Survival, weight changes, and organ pathology scores of BALB/c hosts that received 500 BCL₁ lymphoma cells followed by transplantation of TCD BM from C57BL/6 donors with or without sorted naive, memory, or total CD8⁺ T cells. The hosts received 500 BCL₁ lymphoma cells 6 hours after irradiation. (A) Survival of irradiated hosts given 2 × 10⁶ TCD BM cells from C57BL/6 donors with or without (n = 10) 0.5 × 10⁶ sorted naive T cells (n = 14), memory T cells (n = 12), or total CD8⁺ T cells (n = 10). The data were pooled from 2–4 independent experiments. (B) Percentage of starting body weight of host mice given TCD BM with or without sorted naive, memory, or total CD8⁺ T cells as in panel A. Brackets show SEs of the mean. (C) Histopathologic changes induced with naive, memory phenotype, or total CD8⁺ T cells and TCD BM only. Representative tissue sections were obtained from the hosts from panel A. Histopathologic specimens from the liver and large intestines of surviving hosts were obtained at 100 days after transplantation and fixed in formalin before embedding into paraffin blocks. Tissue sections of 4- to 5-mm thickness were stained with hematoxylin and eosin. Microscopic images were obtained using an Eclipse E1000M microscope (Nikon) with a SPOT RT digital camera and acquisition software (SPOT advanced 4.6, Diagnostic Instruments) with a final magnification of 300× for all images. Image processing was performed with Adobe Photoshop CS with standard adjustments of brightness, contrast, and color balance to the entire image. Histopathology at day 21 in the TCD BM group is shown (top photos). Except for rare apoptosis (arrow left photo), there is no evidence of GVHD in the colon, but lymphoma is evident (arrowhead right photo) in the liver. In the naive group (second row photos), there was no evidence of GVHD in the colon. Liver portal tracts have prominent lymphocytic infiltrates compatible with grade II GVHD (* right photo). In the memory group (third row of photos), there is no evidence of GVHD or lymphoma in either colon or liver. In TCD BM with total CD8⁺ T-cell group, increased apoptosis was seen in colonic crypts (arrow), along with increased lamina propria inflammation (open arrowhead left photo fourth row). Similarly, portal inflammation and bile duct injury (*) was seen in liver and was compatible with GVHD. Tissue sections were stained with hematoxylin and eosin. Each photo is representative of 5-10 hosts examined. (D) Mean (± SE) of histopathologic GVHD scores of liver, small bowel, and colon on day 21 or 100 from the 4 groups (n = 6 per group). NS indicates not significant; P > .05.