Blockage of alpha beta T-cell development by TCR gamma delta transgenes

Article Abstract:

The body's natural defense system, the immune system, consists of cells and factors such as antibodies, that inactivate invading foreign substances called antigens. In the presence of an antigen, the immune B cells produce proteins called antibodies, that specifically attach to and destroy the antigen. The immune T cells consist of three types: helper T cells enhance the production of antibody by B cells; suppressor T cells decrease the production of antibody by B cells; and killer T cells directly interact with and destroy the antigen. The sites or receptors on T cells that recognize the antigen are heterodimers, compounds containing two units. One type of heterodimer is the alpha-beta form and the other is the gamma-delta form. The mechanism determining the development of the alpha-beta and gamma-delta receptors of the T cell is not known. It was suggested that the genes coding for the gamma-delta form were expressed first, and that the alpha-beta T cells resulted from the failure of expression of the gamma-delta genes. However, it was found that a certain factor called the transcription silencer element normally prevented the expression of the gamma gene. This possibility was investigated by examining mutant mice that genetically lacked the transcription silencer element. It was found that the production of alpha-beta type T cells was prevented in mice that genetically lacked the silencer element. (Consumer Summary produced by Reliance Medical Information, Inc.)

Genetic aspects

---

Homing of a gamma-delta thymocyte subset with homogeneous T-cell receptors to mucosal epithelia

Article Abstract:

T cells (a subset of lymphocytes) with T cell receptors comprised of two chains, gamma and delta, are found in lymphoid organs, such as the spleen and lymph nodes. They are also found in the epithelia, the outer most layer of cells of the intestines, in mice. The T cell receptors bind foreign antigens in context with the histocompatibility antigens, molecules that determine if a molecule is foreign or not. The T cell receptors found in the lymphoid organs and intestinal epithelia contain various types of gamma and delta chains that make up the receptor which binds antigens associated with the major histocompatibility antigens. T cells with receptors comprised of gamma and delta chains have been isolated from the skin of mice, but these receptors are comprised only of one particular type in each chain. A second group of receptors have been isolated that are also only comprised of a particular chain of each molecule. This type of T cell receptor was found in the epithelial cells of the vagina, the uterus, and the tongue of mice. It is thought that T cells with the gamma and delta T cell receptor are involved in the immune protection of body surfaces that are exposed to the environment, and to noninfectious and infectious agents. (Consumer Summary produced by Reliance Medical Information, Inc.)

Cell receptors, Epithelium, Mucous membrane

---

Mutations in T-cell antigen receptor genes alpha and beta block thymocyte development at different stages

Article Abstract:

Research using mice with mutant T-cell antigen receptor (TCR) genes shows that rearrangement or expression of the TCR-beta gene is necessary and sufficient for differentiation of CD4-CD8-thymocytes into the CD4+CD8+ form and for expanding the pool of thymocytes. Expression of the TCR-alpha gene is irrelevant to these processes. Furthermore, the TCR-alpha and TCR-beta mutation does not hinder development of gamma and delta T-cells.

Antigen receptors, T cell, T cell antigen receptors

Similar abstracts:

• Abstracts: Evolution: generating novelty by symbiosis. The major evolutionary transitions. Evolution of genetic redundancy
• Abstracts: Human genome project a cause of friction. Japan begins processing data for genome programme. Institute files for patents on first Japanese sequences
• Abstracts: Stimulating killer cells. Polarizing a T-cell response. Selecting and maintaining a diverse T-cell repertoire
• Abstracts: Limbs: a pattern emerges. Actin cables and epidermal movement in embryonic wound healing. Giving limbs a hand
• Abstracts: Mechanism of antigen-driven selection in germinal centres. Soluble antigen can cause enhanced apoptosis of germinal-centre B cells

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.