Page 221 - Haematologica Vol. 110 - January 2025

LETTER TO THE EDITOR AB
Figure 1. TIB-49 cells acquire Cd39 from host cells and levels of Cd39 expression promote TIB-49 AML cell engraftment in vivo. (A) To track the engraftment of TIB-49 in vivo, TIB-49 cells were transduced with TdTomato and then administered intravenously via the tail vein into mice. The figure shows the altered patterns of Cd39 expression on transplanted TIB-49 cells obtained from blood, spleen, and bone marrow (BM) of wild-type mice and Cd39-/- mice. (B) Schematic dia- gram depicting proposed trogocytosis and membrane transfer resulting in changes in Cd39 levels on transplant- ed TIB-49 and recipient cells. (C) C57BL/6 wild-type (WT) and Cd39-/- mice were inoculated with 1×106 TIB-49 cells (TdTomato+) through tail vein in- jection. Quantification of TIB-49 cell percentages in blood, spleen, and BM of TIB-49-inoculated WT and Cd39-/- mice was analyzed at day 31. Data are shown as mean ± standard error of mean. A t test was used for the sta- tistical analysis. *P<0.05. NS: not sig- nificant. (D) TIB-49-luciferase/mCher- ry cells were retro-orbitally inoculated into WT and Cd39-/- mice for biolumi- nescence imaging experiments. Com- pared with leukemia cell engraftment in WT mice, engraftment was delayed in Cd39-/- mice with decreased disease burdens. (E) TIB-49 and TIB-Cd39high cell proportions in blood, splenocytes and BM of WT mice were analyzed at day 19. (F) Survival of TIB-49 (N=9) and TIB-Cd39high (N=10) bearing mice was compared. The log-rank test was used for statistical analyses.
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