Figure 7.

Killer artificial antigen-presenting cells (KaAPCs) circulate into secondary lymphoid organs and colocalize with CD8⁺ T cells. KaAPCs were coupled with R-phycoerythrin (PE)-labeled streptavidin and characterized by flow cytometry (A) and then injected i.v. into recipient bm1 mice on days 9, 11, and 13 after transplantation as described. At 12 h after the final injection, spleen and lymph nodes (LNs) were harvested from recipients. LNs and half of spleen were processed into single cell suspensions and freshly detected by flow cytometry without any staining. (B) A visible population of PE-KaAPCs was found in spleen and LNs, respectively. n = 3 mice in each group. Representative dot plots for flow cytometry analyses were presented in panel (C). Another half of spleen was embedded into O.C.T. followed by frozen section preparation and IHC staining with fluorescein-5-isothiocyanate (FITC)-labeled-anti-mouse CD8a and DAPI. Confocal photomicrographs of PE-KaAPCs and CD8⁺ T cells in spleen section were presented in panel (D), at 100× magnification. ***p < 0.001.