Figure 4. Depletion of Gr-1⁺ cells ablates detectable MMP-9 activity in lungs of challenged mice.

Mice were treated with anti-Gr-1 or control mAb followed by DO Th1 and Th2 cells and challenged with the low dose of OVA. (A) 12 h later, proteins were extracted from lungs and analyzed by PAGE-zymography to identify the activities of MMP-2 and MMP-9. (B) Gelatinase activities in the PAGE zymograms were quantified using a Kodak Image Analysis workstation. The signals for MMP-9 activity from the lungs of mice that were treated with the anti-Gr-1 mAb were below the detection limit; therefore, the observed differences compared to the signals in mice that received the control mAb were highly significant. Data shown are representative of three independent experiments, each with 2 animals per group.