InVivoMAb anti-rat CTLA-4 (CD152)

Catalog #BE0424
Clone:
WKH203
Reactivities:
Rat

$164.00 - $4,280.00

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  • 100 mg - $4,280.00
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Product Details

The WKH203 monoclonal antibody reacts with rat CTLA-4 (cytotoxic T-lymphocyte- antigen 4) (CTLA-4), also known as CD152. CTLA-4 is an inhibitory receptor acting as a key negative regulator of T-cell immune responses. CTLA-4 protein is expressed by activated T cells and by suppressor T regulatory cells. Rat CTLA-4 is a 223 amino acid long single-pass type I membrane protein (encoded by gene Ctla4) and has a predicted molecular weight of 24.9 kDa. CTLA-4 has structural similarities to the T-cell co-stimulatory protein CD28, and both of these molecules bind to the B7 family members B7-1 (CD80) and B7-2 (CD86). CTLA-4ā€™s affinity for its natural B7 family ligands CD80 and CD86 is significantly higher than the affinity of their cognate stimulatory co-receptor CD28. CTLA-4 plays key roles in induction and/or maintenance of immunological tolerance, thymocyte development, and regulation of protective immunity. CTLA-4 is among a group of inhibitory receptors being explored as cancer treatment targets through immune checkpoint blockade. In the last two decades, extensive research on CTLA-4 has led to the clinical approval of therapeutic antibodies for treatment of advanced metastatic melanoma and liver cancer. The binding of the CTLA-4 antibody to the CTLA-4 protein disrupts the key signaling mechanisms linked to the suppression of T cell activity, triggering T cells readily and enhancing the immune systemā€™s capacity to identify and eliminate cancer.

Specifications

Isotype Mouse IgG1, Īŗ
Recommended Isotype Control(s) InVivoMAb mouse IgG1 isotype control, unknown specificity
Recommended Dilution Buffer InVivoPure pH 7.0 Dilution Buffer
Immunogen Purified rat CTLA-4hIg fusion protein
Reported Applications in vitro CTLA-4 neutralization
Flow cytometry
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 cell culture supernatant in an animal-free facility
Purification Protein G
Molecular Weight 150 kDa
Storage The antibody solution should be stored at the stock concentration at 4Ā°C. Do not freeze.
in vitro CTLA-4 neutralization
Takatsuka N, Hasegawa A, Takamori A, Shimizu Y, Kato H, Ohashi T, Amagasa T, Masuda T, Kannagi M. (2009). "Induction of IL-10- and IFN-gamma-producing T-cell responses by autoreactive T-cells expressing human T-cell leukemia virus type I Tax" Int Immunol 21(9):1089-100. PubMed

Human T-cell leukemia virus type I (HTLV-I) is associated with adult T-cell leukemia, HTLV-I-associated myelopathy/tropical spastic paraparesis and various autoimmune-like disorders. T-cell immune suppression is also associated with HTLV-I infection. Mechanisms of diverse immune dysregulation in HTLV-I infection are obscure. Here, we investigated a potential link between autoimmunity and immune suppression in HTLV-I infection. G14, an IL-2-dependent HTLV-I-negative CD4(+)CD8(+) T-cell line previously established from an HTLV-I-infected rat, constantly proliferated and produced IFN-gamma. IFN-gamma production by G14 cells was dependent on interactions between CD4 and MHC-II, suggesting that G14 cells recognized self-antigens presented by MHC-II on themselves. To examine immune response to G14 cells, we inoculated G14 cells into syngeneic naive rats. Interestingly, T-cells isolated from these rats vigorously proliferated when stimulated with G14-Tax cells that stably expressed HTLV-I Tax, but not with G14 cells. G14-Tax-mediated T-cell proliferation was abrogated by antibodies to CD80 and CD86 that were up-regulated in G14-Tax cells. T-cells propagated by repetitive G14-Tax cell stimulations in culture with IL-2 expressed CD4, CD25 and cytolytic T lymphocyte-associated antigen 4 (CTLA-4), produced abundant amounts of IL-10 and IFN-gamma in response to G14 cells and suppressed growth of G14 cells mainly through supernatant-mediated mechanisms. Similar IL-10- and IFN-gamma-producing CD4(+)CD25(+)CTLA-4(+) T-cells were predominantly induced in culture of splenocytes from HTLV-I-infected rats following stimulation with G14-Tax cells. These results implied that expression of Tax in the otherwise low immunogenic autoreactive T-cells induced IL-10- and IFN-gamma-producing T-cell responses with regulatory effects against the autoreactive cells. Our findings provide new insights into the complex immune conditions underlying HTLV-I-associated diseases.

Flow Cytometry, in vitro CTLA-4 neutralization
Beyersdorf N, Gaupp S, Balbach K, Schmidt J, Toyka KV, Lin CH, Hanke T, HĆ¼nig T, Kerkau T, Gold R. (2005). "Selective targeting of regulatory T cells with CD28 superagonists allows effective therapy of experimental autoimmune encephalomyelitis" J Exp Med 202(3):445-55. PubMed

CD4+CD25+ regulatory T cells (T reg cells) play a key role in controlling autoimmunity and inflammation. Therefore, therapeutic agents that are capable of elevating numbers or increasing effector functions of this T cell subset are highly desirable. In a previous report we showed that a superagonistic monoclonal antibody specific for rat CD28 (JJ316) expands and activates T reg cells in vivo and upon short-term in vitro culture. Here we demonstrate that application of very low dosages of the CD28 superagonist into normal Lewis rats is sufficient to induce T reg cell expansion in vivo without the generalized lymphocytosis observed with high dosages of JJ316. Single i.v. administration of a low dose of the CD28 superagonist into Dark Agouti (DA) rats or Lewis rats that suffered from experimental autoimmune encephalomyelitis (EAE) proved to be highly and equally efficacious as high-dose treatment. Finally, we show that T reg cells that were isolated from CD28-treated animals displayed enhanced suppressive activity toward myelin basic protein-specific T cells in vitro, and, upon adoptive transfer, protected recipients from EAE. Our data indicate that this class of CD28-specific monoclonal antibodies targets CD4+CD25+ T reg cells and provides a novel means for the effective treatment of multiple sclerosis and other autoimmune diseases.

Flow Cytometry, in vitro CTLA-4 neutralization
Lin CH, HĆ¼nig T. (2003). "Efficient expansion of regulatory T cells in vitro and in vivo with a CD28 superagonist" Eur J Immunol 33(3):626-38. PubMed

CD4(+)CD25(+) T cells play a central role in the suppression of autoimmunity and inflammation, making their in vivo expansion a highly attractive therapeutic target. By phenotyping with a novel rat CTL antigen-4 (CTLA-4)-specific monoclonal antibody (mAb) and functional in vitro assays, we here first establish that rat CD4(+)CD25(+) T cells correspond to the regulatory T cells (Treg cells) described in mice and humans: they constitutively express CTLA-4, produce IL-10 but not IL-2, and are able to suppress the proliferation of costimulated CD25-negative indicator cells. Furthermore, we show that rat Treg cells respond less well than CD25(-) T cells to conventional costimulation, but are readily expanded in vitro with "superagonistic" CD28-specific mAb which are potent mitogens for all T cells without the need for TCR engagement. In vivo, functional Treg cells are preferentially expanded by CD28 stimulation over other T cell subsets, leading to a 20-fold increase within 3 days in response to a single antibody dose. These data suggest that CD28-driven activation of Treg cells may be highly effective in the treatment of inflammatory and autoimmune diseases.

Flow Cytometry
Elflein K, Rodriguez-Palmero M, Kerkau T, HĆ¼nig T. (2003). "Rapid recovery from T lymphopenia by CD28 superagonist therapy" Blood 102(5):1764-70. PubMed

Slow recovery of T-cell numbers and function contributes to the high incidence of life-threatening infections after cytotoxic cancer therapies. We have tested the therapeutic potential of a novel class of superagonistic CD28-specific antibodies that induce polyclonal T-cell proliferation without T-cell receptor engagement in an experimental rat model of T lymphopenia. We show that in lethally irradiated, bone marrow-reconstituted hosts, CD28 superagonist is able to dramatically accelerate repopulation by a small inoculum of mature, allotype-marked T cells. CD28-driven recovery of CD4 cells was superior to that of CD8 T cells. CD28 superagonist- expanded CD4 T cells had maintained repertoire diversity and were functional both in vitro and in vivo, suggesting that treatment with a human CD28-specific superagonist will protect T-lymphopenic patients from opportunistic infections.