Numerous studies have demonstrated the tumor-promoting role of macrophages in tumors, but the origin and regulatory mechanisms of tumor-infiltrating macrophages remain unclear. Compared to resident macrophages in normal lung tissue, monocyte-derived macrophages in tumors show upregulated IL-4 signaling. This study reveals a novel mechanism by which the IL-4 signaling axis in the bone marrow drives the differentiation of pro-tumor myeloid cells. The TR-FRET IL-4/IL-4Rα assay kit can be used to quantitatively measure the binding activity of IL-4 to its receptor, providing a technical tool for studying the role of this signaling axis in myeloid hematopoietic regulation.
Using Il4raΔMs4a3 tool mice, researchers specifically knocked out IL-4Rα in GMP cells. After tail vein injection of tumor cells, they observed a reduction in monocyte-derived macrophages infiltrating the lungs, decreased lung tumor burden, and an increase in anti-tumor T cells and natural killer cells. In contrast, knockout of IL-4R signaling in common monocyte progenitor cells and granulocyte progenitors had no effect on tumor size, indicating that IL-4Rα signaling primarily functions at the early myeloid progenitor GMP stage in the bone marrow. The TR-FRET IL-4/IL-4Rα assay kit can be used to measure the expression levels and binding activity of IL-4 receptors on the surface of different myeloid progenitor cells, validating this stage-specific role.
In tumor-bearing mice, GMP cells in the bone marrow showed a 2-fold expansion, while Ms4a3-mediated knockout of IL-4Rα restored GMP numbers to normal levels. Detection of the IL-4Rα signaling activation marker pSTAT6 revealed that the bone marrow is the primary site of IL-4Rα signaling in non-small cell lung cancer. Transfer experiments further confirmed that IL-4Rα signaling controls monocyte differentiation. After adding IL-4c, which stabilizes IL-4 half-life, bone marrow monocyte differentiation was enhanced, M2 polarization-related gene expression increased, and cytotoxicity-related gene expression was downregulated. These results indicate that local IL-4 signaling in the bone marrow plays a central regulatory role in pro-tumor myeloid hematopoiesis.
Using IL-4 reporter gene mice, it was found that eosinophils and basophils are the primary producers of IL-4 in the bone marrow. While eosinophils were present in the lungs of tumor-bearing mice, basophils were almost undetectable. To exclude direct effects from the lungs, researchers conducted basophil depletion experiments, observing tumor shrinkage, reduced monocytes and monocyte-derived macrophages in the lungs, and decreased GMP cells in the bone marrow. This discovery highlights the critical role of type 2 granulocytes in the bone marrow as sources of IL-4 in pro-tumor myeloid hematopoiesis. TR-FRET technology can be applied to measure changes in IL-4 secretion levels from basophils under different stimulation conditions.
Researchers further investigated how tumors regulate IL-4 production in basophils. Through multiplex cytokine assays, they identified multiple cytokines in tumor supernatants that synergistically promote IL-4 production by bone marrow basophils. These factors include IL-18, VEGF-A, IL-6, IL-1α, IL-7, CCL3, IL-15, and GM-CSF. This finding reveals the molecular mechanism by which tumors remotely regulate IL-4 production in the bone marrow through soluble factors, establishing a signaling link between tumors and bone marrow hematopoiesis.
After validating the synergistic effects of IL-4 antibody combined with PD-L1 in a mouse lung tumor model, researchers conducted a phase 1 clinical study of IL-4Rα-blocking antibody combined with PD-1/PD-L1 immune checkpoint therapy in non-small cell lung cancer patients. The combined treatment reduced the proportion and number of peripheral blood monocytes, increased effector CD8-positive T cells and plasma cells, and had minimal effects on circulating granulocytes. Analysis of lung puncture tissues showed increased infiltration of CD8-positive T cells, activated dendritic cells, and B cells in lung tissue. Long-term follow-up revealed near-complete remission of lung tumors on PET scans after combined treatment. The TR-FRET IL-4/IL-4Rα assay kit can be used to screen antibody molecules that block IL-4-receptor binding and evaluate their binding affinity and specificity.
This study innovatively proposes that tumors act on eosinophils and basophils in the bone marrow via cytokines, inducing IL-4 production, which then acts on IL-4Rα in GMP cells to drive their differentiation into pro-tumor monocyte-derived myeloid cells. Unlike most studies focusing on how tumor-resident myeloid cells promote tumors, this research emphasizes the origin of myeloid cells, blocking the generation of pro-tumor myeloid cells upstream. TR-FRET technology, as a quantitative detection tool for studying IL-4/IL-4Rα interactions, plays a crucial role in elucidating the mechanism of this signaling axis and screening related regulatory molecules. Future studies will further explore the synergistic effects of targeting the IL-4/IL-4Rα axis with other immunotherapy strategies, providing new insights for tumor immunotherapy.
The "UniOne® TR-FRET Human IL4/IL4RA Binding Kit" (Catalog No.: UA086012), independently developed by Nanjing UA-Bio Technology Co., Ltd. (UA-Bio), is a high-performance analysis platform specifically designed for studying the interaction between interleukin-4 (IL-4) and its specific receptor IL-4Rα. Based on time-resolved fluorescence resonance energy transfer (TR-FRET) technology, this kit accurately and efficiently evaluates the binding activity between human IL-4 and IL-4Rα, providing a stable and reliable standardized solution for research in Th2 immune responses, allergic disease mechanisms, drug screening, and other fields.
| Core Product Advantages | Detailed Parameters / Functional Description |
|---|---|
| High Purity and Intact Biological Activity | The core components of the kit include high-purity, biologically active human IL-4 protein and IL-4Rα receptor, validated through multi-dimensional quality control. Both maintain correct native conformations and intact binding functions, accurately simulating the specific high-affinity binding of IL-4 to IL-4Rα under physiological conditions, ensuring experimental data accuracy, reproducibility, and functional relevance. |
| Excellent Batch-to-Batch Consistency and Stability | Relying on an internationally leading protein expression platform and highly standardized production processes, combined with a strict quality control system, the product exhibits outstanding long-term stability and excellent batch-to-batch consistency, providing solid and reliable quality assurance for long-term, continuous drug screening and mechanistic research. |
| Ready-to-Use Flexible Experimental Platform | This kit, based on homogeneous TR-FRET technology, adopts a simple "add-incubate-read" operation mode without cumbersome washing steps. Its optimized formulation is compatible with multi-well plate (96/384-well) automation platforms, flexibly applicable to various research needs such as anti-IL-4 antibody/antagonist screening, receptor blocker evaluation, competitive binding assays, affinity analysis, and biosimilar activity assessment. |
| Complete Solution and Professional Support | We provide fully validated standard protocols, typical dose-response curves, and detailed result interpretation guidelines to help quickly establish stable and reproducible experimental workflows. Nanjing UA-Bio's professional technical team offers comprehensive technical consultation and support for research design, experimental optimization, and data analysis. |
Nanjing UA-Bio Technology Co., Ltd. is committed to providing cutting-edge, high-quality core reagents and tools for immunology, cell therapy, and innovative drug development. For detailed technical parameters, validation data, or specific application inquiries regarding the "UniOne® TR-FRET Human IL4/IL4RA Binding Kit" (Catalog No.: UA086012), please feel free to contact us.
