InVivoMAb anti-mouse/human/rat osteopontin (SPP1)
Product Description
Specifications
| Isotype | Mouse IgG1, κ |
|---|---|
| Recommended Isotype Control(s) | InVivoMAb mouse IgG1 isotype control, unknown specificity |
| Recommended Dilution Buffer | InVivoPure pH 7.0 Dilution Buffer |
| Conjugation | This product is unconjugated. Conjugation is available via our Antibody Conjugation Services. |
| Immunogen | Rat bone protein fractions |
| Reported Applications |
in vivo OPN neutralization in vitro OPN neutralization Immunohistochemistry (paraffin) Western blot |
| Formulation |
PBS, pH 7.0 Contains no stabilizers or preservatives |
| Endotoxin |
≤1EU/mg (≤0.001EU/μg) Determined by LAL assay |
| Purity |
≥95% Determined by SDS-PAGE |
| Sterility | 0.2 µm filtration |
| Purification | Protein G |
| RRID | AB_2927519 |
| Molecular Weight | 150 kDa |
| Storage | The antibody solution should be stored at the stock concentration at 4°C. Do not freeze. |
| Need a Custom Formulation? | See All Antibody Customization Options |
Application References
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Jeon, E. Y., et al (2021). "A Pivotal Role for AP-1-Mediated Osteopontin Expression in the Increased Migration of Vascular Smooth Muscle Cells Stimulated With HMGB1" Front Physiol 12: 775464.
PubMed
Migration of vascular smooth muscle cells (VSMCs) plays an essential role in the development of vascular remodeling in the injured vasculatures. Previous studies have identified high-mobility group box 1 (HMGB1) as a principal effector mediating vascular remodeling; however, the mechanisms involved have not been fully elucidated. Thus, this study investigated the role of HMGB1 on VSMC migration and the underlying molecular mechanisms involved. VSMCs were ex plant cultured using rat thoracic aorta, and the cellular migration was measured using wound-healing assay. Osteopontin (OPN) mRNA and protein were determined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot, respectively. The OPN promoter was cloned into pGL3 basic to generate a pLuc-OPN-2284 construct. Migration of VSMCs stimulated with HMGB1 (100ng/ml) was markedly increased, which was significantly attenuated in cells pretreated with MPIIIB10 (100-300ng/ml), a neutralizing monoclonal antibody for OPN as well as in cells deficient of OPN. In VSMCs stimulated with HMGB1, OPN mRNA and protein levels were significantly increased in association with an increased promotor activity of OPN gene. Putative-binding sites for activator protein 1 (AP-1) and CCAAT/enhancer-binding protein beta (C/EBPbeta) in the indicated promoter region were suggested by TF Search, and the HMGB1-induced expression of OPN was markedly attenuated in cells transfected with siRNA for AP-1. VSMC stimulated with HMGB1 also showed an increased expression of AP-1. Results of this study suggest a pivotal role for AP-1-induced OPN expression in VSMC migration induced by HMGB1. Thus, the AP-1-OPN signaling axis in VSMC might serve as a potential therapeutic target for vascular remodeling in the injured vasculatures.
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Fatkhullina, A. R., et al (2018). "An Interleukin-23-Interleukin-22 Axis Regulates Intestinal Microbial Homeostasis to Protect from Diet-Induced Atherosclerosis" Immunity 49(5): 943-957 e949.
PubMed
Although commensal flora is involved in the regulation of immunity, the interplay between cytokine signaling and microbiota in atherosclerosis remains unknown. We found that interleukin (IL)-23 and its downstream target IL-22 restricted atherosclerosis by repressing pro-atherogenic microbiota. Inactivation of IL-23-IL-22 signaling led to deterioration of the intestinal barrier, dysbiosis, and expansion of pathogenic bacteria with distinct biosynthetic and metabolic properties, causing systemic increase in pro-atherogenic metabolites such as lipopolysaccharide (LPS) and trimethylamine N-oxide (TMAO). Augmented disease in the absence of the IL-23-IL-22 pathway was mediated in part by pro-atherogenic osteopontin, controlled by microbial metabolites. Microbiota transfer from IL-23-deficient mice accelerated atherosclerosis, whereas microbial depletion or IL-22 supplementation reduced inflammation and ameliorated disease. Our work uncovers the IL-23-IL-22 signaling as a regulator of atherosclerosis that restrains expansion of pro-atherogenic microbiota and argues for informed use of cytokine blockers to avoid cardiovascular side effects driven by microbiota and inflammation.
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Kim, E. K., et al (2014). "Tumor-derived osteopontin suppresses antitumor immunity by promoting extramedullary myelopoiesis" Cancer Res 74(22): 6705-6716.
PubMed
Extramedullary myelopoiesis occurs commonly in tumor-bearing animals and is known to lead to accumulation of peripheral myeloid-derived suppressor cells (MDSC), which play an important role in immune escape. However, the cellular and molecular mechanisms by which tumors induce extramedullary myelopoiesis are poorly understood. In this study, we found that osteopontin expressed by tumor cells enhances extramedullary myelopoiesis in a CD44-dependent manner through the Erk1/2-MAPK pathway. Osteopontin-mediated extramedullary myelopoiesis was directly associated with increased MDSCs in tumor-bearing hosts. More importantly, osteopontin silencing in tumor cells delayed both tumor growth and extramedullary myelopoiesis, while the same treatment did not affect tumor growth in vitro. Finally, treatment with an antibody against osteopontin inhibited tumor growth and synergized with cell-based immunotherapeutic vaccines in mediating antitumor immunity. Our findings unveil a novel immunosuppressive role for tumor-derived osteopontin and offer a rationale for its therapeutic targeting in cancer treatment.
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Ichikawa, H., et al (2009). "Involvement of osteopontin as a core protein in cholesterol gallstone formation" J Hepatobiliary Pancreat Surg 16(2): 197-203.
PubMed
Matrix proteins are considered to be essential for biomineralization and to be important factors in the formation and growth of gallstones. Osteopontin (Opn) is a noncollagenous, acidic bone-matrix glycoprotein, which is sialated and phosphorylated and which has a cell-binding peptide sequence of glycine-arginine-glycine-aspartate-serine (GRGDS). To investigate the role of Opn in cholesterol gallstone formation, we have studied the involvement of Opn in cholesterol gallstone formation in the human gallbladder wall, in the stones, and in the mouse gallbladder using a gallstone experimental model. METHODS: Immunohistochemical staining was used in the human gallbladder wall and human gallstones and the determination of mRNA expression by reverse transcriptase-PCR was used in the mouse gallbladder of a gallstone experimental model. RESULTS: The epithelium of stone-laden gallbladders demonstrated high Opn reactivity, as did the core of the stones. Microscopically detected early stones without macroscopic evidence of lithiasis showed the same immunoreactivity as larger stones. Stone-laden gallbladders were infiltrated by macrophages showing intense Opn expression. In gallstone-forming mice, the expression of Opn mRNA and its protein were significantly increased in the gallbladder wall in the early phase of a lithogenic diet intake, before the initiation of inflammation. CONCLUSION: These results suggest that Opn is possibly involved as a core protein in the formation of cholesterol gallstones.
Product Citations
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Tumor cell-derived IFN spatially reprograms osteopontin-enriched macrophage niches to promote PARP inhibitor resistance.
In J Clin Invest on 15 April 2026 by Liu, D., Tao, K., et al.
PubMed
Poly (ADP-ribose) polymerase inhibitors (PARPis) benefit homologous recombination-deficient (HRD) malignancies, yet resistance remains a major challenge. Leveraging specimens from a prospective neoadjuvant niraparib monotherapy trial in treatment-naive, high-grade serous ovarian cancer, we integrated PhenoCycler-Fusion spatial profiling, scRNA-Seq, and multiplex immunohistochemistry to identify 2 therapeutic-modulated cellular neighborhoods: an IFN+ tumor cell-enriched niche that expands in resistant lesions and a niche enriched in tumor-associated macrophage (TAM) that persists but acquires enhanced immunosuppressive features. Mechanistically, sustained tumor cell-derived IFN induced osteopontin (SPP1) expression in TAMs via STAT signaling, creating immunosuppressive niches enriched in Tregs and myofibroblastic cancer-associated fibroblasts with intensified cell-cell interactions. SPP1 directly suppressed T cell signaling and effector function. High baseline SPP1+ cells predicted lower response rate (30.0% vs. 76.2%; P = 0.021) and shorter progression-free survival (median 13.5 vs. 28.3 months; P = 0.0006). In HRD mouse models, SPP1 blockade restored PARPi sensitivity, reversed acquired resistance, and enhanced T cell cytotoxicity-effects abrogated in immunodeficient mice, confirming immune dependence. These data establish a spatial IFN-SPP1 axis whereby persistent tumor cell IFN reprograms TAMs to promote PARPi resistance, position SPP1 as a key therapeutic target and prognostic biomarker for this therapy, and underscore therapeutic potential of microenvironment-targeted strategies to overcome PARPi resistance.
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Tumor cell-derived IFN spatially reprograms osteopontin-enriched macrophage niches to promote PARP inhibitor resistance.
In J Clin Invest on 6 March 2026 by Liu, D., Tao, K., et al.
PubMed
Poly (ADP-ribose) polymerase inhibitors (PARPi) benefit homologous recombination-deficient (HRD) malignancies, yet resistance remains a major challenge. Leveraging specimens from a prospective neoadjuvant niraparib monotherapy trial in treatment-naïve high-grade serous ovarian cancer, we integrated PhenoCycler-Fusion spatial profiling, scRNA-seq, and multiplex immunohistochemistry to identify two therapeutic-modulated cellular neighborhoods: an IFN+ tumor cell-enriched niche that expands in resistant lesions and a tumor-associated macrophage (TAM)-enriched niche that persists but acquires enhanced immunosuppressive features. Mechanistically, sustained tumor cell-derived IFN induced osteopontin (SPP1) expression in TAMs via STAT signaling, creating immunosuppressive niches enriched in Tregs and myofibroblastic cancer-associated fibroblasts with intensified cell-cell interactions. SPP1 directly suppressed T cell signaling and effector function. High baseline SPP1+ cells predicted lower response rate (30.0% vs 76.2%, P = 0.021) and shorter progression-free survival (median 13.5 vs 28.3 months, P = 0.0006). In HRD mouse models, SPP1 blockade restored PARPi sensitivity, reversed acquired resistance, and enhanced T cell cytotoxicity-effects abrogated in immunodeficient mice, confirming immune dependence. These data establish a spatial IFN-SPP1 axis whereby persistent tumor cell IFN reprograms TAMs to promote PARPi resistance, position SPP1 as a key therapeutic target and prognostic biomarker for this therapy, and underscore therapeutic potential of microenvironment-targeted strategies to overcome PARPi resistance.
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Single cell atlas decodes the molecular dynamics of scar repair after human rotator cuff tear.
In Bone Res on 5 February 2026 by Qin, Y., Yang, G., et al.
PubMed
Irreversible fibrotic scarring after rotator cuff tear (RCT) compromises the mechanical properties of the healing tendon, yet the underlying mechanisms remain poorly understood. Here, we analyzed the histological features of human RCT scars, characterized by disruption of tendon architecture, disorganized collagen fibrils, and imbalance in type I/III collagen ratios and fibril diameters. Using single-cell RNA sequencing of tendon stumps from patients with RCT, we deconvolved the cellular and molecular landscape of the fibrotic scarring microenvironment. Heterogenous pro-fibrotic subclusters were identified and validated to participate into scar formation, including tendon stem cell, senescent tenocyte, SOX9-driven pro-fibrotic macrophage, and pro-fibrotic endothelial cells undergoing endothelial-mesenchymal transition (EndoMT). Furthermore, we found that osteopontin and TGF-β signaling were key drivers of extracellular matrix deposition, and their blockade ameliorated fibrotic scarring after RCT. Collectively, our study dissected the dynamic scarring microenvironment in human RCT and highlights potential therapeutic targets for preventing pathological scar formation.
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SPP1+ Tumor-Associated Macrophages Drive Immunotherapy Resistance via CD8+ T-cell Dysfunction in Clear-Cell Renal Cell Carcinoma.
In Cancer Immunol Res on 1 October 2025 by Jiang, W., Liu, L., et al.
PubMed
Tumor-associated macrophages (TAM) are key regulators of tumor immunity. With advances in single-cell analyses, secreted phosphoprotein 1 (SPP1)-positive TAMs have been observed across multiple tumor sites. However, their clinical relevance and phenotypic characteristics in clear-cell renal cell carcinoma (ccRCC) have not been comprehensively delineated. Using patient-level data from two in-house cohorts (n = 355), we explored the relationship between SPP1+ TAM infiltration and therapeutic response and prognosis in ccRCC. Four publicly available datasets consisting of 1,741 patients with ccRCC were included for external validation. Cytometry by time-of-flight and flow cytometry were utilized to phenotype SPP1+ TAMs and establish their impact on CD8+ T cells. Furthermore, we established an ex vivo culture system to test the potential therapeutic value of targeting SPP1 alone and in conjunction with PD-1 inhibitors in ccRCC. We found that patients with high SPP1+ TAM infiltration exhibited worse response to immunotherapy and dismal prognosis in ccRCC. SPP1+ TAMs exhibited an immunosuppressive and protumor phenotype, and were related to impaired effector function and terminal differentiation of CD8+ T cells. Blockade of SPP1 mitigated the protumor tumor microenvironment and reinvigorated CD8+ T-cell function. Combining PD-1 blockade with SPP1 blockade boosted the expansion of CD8+ T cells and enhanced antitumor efficacy. Together, these data indicate that elevated infiltration of SPP1+ TAMs is related to worse response to immunotherapy and dysfunction of CD8+ T cells in ccRCC. We conclude that SPP1 may serve as a potential therapeutic target in ccRCC.