GIFT15 and allogeneic tumor transplantation. (A) GIFT15 direct effect on the 2-way MLR. Purified GIFT15 (0.18 pmol) was added directly to 1.5 × 105 BALB/c + 1.5 × 105 C57Bl/6 splenocytes for 72 hours. The supernatant was tested by ELISA for IFN-γ. Every condition was performed in sixplicata ± SED (P < .001 between MLR condition containing GIFT15 and BALB/c + C57BL/6 only). (B) Effect of GIFT15 on B16F0 tumor growth in allogeneic BALB/c mice. Live B16-GFP or GIFT15 cells (107) were transplanted subcutaneously in immunocompetent BALB/c mice (n = 10), and tumor volume was monitored over time. The GIFT15 experiment had to be stopped by day 28 after transplantation due to large tumors developed by these mice (P < .05 between B16-GIFT15 and GFP group). Results are shown as mean tumor volume ± SED. (C) GIFT15 BALB/c mice developed splenomegaly. Splenomegaly was observed in mice that had received a transplant of a GIFT15 tumor, based on the spleen's weight characterized by white pulp structural loss as shown by H&E staining. Spleens from naive or B16-GFP mice were used for comparison. Results are shown as mean ± SED. (D) Increased T- and NK-cell number within the GIFT15 group. Flow cytometry analysis performed on splenocytes from GIFT15 or GFP mice revealed a significant increase in the absolute number of T and NK cells (n = 3; P < .02 between the GIFT15 and GFP group). Results are shown as mean average of triplicate ± SED.
