Contemporary Topics in Molecular Immunology


Book Description

A series of volumes devoted to molecular immunology will contain, for the most part, articles which attempt to explain immunological phenomena in terms of the behavior and properties of particular molecules. Many of the articles in this volume do this. At the same time, there are many instances-and this is particularly so in the case of immunology-where phenomena must first be described and interpreted in terms of the properties and behavior of cells. Most of us would hope that in due course a fuller understanding will be forthcoming. This volume starts off with such a contribution. Perhaps the most fascinat ing problem in immunology is how diversity is generated. There are two broad proposals: (1) that complete information exists ab initio (the germ-line theory), and (2) that there is initially a limited amount of information, and diversity is generated by somatic mutation. The issue is unresolved, but Cunningham has taken many of the data which have previously been used to support the germ-line theory and shows that the interpretations are not always clear-cut and can frequently be used to support another possibility-that new specificities may arise after stimulation of appropriate cells by antigens. And he has produced experimental evidence to support this notion. On the other hand, there can be little doubt that to a considerable degree the specificity of the immune response is determined by the selection by antigen of cells with receptors of appropriate specificity. This is essentially a surface phenomenon.




Contemporary Topics in Molecular Immunology


Book Description

The distinction between molecular immunology and immunobiology is neces sarily arbitrary. The most rapid progress is usually made in the blurred area between the two, when the chemist is aware of the full significance of the biological problems, and the biologist is alert to the contribution that a knowl edge of molecular structure can be made to their solution. The range of scientific disciplines able to contribute to research in immunology, which this approach brings, is reflected in the present volume. Protein chemists worked out the arrangement of the polypeptide chains and the amino acid sequences of antibodies and X-ray crystallographers the three dimensional structure, but more precise definition of the amino acid side chain positions in the combining site is required for an understanding of the subtleties of antibody specificity. That this can be achieved with physical techniques such as nuclear magnetic resonance has been shown by R. A. Dwek, and in his chapter he summarizes these results with a minimum of technical detail. The immune response has been shown to be dependent on complex cellular interactions and further progress will be facilitated by investigation of the molecular basis of these interactions. This necessitates study of the structure and organization of the molecules in the surfaces of lymphocytes and other cells.




Contemporary Topics in Molecular Immunology


Book Description

New information is developing so rapidly in the entire field of immunology that one is unable to remain abreast of all advancing fronts. In many cases, consider able information has accumulated as the result of the efforts of many investigators, but the conclusions from the various laboratories have not been summarized recently in a comprehensible manner. One such situation has to do with work on IgD. An up-to-date report on this immunoglobulin was included in Volume 10f this series, but since that time there has been considerable progress in the deter mination of its structure and function. In the present volume Leslie and Martin have reviewed the accomplishments of recent years and the problems remaining to be solved. New information regarding the concentration of IgD in body fluids in normal and disease states is presented. Studies of the ontogeny of surface IgD in animals are described, and the fmdings imply that it may be important in the primary immune response. The role of IgD on lymphocyte surfaces is thoroughly discussed especially in terms of stimulating or suppressive combinations of signals delivered to the lymphocyte by agents which bind or alter the surface rt:ceptors. The authors conclude by proposing a model for plasma-cell differentiation which accounts fo~ the existence of triple Ig-bearing cells, many IgM-IgD-bearing cells, and the low percentage of cells bearing a single isotype. Sometimes the serum of an individual contains abnormally large amounts of two distinct, homogeneous populations of immunoglobulins.




Contemporary Topics in Molecular Immunology


Book Description

Immunochemistry, recently rechristened molecular immunology, has been pre occupied throughout its long history with the structure and function of antibodies and the specificity of antibody-antigen reactions. With the recent X-ray diffrac of several crystallized immunoglobulin (Ig) fragments and a whole tion analyses Ig molecule, the three-dimensional structure of antibodies and their ligand combining sites has been realized, marking the concluding stages of a phase of immunological research that can be traced back at least 75 years. At the same time chemically minded immunologists have been moving in new directions. A substantial beginning in one direction has been made with the purification of messenger RNAs (mRNAs) for Ig chains. Hybridization of these RNAs (or their DNA copies made with the enzyme reverse transcriptase) to cell DNA is beginning to provide convincing estimates of the number of germ-line Ig genes. And some hybridization studies have already yielded suggestive evidence for translocation of V and C genes from separate to contiguous positions in DNA isolated from cells at different stages of differentiation. Moreover, in vitro trans lation of Ig mRNAs has revealed a remarkably hydrophobic stretch of about 20 amino acids at the N-terminus of the nascent Ig chain. This extra piece is absent in the Ig extracted from or secreted by plasma cells, presumably because it is rapidly cleaved from the "preimmunoglobulin" chain within the cell, but the extra piece probably plays a key role in directing the synthesis of prelg to the cell's secretory pathway.




Contemporary Topics in Molecular Immunology


Book Description

There are many unanswered questions regarding the molecular nature of antibodies, components of complement, and other substances which participate in the immune response. The list of substances which need to be analyzed chemically is increasing. Plasma cell products, of course, have long been of great interest because the most prevalent ones are immunoglobulins. Other cell types, however, are the source of the broad spectrum of additional substances which classically fall into the sanctum of the molecular immunologist. It is these substances, and especially those more recently discovered, which are responsible for the broadening investigative interests of immunologists. In this volume we have provided you with descriptions of research being done with immunoglobulins and with complement. Additionally, we have in cluded two reports that deal with molecules which are among the more recent acquisitions of the molecular immunologist. The components of complement are known to react in a cascading manner which results in the lysis of cellular antigens. The first step in the classical pathway requires the activation of CI by the antibody-antigen aggregates. This volume of Contemporary Topics in Molecular Immunology begins with the report of Reid and Porter which describes their investigation of the mechanism of activation of C I. Their descriptions of C I q and of the reaction of C I with immunoglobulins are especially intriguing. It is clearly apparent from their report that activation of the components of complement is a complex phenome non.




Contemporary Topics in Molecular Immunology


Book Description

recipients and acceptance of allografts can be made. The authors have the experi ence and ability to bridge the entire field of transplantation and their article encompasses both clinical and immunochemical data in this area. Their data show clearly that matches for the DR antigens are more important than those at the ABC loci in determination of graft survival. Additional relevant factors, in cluding autoimmunity and other B-cell antigens, are discussed and correlated with graft survival. The authors also present pathology data concerning the distribution of HLA-DR antigens in various tissues. These data indicate a fruitful area for future investigations on the chemical aspects of the various antigens encoded within the human MHC. Do changes in the structure of lymphocyte surface glycoproteins, especially changes in their carbohydrate portions, occur during normal lymphoid differen tiation? Information about this question is limited, and pertinent data are avail able for only a few proteins. Three of the proteins are major glycoprotein con stituents of rodent thymocyte membranes: the Thy-! antigen, a glycosylated leukocyte sialoglycoprotein called W3/13, and a high-molecular-weight glycopro tein known as the leukocyte-common antigen. In his contribution, Pink thor oughly characterizes these glycoproteins and discusses the evidence that the structures change when a thymocyte differentiates into a mature, peripheral T cell. A comparison is drawn between lymphocyte glycoprotein changes and those that occur during red blood cell differentiation. The reader will find Pink's discourse informative and provocative. Mast cells, basophils, and related tumor lines bind IgE with very high affinity.




Cellular and Molecular Immunology


Book Description

The 5th Edition of this comprehensive title continues the tradition of delivering an accessible, engaging, and current introduction to this essential subject. The authors describe the principles of basic and applied immunology in a concise, straightforward manner, while incorporating the most up-to-date information. Over 400 illustrations help readers quickly and easily grasp key concepts. The entire text has been revised and includes new information about the organization of lymphoid organs and the mechanisms of innate immunity. (Midwest).