B7-H1 expression is associated with expansion of regulatory T cells in colorectal carcinoma

Figure 1 B7-H1 and CD3 immunostaining of colorectal carcinoma tissues. A and B: B7-H1 immunostaining in colorectal carcinoma tissues (A: Magnification 400 ×; B: Magnification 200 ×); C: B7-H1 immunostaining in normal colorectal tissues; D: Negative control in colorectal carcinoma tissues; E and F: CD3 stained infiltrating T lymphocytesb (E: Tumor stroma; F: Tumor nest).

Figure 2 B7-H1 expression level in colorectal carcinoma tissues and adjacent normal tissues from 33 patients evaluated by immunohistochemisty. IHC: Immunohistochemisty.

Figure 3 An elevated CD4⁺Foxp3⁺ and CD8⁺Foxp3⁺T cell amount observed in B7-H1^high colorectal carcinoma tissues. Mononuclear cells were harvested from fresh tumor tissues (A) and the peripheral blood (B) of the same colorectal carcinoma patient. The percentage of the Foxp3⁺ T cells was determined by fluorescence-activated cell sorting analysis. A: The population of CD4⁺Foxp3⁺ and CD8⁺Foxp3⁺T cells was increased remarkably in B7-H1^high colorectal carcinoma (CRC) tissues compared with B7-H1^low CRC tissues; B: In peripheral blood, there was no significant diversity of regulatory T cells between the B7-H1low and B7-H1high CRC patients.

Figure 4 PD-1 expression on CD4⁺Foxp3⁺ or CD8⁺Foxp3⁺ regulatory T cells and conventional T cells in colorectal carcinoma tissues. Mononuclear cells were harvested from fresh tumor tissues of the same colorectal carcinoma patient. The PD-1 expression was determined by fluorescence-activated cell sorting analysis, gated on CD4⁺Foxp3^+/- or CD8⁺Foxp3^+/- T cells. A: CD4⁺Foxp3⁺ regulatory T cells could hardly express PD-1 on the cell surface, while PD-1 expression level was significantly higher on the conventional CD4⁺T cells; B: CD8⁺Foxp3⁺ regulatory T cells almost failed to express PD-1, while PD-1 expression was significantly higher on the conventional CD8⁺T cells as well.