Fig. 2.
Mice sensitized to E. coli asparaginase developed asparaginase-induced hypersensitivity reactions when challenged. (A) The rectal temperature of sensitized (○) and nonsensitized (□) mice was monitored for 2 hours after intravenous administration of E. coli asparaginase (100 μg) at day 24 (as per Fig. 1A). (B) Compared with nonsensitized controls, sensitized mice with asparaginase-induced allergies experienced a drop in rectal temperature that was quantified by the AUC of the rectal temperature versus time curve (P = 3.3 × 10−10). (C) Sensitized mice had low to no detectable asparaginase activity (P = 4.2 × 10−13) and (D) developed high anti-asparaginase IgG antibody titers compared with nonsensitized mice (red open circles, P = 1.1 × 10−7). Sensitized mice showed a drop in antibody levels when comparing the prechallenge and postchallenge samples at day 23 versus day 24 (red versus black open circles, P = 6.7 × 10−5), suggesting the formation of asparaginase–anti-asparaginase IgG immune complexes. (E) Sensitized mice with asparaginase-induced allergies had elevated levels of mMCP-1 compared with nonsensitized mice in samples collected 2 hours after the challenge (P = 6.1 × 10−3).