

Inhibition of K. pneumoniae-induced mortality by ConA. (A) ConA inhibits K. pneumoniae NK-5-induced death in B6 mice in a dose-dependent manner. Groups of 6 to 14 B6 mice were inoculated via the intragastric route with 2 × 10⁸ K. pneumoniae NK-5 cells per mouse. Various doses of ConA were administrated intravenously 2 h before infection followed by ConA treatment at day 3 postinfection. ConA alone at 2 mg/kg of body weight had no effect on mice. Survival curves were compared for significance using the Mantel-Haenszel log rank test of NK-5 plus ConA (1 mg/kg) treatment versus the NK-5 group (P = 0.007) and NK-5 plus ConA (2 mg/kg) treatment versus the NK-5 group (P = 0.033). (B) Increasing the frequency of ConA treatment after K. pneumoniae infection inhibits mouse death. Groups of six B6 mice were inoculated intragastrically with 2 × 10⁸ K. pneumoniae NK-5 cells per mouse. Various doses of ConA were administrated intravenously 2 h before infection followed by ConA treatment every 2 days until day 4 postinfection. Survival curves were compared for significance using the Mantel-Haenszel log rank test of NK-5 plus ConA (1 mg/kg) treatment versus the NK-5 group (P = 0.0196) and NK-5 plus ConA (2 mg/kg) treatment versus the NK-5 group (P = 0.028). (C) Therapeutic effect of ConA against K. pneumoniae NK-5 infection in B6 mice. Groups of 6 to 13 B6 mice were inoculated intragastrically with 2 × 10⁸ K. pneumoniae NK-5 cells per mouse. ConA (1 mg or 2 mg/kg) was administrated intravenously at day 1 and day 3 postinfection. Survival curves were compared for significance using the Mantel-Haenszel log rank test of NK-5 plus ConA (2 mg/kg) treatment versus the NK-5 group (P = 0.0451).