MMP9 and infection: The activity of proMMP-9 increased by ∼6 fold in PPARγVillinCre- mice and ∼15 fold in PPARγVillinCre+ mice after infection, while MMP-9 activity rose from ∼4 fold in PPARγVillinCre- mice to ∼7 fold in PPARγVillinCre+ mice after infection (Fig. 5A and B).