CD19 and neoplasm: The siPD-L1@PLGA-treated mice exhibited more tumor-infiltrated lymphocytes (TILs) than the only vehicle-treated control mice (although the difference was not statistically significant; see Section 4), as evidenced by an increased CD45+CD3+ (T cells) or CD45+CD19+ (B cells) population (Figure 4B for count and Supplementary Figure S4A for composition, which was increased from 5.6% to 8.0%).