InVivoMAb anti-mouse CD45RB

Catalog #BE0019
Product Citations:
4
Clone:
MB23G2 (HB220)
Reactivities:
Mouse

$164.00 - $4,280.00

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Product Details

The HB220 antibody reacts with mouse CD45RB a 220 kDa transmembrane protein tyrosine phosphatase expressed on peripheral B cells naëâve T cells thymocytes and weakly on macrophages and dendritic cells. CD45RB is one of 5 isoforms of CD45 which result from alternative splicing of exons 4-6. CD45RB results from exon 5 splicing. CD45RB is critical for intracellular signaling in T cells in response to antigen stimulation as indicated by the severe immunodeficiency observed in CD45-deficient mice. As T cells progress from naëâve to memory cells and become activated CD45RB expression is downregulated. Additionally the intensity of CD45RB expression can be used to differentiate between functionally distinct CD4+ T cell subsets which secrete differing cytokine profiles. The primary ligands for CD45 include galectin-1 CD2 CD3 CD4 and Thy-1.

Specifications

Isotype Rat IgG2a, κ
Recommended Isotype Control(s) InVivoMAb rat IgG2a isotype control, anti-trinitrophenol
Recommended Dilution Buffer InVivoPure pH 7.0 Dilution Buffer
Conjugation This product is unconjugated. Conjugation is available via our Antibody Conjugation Services.
Immunogen Anti-immunoglobulin activated mouse B cells
Reported Applications in vivo anti-CD45RB_mediated tolerance induction
in vivo pre-mNK cell depletion
Formulation PBS, pH 7.0
Contains no stabilizers or preservatives
Endotoxin <2EU/mg (<0.002EU/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_1107653
Molecular Weight 150 kDa
Storage The antibody solution should be stored at the stock concentration at 4°C. Do not freeze.
in vivo pre-mNK cell depletion
Wilson, K. A., et al. (2015). "Depletion of B220NK1.1 cells enhances the rejection of established melanoma by tumor-specific CD4 T cells" Oncoimmunology 4(8): e1019196. PubMed

Five-year survival rates for patients diagnosed with metastatic melanoma are less than 5%. Adoptive cell transfer (ACT) has achieved an objective response of 50% by Response Evaluation Criteria in Solid Tumors (RECIST) in this patient population. For ACT to be maximally effective, the host must first be lymphodepleted. It is hypothesized that lymphodepletion may remove regulatory elements and cytokine sinks, or increase the activation and availability of antigen presenting cells (APCs). We use an in vivo model to study the ACT of tumor-associated antigen (TAA)-specific CD4+ T cells (TRP-1 cells). We have discovered that depletion of NK1.1+ cells enhances the rejection of established melanoma tumors by adoptively transferred TRP-1 CD4+ T cells. NK1.1+ cell depletion increases the number of CD4+ T cells, the serum concentration of pro-inflammatory cytokines, autoimmune vitiligo, host survival and prevented recurrence after ACT. Because multiple cells express NK1.1, we targeted different NK1.1+ cell populations using antibodies specific for NK cells, pre-mNK cells, and innate lymphoid cells (ILCs). Our data suggests that NK1.1+B220+ pre-mNK cells (also known as interferon-producing killer dendritic cells; IKDCs) are an important inhibitor of the CD4+ T cell response to melanoma. Understanding this mechanism may help design new immunotherapies to modulate the activity of pre-mNKs in the face of an antitumor immune response and inhibit their suppression of adoptively transferred T cells.

in vivo anti-CD45RB–mediated tolerance induction
Stocks, B. T., et al. (2015). "Lupus-Prone Mice Resist Immune Regulation and Transplant Tolerance Induction" Am J Transplant . PubMed

The strongly immunogenic environment in autoimmune diseases such as lupus may pose a stringent barrier to transplantation. Despite available murine models of lupus, transplant tolerance in this setting has yet to be fully investigated in highly penetrant genetic models of disease. Such studies are of clear clinical importance because lupus is a transplant indication in which transplanted kidneys have a substantially increased risk of rejection including a role for recurrent nephritis. In the fully penetrant B6.SLE123 mouse, we determined that CD4 T follicular helper and germinal center B cells were significantly expanded compared with healthy controls. We traced this expansion to resistance of effector CD4 T and B cells in B6.SLE123 mice to regulation by either CD4 T regulatory cells (CD4Tregs) or CD8 T regulatory cells (CD8Tregs), despite demonstrating normal function by Tregs in this strain. Finally, we determined that B6.SLE123 mice resist anti-CD45RB-mediated tolerance induction to foreign islet allografts, even in the absence of islet autoimmunity. Overall, B6.SLE123 lupus-prone mice are highly resistant to transplant tolerance induction, which provides a new model of failed tolerance in autoimmunity that may elucidate barriers to clinical transplantation in lupus through further cellular and genetic dissection.

in vivo anti-CD45RB–mediated tolerance induction
Lee, K. M., et al. (2014). "TGF-beta-producing regulatory B cells induce regulatory T cells and promote transplantation tolerance" Eur J Immunol 44(6): 1728-1736. PubMed

Regulatory B (Breg) cells have been shown to play a critical role in immune homeostasis and in autoimmunity models. We have recently demonstrated that combined anti-T cell immunoglobulin domain and mucin domain-1 and anti-CD45RB antibody treatment results in tolerance to full MHC-mismatched islet allografts in mice by generating Breg cells that are necessary for tolerance. Breg cells are antigen-specific and are capable of transferring tolerance to untreated, transplanted animals. Here, we demonstrate that adoptively transferred Breg cells require the presence of regulatory T (Treg) cells to establish tolerance, and that adoptive transfer of Breg cells increases the number of Treg cells. Interaction with Breg cells in vivo induces significantly more Foxp3 expression in CD4(+) CD25(-) T cells than with naive B cells. We also show that Breg cells express the TGF-beta associated latency-associated peptide and that Breg-cell mediated graft prolongation post-adoptive transfer is abrogated by neutralization of TGF-beta activity. Breg cells, like Treg cells, demonstrate preferential expression of both C-C chemokine receptor 6 and CXCR3. Collectively, these findings suggest that in this model of antibody-induced transplantation tolerance, Breg cells promote graft survival by promoting Treg-cell development, possibly via TGF-beta production.

in vivo anti-CD45RB–mediated tolerance induction
Kim, J. I., et al. (2013). "Elevated levels of interferon-gamma production by memory T cells do not promote transplant tolerance resistance in aged recipients" PLoS One 8(12): e82856. PubMed

Immunosenescence predisposes the elderly to infectious and autoimmune diseases and impairs the response to vaccination. We recently demonstrated that ageing also impedes development of transplantation tolerance. Unlike their young counterparts (8-12 weeks of age) aged male recipients (greater than 12 months of age) transplanted with a full MHC-mismatched heart are resistant to tolerance mediated by anti-CD45RB antibody. Surprisingly, either chemical or surgical castration restored tolerance induction to levels observed using young recipients. Based on the strong impact of endocrine modulation on transplant tolerance, we explored the impact of ageing and castration on the immune system. Here we report a significant increase in the percentage of T cells that produce interferon-gamma (IFN-gamma) in aged male versus young male animals and that the overall increase in IFN-gamma production was due to an expansion of IFN-gamma-producing memory T cells in aged animals. In contrast to IFN-gamma production, we did not observe differences in IL-10 expression in young versus old male mice. We hypothesized that endocrine modulation would diminish the elevated levels of IFN-gamma production in aged recipients, however, we observed no significant reduction in the percentage of IFN-gamma+ T cells upon castration. Furthermore, we neutralized interferon-gamma by antibody and did not observe an effect on graft survival. We conclude that while elevated levels of interferon-gamma serves as a marker of tolerance resistance in aged mice, other as yet to be identified factors are responsible for its cause. Defining these factors may be relevant to design of tolerogenic strategies for aged recipients.

in vivo anti-CD45RB–mediated tolerance induction
Ge, W., et al. (2010). "Regulatory T cells are critical to tolerance induction in presensitized mouse transplant recipients through targeting memory T cells" Am J Transplant 10(8): 1760-1773. PubMed

Memory T cells are a significant barrier to induction of transplant tolerance. However, reliable means to target alloreactive memory T cells have remained elusive. In this study, presensitization of BALB/c mice with C57BL/6 skin grafts generated a large number of OX40(+)CD44(hi)effector/memory T cells and resulted in rapid rejection of donor heart allografts. Recognizing that anti-OX40L monoclonal antibody (mAb) (alpha-OX40L) monotherapy prolonged graft survival through inhibition and apoptosis of memory T cells in presensitized recipients, alpha-OX40L was added to the combined treatment protocol of LF15-0195 (LF) and anti-CD45RB (alpha-CD45RB) mAb-a protocol that induced heart allograft tolerance in non-presensitized recipients but failed to induce tolerance in presensitized recipients. Interestingly, this triple therapy restored donor-specific heart allograft tolerance in our presensitized model that was associated with induction of tolerogenic dendritic cells and CD4(+)CD25(+)Foxp3(+) T regulatory cells (Tregs). Of note, CD25(+) T cell depletion in triple therapy recipients prevented establishment of allograft tolerance. In addition, adoptive transfer of donor-primed effector/memory T cells into tolerant recipients markedly reduced levels of Tregs and broke tolerance. Our findings indicated that targeting memory T cells, by blocking OX40 costimulation in presensitized recipients was very important to expansion of Tregs, which proved critical to development of tolerance.

in vivo anti-CD45RB–mediated tolerance induction
Shen, H. and D. R. Goldstein. (2009). "IL-6 and TNF-alpha synergistically inhibit allograft acceptance" J Am Soc Nephrol 20(5): 1032-1040. PubMed

Previous studies suggested that activation of the innate immune system impairs the induction of transplantation tolerance, but the responsible inflammatory mediators have not been identified. In this study, we examined whether IL-6 and TNF-alpha promote resistance to transplantation tolerance. Using a highly immunogenic murine skin allograft model, we found that the absence of both IL-6 and TNF-alpha in the graft recipient synergized with co-stimulatory blockade to induce tolerance. Furthermore, IL-6 and TNF-alpha acted together to promote T cell alloimmune responses both in vitro and in vivo and to impair the ability of regulatory T cells to suppress effector T cell alloimmunity. In addition, deficiency of recipient IRAK-M, a negative regulator of certain innate immune pathways, augmented cellular IL-6 and TNF-alpha responses and impaired the ability of co-stimulatory blockade to extend allograft survival. In summary, IL-6 and TNF-alpha synergistically impair the efficacy of therapies that promote allograft acceptance.

    A novel prevascularized tissue-engineered chamber as a site for allogeneic and xenogeneic islet transplantation to establish a bioartificial pancreas.

    In PLoS ONE on 4 December 2020 by Liu, Y., Yang, M., et al.

    PubMed

    Although sites for clinical or experimental islet transplantation are well established, pancreatic islet survival and function in these locations remain unsatisfactory. A possible factor that might account for this outcome is local hypoxia caused by the limited blood supply. Here, we modified a prevascularized tissue-engineered chamber (TEC) that facilitated the viability and function of the seeded islets in vivo by providing a microvascular network prior to transplantation. TECs were created, filled with Growth Factor-Matrigel™ (Matrigel™) and then implanted into the groins of mice with streptozotocin-induced diabetes. The degree of microvascularization in each TECs was analyzed by histology, real-time PCR, and Western blotting. Three hundred syngeneic islets were seeded into each chamber on days 0, 14, and 28 post-chamber implantation, and 300, 200, or 100 syngeneic islets were seeded into additional chambers on day 28 post-implantation, respectively. Furthermore, allogeneic or xenogeneic islet transplantation is a potential solution for organ shortage. The feasibility of TECs as transplantation sites for islet allografts or xenografts and treatment with anti-CD45RB and/or anti-CD40L (MR-1) was therefore explored. A highly developed microvascularized network was established in each TEC on day 28 post-implantation. Normalization of blood glucose levels in diabetic mice was negatively correlated with the duration of prevascularization and the number of seeded syngeneic islets. Combined treatment with anti-CD45RB and MR-1 resulted in long-term survival of the grafts following allotransplantation (5/5, 100%) and xenotransplantation (16/20, 80%). Flow cytometry demonstrated that the frequency of CD4+Foxp3-Treg and CD4+IL-4+-Th2 cells increased significantly after tolerogenic xenograft transplantation, while the number of CD4+IFN-γ-Th1 cells decreased. These findings demonstrate that highly developed microvascularized constructs can facilitate the survival of transplanted islets in a TECs, implying its potential application as artificial pancreas in the future.

    • In Vivo
    • ,
    • Mus musculus (House mouse)
    • ,
    • Immunology and Microbiology
    Therapeutic modulation of phagocytosis in glioblastoma can activate both innate and adaptive antitumour immunity.

    In Nature Communications on 20 March 2020 by von Roemeling, C. A., Wang, Y., et al.

    PubMed

    Tumour cell phagocytosis by antigen presenting cells (APCs) is critical to the generation of antitumour immunity. However, cancer cells can evade phagocytosis by upregulating anti-phagocytosis molecule CD47. Here, we show that CD47 blockade alone is inefficient in stimulating glioma cell phagocytosis. However, combining CD47 blockade with temozolomide results in a significant pro-phagocytosis effect due to the latter's ability to induce endoplasmic reticulum stress response. Increased tumour cell phagocytosis subsequently enhances antigen cross-presentation and activation of cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) in APCs, resulting in more efficient T cell priming. This bridging of innate and adaptive responses inhibits glioma growth, but also activates immune checkpoint. Sequential administration of an anti-PD1 antibody overcomes this potential adaptive resistance. Together, these findings reveal a dynamic relationship between innate and adaptive immune regulation in tumours and support further investigation of phagocytosis modulation as a strategy to enhance cancer immunotherapy responses.

    • FC/FACS
    • ,
    • Mus musculus (House mouse)
    • ,
    • Homo sapiens (Human)
    • ,
    • Cancer Research
    • ,
    • Immunology and Microbiology
    • ,
    • Pharmacology
    Macrophage activation by a substituted pyrimido[5,4-b]indole increases anti-cancer activity.

    In Pharmacological Research : the Official Journal of the Italian Pharmacological Society on 1 October 2019 by Hardie, J., Mas-Rosario, J. A., et al.

    PubMed

    Immunotherapy has become a promising new approach for cancer treatment due to the immune system's ability to remove tumors in a safe and specific manner. Many tumors express anti-inflammatory factors that deactivate the local immune response or recruit peripheral macrophages into pro-tumor roles. Because of this, effective and specific ways of activating macrophages into anti-tumor phenotypes is highly desirable for immunotherapy purposes. Here, the use of a small molecule TLR agonist as a macrophage activator for anti-cancer therapy is reported. This compound, referred to as PBI1, demonstrated unique activation characteristics and expression patterns compared to treatment with LPS, through activation of TLR4. Furthermore, PBI1 treatment resulted in anti-tumor immune behavior, enhancing macrophage phagocytic efficiency five-fold versus non-treated macrophages. Additive effects were observed via use of a complementary strategy (anti-CD47 antibody), resulting in ∼10-fold enhancement of phagocytosis, suggesting this small molecule approach could be used in conjunction with other therapeutics. Copyright © 2019 Elsevier Ltd. All rights reserved.

    • Cancer Research
    Characterization of cluster of differentiation 47 expression and its potential as a therapeutic target in esophageal squamous cell cancer.

    In Oncology Letters on 1 February 2018 by Zhao, C. L., Yu, S., et al.

    PubMed

    The increased expression of cluster of differentiation (CD)47 has been identified in a number of different tumor types and is recognized as an adverse prognostic factor that indicates an increased risk of mortality in patients. The binding of CD47 to signal regulatory protein α (SIRPα) inhibits the macrophage phagocytosis of tumor cells by triggering an inhibitory 'do not eat me' signal. This is one of the mechanisms used by tumor cells to evade immune surveillance. In the present study, CD47 levels and macrophage infiltration were assessed in patients with esophageal squamous cell cancer (ESCC). CD47-overexpressing ESCC cell lines were selected and human M2 macrophage phagocytic activity was measured. The results revealed that CD47 is highly expressed and macrophages are markedly infiltrated in cancerous tissue compared with non-cancerous tissue. High CD47 expression was detected in ESCC cell lines and the results of a phagocytosis assay indicated that human M2 macrophages phagocytized tumor cells in a dose-dependent manner following the blocking of CD47-SIRPα signaling by anti-CD47 antibodies. The results of the present study therefore support the use of anti-CD47 immunotherapy to treat patients with ESCC.