Enhanced transmembrane signalling activity of monoclonal antibody heteroconjugates suggests molecular interactions between receptors on the T cell surface

Ledbetter, Jeffrey A.; Norris, Nancy; Grossmann, Angelika; Grosmaire, Laura S.; June, Carl H.; Uckun, Fatih M.; Cosand, Wesley L.; Rabinovitch, Peter S.

doi:10.1016/0161-5890(89)90095-3

Cited by 35 publications

(19 citation statements)

References 34 publications

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“…Clearly such a situation will only arise when the antigen co-ligated with CD3 does not itself provide a co-stimulatory signal. In agreement with previous reports [49], intracellular signals were amplified in the T cells used in the present work following CD8-CD3 or CD2-CD3 cross-linking.…”

Section: Discussionsupporting

confidence: 90%

Does co‐aggregation of the CD45 and CD3 antigens inhibit T cell antigen receptor complex‐mediated activation of phospholipase C and protein kinase C?

et al. 1992

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The binding of agonistic monoclonal antibodies (mAb) to the CD3 antigen in T cells induces a rapid increase in tyrosine phosphorylation, inositive phosphate (IP) production, a rise in intracellular calcium and protein kinase C (PKC) activation. These intracellular signals have been implicated in the control of interleukin-2 and interleukin-2R receptor gene expression, thereby regulating T cell proliferation. Previous studies have shown that co-ligation of the CD45 and CD3 antigens inhibits CD3-induced tyrosine phosphorylation, IP production, calcium signals and T cell proliferation. It has therefore been suggested that the CD45 antigen uncouples the T cell receptor (TcR) from mitogenic signal pathways. In this study co-ligation of the CD3 and CD45 antigens with precisely constructed bispecific mAb did not inhibit CD3-induced T cell proliferation, IP production, calcium signals, diacylglycerol production or PKC activation. Furthermore, co-ligation of CD3 and CD45 antigens already cross-linked with IgM mAb did not lead to inhibition of CD3-induced calcium signals. Inhibitions of CD3-induced intracellular signals were observed following co-ligation of IgG CD45 and CD3 mAb with anti-IgG (F(ab')2 fragments. However, comparable inhibitions were also noted following co-ligation of CD3 with other abundant cell-surface antigens such as CD5 and LFA-1, and inhibitions were only observed when the CD3 mAb used required cross-linking to induce signals. These results suggested that the inhibitory effects of CD45 IgG mAb were not specific and were caused by the prevention of CD3-CD3 cross-linking following CD3 antigen co-ligation with other cell surface molecules. These findings are inconsistent with a specific inhibitory role for the CD45 phosphotyrosine phosphatase in uncoupling the TcR from mitogenic signal pathways.

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Section: Discussionsupporting

confidence: 90%

Does co‐aggregation of the CD45 and CD3 antigens inhibit T cell antigen receptor complex‐mediated activation of phospholipase C and protein kinase C?

et al. 1992

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“…These results validate and extend previous findings that simultaneous CD6 and CD3 crosslinking increases intracellular calcium levels and T-cell proliferation. [33][34][35] Although CD28 is generally appreciated as the primary costimulatory receptor used by APCs to augment T-cell proliferation, 36,37 we now show that CD6 blockade completely impaired DC-induced T-cell proliferation up to 7 days after activation. Thus, the function of CD6 may comprise the long-term maintenance and/or elevation of existing costimulatory signals, whereas CD28 may boost T-cell costimulation at the early activation phase of the immune response.…”

Section: Cd6-alcam Interactions In T-cell-dc Contact 3217mentioning

confidence: 94%

Long-term engagement of CD6 and ALCAM is essential for T-cell proliferation induced by dendritic cells

Zimmerman

Joosten

Torensma

et al. 2006

Blood

188

213

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IntroductionThe interaction between a T cell and an antigen-presenting cell (APC) is the central event in the induction of an adaptive immune response and involves different and sequential cellular events. Initially, the T cell transiently adheres to the APC and scans its surface for the presence of specific peptide-major histocompatibility (MHC) complexes in an antigen-independent manner. Several receptor-ligand pairs such as CD2/lymphocyte function-associated antigen-3 (LFA-3), LFA-1/intercellular adhesion molecule-1 (ICAM-1) and ICAM-3, and ICAM-3/dendritic cell (DC)-specific ICAM-3-grabbing nonintegrin (DC-SIGN) have been implicated in these early T-cell-APC interactions. 1 In particular, ICAM-1 and -3 play a key role in mediating the initial, antigen-independent adhesion of T cells and APC. 1,2 Once the initial contact has been generated, the contact interface is stabilized by molecular reorganization of antigen receptors, adhesion molecules, costimulatory molecules, and the actin cytoskeleton. This highly organized supramolecular structure is known as the immunological synapse. 3 Adhesion molecules and T-cell-receptor (TCR)-associated components are segregated into 2 major areas within the immunological synapse: the central supramolecular activation cluster (SMAC), which is enriched in TCR/CD3 complexes, costimulatory molecules (CD4, CD2, CD28), and kinases (protein kinase C-[PKC-], Lck, and Fyn), and the peripheral SMAC, including LFA-1 and talin. 4,5 Synapse formation is accompanied by cytoskeletal rearrangements, induction of tyrosine phosphorylation and an increase in intracellular free Ca 2ϩ . Upon Ca 2ϩ mobilization, the nuclear factor of activated T cells (NFAT) is dephosphorylated and translocates to the nucleus, where it acts as a transcriptional regulator of interleukin-2 (IL-2) expression. 6 Activated leukocyte cell adhesion molecule (ALCAM; CD166) is a member of the immunoglobulin (Ig) superfamily of proteins. 7 Although ALCAM is expressed on a wide variety of cells, within the leukocyte population its expression is particularly high on DC. In addition, monocytic cells in synovium from patients with rheumatoid arthritis show strongly increased ALCAM levels compared with resting monocytes, suggesting that ALCAM is involved in regulating immunologic processes such as inflammation. 8 However, the precise role of ALCAM in the immune system is as yet unclear. Similar to several other Ig-like adhesion molecules (NCAM, CEA), ALCAM mediates homotypic ALCAM-ALCAM interactions, 7,9,10 but also heterotypic interactions with the T-cell antigen CD6 have been described. 7 CD6 is a surface receptor expressed by T lymphocytes, thymocytes, and a subset of B cells. [11][12][13] 18 It has been suggested that CD6 fine-tunes CD5 tyrosine phosphorylation by recruiting specific kinases of different families, such as Itk and Lck. 19 CD6 physically associates with the TCR/CD3 complex, it relocalizes upon T-cell activation at the central SMAC (cSMAC) and it modulates immunological synapse maturation in a Jurkat-Raji mo...

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“…Rather, clustering of multiple receptors may be required, as proposed for CD28/CTLA4 (35). On T cells, clustering or crosslinking CD6 using mAb is not sufficient to cause Ca 2ϩ fluxing (29,36), phosphorylation of CD6 on Tyr residues (19), or T cell proliferation. These effects require additional stimuli such as CD2 or CD3 ligation, phorbol 12-myristate 13-acetate, or the presence of accessory cells (10,13,29).…”

Section: Discussionmentioning

confidence: 99%

The Amino-terminal Immunoglobulin-like Domain of Activated Leukocyte Cell Adhesion Molecule Binds Specifically to the Membrane-proximal Scavenger Receptor Cysteine-rich Domain of CD6 with a 1:1 Stoichiometry

Bowen

Bajorath

Siadak

et al. 1996

Journal of Biological Chemistry

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Activated leukocyte cell adhesion molecule (ALCAM)was recently identified as a ligand for CD6, a signaling receptor expressed on T cells, a subset of B cells, and some cells in the brain. Receptor-ligand binding assays, antibody blocking experiments, and examination of the tissue distribution of these two cell surface proteins suggest that CD6-ALCAM interactions play an important role in mediating the binding of thymocytes to thymic epithelial cells and of T cells to activated leukocytes. Presently, the details of CD6-ALCAM interactions and of signaling through CD6 are unknown. A series of truncated human ALCAM and CD6 immunoglobulin fusion proteins were produced and tested in different binding assays to analyze ALCAM-CD6 interactions in more detail. In this study, we report that the amino-terminal Ig-like domain of human ALCAM specifically binds to the third membrane-proximal scavenger receptor cysteine-rich (SRCR) domain of human CD6. Using thrombin-cleaved Ig fusion proteins containing single or multiple ALCAM or CD6 domains, we were able to determine that the stoichiometry of the interaction between the amino-terminal ALCAM domains and the membrane-proximal CD6 SRCR domain is 1:1. These results provide the first example of an Ig-like domain mediating an interaction with an SRCR domain. Ig supergene family (IgSF)1 members have been shown to interact with a wide variety of other molecules, including integrins, cytokines, and other IgSF members. Many of these interactions are mediated through protein-protein contacts, although a subset of these proteins, known as sialoadhesins, recognize sialic acid (1). Recently, we have reported on a novel interaction between an IgSF member, activated leukocyte cell adhesion molecule (ALCAM), and a member of the scavenger receptor cysteine-rich (SRCR) family of proteins, CD6 (2). Soluble recombinant proteins consisting of the extracellular domains of either ALCAM or CD6 fused to human IgG1 constant domains were shown to specifically bind to COS cell transfectants expressing CD6 or ALCAM, respectively.ALCAM is a type I membrane protein whose extracellular domain is composed of five Ig-like domains: two amino-terminal V set Ig domains followed by three domains of the C2 set, a hydrophobic transmembrane domain, and a short cytoplasmic anchor sequence (2). ALCAM is also known as SC-1/DM-GRASP/ BEN in the chicken (3-5) and as KG-CAM in the rat (6). The chicken counterpart of ALCAM is a neural adhesion molecule capable of supporting neurite outgrowth (4, 5). Data from the chicken indicate that ALCAM is capable of homophilic interactions (4, 5), and the possibility of such interactions has also been suggested on the basis of molecular modeling (7). We have previously reported that COS cells that expressed CD6 were able to bind to ALCAM positive thymic epithelial cells, which suggested that CD6 and ALCAM binding can mediate adhesive interactions between thymocytes and thymic epithelial cells (2).CD6, also a type I membrane protein (8), is expressed by thymocytes, T cells, a subset of...

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Enhanced transmembrane signalling activity of monoclonal antibody heteroconjugates suggests molecular interactions between receptors on the T cell surface

Cited by 35 publications

References 34 publications

Does co‐aggregation of the CD45 and CD3 antigens inhibit T cell antigen receptor complex‐mediated activation of phospholipase C and protein kinase C?

Does co‐aggregation of the CD45 and CD3 antigens inhibit T cell antigen receptor complex‐mediated activation of phospholipase C and protein kinase C?

Long-term engagement of CD6 and ALCAM is essential for T-cell proliferation induced by dendritic cells

The Amino-terminal Immunoglobulin-like Domain of Activated Leukocyte Cell Adhesion Molecule Binds Specifically to the Membrane-proximal Scavenger Receptor Cysteine-rich Domain of CD6 with a 1:1 Stoichiometry

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