FlowMAb PE anti-human/monkey CD28
Product Details
The CD28.2 monoclonal antibody reacts with human and monkey CD28, a 45 kDa costimulatory receptor and a member of the Ig superfamily. CD28 is expressed by thymocytes, most peripheral T cells, and NK cells. CD28 is a receptor for CD80 (B7-1) and CD86 (B7-2). Signaling through CD28 augments IL-2 and IL-2 receptor expression as well as the cytotoxicity of CD3-activated T cells. This R-phycoerythrin (R-PE or PE)-conjugated version of the antibody is useful for flow cytometry and immunohistochemistry (frozen) applications.Specifications
| Isotype | Mouse IgG1,Ā Īŗ |
|---|---|
| Recommended Isotype Control(s) | FlowMAb PE mouse IgG1 isotype control, unknown specificity |
| Conjugation | PE |
| Excitation Source | Yellow-Green 488 nm, 532 nm, 561 nm |
| Excitation Max | 496 nm, 566 nm |
| Emission Max | 576 nm |
| Immunogen | Human CD28 transfected cell line |
| Reported Applications |
Flow cytometry Immunohistochemistry (frozen) |
| Formulation |
PBS, pH 7.0 Contains 0.09% Sodium Azide |
| Production | Purified from cell culture supernatant in an animal-free facility |
| Purification | Protein G. Conjugated with R-phycoerythrin under optimal conditions. |
| Storage | The antibody solution should be stored at the stock concentration at 4Ā°C and protected from prolonged exposure to light. Do not freeze. |
Additional Formats
Recommended Products
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Recommended Isotype Control(s)
FlowMAb PE mouse IgG1 isotype control, unknown specificity
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Recommended Dilution Buffer
InVivoPure pH 7.0 Dilution Buffer
Flow Cytometry
Leonard, J. A., et al. (2011). "HIV-1 Nef disrupts intracellular trafficking of major histocompatibility complex class I, CD4, CD8, and CD28 by distinct pathways that share common elements" J Virol 85(14): 6867-6881. PubMed
The Nef protein is an important HIV virulence factor that promotes the degradation of host proteins to augment virus production and facilitate immune evasion. The best-characterized targets of Nef are major histocompatibility complex class I (MHC-I) and CD4, but Nef also has been reported to target several other proteins, including CD8beta, CD28, CD80, CD86, and CD1d. To compare and contrast the effects of Nef on each protein, we constructed a panel of chimeric proteins in which the extracellular and transmembrane regions of the MHC-I allele HLA-A2 were fused to the cytoplasmic tails of CD4, CD28, CD8beta, CD80, CD86, and CD1d. We found that Nef coprecipitated with and disrupted the expression of molecules with cytoplasmic tails from MHC-I HLA-A2, CD4, CD8beta, and CD28, but Nef did not bind to or alter the expression of molecules with cytoplasmic tails from CD80, CD86, and CD1d. In addition, we used short interfering RNA (siRNA) knockdown and coprecipitation experiments to implicate AP-1 as a cellular cofactor for Nef in the downmodulation of both CD28 and CD8beta. The interaction with AP-1 required for CD28 and CD8beta differed from the AP-1 interaction required for MHC-I downmodulation in that it was mediated through the dileucine motif within Nef (LL(164,165)AA) and did not require the tyrosine binding pocket of the AP-1 mu subunit. In addition, we demonstrate a requirement for beta-COP as a cellular cofactor for Nef that was necessary for the degradation of targeted molecules HLA-A2, CD4, and CD8. These studies provide important new information on the similarities and differences with which Nef affects intracellular trafficking and help focus future research on the best potential pharmaceutical targets.
Flow Cytometry
Rout, N., et al. (2010). "Paucity of CD4+ natural killer T (NKT) lymphocytes in sooty mangabeys is associated with lack of NKT cell depletion after SIV infection" PLoS One 5(3): e9787. PubMed
Lack of chronic immune activation in the presence of persistent viremia is a key feature that distinguishes nonpathogenic simian immunodeficiency virus (SIV) infection in natural hosts from pathogenic SIV and HIV infection. To elucidate novel mechanisms downmodulating immune activation in natural hosts of SIV infection, we investigated natural killer T (NKT) lymphocytes in sooty mangabeys. NKT lymphocytes are a potent immunoregulatory arm of the innate immune system that recognize glycolipid antigens presented on the nonpolymorphic MHC-class I-like CD1d molecules. In a cross-sectional analysis of 50 SIV-negative and 50 naturally SIV-infected sooty mangabeys, ligand alpha-galactosylceramide loaded CD1d tetramers co-staining with Valpha24-positive invariant NKT lymphocytes were detected at frequencies >or=0.002% of circulating T lymphocytes in approximately half of the animals. In contrast to published reports in Asian macaques, sooty mangabey NKT lymphocytes consisted of CD8(+) and CD4/CD8 double-negative T lymphocytes that were CXCR3-positive and CCR5-negative suggesting that they trafficked to sites of inflammation without being susceptible to SIV infection. Consistent with these findings, there was no difference in the frequency or phenotype of NKT lymphocytes between SIV-negative and SIV-infected sooty mangabeys. On stimulation with alpha-galactosylceramide loaded on human CD1d molecules, sooty mangabey NKT lymphocytes underwent degranulation and secreted IFN-gamma, TNF-alpha, IL-2, IL-13, and IL-10, indicating the presence of both effector and immunoregulatory functional capabilities. The unique absence of CD4(+) NKT lymphocytes in sooty mangabeys, combined with their IL-10 cytokine-secreting ability and preservation following SIV infection, raises the possibility that NKT lymphocytes might play a role in downmodulating immune activation in SIV-infected sooty mangabeys.
Immunohistochemistry (frozen)
Tazi, A., et al. (1999). "Evidence that Langerhans cells in adult pulmonary Langerhans cell histiocytosis are mature dendritic cells: importance of the cytokine microenvironment" J Immunol 163(6): 3511-3515. PubMed
Because Langerhans cells (LC) in peripheral tissues are generally āimmatureā cells with poor lymphostimulatory activity, the contribution of immune responses initiated by LC to the pathogenesis of pulmonary LC histiocytosis (LCH) has been uncertain. In this study we demonstrate that LC accumulating in LCH granulomas are phenotypically similar to mature lymphostimulatory dendritic cells present in lymphoid organs. LC in LCH granulomas intensely expressed B7-1 and B7-2 molecules, whereas normal pulmonary LC and LC accumulating in other pathologic lung disorders did not express these costimulatory molecules. The presence of B7+ LC in LCH granulomas was associated with the expression in these lesions, but not at other sites in the lung, of a unique profile of cytokines (presence of GM-CSF, TNF-alpha, and IL-1beta and the absence of IL-10) that is known to promote the in vitro differentiation of LC into cells expressing a lymphostimulatory phenotype. Finally, LCH granulomas were the only site where CD154-positive T cells could be identified in close contact with LC intensely expressing CD40 Ags. Taken together, these results strongly support the idea that an abnormal immune response initiated by LC may participate in the pathogenesis of pulmonary LCH, and suggest that therapeutic strategies aimed at modifying the lymphostimulatory phenotype of LC may be useful in the treatment of this disorder.
Immunohistochemistry (frozen)
Battifora, M., et al. (1998). "B7.1 costimulatory molecule is expressed on thyroid follicular cells in Hashimotoās thyroiditis, but not in Gravesā disease" J Clin Endocrinol Metab 83(11): 4130-4139. PubMed
The molecules of the B7 family play a major role in T-lymphocyte costimulation through interaction with their counterreceptors CD28 and CTLA4. In the present study, we analyzed the possible expression of B7 molecules on surgically removed thyroid tissue of patients with autoimmune [Hashimotoās thyroiditis (HT) or Gravesā disease (GD)] or nonautoimmune [nontoxic goiter (NTG) or papillary cancer (PC)] thyroid diseases. We found clear positivity of thyroid follicular cells for B7.1 in HT but not in GD, nor in nonautoimmune specimens (NTG, PC) using in situ analysis by alkaline phosphatase anti-alkaline phosphatase (APAAP) technique. Double immunostaining experiments in combination with an anti-human thyroglobulin antibody confirmed follicular B7.1 localization. On the contrary, no follicular B7.2 expression was observed in any specimen analyzed. These findings were confirmed by immunofluorescence flow cytometry on isolated follicular cells. The cytokines IL1beta and LPS were able to induce de novo B7.1 expression on cultured thyroid follicular cells. Intrathyroid T cells proved responsive to stimulation via the B7 ligand CD28, even in the absence of IL2. Moreover preliminary evidence was obtained for an inhibitory effect of anti-B7.1 mAb on T-cell proliferation in coculture with isolated thyroid follicular cells. It is conceivable that in HT, expression of B7.1 on follicular cells, together with MHC class II antigens and ICAM1, could provide a local costimulatory signal for T-lymphocyte differentiation toward the type 1 cytokine secretion pattern and maintenance of the autoimmune process.