CD27: marker and mediator of T-cell activation?

CD27 is a lymphocyte-specific member of the tumour necrosis factor receptor (TNF-R) family, expression of which is tightly regulated during T-cell ontogeny. Recently, the ligand for CD27 was identified and was shown to be identical to CD70, a novel member of the TNF family. Functional experiments show that the interaction between CD27 and its ligand generates a co-stimulatory signal for T-cell activation.

CD70 represents the human ligand for CD27.

The recently identified CD27 ligand (L) is a type II transmembrane molecule with significant structural homology to tumor necrosis factor (TNF)-alpha, TNF-beta, lymphotoxin beta, CD40L, and CD30L. Using a CD27L specific mAb we examined the tissue distribution of the molecule, and found its expression to be restricted to B cells in occasional germinal centers, stromal cells in the thymic medulla, and scattered T cells in tonsils, skin and gut. As the limited expression of CD27L closely resembled the reported distribution of the activation antigen CD70, we tested whether CD70 represents the human CD27L.

Characterization of the human CD27 ligand, a novel member of the TNF gene family.

CD27 is a lymphocyte-specific member of the TNF/NGF-R family that is highly induced on T cells after TCR stimulation, primarily on lymphocytes belonging to the unprimed CD45RA+ subset. However, after prolonged activation both in vivo and in vitro, CD27 expression is gradually switched off. In search of physiologic signals that influence CD27 expression, we found that B cell lines can mediate down-regulation of CD27 surface expression on activated T cells via direct cell-to-cell contact and that preincubation of activated T cells with CD27 mAbs prevented this modulation.

Regulation of CD27 expression on subsets of mature T-lymphocytes.

CD27, a lymphocyte-specific member of the TNF/NGF-R family, is expressed on the majority of peripheral blood T cells. Activation of T cells via TCR/CD3 induces high CD27 surface expression and the release of a soluble extracellular part of the molecule. After prolonged activation in vitro, CD27 becomes gradually switched off.

The role of the pharmaceutical animal health industry in post-marketing surveillance of resistance.

The pharmaceutical animal health industry must be committed to the total life cycle of products, i.e. during both the pre- and post-marketing period.

Preliminary studies on the interaction of TNF alpha and IFN gamma with alpha 2-macroglobulin.

The binding of 125I-labelled recombinant human TNF alpha and IFN gamma to isolated human blood alpha 2-macroglobulin has been investigated using molecular sieving procedures and non-denaturing PA gel electrophoresis in combination with autoradiography. These studies revealed that both cytokines readily bind to the electrophoretically fast form of alpha 2M generated by methylamine or protease treatment of this protein. PAGE/SDS gel investigations indicated that TNF alpha bound non-covalently while the IFN gamma interaction was covalent in nature.

Risk assessment of antibiotic residues of beta-lactams and macrolides in food products with regard to their immuno-allergic potential.

In human medicine drug allergy is a well-established side-effect of the therapeutic use of antibiotics, especially the beta-lactams. Side-effects caused by macrolides are uncommon and only a very few of these seem to be caused by allergic mechanisms. Clinically, drug allergy is characterized by a spectrum of reactions ranging from mild skin rashes to angio-oedema or life-threatening anaphylaxis.