T cells also originate in the bone marrow, but all the important events in their development occur in the thymus Fully phosphorylated ITAMs bind the protein tyrosine kinases Syk and ZAP-70 and enable them to be activated

The MHC class I and class II molecules deliver peptides to the cell surface from two distinct intracellular compartmentsThe humoral immune response is initiated when B cells that bind antigen are signaled by helper T cells or by certain microbial antigens alone Phagocyte ingestion of complement-tagged pathogens is mediated by receptors for the bound complement proteins Activation of macrophages by armed T H1 cells promotes microbial killing and must be tightly regulated to avoid The immunoglobulin heavy-chain isotypes are distinguished by the structure of their constant regions

Most thymocytes express receptors that cannot interact with self MHC and these cells die in the thymus HIV infection leads to low levels of CD4 T cells, increased susceptibility to opportunistic infection, and eventually to deathX-linked lymphoproliferative syndrome is associated with fatal infection by Epstein-Barr virus and with the development of lymphomas Conjugate vaccines have been developed as a result of understanding how T and B cells collaborate in an immune response Stages in B-cell development are distinguished by the expression of immunoglobulin chains and particular cell-surface proteins

Many proteins involved in antigen processing and presentation are encoded by genes within the major histocompatibility complex Many genes that operate in fruit fly immunity also operate in humans and plants and appear to be universal components of host defense Mast cells, basophils, and activated eosinophils bind IgE antibody via the high-affinity Fcε receptorRearrangement at the immunoglobulin light-chain locus leads to cell-surface expression of the B-cell receptor In the early 1890s, Emil von Behring and Shibasaburo Kitasato discovered that the serum of animals immune to diphtheria or tetanus contained a specific ‘antitoxic activity’ that could confer short-lived protection against the effects of diphtheria or tetanus toxins in people. These practical triumphs led to a search for vaccination’s mechanism of protection and to the development of the science of immunology.

The 9th edition also includes updates on recent developments in multiple immunology subfields. Notably, the section on innate immunity has added a discussion of immune effector modules, which are critical to understanding the pathogenesis of inflammatory bowel disease, intestinal infection, and several other diseases. The section on therapeutics now contains a discussion of chimeric antigen receptors, an active and important area of cancer immunotherapy research. A particularly significant feature of this edition is an overhaul of the end-of-chapter questions and the addition of an instructors’ question bank. The 9th edition replaces the handful of often open-ended review questions at the end of each chapter with multiple-choice and true-false questions, providing an easier avenue for instructors to test the material. An important question is whether vaccination can be used therapeutically to control existing chronic infections Whereas these cells— which Metchnikoff called ‘macrophages’—are always present and ready to act, adaptive immunity requires time to develop but is highly specific. Stable binding of peptides by MHC molecules provides effective antigen presentation at the cell surfaceDominant immune suppression can be demonstrated in models of tolerance and can affect the course of autoimmune disease Naive T cells sample the MHC:peptide complexes on the surface of antigen-presenting cells as they migrate through peripheral lymphoid tissue The two classes of MHCmolecule have distinct subunit structures but similar three-dimensional structures. / 3-15 Peptides are stably bound to MHC molecules, and also serve to stabilize the MHC molecule on the cell surface