7/8/2023 0 Comments Irip antibody( A) Flow cytometry pseudocolor plots from analyzed BM of all NOD/SCID mice transplanted with sample AML2 and treated with mAb81.2 or isotype control antibody. Treatment with mAb81.2 has an antileukemic effect in mice engrafted with primary human AML cells. P values were calculated with Student’s t test. ( F) Absorbance of NF-kβ activation in the HEKblue IL1R1 reporter cell assay in the absence of IL-1 with IL1RA included as a control (one representative experiment out of three). The graph shows the NF-kβ activation measured by absorbance in the presence of IL-1 upon addition of mAb81.2 or mAb3F8 or an isotype control antibody (means ± SEM from technical duplicates one representative experiment out of three). ( E) IL-1 activates NF-kβ in the HEKblue IL1R1 reporter cell line. Graphs show BM ( C) and spleen ( D) leukemic cell frequency at death 39 d after transplantation (means ± SD). ( C and D) NSG mice were engrafted with MA9Ras cells and treated with mAb81.2 or an isotype control antibody ( n = 5 in both groups). Staurosporine treatment (STP) was used as positive control for apoptosis (means ± SEM from three experiments with technical duplicates). ( B) Relative levels of viable, apoptotic, and necrotic MA9Ras cells after treatment with 10 μg/mL mAb81.2, mAb3F8, or an isotype control antibody. ( A) Fold expansion of MA9Ras cells in suspension cultures with addition of 10 μg/mL IL1RAP-targeting antibodies mAb81.2 and mAb3F8 or an isotype control antibody (means ± SEM from four experiments with technical duplicates). (Scale bars, 300 μm.) Unless otherwise stated, P values were calculated with Student’s t test.Īntileukemic in vivo effect on MA9Ras cells depends on murine effector cells. ( H) H&E-stained and human CD45-immunostained BM sections from representative isotype control and mAb81.2-treated mice. ( F and G) Leukemic cell frequency in BM and spleen (means ± SD). P value was calculated by using the Mantel Cox log rank test. ( E) Overall survival rates with mAb81.2 (median 75 d) compared with isotype control (median 64 d). ( D) Leukemic cell frequency in PB 62 d after transplantation (means ± SD). ( B and C) Frequency of leukemic cells and platelet counts in PB 35 d after transplantation of MA9Ras AML cells into NOD/SCID mice treated with the IL1RAP-targeting antibody mAb81.2 or a mIgG2a isotype control antibody (means ± SD n = 7 in both groups). ( A) Expression of IL1RAP on the surface of human MA9Ras AML cells (red, isotype control blue, anti-IL1RAP) using flow cytometry analysis. ![]() Treatment with mAb81.2 has antileukemic effects and prolongs survival in the MA9Ras xenotransplantation model. ![]() Collectively, these results provide important evidence in support of IL1RAP as a target for antibody-based treatment of AML.ĪML IL1RAP antibody immunotherapy leukemia. Hence, IL1RAP can be efficiently targeted with an anti-IL1RAP antibody capable of both achieving antibody-dependent cellular cytotoxicity and blocking of IL-1 signaling as modes of action. Because IL-1 signaling is important for the growth of AML cells, we generated an IL1RAP-targeting antibody capable of blocking IL-1 signaling and show that this antibody suppresses the proliferation of primary human AML cells. We demonstrate that effector-cell-mediated killing is essential for the observed therapeutic effects and that natural killer cells constitute a critical human effector cell type. We show here that monoclonal antibodies targeting IL1RAP have strong antileukemic effects in xenograft models of human AML. The interleukin 1 receptor accessory protein (IL1RAP IL1R3) is expressed on candidate leukemic stem cells in the majority of AML patients, but not on normal hematopoietic stem cells. Acute myeloid leukemia (AML) is associated with a poor survival rate, and there is an urgent need for novel and more efficient therapies, ideally targeting AML stem cells that are essential for maintaining the disease.
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