InVivoMAb human IgG1 isotype control
Product Details
The human IgG1 isotype control antibody is purified from human myeloma serum and is of unknown specificity. This antibody is suitable for use as a non-targeting isotype control in various in vitro and in vivo studies. It can also be used as a negative control in various diagnostic applications such as ELISA, Western blot, immunofluorescence, immunohistochemistry, immunoprecipitation, and flow cytometry. For research use only.Specifications
| Isotype | Human IgG1, Īŗ |
|---|---|
| Recommended Dilution Buffer | InVivoPure pH 7.0 Dilution Buffer |
| Conjugation | This product is unconjugated. Conjugation is available via our Antibody Conjugation Services. |
| Formulation |
PBS, pH 7.0 Contains no stabilizers or preservatives |
| Endotoxin |
<2EU/mg (<0.002EU/Ī¼g) Determined by LAL gel clotting assay |
| Purity |
>95% Determined by SDS-PAGE |
| Sterility | 0.2 Āµm filtration |
| Production | Purified from human myeloma serum |
| Purification | Protein A |
| RRID | AB_2687817 |
| Molecular Weight | 150 kDa |
| Human Pathogen Test Results |
Hepatitis B Surface Antigen: Negative Human Immunodeficiency Virus 1 antibodies: Negative Human Immunodeficiency Virus 2 antibodies: Negative Hepatitis C Virus antibodies: Negative * These tests cannot guarantee the absence of infective agents |
| Storage | The antibody solution should be stored at the stock concentration at 4Ā°C. Do not freeze. |
Additional Formats
Recommended Products
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Recommended Dilution Buffer
InVivoPure pH 7.0 Dilution Buffer
Li, M., et al. (2019). "Genomic ERBB2/ERBB3 mutations promote PD-L1-mediated immune escape in gallbladder cancer: a whole-exome sequencing analysis" Gut 68(6): 1024-1033. PubMed
OBJECTIVES: Patients with gallbladder carcinoma (GBC) lack effective treatment methods largely due to the inadequacy of both molecular characterisation and potential therapeutic targets. We previously uncovered a spectrum of genomic alterations and identified recurrent mutations in the ErbB pathway in GBC. Here, we aimed to study recurrent mutations of genes and pathways in a larger cohort of patients with GBC and investigate the potential mechanisms and clinical significance of these mutations. DESIGN: We performed whole-exome sequencing (WES) in 157 patients with GBC. Functional experiments were applied in GBC cell lines to explore the oncogenic roles of ERBB2/ERBB3 hotspot mutations, their correlation with PD-L1 expression and the underlying mechanisms. ERBB inhibitors and a PD-L1 blocker were used to evaluate the anticancer activities in co-culture systems in vitro and in vivo. RESULTS: WES identified ERBB2 and ERBB3 mutations at a frequency of 7%-8% in the expanded cohort, and patients with ERBB2/ERBB3 mutations exhibited poorer prognoses. A set of in vitro and in vivo experiments revealed increased proliferation/migration on ERBB2/ERBB3 mutation. Ectopic expression of ERBB2/ERBB3 mutants upregulated PD-L1 expression in GBC cells, effectively suppressed normal T-cell-mediated cytotoxicity in vitro through activation of the PI3K/Akt signalling pathway and contributed to the growth and progression of GBC in vivo. Treatment with an ERBB2/ERBB3 inhibitor or a PD-L1 monoclonal antibody reversed these immunosuppressive effects, and combined therapy revealed promising therapeutic activities. CONCLUSIONS: ERBB2/ERBB3 mutations may serve as useful biomarkers in identifying patients who are sensitive to ERBB2/ERBB3 inhibitors and PD-L1 monoclonal antibody treatment. TRIAL REGISTRATION NUMBER: NCT02442414;Pre-results.
- Immunology and Microbiology,
Reactivation of CTLA4-expressing T cells accelerates resolution of lung fibrosis in a humanized mouse model.
In The Journal of Clinical Investigation on 15 May 2025 by Yadav, S., Anbalagan, M., et al.
Tissue regenerative responses involve complex interactions between resident structural and immune cells. Recent reports indicate that accumulation of senescent cells during injury repair contributes to pathological tissue fibrosis. Using tissue-based spatial transcriptomics and proteomics, we identified upregulation of the immune checkpoint protein, cytotoxic T lymphocyte-associated protein 4 (CTLA4), on CD8+ T cells adjacent to regions of active fibrogenesis in human idiopathic pulmonary fibrosis and in a repetitive bleomycin lung injury murine model of persistent fibrosis. In humanized CTLA4-knockin mice, treatment with ipilimumab, an FDA-approved drug that targets CTLA4, resulted in accelerated lung epithelial regeneration and diminished fibrosis from repetitive bleomycin injury. Ipilimumab treatment resulted in the expansion of Cd3e+ T cells, diminished accumulation of senescent cells, and robust expansion of type 2 alveolar epithelial cells, facultative progenitor cells of the alveolar epithelium. Ex vivo activation of isolated CTLA4-expressing CD8+ cells from mice with established fibrosis resulted in enhanced cytolysis of senescent cells, suggesting that impaired immune-mediated clearance of these cells contributes to persistence of lung fibrosis in this murine model. Our studies support the concept that endogenous immune surveillance of senescent cells may be essential in promoting tissue regenerative responses that facilitate the resolution of fibrosis.
- Cancer Research,
- Immunology and Microbiology
N-glycosylation of PD-L1 modulates the efficacy of immune checkpoint blockades targeting PD-L1 and PD-1.
In Molecular Cancer on 10 May 2025 by Kaufman, B., Abu-Ahmad, M., et al.
The PD-L1/PD-1 pathway is crucial for immune regulation and has become a target in cancer immunotherapy. However, in order to improve patient selection for immune checkpoint blockade (ICB) therapies, better selection criteria are needed. This study explores how the N-glycosylation of PD-L1 affects its interaction with PD-1 and ICB efficacy, focusing on its four N-linked glycosylation sites: N35, N192, N200, and N219. Human PD-L1 glycosylation mutants-at each individual site or at all four sites together (Nx4)-were tested for their functional interaction with PD-1 using an artificial immune checkpoint reporter assay (IcAR-PD1). The blocking efficacy of anti-PD-L1 and anti-PD-1 antibodies was evaluated using human breast cancer cell lines (MDA-MB231 and MCF7), as well as A375 melanoma and A549 lung carcinoma cells expressing the glycosylation mutants. Results were validated through ex vivo activation and cytotoxicity assays using human CD8+āT cells. The binding of the PD-L1N35A mutant to PD-1 was not effectively blocked by anti-PD-L1 and anti-PD-1 ICBs. In contrast, high blocking efficacy of PD-L1 binding to PD-1 was obtained at minimal ICB concentrations when PD-L1 did not express any glycosylation site (PD-L1Nx4 mutant). The PD-L1N35A mutant produced elevated levels of PD-L1 as a soluble (sPD-L1) and extracellular vesicles (EV)-bound molecule; in contrast, the PD-L1Nx4 mutant had lower sPD-L1 and EV levels. PD-L1 glycosylation status influenced the ability of PD-L1 interactions with PD-1 to down-regulate T-cell activation and cytotoxicity, with the PD-L1N35A mutant showing the lowest levels of T cell functions and the PD-L1Nx4 mutant the highest. The N-glycosylation of PD-L1 at all four sites interferes with the ability of anti-PD-L1 and anti-PD-1 ICBs to block PD-L1 interactions with PD-1; in contrast, glycosylation at the N35 site enhances ICB blocking efficacy. These effects are connected to the ability of sPD-L1 to compete with ICB binding to PD-L1 or PD-1. Thus, assessing PD-L1 glycosylation, beyond expression levels, could improve patient stratification and outcomes. Ā© 2025. The Author(s).
- Cancer Research,
- Immunology and Microbiology
Synergistic activity of tafasitamab and metronomic chemotherapy on diffuse large B-cell lymphoma through inhibition of the AKT/mTOR signaling pathway.
In Scientific Reports on 3 April 2025 by Banchi, M., Cox, M. C., et al.
Tafasitamab is a novel humanized anti-CD19 monoclonal antibody, designed for the treatment of B-cell malignancies. Our study aims to enhance the direct, non-immune-mediated, activity of tafasitamab (TAFA) with the combination of metronomic chemotherapy (mCHEMO), including vinorelbine (mVNR) and etoposide (mETO), in preclinical models of diffuse large B-cell lymphoma (DLBCL). In vitro, the 144Ā h exposure of thrice-weekly mVNR, daily mETO, and single-dose TAFA significantly inhibited the viability of human CD19+ DLBCL cell lines (i.e., Toledo, OCI-LY3, and SU-DHL10) in a concentration-dependent manner. In all cell lines, the concomitant treatment with TAFA and mVNR or mETO showed a marked synergism, except for TAFAā+āmETO on SU-DHL10 cells. The TAFAā+āmCHEMO treatments promoted apoptosis, and the TAFAā+āmVNR combination significantly inhibited, already after 24Ā h, the phosphorylation of GSK3Ī±/Ī², mTOR, p70S6K, RPS6, and TSC2 proteins in DLBCL cells. TAFA significantly increased the VNR and ETO intracellular concentrations in all DLBCL cells after 24Ā h, except for ETO levels in SU-DHL10. The TAFAā+āmCHEMO treatment strongly reduced the ABCB1, ABCG2, and c-MYC gene expression in SU-DHL10 cells. In vivo, the TAFAā+āmVNR combination was well tolerated, significantly reduced the volumes of subcutaneous DLBCL masses, and increased the overall survival of mice affected by systemic DLBCL. We report additional mechanisms to enhance the direct activity of TAFA with mCHEMO synergistically in DLBCL cells in vitro and in vivo, suggesting the use of this combination schedule into future clinical trials. Ā© 2025. The Author(s).
- Immunology and Microbiology
Single cell suppression profiling of human regulatory T cells.
In Nature Communications on 3 February 2025 by SĆøndergaard, J. N., Tulyeu, J., et al.
Regulatory T cells (Treg) play an important role in regulating immune homeostasis in health and disease. Traditionally their suppressive function has been assayed by mixing purified cell populations, which does not provide an accurate picture of a physiologically relevant response. To overcome this limitation, we here develop 'single cell suppression profiling of human Tregs' (scSPOT). scSPOT uses a 52-marker CyTOF panel, a cell division detection algorithm, and a whole PBMC system to assess the effect of Tregs on all other cell types simultaneously. In this head-to-head comparison, we find Tregs having the clearest suppressive effects on effector memory CD8 T cells through partial division arrest, cell cycle inhibition, and effector molecule downregulation. Additionally, scSPOT identifies a Treg phenotypic split previously observed in viral infection and propose modes of action by the FDA-approved drugs Ipilimumab and Tazemetostat. scSPOT is thus scalable, robust, widely applicable, and may be used to better understand Treg immunobiology and screen for therapeutic compounds. Ā© 2025. The Author(s).
- Cancer Research,
- Cardiovascular biology,
- Immunology and Microbiology
Lymphoma cell-driven IL-16 is expressed in activated B-cell-like diffuse large B-cell lymphomas and regulates the pro-tumor microenvironment.
In Haematologica on 1 February 2025 by Guan, X., Wang, Y., et al.
The activated B-cell-like subtype of diffuse large B-cell lymphoma (ABC-DLBCL) displays a worse outcome than the germinal center B-cell-like subtype (GCB-DLBCL). Currently, targeting the tumor microenvironment (TME) is the most promising approach to cure DLBCL with profound molecular heterogeneity; however, the factors affecting the tumor-promoting TME of ABC-DLBCL remain elusive. Here, cytokine interleukin-16 (IL-16) is expressed in tumor cells of ABC-DLBCL and secreted by the cleavage of active caspase-3. The serum IL-16 levels are not only a sensitive marker of treatment response, but also positively correlated with unfavorable prognosis in DLBCL patients. While IL-16 shows few direct promotional effects on tumor cell growth in vitro, its bioactive form significantly promotes tumor progression in vivo. Mechanically, IL-16 increases the infiltration of macrophages by the chemotaxis of CD4+ monocytes in the TME, enhancing angiogenesis and the expression of cytokine IL-6 and IL-10, as well as decreasing T-cell infiltration to accelerate tumor progression. This study demonstrates that IL-16 exerts a novel role in co-ordinating the bidirectional interactions between tumor progression and the TME. IMM0306, a fusion protein of CD20 mAb with the CD47 binding domain of SIRPĪ±, reverses the tumor-promoting effects of IL-16, providing new insights into treatment strategy in ABC-DLBCL.
- Immunology and Microbiology
Targeting Caveolin-1 in Multiple Myeloma Cells Enhances Chemotherapy and Natural Killer Cell-Mediated Immunotherapy.
In Advanced Science (Weinheim, Baden-Wurttemberg, Germany) on 1 January 2025 by Zhan, D., Du, Z., et al.
The cell membrane transport capacity and surface targets of multiple myeloma (MM) cells heavily influence chemotherapy and immunotherapy. Here, it is found that caveolin-1 (CAV1), a primary component of membrane lipid rafts and caveolae, is highly expressed in MM cells and is associated with MM progression and drug resistance. CAV1 knockdown decreases MM cell adhesion to stromal cells and attenuates cell adhesion-mediated drug resistance to bortezomib. CAV1 inhibition in MM cells enhances natural killer cell-mediated cytotoxicity through increasing CXCL10, SLAMF7, and CD112. CAV1 suppression reduces mitochondrial membrane potential, increases reactive oxygen species, and inhibits autophagosome-lysosome fusion, resulting in the disruption of redox homeostasis. Additionally, CAV1 knockdown enhances glutamine addiction by increasing ASCT2 and LAT1 and dysregulates glutathione metabolism. As a result of CAV1 inhibition, MM cells are more sensitive to starvation, glutamine depletion, and glutamine transporter inhibition, and grow more slowly in vivo in a mouse model treated with bortezomib. The observation that CAV1 inhibition modulated by 6-mercaptopurine, daidzin, and statins enhances the efficacy of bortezomib in vitro and in vivo highlights the translational significance of these FDA-approved drugs in improving MM outcomes. These data demonstrate that CAV1 serves as a potent therapeutic target for enhancing chemotherapy and immunotherapy for MM. Ā© 2024 The Author(s). Advanced Science published by WileyāVCH GmbH.
- Cancer Research
Breast Cancer Remodels Lymphatics in Sentinel Lymph Nodes
Preprint on BioRxiv : the Preprint Server for Biology on 30 December 2024 by Eichin, D., Takeda, A., et al.
ABSTRACT Cancer metastasis to sentinel lymph nodes (LNs) is often the first marker of potential disease progression. Although it is recognized that tumor-induced lymphangiogenesis facilitates metastasis into LNs in murine models, tumor-induced alterations in human lymphatic vessels remain obscure. We used single-cell RNA sequencing to profile lymphatic endothelial cell (LEC) subsets in paired metastatic and non-metastatic LNs obtained from patients with treatment-naĆÆve breast cancer. Tumor metastasis decreases immunoregulatory LEC subsets, such as PD-L1 + subcapsular sinus LECs, while inducing an increase in capillary-like CD200 + HEY1 + LECs. Matrix Gla protein (MGP) was the most upregulated gene in metastatic LN LECs, and its expression on LECs was TGF-Ī² and VEGF dependent. Upregulated MGP promotes cancer cell adhesion to LN lymphatics. Thus, breast cancer cell metastasis to LNs remodels LEC subsets in human LNs and escalates MGP expression, potentially facilitating cancer cell dissemination through the lymphatic system.
- cELISA,
- Homo sapiens (Human),
- COVID-19
Discovery of anti-SARS-CoV-2 S2 protein antibody CV804 with broad-spectrum reactivity with various beta coronaviruses and analysis of its pharmacological properties in vitro and in vivo.
In PLoS ONE on 2 December 2024 by Tsugawa, Y., Furukawa, K., et al.
The SARS-CoV-2 pandemic alerted the potential for significant harm due to future cross-species transmission of various animal coronaviruses to human. There is a significant need of antibody-based drugs to treat patients infected with previously unseen coronaviruses. In this study, we generated CV804, an antibody that binds to the S2 domain of SARS-CoV-2 spike protein, which is highly conserved across the coronavirus family and less susceptible to mutations. CV804 demonstrated broad cross-reactivities not only disease-associated human beta coronaviruses including SARS-CoV, MERS-CoV, HCoV-OC43, HCoV-HKU1 and with existing mutant strains of SARS-CoV-2 and but also with 20 representative animal-origin coronaviruses. CV804 exhibits strong antibody-dependent cellular cytotoxicity (ADCC) to SARS-CoV-2 spike protein expressed on cells in vitro, while completely lacks virus-neutralization activity. In animal models, CV804 suppressed disease progression caused by SARS-CoV-2 infection. Structural studies using HDX-MS combined with reactivity analysis with point mutants of recombinant spike proteins revealed that CV804 binds to a unique conformational epitope within the S2 domain of the spike proteins that is highly conserved among various coronaviruses. Overall, obtained data suggest that the non-neutralizing CV804 antibody recognizes the conformational structure of the spike protein displayed on the surface of infected cells and weakens the viral virulence by supporting the host immune cells' attack through ADCC activity in vivo. The CV804 epitope information revealed in this study is useful for designing pan-corona antibody therapeutics and universal coronavirus vaccines for preparing potential future pandemics. Copyright: Ā© 2024 Tsugawa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
- Cancer Research
Directed protein engineering identifies a human TIM-4 blocking antibody that enhances anti-tumor response to checkpoint inhibition in murine colon carcinoma.
In Antibody Therapeutics on 1 October 2024 by Frietze, K. K., Anumukonda, K., et al.
T-cell immunoglobulin and mucin domain containing molecule-4 (TIM-4) is a scavenger receptor best known for its role in recognizing dying cells. TIM-4 orchestrates phagocytosis allowing for cellular clearance of apoptotic cells, termed efferocytosis. It was previously shown that TIM-4 directly interacts with AMPKĪ±1, activating the autophagy pathway, leading to degradation of ingested tumors, and effectively reducing antigen presentation. This study sought to identify a novel human TIM-4 antibody that can prevent phagocytosis of tumor cells thereby allowing for more antigen presentation resulting in anti-tumor immunological response. Using phage display panning directed against human TIM-4, we engineered a novel human TIM-4 antibody (SKWX301). Combination of in vitro phagocytosis assays and cell viability assays were used to test functionality of SKWX301. To examine the effect of SKWX301 in mouse models, we employed a syngeneic mouse model. CT26 cells were subcutaneously injected into BALB/c mice and tumor growth and mouse survival were analyzed. SKWX301 can prevent human macrophage phagocytosis of cancer cells in vitro. Combination of low dose SKWX301 and anti-PD1 antibody significantly inhibited tumor growth and increased overall survival in mice. This demonstrates that SKWX301 is effective in both human in vitro models and mouse in vivo models. Our study has demonstrated a rapid antibody discovery approach and identified a novel human TIM-4 antibody that can serve as a therapeutic for antitumor immunity to improve cancer therapy. Ā© The Author(s) 2024. Published by Oxford University Press on behalf of Antibody Therapeutics.
- Immunology and Microbiology
Fc-engineered antibodies promote neutrophil-dependent control of Mycobacterium tuberculosis.
In Nature Microbiology on 1 September 2024 by Irvine, E. B., Nikolov, A., et al.
Mounting evidence indicates that antibodies can contribute towards control of tuberculosis (TB). However, the underlying mechanisms of humoral immune protection and whether antibodies can be exploited in therapeutic strategies to combat TB are relatively understudied. Here we engineered the receptor-binding Fc (fragment crystallizable) region of an antibody recognizing the Mycobacterium tuberculosis (Mtb) capsule, to define antibody Fc-mediated mechanism(s) of Mtb restriction. We generated 52 Fc variants that either promote or inhibit specific antibody effector functions, rationally building antibodies with enhanced capacity to promote Mtb restriction in a human whole-blood model of infection. While there is likely no singular Fc profile that universally drives control of Mtb, here we found that several Fc-engineered antibodies drove Mtb restriction in a neutrophil-dependent manner. Single-cell RNA sequencing analysis showed that a restrictive Fc-engineered antibody promoted neutrophil survival and expression of cell-intrinsic antimicrobial programs. These data show the potential of Fc-engineered antibodies as therapeutics able to harness the protective functions of neutrophils to promote control of TB. Ā© 2024. The Author(s).
- Cancer Research,
- Immunology and Microbiology
Interferon signaling and ferroptosis in tumor immunology and therapy.
In NPJ Precision Oncology on 10 August 2024 by Hu, W., Zhao, Z., et al.
This study sought to elucidate the mechanisms underlying the impact of the interferon signaling pathway on Ferroptosis in tumor cells and its correlation with CD8ā+āT cell exhaustion. Using mouse models and single-cell sequencing, the researchers studied the interaction between CD8ā+āT cells and the interferon signaling pathway. Differential gene analysis revealed key genes involved in CD8ā+āT cell exhaustion, and their downstream factors were explored using bioinformatics tools. The expression levels of interferon-related genes associated with Ferroptosis were analyzed using data from the TCGA database, and their relevance to tumor tissue Ferroptosis and patients' prognosis was determined. In vitro experiments were conducted to measure the levels of IFN-Ī³, MDA, and LPO, as well as tumor cell viability and apoptosis. In vivo validation using a mouse tumor model confirmed the results obtained from the in vitro experiments, highlighting the potential of silencing HSPA6 or DNAJB1 in enhancing the efficacy of PD-1 therapy and inhibiting tumor growth and migration. Ā© 2024. The Author(s).
- Cancer Research
Comparison of Tumor Non-specific and PD-L1 Specific Imaging by Near-Infrared Fluorescence/Cerenkov Luminescence Dual-Modality In-situ Imaging.
In Molecular Imaging on 2 July 2024 by Zhang, L., Zhao, L., et al.
Labeled antibodies are excellent imaging agents in oncology to non-invasively visualize cancer-related antigens expression levels. However, tumor tracer uptake (TTU) of specific antibodies in-vivo may be inferior to non-specific IgG in some cases. To explore factors affecting labeled antibody visualization by PD-L1 specific and non-specific imaging of nude mouse tumors. TTU was observed in RKO model on Cerenkov luminescence (CL) and near-infrared fluorescence (NIRF) imaging of radionuclide 131I or NIRF dyes labeled Atezolizumab and IgG. A mixture of NIRF dyes labeled Atezolizumab and 131I-labeled IgG was injected, and TTU was observed in the RKO and HCT8 model by NIRF/CL dual-modality in-situ imaging. TTU were observed by 131I-labeled Atezolizumab and IgG in-vitro distribution. Labeled IgG concentrated more in tumors than Atezolizumab. NIRF/CL imaging in 24 to 168 h showed that TTU gradually decreased over time, which decreased more slowly on CL imaging compared to NIRF imaging. The distribution data in-vitro showed that TTU of 131I-labeled IgG was higher than that of 131I-labeled Atezolizumab at any time point. Non-specific IgG may not be suitable as a control for Atezolizumab in comparing tumor PD-L1 expression in nude mice via labeled antibody optical imaging under certain circumstances. Ā© The Author(s) 2024.
- Immunology and Microbiology
Transcobalamin receptor antibodies in autoimmune vitamin B12 central deficiency.
In Science Translational Medicine on 26 June 2024 by Pluvinage, J. V., Ngo, T., et al.
Vitamin B12 is critical for hematopoiesis and myelination. Deficiency can cause neurologic deficits including loss of coordination and cognitive decline. However, diagnosis relies on measurement of vitamin B12 in the blood, which may not accurately reflect the concentration in the brain. Using programmable phage display, we identified an autoantibody targeting the transcobalamin receptor (CD320) in a patient with progressive tremor, ataxia, and scanning speech. Anti-CD320 impaired cellular uptake of cobalamin (B12) in vitro by depleting its target from the cell surface. Despite a normal serum concentration, B12 was nearly undetectable in her cerebrospinal fluid (CSF). Immunosuppressive treatment and high-dose systemic B12 supplementation were associated with increased B12 in the CSF and clinical improvement. Optofluidic screening enabled isolation of a patient-derived monoclonal antibody that impaired B12 transport across an in vitro model of the blood-brain barrier (BBB). Autoantibodies targeting the same epitope of CD320 were identified in seven other patients with neurologic deficits of unknown etiology, 6% of healthy controls, and 21.4% of a cohort of patients with neuropsychiatric lupus. In 132 paired serum and CSF samples, detection of anti-CD320 in the blood predicted B12 deficiency in the brain. However, these individuals did not display any hematologic signs of B12 deficiency despite systemic CD320 impairment. Using a genome-wide CRISPR screen, we found that the low-density lipoprotein receptor serves as an alternative B12 uptake pathway in hematopoietic cells. These findings dissect the tissue specificity of B12 transport and elucidate an autoimmune neurologic condition that may be amenable to immunomodulatory treatment and nutritional supplementation.
Synthetic integrin antibodies discovered by yeast display reveal Ī±V subunit pairing preferences with Ī² subunits.
In MAbs on 18 June 2024 by Hao, Y., Yan, J., et al.
Integrins are cell surface receptors that mediate the interactions of cells with their surroundings and play essential roles in cell adhesion, migration, and homeostasis. Eight of the 24 integrins bind to the tripeptide Arg-Gly-Asp (RGD) motif in their extracellular ligands, comprising the RGD-binding integrin subfamily. Despite similarity in recognizing the RGD motif and some redundancy, these integrins can selectively recognize RGD-containing ligands to fulfill specific functions in cellular processes. Antibodies against individual RGD-binding integrins are desirable for investigating their specific functions, and were selected here from a synthetic yeast-displayed Fab library. We discovered 11 antibodies that exhibit high specificity and affinity toward their target integrins, i.e. Ī±VĪ²3, Ī±VĪ²5, Ī±VĪ²6, Ī±VĪ²8, and Ī±5Ī²1. Of these, six are function-blocking antibodies and contain a ligand-mimetic R(G/L/T)D motif in their CDR3 sequences. We report antibody-binding specificity, kinetics, and binding affinity for purified integrin ectodomains, as well as intact integrins on the cell surface. We further used these antibodies to reveal binding preferences of the Ī±V subunit for its 5 Ī²-subunit partners: Ī²6 = Ī²8 > Ī²3 > Ī²1 = Ī²5.
- Biochemistry and Molecular biology
Systematic identification of structure-specific protein-protein interactions.
In Molecular Systems Biology on 1 June 2024 by Holfeld, A., Schuster, D., et al.
The physical interactome of a protein can be altered upon perturbation, modulating cell physiology and contributing to disease. Identifying interactome differences of normal and disease states of proteins could help understand disease mechanisms, but current methods do not pinpoint structure-specific PPIs and interaction interfaces proteome-wide. We used limited proteolysis-mass spectrometry (LiP-MS) to screen for structure-specific PPIs by probing for protease susceptibility changes of proteinsĀ in cellular extracts upon treatment with specific structural states of a protein. We first demonstrated that LiP-MS detects well-characterized PPIs, including antibody-target protein interactions and interactions with membrane proteins, and that it pinpoints interfaces, including epitopes. We then applied the approach to study conformation-specific interactors of the Parkinson's disease hallmark protein alpha-synuclein (aSyn). We identified known interactors of aSyn monomer and amyloid fibrils and provide a resource of novel putative conformation-specific aSyn interactors for validation in further studies. We also used our approach on GDP- and GTP-bound forms of two Rab GTPases, showing detection of differential candidate interactors of conformationally similar proteins. This approach is applicable to screen for structure-specific interactomes of any protein, including posttranslationally modified and unmodified, or metabolite-bound and unbound protein states. Ā© 2024. The Author(s).
- COVID-19
Functional and structural investigation of a broadly neutralizing SARS-CoV-2 antibody.
In JCI Insight on 22 May 2024 by Chang, Y. H., Hsu, M. F., et al.
Since its emergence, SARS-CoV-2 has been continuously evolving, hampering the effectiveness of current vaccines against COVID-19. mAbs can be used to treat patients at risk of severe COVID-19. Thus, the development of broadly protective mAbs and an understanding of the underlying protective mechanisms are of great importance. Here, we isolated mAbs from donors with breakthrough infection with Omicron subvariants using a single-B cell screening platform. We identified a mAb, O5C2, which possesses broad-spectrum neutralization and antibody-dependent cell-mediated cytotoxic activities against SARS-CoV-2 variants, including EG.5.1. Single-particle analysis by cryo-electron microscopy revealed that O5C2 targeted an unusually large epitope within the receptor-binding domain of spike protein that overlapped with the angiotensin-converting enzyme 2 binding interface. Furthermore, O5C2 effectively protected against BA.5 Omicron infection in vivo by mediating changes in transcriptomes enriched in genes involved in apoptosis and interferon responses. Our findings provide insights into the development of pan-protective mAbs against SARS-CoV-2.
- Cancer Research
Development of a [89Zr]Zr-labeled Human Antibody using a Novel Phage-displayed Human scFv Library.
In Clinical Cancer Research on 1 April 2024 by Singh, A. K., Lewis, C. D., et al.
Tax-interacting protein 1 (TIP1) is a cancer-specific radiation-inducible cell surface antigen that plays a role in cancer progression and resistance to therapy. This study aimed to develop a novel anti-TIP1 human antibody for noninvasive PET imaging in patients with cancer. A phage-displayed single-chain variable fragment (scFv) library was created from healthy donors' blood. High-affinity anti-TIP1 scFvs were selected from the library and engineered to human IgG1. Purified Abs were characterized by size exclusion chromatography high-performance liquid chromatography (SEC-HPLC), native mass spectrometry (native MS), ELISA, BIAcore, and flow cytometry. The labeling of positron emitter [89Zr]Zr to the lead Ab, L111, was optimized using deferoxamine (DFO) chelator. The stability of [89Zr]Zr-DFO-L111 was assessed in human serum. Small animal PET studies were performed in lung cancer tumor models (A549 and H460). We obtained 95% pure L111 by SEC-HPLC. Native MS confirmed the intact mass and glycosylation pattern of L111. Conjugation of three molar equivalents of DFO led to the optimal DFO-to-L111 ratio of 1.05. Radiochemical purity of 99.9% and specific activity of 0.37 MBq/Ī¼g was obtained for [89Zr]Zr-DFO-L111. [89Zr]Zr-DFO-L111 was stable in human serum over 7 days. The immunoreactive fraction in cell surface binding studies was 96%. In PET, preinjection with 4 mg/kg cold L111 before [89Zr]Zr-DFO-L111 (7.4 MBq; 20 Ī¼g) significantly (P < 0.01) enhanced the tumor-to-muscle standard uptake values (SUVmax) ratios on day 5 compared with day 2 postinjection. L111 Ab targets lung cancer cells in vitro and in vivo. [89Zr]Zr-DFO-L111 is a human antibody that will be evaluated in the first in-human study of safety and PET imaging. Ā©2024 American Association for Cancer Research.
- Cancer Research,
- Immunology and Microbiology
FcĪ³RIIB Is an Immune Checkpoint Limiting the Activity of Treg-Targeting Antibodies in the Tumor Microenvironment.
In Cancer Immunology Research on 4 March 2024 by Knorr, D. A., Blanchard, L., et al.
Preclinical murine data indicate that fragment crystallizable (Fc)-dependent depletion of intratumoral regulatory T cells (Treg) is a major mechanism of action of anti-CTLA-4. However, the two main antibodies administered to patients (ipilimumab and tremelimumab) do not recapitulate these effects. Here, we investigate the underlying mechanisms responsible for the limited Treg depletion observed with these therapies. Using an immunocompetent murine model humanized for CTLA-4 and FcĪ³ receptors (FcĪ³R), we show that ipilimumab and tremelimumab exhibit limited Treg depletion in tumors. Immune profiling of the tumor microenvironment (TME) in both humanized mice and humans revealed high expression of the inhibitory Fc receptor, FcĪ³RIIB, which limits antibody-dependent cellular cytotoxicity/phagocytosis. Blocking FcĪ³RIIB in humanized mice rescued the Treg-depleting capacity and antitumor activity of ipilimumab. Furthermore, Fc engineering of antibodies targeting Treg-associated targets (CTLA-4 or CCR8) to minimize FcĪ³RIIB binding significantly enhanced Treg depletion, resulting in increased antitumor activity across various tumor models. Our results define the inhibitory FcĪ³RIIB as an immune checkpoint limiting antibody-mediated Treg depletion in the TME, and demonstrate Fc engineering as an effective strategy to overcome this limitation and improve the efficacy of Treg-targeting antibodies. Ā©2023 The Authors; Published by the American Association for Cancer Research.
- Cancer Research,
- Immunology and Microbiology
Siglec-15/sialic acid axis as a central glyco-immune checkpoint in breast cancer bone metastasis.
In Proceedings of the National Academy of Sciences of the United States of America on 30 January 2024 by Wang, Y., Xu, Z., et al.
Immunotherapy is a promising approach for treating metastatic breast cancer (MBC), offering new possibilities for therapy. While checkpoint inhibitors have shown great progress in the treatment of metastatic breast cancer, their effectiveness in patients with bone metastases has been disappointing. This lack of efficacy seems to be specific to the bone environment, which exhibits immunosuppressive features. In this study, we elucidate the multiple roles of the sialic acid-binding Ig-like lectin (Siglec)-15/sialic acid glyco-immune checkpoint axis in the bone metastatic niche and explore potential therapeutic strategies targeting this glyco-immune checkpoint. Our research reveals that elevated levels of Siglec-15 in the bone metastatic niche can promote tumor-induced osteoclastogenesis as well as suppress antigen-specific T cell responses. Next, we demonstrate that antibody blockade of the Siglec-15/sialic acid glyco-immune checkpoint axis can act as a potential treatment for breast cancer bone metastasis. By targeting this pathway, we not only aim to treat bone metastasis but also inhibit the spread of metastatic cancer cells from bone lesions to other organs.
Synthetic integrin antibodies discovered by yeast display reveal Ī±V subunit pairing preferences with Ī² subunits
Preprint on BioRxiv : the Preprint Server for Biology on 27 January 2024 by Hao, Y., Yan, J., et al.
Eight of the 24 integrin heterodimers bind to the tripeptide Arg-Gly-Asp (RGD) motif in their extracellular ligands, and play essential roles in cell adhesion, migration, and homeostasis. Despite similarity in recognizing the RGD motif and some redundancy, these integrins can selectively recognize RGD-containing ligands including fibronectin, vitronectin, fibrinogen, nephronectin and the prodomain of the transforming growth factors to fulfill specific functions in cellular processes. Subtype-specific antibodies against RGD-binding integrins are desirable for investigating their specific functions. In this study, we discovered 11 antibodies that exhibit high specificity and affinity towards integrins Ī±VĪ²3, Ī±VĪ²5, Ī±VĪ²6, Ī±VĪ²8, and Ī±5Ī²1 from a synthetic yeast-displayed Fab library. Of these, 6 are function-blocking antibodies containing an R(G/L/T) D motif in their CDR3 sequences. We report antibody binding specificity, kinetics, and binding affinity for purified integrin ectodomains as well as intact integrins on the cell surface. We further employed these antibodies to reveal binding preferences of the Ī±V subunit for its 5 Ī²-subunit partners: Ī²6=Ī²8>Ī²3>Ī²1=Ī²5.
