D Gerdes — Page 2 | PubMed Health

PubMedDate not supplied

Human T cells expressing an invariant V alpha 24-J alpha Q TCR alpha are CD4- and heterogeneous with respect to TCR beta expression.

A population of mature CD4-CD8-double-negative T cells that expresses an invariant Valpha24-JalphaQ TCR has been identified in humans; the majority of these cells appear to express Vbeta11. A closely related in variant TCRalpha chain is also expressed by a population of NK1+ murine T cells, but these cells may be either CD4+ or double negative. In this report, multiple CD4+ or double-negative Valpha24+Vbeta11+ T-cell clones were isolated, and only the double-negative clones were found to express the invariant TCRalpha chain. Studies of TCRbeta chains expressed by these cells demonstrate that a subset in some donors use Vbeta genes other than Vbeta11. Characterization of Vbeta11 TCRs in one donor by CDR3-length analysis was also carried out. The results indicate that multiple Vbeta11 TCRs of differing CDR3 lengths may associate with the invariant TCRalpha chain.

CD4 Antigens↗

PubMedDate not supplied

Nongenomic actions of steroids--from the laboratory to clinical implications.

In the classical concept of steroid action, steroids bind to cytoplasmic receptors and modulate nuclear transcription after translocation of steroid-receptor complexes into the nucleus. Due to similarities of molecular structure, receptors for steroids, retinoids, vitamin D3 and thyroid hormone are considered to represent a superfamily of receptors. While genomic steroid effects been evident for several decades, rapid effects of steroids have been characterized only recently. These rapid actions are likely to be transmitted by specific membrane receptors. Binding sites in membranes have been characterized which display binding features compatible with an involvement in rapid steroid signaling. Characteristics of putative membrane receptors are completely distinct from those of intracellular steroid receptors, a fact which is further supported by the inability of classic steroid receptor antagonists to suppress nongenomic steroid actions. The cloning and functional expression of a putative progesterone membrane receptor has been achieved. Drugs that specifically modulate nongenomic action alone or even both genomic and nongenomic actions may be applied in various areas such as the cardiovascular and central nervous systems, and treatment of infertility and electrolyte homeostasis.

Genome↗