Targeting tumor-associated macrophages as a novel strategy against breast cancer
J. Clin. Invest. Yunping Luo, et al. 116:2132 doi:10.1172/JCI27648 [Go to this article.]

Figure 4
MHC class I antigen–restricted specific CD8⁺ T cell response against legumain-expressing cells. (A) DNA vaccination enhances expression of costimulatory molecules by DCs. Lymphocytes from Peyer’s patches obtained 3 days after vaccination were stained with FITC-labeled anti-CD11cAb in combination with PE-conjugated anti-CD80, anti–MHC class I, or anti-CD40 Abs. *P < 0.05 compared with control groups. (B) Intracytoplasmic IFN-γ release of CD8⁺ T cells was measured by FACS analysis. **P < 0.005 compared with control groups. (C) Production of specific IFN-γ was verified at the single-cell level by ELISPOT. This is indicated for lymphocytes from immunized mice restimulated with either legumain⁺ 4T1 tumor tissue cells or legumain^– 4T1 cells, as indicated by the number of immunospots formed per well. **P < 0.005 compared with treatment group without stimulation; ^##P < 0.005 compared with control groups. (D) Splenocytes isolated from treated mice were effective in killing TAMs according to a ⁵¹Cr release assay (^#P < 0.01 compared with control groups). Inhibition experiments with Abs against H-2K^d/H-2D^d MHC class I antigens showed that T cell–mediated tumor cell lysis was MHC class I antigen restricted. Furthermore, in vivo depletions of CD4⁺ or CD8⁺ T cells indicated that lymphocytes isolated from vaccinated mice, which were thereafter depleted of CD8⁺ T cells, failed to induce cytotoxic killing of target cells. However, depletion of CD4⁺ T cells did not abrogate cytotoxic killing of these same target cells. ^#P < 0.01 compared with PBS or empty vector group.