B7-H3 is a type I transmembrane protein belonging to the B7 family of co-stimulatory and co-inhibitory molecules, encoded by chromosome 15q24. It consists of an extracellular domain, a transmembrane domain, and a short intracellular domain without known signaling motifs. B7-H3 exists in two isoforms: 2IgB7-H3, composed of one pair of immunoglobulin variable-like and constant-like extracellular domains, and 4IgB7-H3, containing two identical pairs of IgV-like and IgC-like extracellular domains, with the latter being the predominant isoform in human cells. The precise biological functions and receptors of B7-H3 remain unelucidated, as it appears to function as both a co-stimulatory and co-inhibitory molecule depending on the immune cell type and microenvironmental conditions. FITC-labeled B7-H3/CD276 Fc chimera protein can be used to quantitatively assess B7-H3 protein expression levels and binding activity, providing a technical tool for tumor immunotargeting therapy research.
In non-malignant tissues, B7-H3 plays a significant role in adaptive immunity by modulating T-cell function. Although early studies supported its role as a co-stimulatory molecule essential for T-cell activation, recent research indicates that B7-H3 primarily exerts inhibitory effects in adaptive immunity, suppressing T-cell activation, proliferation, and the release of effector cytokines such as IFN-γ and IL-2. In mice, B7-H3 appears to have anti-tumor functions mediated by CD8-positive T cells and NK cell activation, potentially through binding to the Trem-like transcript 2 receptor on CD8-positive T cells. The role of B7-H3 in the tumor microenvironment is more complex, with its function likely dependent on specific immune cell types and microenvironmental conditions.
Overwhelming evidence suggests that B7-H3 has pro-tumor effects. Numerous preclinical and clinical studies demonstrate that B7-H3 suppresses tumor antigen-specific immune responses through multiple mechanisms, including reduced immune cell infiltration into tumors, inhibition of NK cell-mediated tumor cell lysis, increased regulatory T-cell infiltration, decreased release of effector cytokines, and suppression of key transcription factors. These mechanisms contribute to aggressive cancer biology and metastatic potential, ultimately leading to poor prognosis. Additionally, B7-H3 appears to promote cancer progression through non-immune functions, such as enhancing cancer cell migration, invasion, and metastatic potential, increasing chemotherapy resistance, and promoting pro-tumor metabolic profiles. B7-H3 also participates in angiogenesis and gene regulation via epigenetic modifications during tumor progression. FITC-labeled B7-H3/CD276 Fc chimera protein can be used to study interactions between B7-H3 and potential receptors, providing quantitative analytical tools for mechanistic research.
B7-H3 expression is restricted in normal tissues. Extensive immunohistochemical analysis of normal tissues reveals that B7-H3 is expressed at low levels or undetectable in most tissues. Staining with B7-H3-specific monoclonal antibodies on tissue microarrays shows only weak cytoplasmic staining in salivary gland acinar cells, gastric epithelial cells, and adrenal cells. Other studies have observed weak basolateral membrane staining in the stomach, gallbladder, prostate, cervix, and endometrium. In contrast, B7-H3 is widely expressed in primary malignant tumors. Multiple studies indicate B7-H3 expression rates of 33.0% in renal cell carcinoma and 91.8% in hepatocellular carcinoma. Among gastrointestinal tumors, hepatocellular carcinoma exhibits the highest frequency of B7-H3 expression, while gastric cancer shows the lowest. In genitourinary malignancies, renal cell carcinoma has the lowest expression frequency, whereas ovarian cancer has the highest. Across all cancer types, the cumulative frequency of B7-H3 positivity is 59.5%. FITC-labeled B7-H3/CD276 Fc chimera protein can be used to assess B7-H3 expression distribution in tumor tissues, providing quantitative data for target validation.
In addition to high expression on cancer cells, B7-H3 is also highly expressed on stromal fibroblasts and tumor-associated blood vessels within the tumor microenvironment. This expression pattern may allow B7-H3-targeted therapies to eliminate cancer cells that do not express detectable levels of B7-H3. The expression of B7-H3 on tumor-associated blood vessels provides a novel target for anti-angiogenic therapy. B7-H3 expression on stromal fibroblasts contributes to the immunomodulatory suppression within the tumor microenvironment. This broad expression profile makes B7-H3 an attractive target for tumor-targeted therapies, particularly for highly heterogeneous solid tumors. FITC-labeled B7-H3/CD276 Fc chimera protein can be used to evaluate B7-H3 expression levels across different cell types in the tumor microenvironment.
Currently, B7-H3-targeted immunotherapy strategies have been tested in various cancer types. Due to its critical role in tumor immune evasion, B7-H3 has emerged as a promising immunotherapeutic target. The broad applicability of B7-H3-targeted strategies is demonstrated by the diverse effector mechanisms tested, including blocking antibodies, radioisotope conjugates, antibody-drug conjugates, bispecific and trispecific antibodies, Fc-enhanced monoclonal antibodies, and B7-H3-specific CAR-T cells. Antibody-drug conjugates precisely deliver cytotoxic agents to B7-H3-positive tumor cells through antibody-mediated targeting. CAR-T cells engineered to express chimeric antigen receptors specific for B7-H3 can accurately target and eliminate B7-H3-expressing tumor cells. FITC-labeled B7-H3/CD276 Fc chimera protein can be used to assess the binding capability of antibody drugs and CAR-T cells to B7-H3 antigen, validating their functional activity.
Nanjing UA-Bio Technology Co., Ltd. (UA-Bio) has independently developed the "FITC-Labeled B7-H3/CD276 Fc Chimera Protein, Human" (Catalog No.: UA011268), a high-performance green fluorescent-labeled probe specifically designed for B7-H3-targeted research and solid tumor immunotherapy evaluation. B7-H3 (also known as CD276) is a critical immune checkpoint molecule in the B7 family, aberrantly overexpressed on the surface of various solid tumor cells (e.g., non-small cell lung cancer, prostate cancer, breast cancer, renal cell carcinoma). Its association with tumor immune evasion and poor prognosis makes it a highly promising anti-tumor target.
| Core Advantages | Detailed Parameters / Functional Description |
|---|---|
| High Purity & Full Bioactivity | The product employs internationally leading eukaryotic expression systems and highly standardized purification processes, validated through multi-dimensional quality control to ensure >95% purity and correct native conformation (retaining intact glycosylation modifications). The Fc chimera format enhances protein stability and proper folding. The FITC labeling process is optimized to maintain high labeling efficiency while preserving B7-H3's high-affinity binding to antibodies, accurately mimicking its antigenic properties on tumor cell surfaces under physiological conditions.-- |
| High-Brightness FITC Labeling | The optimized FITC labeling ratio ensures stable fluorescent dye conjugation per B7-H3-Fc chimera molecule, yielding bright green fluorescence signals under 488 nm excitation. Suitable for flow cytometry (FACS) and fluorescence microscopy, it provides reliable support for B7-H3-targeted molecule evaluation and precise quantification.-- |
| Exceptional Batch Consistency & Stability | Rigorous quality control from protein expression to labeling and purification, combined with comprehensive release testing, guarantees consistent binding activity, uniform fluorescence intensity, and excellent long-term stability. Ensures reliable quality for long-term B7-H3-targeted research.-- |
| Versatile Application Scenarios | This protein excels in CAR-T cell positivity rate assessment by flow cytometry, anti-B7-H3 antibody/antagonist screening, competitive binding assays, solid tumor biomarker analysis (e.g., NSCLC/prostate/breast cancer), and other applications. Ideal for B7-H3-targeted CAR-T cell therapy development, tumor immunotherapy research, and drug activity evaluation.-- |
| Comprehensive Solutions & Expert Support | We provide thoroughly validated standard protocols, exemplary flow cytometry data, and detailed interpretation guides to facilitate rapid establishment of stable, reproducible B7-H3-targeted molecule detection workflows. Nanjing UA-Bio's professional team offers end-to-end technical consultation and support for research design, optimization, and data analysis.-- |
Nanjing UA-Bio Technology Co., Ltd. is dedicated 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 application inquiries regarding the "FITC-Labeled B7-H3/CD276 Fc Chimera Protein, Human" (Catalog No.: UA011268), please feel free to contact us.
