InVivoMAb anti-human MHC Class I (HLA-A, HLA-B, HLA-C)
Product Description
Specifications
| Isotype | Mouse IgG2a, κ |
|---|---|
| Recommended Isotype Control(s) | InVivoMAb mouse IgG2a isotype control, unknown specificity |
| Recommended Dilution Buffer | InVivoPure pH 6.5 Dilution Buffer |
| Conjugation | This product is unconjugated. Conjugation is available via our Antibody Conjugation Services. |
| Immunogen | Human tonsil cell membrane |
| Reported Applications | Functional assays |
| Formulation |
PBS, pH 6.5 Contains no stabilizers or preservatives |
| Endotoxin |
≤1EU/mg (≤0.001EU/μg) Determined by LAL gel clotting assay |
| Purity |
≥95% Determined by SDS-PAGE |
| Sterility | 0.2 µm filtration |
| Production | Purified from cell culture supernatant in an animal-free facility |
| Purification | Protein G |
| RRID | AB_1107730 |
| 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
Functional Assays
Valenzuela, N. M., et al. (2013). "HLA class I antibodies trigger increased adherence of monocytes to endothelial cells by eliciting an increase in endothelial P-selectin and, depending on subclass, by engaging FcgammaRs" J Immunol 190(12): 6635-6650.
PubMed
Ab-mediated rejection (AMR) of solid organ transplants is characterized by intragraft macrophages. It is incompletely understood how donor-specific Ab binding to graft endothelium promotes monocyte adhesion, and what, if any, contribution is made by the Fc region of the Ab. We investigated the mechanisms underlying monocyte recruitment by HLA class I (HLA I) Ab-activated endothelium. We used a panel of murine mAbs of different subclasses to crosslink HLA I on human aortic, venous, and microvascular endothelial cells and measured the binding of human monocytic cell lines and peripheral blood monocytes. Both anti-HLA I murine (m)IgG1 and mIgG2a induced endothelial P-selectin, which was required for monocyte adhesion to endothelium irrespective of subclass. mIgG2a but not mIgG1 could bind human FcgammaRs. Accordingly, HLA I mIgG2a but not mIgG1 treatment of endothelial cells significantly augmented recruitment, predominantly through FcgammaRI, and, to a lesser extent, FcgammaRIIa. Moreover, HLA I mIgG2a promoted firm adhesion of monocytes to ICAM-1 through Mac-1, which may explain the prominence of monocytes during AMR. We confirmed these observations using human HLA allele-specific mAbs and IgG purified from transplant patient sera. HLA I Abs universally elicit endothelial exocytosis leading to monocyte adherence, implying that P-selectin is a putative therapeutic target to prevent macrophage infiltration during AMR. Importantly, the subclass of donor-specific Ab may influence its pathogenesis. These results imply that human IgG1 and human IgG3 should have a greater capacity to trigger monocyte infiltration into the graft than IgG2 or IgG4 due to enhancement by FcgammaR interactions.
Functional Assays
Valenzuela, N. M., et al. (2013). "Blockade of p-selectin is sufficient to reduce MHC I antibody-elicited monocyte recruitment in vitro and in vivo" Am J Transplant 13(2): 299-311.
PubMed
Donor-specific HLA antibodies significantly lower allograft survival, but as yet there are no satisfactory therapies for prevention of antibody-mediated rejection. Intracapillary macrophage infiltration is a hallmark of antibody-mediated rejection, and macrophages are important in both acute and chronic rejection. The purpose of this study was to investigate the Fc-independent effect of HLA I antibodies on endothelial cell activation, leading to monocyte recruitment. We used an in vitro model to assess monocyte binding to endothelial cells in response to HLA I antibodies. We confirmed our results in a mouse model of antibody-mediated rejection, in which B6.RAG1(-/-) recipients of BALB/c cardiac allografts were passively transferred with donor-specific MHC I antibodies. Our findings demonstrate that HLA I antibodies rapidly increase intracellular calcium and endothelial presentation of P-selectin, which supports monocyte binding. In the experimental model, donor-specific MHC I antibodies significantly increased macrophage accumulation in the allograft. Concurrent administration of rPSGL-1-Ig abolished antibody-induced monocyte infiltration in the allograft, but had little effect on antibody-induced endothelial injury. Our data suggest that antagonism of P-selectin may ameliorate accumulation of macrophages in the allograft during antibody-mediated rejection.
Product Citations
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Cancer Research
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Genetics
Tumour-wide RNA splicing aberrations generate actionable public neoantigens.
In Nature on 1 March 2025 by Kwok, D. W., Stevers, N., et al.
PubMed
T cell-based immunotherapies hold promise in treating cancer by leveraging the immune system's recognition of cancer-specific antigens1. However, their efficacy is limited in tumours with few somatic mutations and substantial intratumoural heterogeneity2-4. Here we introduce a previously uncharacterized class of tumour-wide public neoantigens originating from RNA splicing aberrations in diverse cancer types. We identified T cell receptor clones capable of recognizing and targeting neoantigens derived from aberrant splicing in GNAS and RPL22. In cases with multi-site biopsies, we detected the tumour-wide expression of the GNAS neojunction in glioma, mesothelioma, prostate cancer and liver cancer. These neoantigens are endogenously generated and presented by tumour cells under physiologic conditions and are sufficient to trigger cancer cell eradication by neoantigen-specific CD8+ T cells. Moreover, our study highlights a role for dysregulated splicing factor expression in specific cancer types, leading to recurrent patterns of neojunction upregulation. These findings establish a molecular basis for T cell-based immunotherapies addressing the challenges of intratumoural heterogeneity.
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Binding experiments
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Homo sapiens (Human)
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COVID-19
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Immunology and Microbiology
Machine learning-enhanced immunopeptidomics applied to T-cell epitope discovery for COVID-19 vaccines.
In Nat Commun on 28 November 2024 by Kovalchik, K. A., Hamelin, D. J., et al.
PubMed
Next-generation T-cell-directed vaccines for COVID-19 focus on establishing lasting T-cell immunity against current and emerging SARS-CoV-2 variants. Precise identification of conserved T-cell epitopes is critical for designing effective vaccines. Here we introduce a comprehensive computational framework incorporating a machine learning algorithm-MHCvalidator-to enhance mass spectrometry-based immunopeptidomics sensitivity. MHCvalidator identifies unique T-cell epitopes presented by the B7 supertype, including an epitope from a + 1-frameshift in a truncated Spike antigen, supported by ribosome profiling. Analysis of 100,512 COVID-19 patient proteomes shows Spike antigen truncation in 0.85% of cases, revealing frameshifted viral antigens at the population level. Our EpiTrack pipeline tracks global mutations of MHCvalidator-identified CD8 + T-cell epitopes from the BNT162b4 vaccine. While most vaccine epitopes remain globally conserved, an immunodominant A*01-associated epitope mutates in Delta and Omicron variants. This work highlights SARS-CoV-2 antigenic features and emphasizes the importance of continuous adaptation in T-cell vaccine development.
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Cancer Research
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Immunology and Microbiology
HERV-derived epitopes represent new targets for T-cell based immunotherapies in ovarian cancer
In bioRxiv on 17 July 2024 by Bonaventura, P., Tabone, O., et al.
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Cancer Research
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Genetics
Tumor-wide RNA splicing aberrations generate immunogenic public neoantigens
In Research Square on 16 November 2023 by Okada, H., Kwok, D., et al.
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Cancer Research
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Genetics
Tumor-wide RNA splicing aberrations generate immunogenic public neoantigens
In bioRxiv on 20 October 2023 by Kwok, D. W., Stevers, N. O., et al.
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Biochemistry and Molecular biology
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Cancer Research
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Immunology and Microbiology
Identification of tumor-specific MHC ligands through improved biochemical isolation and incorporation of machine learning
In bioRxiv on 10 June 2023 by Mecklenbräuker, S., Skoczylas, P., et al.
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Homo sapiens (Human)
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Cancer Research
Single-cell protein profiling defines cell populations associated with triple-negative breast cancer aggressiveness.
In Mol Oncol on 1 June 2023 by Kvokačková, B., Fedr, R., et al.
PubMed
Triple-negative breast cancer (TNBC) is an aggressive and complex subtype of breast cancer that lacks targeted therapy. TNBC manifests characteristic, extensive intratumoral heterogeneity that promotes disease progression and influences drug response. Single-cell techniques in combination with next-generation computation provide an unprecedented opportunity to identify molecular events with therapeutic potential. Here, we describe the generation of a comprehensive mass cytometry panel for multiparametric detection of 23 phenotypic markers and 13 signaling molecules. This single-cell proteomic approach allowed us to explore the landscape of TNBC heterogeneity, with particular emphasis on the tumor microenvironment. We prospectively profiled freshly resected tumors from 26 TNBC patients. These tumors contained phenotypically distinct subpopulations of cancer and stromal cells that were associated with the patient's clinical status at the time of surgery. We further classified the epithelial-mesenchymal plasticity of tumor cells, and molecularly defined phenotypically diverse populations of tumor-associated stroma. Furthermore, in a retrospective tissue-microarray TNBC cohort, we showed that the level of CD97 at the time of surgery has prognostic potential.
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COVID-19
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Immunology and Microbiology
The T-cell-directed vaccine BNT162b4 encoding conserved non-spike antigens protects animals from severe SARS-CoV-2 infection.
In Cell on 25 May 2023 by Arieta, C. M., Xie, Y. J., et al.
PubMed
T cell responses play an important role in protection against beta-coronavirus infections, including SARS-CoV-2, where they associate with decreased COVID-19 disease severity and duration. To enhance T cell immunity across epitopes infrequently altered in SARS-CoV-2 variants, we designed BNT162b4, an mRNA vaccine component that is intended to be combined with BNT162b2, the spike-protein-encoding vaccine. BNT162b4 encodes variant-conserved, immunogenic segments of the SARS-CoV-2 nucleocapsid, membrane, and ORF1ab proteins, targeting diverse HLA alleles. BNT162b4 elicits polyfunctional CD4+ and CD8+ T cell responses to diverse epitopes in animal models, alone or when co-administered with BNT162b2 while preserving spike-specific immunity. Importantly, we demonstrate that BNT162b4 protects hamsters from severe disease and reduces viral titers following challenge with viral variants. These data suggest that a combination of BNT162b2 and BNT162b4 could reduce COVID-19 disease severity and duration caused by circulating or future variants. BNT162b4 is currently being clinically evaluated in combination with the BA.4/BA.5 Omicron-updated bivalent BNT162b2 (NCT05541861).
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Homo sapiens (Human)
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Biochemistry and Molecular biology
Proteomic discovery of chemical probes that perturb protein complexes in human cells.
In Mol Cell on 18 May 2023 by Lazear, M. R., Remsberg, J. R., et al.
PubMed
Most human proteins lack chemical probes, and several large-scale and generalizable small-molecule binding assays have been introduced to address this problem. How compounds discovered in such "binding-first" assays affect protein function, nonetheless, often remains unclear. Here, we describe a "function-first" proteomic strategy that uses size exclusion chromatography (SEC) to assess the global impact of electrophilic compounds on protein complexes in human cells. Integrating the SEC data with cysteine-directed activity-based protein profiling identifies changes in protein-protein interactions that are caused by site-specific liganding events, including the stereoselective engagement of cysteines in PSME1 and SF3B1 that disrupt the PA28 proteasome regulatory complex and stabilize a dynamic state of the spliceosome, respectively. Our findings thus show how multidimensional proteomic analysis of focused libraries of electrophilic compounds can expedite the discovery of chemical probes with site-specific functional effects on protein complexes in human cells.
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Immunohistochemistry
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Cancer Research
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Immunology and Microbiology
Combinatory EHMT and PARP inhibition induces an interferon response and a CD8 T cell-dependent tumor regression in PARP inhibitor-resistant models
In bioRxiv on 23 February 2023 by Nguyen, L. L., Watson, Z. L., et al.
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Functional assays
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Homo sapiens (Human)
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Cancer Research
Neutrophil-activating therapy for the treatment of cancer.
In Cancer Cell on 13 February 2023 by Linde, I. L., Prestwood, T. R., et al.
PubMed
Despite their cytotoxic capacity, neutrophils are often co-opted by cancers to promote immunosuppression, tumor growth, and metastasis. Consequently, these cells have received little attention as potential cancer immunotherapeutic agents. Here, we demonstrate in mouse models that neutrophils can be harnessed to induce eradication of tumors and reduce metastatic seeding through the combined actions of tumor necrosis factor, CD40 agonist, and tumor-binding antibody. The same combination activates human neutrophils in vitro, enabling their lysis of human tumor cells. Mechanistically, this therapy induces rapid mobilization and tumor infiltration of neutrophils along with complement activation in tumors. Complement component C5a activates neutrophils to produce leukotriene B4, which stimulates reactive oxygen species production via xanthine oxidase, resulting in oxidative damage and T cell-independent clearance of multiple tumor types. These data establish neutrophils as potent anti-tumor immune mediators and define an inflammatory pathway that can be harnessed to drive neutrophil-mediated eradication of cancer.
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Immunology and Microbiology
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Cancer Research
The ectonucleotidase CD39 identifies tumor-reactive CD8+ T cells predictive of immune checkpoint blockade efficacy in human lung cancer.
In Immunity on 10 January 2023 by Chow, A., Uddin, F. Z., et al.
PubMed
Improved identification of anti-tumor T cells is needed to advance cancer immunotherapies. CD39 expression is a promising surrogate of tumor-reactive CD8+ T cells. Here, we comprehensively profiled CD39 expression in human lung cancer. CD39 expression enriched for CD8+ T cells with features of exhaustion, tumor reactivity, and clonal expansion. Flow cytometry of 440 lung cancer biospecimens revealed weak association between CD39+ CD8+ T cells and tumoral features, such as programmed death-ligand 1 (PD-L1), tumor mutation burden, and driver mutations. Immune checkpoint blockade (ICB), but not cytotoxic chemotherapy, increased intratumoral CD39+ CD8+ T cells. Higher baseline frequency of CD39+ CD8+ T cells conferred improved clinical outcomes from ICB therapy. Furthermore, a gene signature of CD39+ CD8+ T cells predicted benefit from ICB, but not chemotherapy, in a phase III clinical trial of non-small cell lung cancer. These findings highlight CD39 as a proxy of tumor-reactive CD8+ T cells in human lung cancer.
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Proteomic discovery of chemical probes that perturb protein complexes in human cells
In bioRxiv on 13 December 2022 by Lazear, M. R., Remsberg, J. R., et al.
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Cancer Research
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Immunology and Microbiology
MEK inhibition enhances presentation of targetable MHC-I tumor antigens in mutant melanomas.
In Proc Natl Acad Sci U S A on 6 December 2022 by Stopfer, L. E., Rettko, N. J., et al.
PubMed
Combining multiple therapeutic strategies in NRAS/BRAF mutant melanoma-namely MEK/BRAF kinase inhibitors, immune checkpoint inhibitors (ICIs), and targeted immunotherapies-may offer an improved survival benefit by overcoming limitations associated with any individual therapy. Still, optimal combination, order, and timing of administration remains under investigation. Here, we measure how MEK inhibition (MEKi) alters anti-tumor immunity by utilizing quantitative immunopeptidomics to profile changes in the peptide major histocompatibility molecules (pMHC) repertoire. These data reveal a collection of tumor antigens whose presentation levels are selectively augmented following therapy, including several epitopes present at over 1,000 copies per cell. We leveraged the tunable abundance of MEKi-modulated antigens by targeting four epitopes with pMHC-specific T cell engagers and antibody drug conjugates, enhancing cell killing in tumor cells following MEK inhibition. These results highlight drug treatment as a means to enhance immunotherapy efficacy by targeting specific upregulated pMHCs and provide a methodological framework for identifying, quantifying, and therapeutically targeting additional epitopes of interest.
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Enzyme-linked immunosorbent assay
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Enzyme-linked immunosorbent assay
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Cancer Research
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Immunology and Microbiology
A covalent inhibitor of K-Ras(G12C) induces MHC class I presentation of haptenated peptide neoepitopes targetable by immunotherapy.
In Cancer Cell on 12 September 2022 by Zhang, Z., Rohweder, P. J., et al.
PubMed
Immunotargeting of tumor-specific antigens is a powerful therapeutic strategy. Immunotherapies directed at MHC-I complexes have expanded the scope of antigens and enabled the direct targeting of intracellular oncoproteins at the cell surface. We asked whether covalent drugs that alkylate mutated residues on oncoproteins could act as haptens to generate unique MHC-I-restricted neoantigens. Here, we report that KRAS G12C mutant cells treated with the covalent inhibitor ARS1620 present ARS1620-modified peptides in MHC-I complexes. Using ARS1620-specific antibodies identified by phage display, we show that these haptenated MHC-I complexes can serve as tumor-specific neoantigens and that a bispecific T cell engager construct based on a hapten-specific antibody elicits a cytotoxic T cell response against KRAS G12C cells, including those resistant to direct KRAS G12C inhibition. With multiple K-RAS G12C inhibitors in clinical use or undergoing clinical trials, our results present a strategy to enhance their efficacy and overcome the rapidly arising tumor resistance.
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Cancer Research
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Cardiovascular biology
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Immunology and Microbiology
A TCR mimic CAR T cell specific for NDC80 is broadly reactive with solid tumors and hematologic malignancies.
In Blood on 25 August 2022 by Klatt, M. G., Dao, T., et al.
PubMed
Target identification for chimeric antigen receptor (CAR) T-cell therapies remains challenging due to the limited repertoire of tumor-specific surface proteins. Intracellular proteins presented in the context of cell surface HLA provide a wide pool of potential antigens targetable through T-cell receptor mimic antibodies. Mass spectrometry (MS) of HLA ligands from 8 hematologic and nonhematologic cancer cell lines identified a shared, non-immunogenic, HLA-A*02-restricted ligand (ALNEQIARL) derived from the kinetochore-associated NDC80 gene. CAR T cells directed against the ALNEQIARL:HLA-A*02 complex exhibited high sensitivity and specificity for recognition and killing of multiple cancer types, especially those of hematologic origin, and were efficacious in mouse models against a human leukemia and a solid tumor. In contrast, no toxicities toward resting or activated healthy leukocytes as well as hematopoietic stem cells were observed. This shows how MS can inform the design of broadly reactive therapeutic T-cell receptor mimic CAR T-cell therapies that can target multiple cancer types currently not druggable by small molecules, conventional CAR T cells, T cells, or antibodies.
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Cancer Research
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Immunology and Microbiology
Unmasking the suppressed immunopeptidome of EZH2-mutated diffuse large B-cell lymphomas through combination drug treatment.
In Blood Adv on 26 July 2022 by Bourne, C. M., Mun, S. S., et al.
PubMed
Exploring the repertoire of peptides presented on major histocompatibility complexes (MHCs) helps identify targets for immunotherapy in many hematologic malignancies. However, there is a paucity of such data for diffuse large B-cell lymphomas (DLBCLs), which might be explained by the profound downregulation of MHC expression in many DLBCLs, and in particular in the enhancer of zeste homolog 2 (EZH2)-mutated subgroup. Epigenetic drug treatment, especially in the context of interferon-γ (IFN-γ), restored MHC expression in DLBCL. In DLBCL, peptides presented on MHCs were identified via mass spectrometry after treatment with tazemetostat or decitabine alone or in combination with IFN-γ. Such treatment synergistically increased the expression of MHC class I surface proteins up to 50-fold and the expression of class II surface proteins up to threefold. Peptides presented on MHCs increased to a similar extent for both class I and class II MHCs. Overall, these treatments restored the diversity of the immunopeptidome to levels described in healthy B cells for 2 of 3 cell lines and allowed the systematic search for new targets for immunotherapy. Consequently, we identified multiple MHC ligands from the regulator of G protein signaling 13 (RGS13) and E2F transcription factor 8 (E2F8) on different MHC alleles, none of which have been described in healthy tissues and therefore represent tumor-specific MHC ligands that are unmasked only after drug treatment. Overall, our results show that EZH2 inhibition in combination with decitabine and IFN-γ can expand the repertoire of MHC ligands presented on DLBCLs by revealing suppressed epitopes, thus allowing the systematic analysis and identification of new potential immunotherapy targets.
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Immunopurification
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Immunology and Microbiology
Immunogenicity and therapeutic targeting of a public neoantigen derived from mutated PIK3CA.
In Nat Med on 1 May 2022 by Chandran, S. S., Ma, J., et al.
PubMed
Public neoantigens (NeoAgs) represent an elite class of shared cancer-specific epitopes derived from recurrently mutated driver genes. Here we describe a high-throughput platform combining single-cell transcriptomic and T cell receptor (TCR) sequencing to establish whether mutant PIK3CA, among the most frequently genomically altered driver oncogenes, generates an immunogenic public NeoAg. Using this strategy, we developed a panel of TCRs that recognize an endogenously processed neopeptide encompassing a common PIK3CA hotspot mutation restricted by the prevalent human leukocyte antigen (HLA)-A*03:01 allele. Mechanistically, immunogenicity to this public NeoAg arises from enhanced neopeptide/HLA complex stability caused by a preferred HLA anchor substitution. Structural studies indicated that the HLA-bound neopeptide presents a comparatively 'featureless' surface dominated by the peptide's backbone. To bind this epitope with high specificity and affinity, we discovered that a lead TCR clinical candidate engages the neopeptide through an extended interface facilitated by an unusually long CDR3β loop. In patients with diverse malignancies, we observed NeoAg clonal conservation and spontaneous immunogenicity to the neoepitope. Finally, adoptive transfer of TCR-engineered T cells led to tumor regression in vivo in mice bearing PIK3CA-mutant tumors but not wild-type PIK3CA tumors. Together, these findings establish the immunogenicity and therapeutic potential of a mutant PIK3CA-derived public NeoAg.
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In vitro experiments
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Homo sapiens (Human)
A TCR mimic monoclonal antibody reactive with the public phospho-neoantigen pIRS2/HLA-A*02:01 complex.
In JCI Insight on 8 March 2022 by Dao, T., Mun, S. S., et al.
PubMed
Phosphopeptides derived from dysregulated protein phosphorylation in cancer cells can be processed and presented by MHC class I and class II molecules and, therefore, represent an untapped class of tumor-specific antigens that could be used as widely expressed "public" cancer neoantigens (NeoAgs). We generated a TCR mimic (TCRm) mAb, 6B1, specific for a phosphopeptide derived from insulin receptor substrate 2 (pIRS2) presented by HLA-A*02:01. The pIRS2 epitope's presentation by HLA-A*02:01 was confirmed by mass spectrometry. The TCRm 6B1 specifically bound to pIRS2/HLA-A2 complex on tumor cell lines that expressed pIRS2 in the context of HLA-A*02:01. Bispecific mAbs engaging CD3 of T cells were able to kill tumor cell lines in a pIRS2- and HLA-A*02:01-restricted manner. Structure modeling shows a prerequisite for an arginine or lysine at the first position to bind mAb. Therefore, 6B1 could recognize phosphopeptides derived from various phosphorylated proteins with similar amino acid compositions. This raised the possibility that a TCRm specific for the pIRS2/HLA-A2 complex could target a range of phosphopeptides presented by HLA-A*02:01 in various tumor cells. This is the first TCRm mAb to our knowledge targeting a phosphopeptide/MHC class I complex; the potential of this class of agents for clinical applications warrants further investigation.
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Immunoprecipitation
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Cancer Research
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Immunology and Microbiology
MEK inhibition enhances presentation of targetable MHC-I tumor antigens in mutant melanomas
In bioRxiv on 12 January 2022 by Stopfer, L. E., Rettko, N. J., et al.
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