Figure 5.

Human hematopoietic cells undergo apoptosis in response to murine sepsis. Eight weeks post-transplantation, humanized mice underwent sham or CLP surgery. Twenty-four hours later, mice were killed and spleens harvested. (A–C) Conventional bright-field microscopy of H&E-stained tissue sections shows normal-appearing splenocytes in a sham-operated mouse (representative of five sham mice). For CLP, sections of two representative mice out of five are shown. (B) H&E staining of Mouse 1, which received CLP, demonstrates germinal centers with foci of cells with compacted and fragmented nuclei, diagnostic of apoptotic cell death (×400 original). (C) H&E staining of Mouse 2 with CLP demonstrates apoptotic cells in the region of the periarteriolar lymphoid sheath (×400 original). (D) Flow cytometry detection of apoptosis by TUNEL and active caspase 3. The increase in lymphocyte apoptosis observed in H&E color photomicrographs was confirmed for human T cells and human B cells in mice by two independent staining methods: TUNEL and staining for active caspase-3.