Recognizing that the interaction between streptokinase and plasminogen is species specific, and that the presence of human plasminogen increases the severity of invasive GAS infection in the murine model [7], [8], [9], [11], we crossed the humanized plasminogen mouse line AlbPLG1 with C57 black/6JuPA−/− mice to establish AlbPLG1/uPA−/− infection model. This evidence concerns the gene PLG and infection.