Expression of ICOSLG on Mouse Hematologic Neoplasm Cell Lines and Their Influence on Cytotoxicity in Allogeneic Mixed Lymphocyte Reactions

Abstract

In this study, we sought to determine whether the expression of inducible co-stimulator ligand (ICOSLG) on mouse hematologic neoplasm cells influences cytotoxicity. Using flow cytometry, we examined the expression of ICOSLG in mouse hematologic neoplasm cell lines for the first time and used FBL3/A20 as targets to study. Effectors and targets were incubated at effector:target (E:T) ratios ranging from 5:1 to 50:1 for 10 h. Enzyme-linked immunosorbent assay was used to assess the expression of cytokines associated with type 2 T helper cells. We found that FBL3, A20 and P388 cells expressed ICOSLG. At E:T ratios ranging from 20:1 to 30:1, the cytotoxic activity of alloreactive T cells was significantly increased when ICOSLG was blocked (p < 0.05). We also found that ICOSLG blockade was associated with decreased expression of interleukin 4 and interleukin 10. Our results indicate that ICOSLG blockade may enhance cytotoxity in allogeneic mixed lymphocyte–hematologic neoplasm cell reactions.