Abstract A cognate antigen engagement of TCR induces a conformation change in the CD3 complex (CD3Δc) that is required for productive T cell activation. CD3Δc fails when TCRs interact with poorly immunogenic antigens, like many tumor-associated-antigens (TAAs), which do not active cells. Anti-CD3 monovalent Fab fragments (Mono-Fabs) bound to mimic CD3Δc, producing “co-potentiation” associated w...

CD2-mediated T lymphocyte activation requires surface expression of CD3-Ti, the T cell receptor (TCR) for antigen major histocompatibility complex protein. Given the importance of CD3~" in TCR signaling, we have directly examined the ability of the CD3~" cytoplasmic domain to couple CD2 to intracellular signal transduction pathways. A cDNA encoding a chimeric protein consisting of the human CD3...

The NKp46 receptor demonstrates a high degree of lineage specificity, being expressed almost exclusively in NK cells. Previous studies have demonstrated NKp46 expression by T cells, but NKp46+ CD3+ cells are rare and almost universally associated with NKp46 acquisition by T cells following stimulation. In this study we demonstrate the existence of a population of NKp46+ CD3+ cells resident in n...

The lymphoproliferative disease of granular lymphocytes (LDGL) results from chronic proliferation of either CD3- or CD3+ large granular lymphocytes (LGLs). Most CD3+ LGLs have been well characterized as clonal LGL proliferations (LGL leukemia). In contrast, the clonal nature and clinical features of patients with CD3- LDGL have not been defined. In this study, we analyzed seven female patients ...

The TCR-CD3 complex consists of the clonotypic disulfide-linked TCRalphabeta or TCRdeltagamma heterodimers, and the invariant CD3delta, epsilon, gamma and zeta chains. We generated plasmid constructs expressing the extracellular domains of the CD3delta, epsilon or gamma subunits fused to human IgG1 Fc. Recombinant fusion proteins consisting of individual CD3delta, epsilon or gamma subunits reac...

Activation of T cells through the TCR is mediated by the TCR-CD3 signaling complex. Cross linking of this complex with Abs directed against CD3 leads to potent activation of T cells. However, such activation is not Ag-specific. We exploited the observation that the TCR-CD3 complex is clustered on T cells that have been activated by Ag by using anti-CD3 nanoparticles to selectively activate Ag-e...

OBJECTIVE Non-Fc-binding anti-CD3-specific antibodies represent a promising therapy for preserving C-peptide production in subjects with recent-onset type 1 diabetes. However, the mechanisms by which anti-CD3 exerts its beneficial effect are still poorly understood, and it is questionable whether this therapeutic approach will prove durable with regard to its ability to impart metabolic preserv...

The T cell receptor (TCR)-CD3 complex is composed of a genetically diverse αβ TCR heterodimer associated noncovalently with the invariant CD3 dimers CD3ϵγ, CD3ϵδ, and CD3ζζ. The TCR mediates peptide-MHC recognition, whereas the CD3 molecules transduce activation signals to the T cell. Although much is known about downstream T cell signaling pathways, the mechanism whereby TCR engagement by pept...

It has previously been shown that nano-meter sized vesicles (30-100 nm), exosomes, secreted by antigen presenting cells can induce T cell responses thus showing the potential of exosomes to be used as immunological tools. Additionally, activated CD3⁺ T cells can secrete exosomes that have the ability to modulate different immunological responses. Here, we investigated what effects exosomes orig...