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T-cell hybridomas were first produced some 20 yr ago (1). They have been used for research in almost all aspects of T-cell biology ranging from experiments on T-cell receptors and their specificity to the cytokines produced by T cells and the factors that lead to T-cell death. For biological studies, T- ...

Intrathymic T-cell differentiation proceeds through a series of discrete stages in which developmental changes in gene expression modify cell surface phenotype and functional potential (reviewed in 1–3). Thymocyte progenitors in the CD4−8− double negative (DN) compartment gi ...

As T cells develop in the thymus, they undergo distinct changes in their morphology and expression of cell surface antigens. Phenotypic changes in mature peripheral T cells also occur subsequent to T-cell activation, resulting from engagement of the T-cell antigen receptor (TCR) or exposu ...

Expression cloning is a powerful tool in isolating a cDNA for a protein when the protein is difficult to purify but can be detected by antibody staining or some biological activity, such as growth promoting activity. In this chapter, we focus on the cloning of cDNAs for surface proteins by expression c ...

T cells are defined by the expression of CD3 molecules on the cell surface in association with the T-cell receptor (TCR) to form the TCR/CD3 complex. Within the CD3+ cell population there are two main subsets identified by the expression of CD4 (CD4+ T cells) and CD8 (CD8+ T cells) cell surface molecules. In add ...

Apoptosis is a highly regulated process by which eukaryotic cells undergo cell death (1–4). Often synonymous with “cell suicide” and “programmed cell death,” apoptosis is distinguishable from another major form of cell death, necrosis, by a number of key morphological and biochemical fea ...

The pathway of T-cell development follows a series of highly regulated steps beginning with the differentiation of bone marrow-resident pluripotent hematopoietic stem cells (HSCs) into T-cell progenitors that migrate to the thymus. Upon colonizing the thymic microenvironment, ...

Superantigens (SAgs) stimulate large fractions of T cells by circumventing normal antigen presentation through binding both class II major histocompatibility complex (MHC) molecules on antigen-presenting cells, and specific variable regions on the β-chain (Vβ) of the T-cell an ...

The small intestine selectively absorbs digested macromolecules, vitamins, minerals, and electrolytes, whereas the large intestine supports the majority of the gut microflora and reabsorbs water. These activities are the primary functions of the intestinal epithelium, a sing ...

The main characteristic of a superantigen (SAg) is that it activates specific subsets of T cells that are composed of particular T-cell receptor (TCR) variable region β chain gene products (TCRBV). SAgs are thought to form a bridge between the TCRBV region on the T cell and the MHC class II molecule on the an ...

In order to get the full picture of the cytokine response generated by stimulation of various pathogens and superantigens in particular it is of crucial importance to collect data at various timepoints after stimulation. It is clear from those experiments performed that the production of t ...

Staphylococcus enterotoxin superantigens (SAgs) have the capacity to strongly activate oligoclonal populations of T lymphocytes expressing T-cell antigen receptors (TCR) that share particular Vβ elements. These superantigens stimulate T lymphocytes by binding simult ...

Among the antigens presented by the major histocompatibility complex (MHC) class II molecules, the superantigens (SAgs) constitute a particular family of ligands that are able to signal via the MHC class II molecules (1). The SAg are characterized by their ability to bind to both the MHC class II mo ...

The T-cell receptor (TCR) is a membrane-bound, multi-subunit complex that plays a key role in antigen recognition of cell-mediated immunity. The α and β chains of the TCR are extracellular domains that are the primary contact regions for two types of antigens. In conventional T-cell recognition, ...

A T-cell recognizes two major classes of antigens. Binding of the αβ T-cell receptor (TCR) to an intracellularly-processed peptide antigen in the context of a major histocompatibility complex (pMHC) provides for the specificity of a cell-mediated immune response. However, this normal a ...

There are several key differences between the nature of interactions of a T-cell receptor (TCR) with a conventional MHCpeptide complex and a bacterial superantigen (SAg). Apart from being powerful T-cell mitogens, these SAgs do not require antigen processing, they interact with the Vβ reg ...

An important characteristic of superantigens (SAgs) is their high structural stability. For instance, it is well known that staphylococcal enterotoxins are stable enough to traverse the stomach while retaining their biological activity. Despite this high stability, structur ...

Mouse mammary tumor viral superantigens (vSAgs) are produced by germline-encoded proviruses and infectious viruses (for reviews see refs. 1,2. Like other superantigens, they interact with class II major histocompatiblity complex (MHC) proteins and trigger T-cell proliferati ...

Superantigens (SAgs) are a class of bacterial or viral proteins that aberrantly alter immune system function through simultaneous interaction with lateral surfaces of major histocompatibility (MHC) class II molecules on antigen presenting cells, and to particular variable re ...

Bacterial superantigens are potent T-cell stimulatory protein molecules produced by Staphylococcus aureus and Streptococcus pyogenes 1. Their function in the microbe appears primarily to debilitate the host sufficiently through their effects on cells of the immune system to pe ...