To further demonstrate that the LGG-MHS + US therapeutic strategy could reduce immunosuppression through improved CRISPR/Cas9 IDO1 knockdown efficiency, the infiltration of regulatory CD3+CD4+Foxp3+ in tumors and overexpression of IDO resulting in accumulation of Tregs and thus blocking the anti-tumor immune CTLs response were investigated. Here, CD4 is linked to neoplasm.