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Receptor Diversity (receptor + diversity)

Distribution by Scientific Domains
Medical Sciences80%

Selected Abstracts

Natural killer cells: integrating diversity with function

IMMUNOLOGY, Issue 4 2009
Kuldeep Cheent
Summary The key role of natural killer cells in many aspects of the immune response is now being recognized. The last decade has seen an exponential increase in our understanding of the workings of these cells. Receptor diversity is crucial in allowing natural killer cells to respond effectively to a variety of different pathogens. This article reviews aspects of natural killer cell diversity that combine to generate populations of functional natural killer cells that exist within both the individual and throughout the population at large. [source]

The phylogenetic origins of the antigen-binding receptors and somatic diversification mechanisms

IMMUNOLOGICAL REVIEWS, Issue 1 2004
John P. Cannon
Summary:, The adaptive immune system arose in ancestors of the jawed vertebrates approximately 500 million years ago. Homologs of immunoglobulins (Igs), T-cell antigen receptors (TCRs), major histocompatibility complex I (MHC I) and MHC II, and the recombination-activating genes (RAGs) have been identified in all extant classes of jawed vertebrates; however, no definitive homolog of any of these genes has been identified in jawless vertebrates or invertebrates. RAG-mediated recombination and associated junctional diversification of both Ig and TCR genes occurs in all jawed vertebrates. In the case of Igs, somatic variation is expanded further through class switching, gene conversion, and somatic hypermutation. Although the identity of the ,primordial' receptor that was interrupted by the recombination mechanism in jawed vertebrates may never be established, many different families of genes that exhibit predicted characteristics of such a receptor have been described both within and outside the jawed vertebrates. Recent data from various model systems point toward a continuum of immune receptor diversity, encompassing many different families of recognition molecules whose functions are integrated in an organism's response to pathogenic invasion. Various approaches, including both genomic and protein-functional analyses, currently are being applied in jawless vertebrates, protochordates, and other invertebrate deuterostome systems and may yield definitive evidence regarding the presence or absence of adaptive immune homologs in species lacking adaptive immune systems. Such studies have the potential for uncovering previously unknown mechanisms of generating receptor diversity. [source]

,, T cell receptor repertoire in blood and colonic mucosa of rhesus macaques

JOURNAL OF MEDICAL PRIMATOLOGY, Issue 6 2000
Eva Rakasz
Although their precise roles are not well defined, ,, T lymphocytes are recognized as regular components of immune responses. These cells express a limited T cell receptor repertoire and they can be stimulated by soluble ligands without conventional processing and presentation by major histocompatibility antigens. Progress in this area has been limited by the substantial differences between murine and human ,, T cells and the lack of knowledge about these cells in nonhuman primates. We used molecular analysis of T cell receptor diversity to characterize ,, T cell populations from peripheral blood and colon of rhesus macaques (Macaca mulatta). The ,, T cell receptor diversity was limited and distinct for these tissue compartments, particularly in the TCRGV2 family. Furthermore, the TCRDV1+ subset of peripheral blood ,, T cells showed signs of progressive oligoclonalization as a function of age. Similar observations have been reported for human tissue samples and our results validate rhesus macaques as an appropriate animal model for studying primate ,, T cell populations. [source]

RIC-3 and nicotinic acetylcholine receptors: Biogenesis, properties, and diversity

BIOTECHNOLOGY JOURNAL, Issue 12 2008
Millet Treinin Dr.Article first published online: 27 OCT 200
Abstract Nicotinic acetylcholine receptors (nAChRs) belong to a diverse and widely expressed family of ion channels. These receptors are pentamers assembled from multiple combinations of subunits, with different subunit compositions producing receptors having different properties and functions. The diverse functions of nAChRs include an essential role in excitation of skeletal muscles and many modulatory roles throughout the central nervous system. Nicotinic receptors are also implicated in a number of brain pathologies such as epilepsy, schizophrenia, and Alzheimer's disease. Thus, it is important to understand the cellular mechanisms controlling both the numbers and the properties of surface expressed nAChRs. Genetic analysis in Caenorhabditis elegans identified a number of proteins specifically needed for biogenesis of nAChRs. Among these proteins is RIC-3, a member of a family of proteins having conserved structure and function. RIC-3 influences both surface expression and properties of nAChRs and its effects are subtype specific. Here we suggest that receptor-specific chaperones such as RIC-3 may play important roles in controlling receptor diversity by selectively regulating surface expression of nAChRs having specific subunit compositions. [source]