These findings were in accordance with the results of our previous studies that down-regulation of activity of CD4+CD25+ Tregs through Astragalus Polysaccharides or high mobility group box-1 protein marked enhanced cell-mediated immunity by modulating the proliferation of CD4+CD25− T cells and the polarization of helper T cells, which was associated with improvement in outcome of burn-induced septic mice and decreasing the probability of secondary infection with P. aeruginosa26, 43, 44. This evidence concerns the gene CD4 and infection.