Antigen

About: Antigen is a research topic. Over the lifetime, 170233 publications have been published within this topic receiving 6982342 citations. The topic is also known as: antibody generator & Antigen.

Enzyme-labeled antibodies: preparation and application for the localization of antigens

Abstract: primiciples of immummiohiistochemist ry to electron niicroscopy have niet with very limited sumccess (Pierce et at., mt. Rev. Exp. Path. 3: 1. 1964). Ins ami effort to obviate somuie of these himnitatiomus, tissumes have beemt staimied with emszymes conujumgated to antibody. Ins the imuitil experintemits, acid phosphsatase was comijugated to antibody (Ram et al., Fed. Proc. 25: 732. 1966). Although these preliminary experiments deniomustrated the feasibility of thie approachu, the resumlts of the couijugatiomss were so variable that search was made for a better enzyme. Imu the presemut stumdy horseradish peroxidase was employed becaumse the enzynte is commercially available ims relatively pure form; the cytochemical amid histochemical methods have been well established, and successfully adapted to electron microscopy (Graham amid Karnovsky, J. Histochem. (Jytochem. 14: 291. 1966). The peroxidase was conjugated to antibody by a method similar to one developed for the comijugations of ferritimi to auitibody (Ram et at., J. Cell Biol. 17: 673. 1963), amid acid phosphiatase to amitibody (Ram et at., Fed. Proc. 25: 732. 1966; Nakane et at., J. Histochein. Cytochem. 7th Anmuumal Meetimig, Abstract, 1966), which employed the bifummictional reagent, p,p’difiumoro-m-m’-diuiitrodiphenyl sulfomie (FNPS). Other bifummuctiomual reagemuts sucht as 1-ethiyl-3-(3dimethylanuino propyl) carbodiimide have also beemi employed, bunt the best amid most consistent resumlts were obtained when FNPS was umsed. For routimie stumdies the conjumgates were pre-

Interleukin 13 induces interleukin 4-independent IgG4 and IgE synthesis and CD23 expression by human B cells.

Abstract: Recently the cDNA encoding interleukin 13 (IL-13), a T-cell-derived cytokine, was cloned and expressed. The present study demonstrates that IL-13 induces IgG4 and IgE synthesis by human B cells. IL-13-induced IgG4 and IgE synthesis by unfractionated peripheral blood mononuclear cells and highly purified B cells cultured in the presence of activated CD4+ T cells or their membranes. IL-13-induced IgG4 and IgE synthesis is IL-4-independent, since it was not affected by neutralizing anti-IL-4 monoclonal antibody. Highly purified, surface IgD+ B cells could also be induced to produce IgG4 and IgE by IL-13, indicating that the production of these isotypes reflected IgG4 and IgE switching and not a selective outgrowth of committed B cells. IL-4 and IL-13 added together at optimal concentrations had no additive or synergistic effect, suggesting that common signaling pathways may be involved. This notion is supported by the observation that IL-13, like IL-4, induced CD23 expression on B cells and enhanced CD72, surface IgM, and class II major histocompatibility complex antigen expression. In addition, like IL-4, IL-13 induced germ-line IgE heavy-chain gene transcription in highly purified B cells. Collectively, our data indicate that IL-13 is another T-cell-derived cytokine that, in addition to IL-4, efficiently directs naive human B cells to switch to IgG4 and IgE production.

Self-tolerance eliminates T cells specific for Mls-modified products of the major histocompatibility complex

Abstract: In mice the product of the Mlsa locus is an unusual antigen capable of interaction with certain products of the major histocompatibility locus (MHC) to form a ligand for a large portion of the T-cell alpha/beta receptor repertoire, including nearly all receptors that use V beta 8.1. The presence of Mlsa/MHC during T-cell development results in the deletion of T cells that express V beta 8.1, documenting the importance of clonal deletion in establishing tolerance to self antigens.

The receptor DEC-205 expressed by dendritic cells and thymic epithelial cells is involved in antigen processing

Abstract: Dendritic cells and thymic epithelial cells perform important immunoregulatory functions by presenting antigens in the form of peptides bound to cell-surface major histocompatibility complex (MHC) molecules to T cells. Whereas B cells are known to present specific antigens efficiently through their surface immunoglobins, a comparable mechanism for the capture and efficient presentation of diverse antigens by dendritic cells and thymic epithelial cells has not previously been described. We show here that their antigen-presentation function is associated with the high-level expression of DEC-205, an integral membrane protein homologous to the macrophage mannose receptor and related receptors which are able to bind carbohydrates and mediate endocytosis. DEC-205 is rapidly taken up by means of coated pits and vesicles, and is delivered to a multivesicular endosomal compartment that resembles the MHC class II-containing vesicles implicated in antigen presentation. Rabbit antibodies that bind DEC-205 are presented to reactive T-cell hybridomas 100-fold more efficiently than rabbit antibodies that do not bind DEC-205. Thus DEC-205 is a novel endocytic receptor that can be used by dendritic cells and thymic epithelial cells to direct captured antigens from the extracellular space to a specialized antigen-processing compartment.