Morphologic and immunophenotypic characteristics of CD34⁺ cells stimulated by allogeneic T cells. (A) Freshly isolated CB CD34⁺ cells were mixed with irradiated autologous CB (AUTOLOGOUS) or allogeneic blood (ALLOGENEIC) T cells at a 1:2 S/R ratio, or with medium alone (MEDIUM), for 6 days and then were analyzed for CD86 and CD1a expression by flow cytometry. The proportion of positive cells is shown in each quadrant. This result is representative of 3 separate experiments. (B) Cytospins of freshly isolated CB CD34⁺ cells (left), or CB CD34⁺ cells that had been in culture with allogeneic T cells for 6 days and then separated on ficoll-gradient (right), were stained with May-Grünwald-Giemsa. Images were visualized under an Axioskop 2 microscope equipped with a 63 ×/1.4 oil-immersion objective lens (Zeiss, Thornwood, NY). Images were captured with a Zeiss Axiocam camera and Zeiss Axiovision software version 3.1, and processed with Adobe Photoshop 5.5 software (Adobe Systems, San Jose, CA). (C) The phenotypic expression of markers such as HLA-DR, CD86, CD40, CD14, and CD11c was evaluated in CD34⁺ cell-derived APCs obtained after culture with allogeneic T cells. The proportion of positive cells is shown in each quadrant. The results are representative of 3 separate experiments.