Figure 2.

Identification and quantitation of a novel subset of B7-H3⁺MDSC in the tumor microenvironment of NSCLC patients. (A) Identification of a novel subset of B7-H3 expressing myeloid-derived suppressor cells (B7-H3⁺MDSCs) in the tumor microenvironment. Single cells from tumor tissues or corresponding normal lung tissues from non-small cell lung cancer (NSCLC) patients (n = 111) were stained with fluorophore conjugated anti-CD45, anti-CD14, anti-HLA-DR, and anti-B7-H3 antibodies. Cells were gated on CD45⁺CD14⁺HLA-DR^−/low cells, and the levels of the B7-H3⁺ MDSC subset was analyzed by fluorescence cytometry. (B) The levels of B7-H3⁺ MDSC subset from tumor tissues or corresponding normal lung tissues from NSCLC patients (n = 111). Wilcoxon matched pairs test were performed and data are represented as median (bar). (C) Distribution of B7-H3⁺MDSC at different sites in the same patients with NSCLC (n = 17). Wilcoxon matched pairs test were performed between blood vs >5 cm region, >5 cm region vs < 2 cm region, and <2 cm region vs tumor nest. (D) Tissue sections from tumor samples were stained with monoclonal antibodies (mAbs) against human B7-H3 and human CD14 and counterstained with DAPI and analyzed with confocal microscopy. B7-H3, green; CD14, red; DAPI, blue. B7-H3⁺CD14⁺ cells are saffron yellow. The micrographs at higher magnification showed the B7-H3⁺CD14⁺ cells (1) and B7-H3⁻CD14⁺ cells (2). Data are representative of 5 independent experiments using samples from 5 NSCLC patients. Scale bar, 20μm.