Front Cover -- Avian Immunology -- Copyright Page -- Contents -- Acknowledgments -- Foreword -- List of Contributors -- 1 The Importance of the Avian Immune System and its Unique Features -- 1.1 Introduction -- 1.2 The Contribution of Avian Lymphocytes -- 1.3 The Contribution of the Bursa of Fabricius -- 1.3.1 Gene Conversion and the Bursa -- 1.4 The Contribution of the Chicken MHC -- 1.5 The Contributions to Vaccinology -- 1.5.1 Embryonic (In Ovo) Vaccination -- 1.6 Conclusions -- References -- 2 Structure of the Avian Lymphoid System -- 2.1 Introduction -- 2.2 The Thymus -- 2.2.1 Anatomy and Histological Organization -- 2.2.2 Thymic Cortex -- 2.2.3 Thymic Medulla -- 2.2.4 Thymic Cortico-Medullary Border -- 2.3 The Bursa of Fabricius -- 2.3.1 Anatomy and Histology -- Bursal Surface Epithelium -- 2.3.2 Bursal Follicle -- 2.3.3 Medulla -- Bursal Medullary Epithelial Cells -- Bursal Secretory Dendritic Cells -- Bursal Macrophages -- Bursal Lymphocytes -- 2.3.4 Cortex -- Peripheral Lymphoid Tissue of the Bursa of Fabricius -- 2.4 Germinal Center of the Peripheral Lymphoid Organs -- 2.5 The Spleen -- 2.5.1 Origin and Anatomy -- 2.5.2 Red Pulp -- 2.5.3 White Pulp -- Peri-Arteriolar Lymphoid Sheath -- Ellipsoids and Peri-Ellipsoid White Pulp -- The Marginal-Zone Equivalent and Antigen Handling -- 2.6 Gut-Associated Lymphoid Tissue -- 2.6.1 Follicle-Associated Epithelium or Lymphoepithelium -- 2.6.2 Esophageal and Pyloric Tonsils -- 2.6.3 Peyer's Patches -- 2.6.4 Meckel's Diverticulum -- 2.6.5 Cecal Tonsils -- 2.7 Harderian and Conjuctiva-Associated Lymphoid Tissue -- 2.8 Mural Lymph Node -- 2.9 Ectopic Lymphatic Tissue and Pineal Gland -- 2.10 Bone Marrow -- 2.11 Blood -- References -- 3 Development of the Avian Immune System -- 3.1 Introduction -- 3.2 Origins and Migration Routes of Hematopoietic Cells Using Quail-Chick Complementary Chimeras.

3.2.1 Looking for the Source of Hematopoeietic Cells during Development -- 3.2.2 Macrophage Production by the Yolk Sac -- 3.2.3 The Aortic Region Produces HSC -- 3.3 Aortic Clusters as the Intra-Embryonic Source of Definitive Hematopoiesis -- 3.3.1 Cellular and Molecular Identification of the Clusters -- 3.3.2 The Para-Aortic Foci -- 3.3.3 Tracing the Origins and Fates of the Aortic Clusters -- 3.4 Formation of the Aorta: A Dorsal Angioblastic Lineage and a Ventral Hemangioblastic Lineage -- 3.4.1 Two Endothelial Lineages Form the Vascular Network of the Embryo -- 3.4.2 Chimeric Origin of the Aortic Endothelial Cells -- 3.4.3 The Allantois: Another Source of Hematopoiesis? -- 3.4.4 Cellular and Molecular Identification of Allantois-Associated Hematopoiesis -- 3.4.5 Hematopoietic Production by the Mammalian Allantois and the Placenta -- 3.5 The Avian Thymus and T Cell Development -- 3.5.1 Thymic Development -- 3.5.2 Colonization of the Thymus -- 3.5.3 T Cell Differentiation -- 3.5.4 TCR Rearrangement -- 3.5.5 T Cell Homing to the Periphery -- 3.6 The Bursa of Fabricius, B-Cell Ontogeny and Immunoglobulins -- 3.6.1 Formation of the Bursal Epithelial Anlage -- 3.6.2 Bursal Development -- 3.6.3 Hematopoietic Colonization of the Bursal Rudiment and Follicle Bud Formation -- 3.6.4 Development of the Follicle-Associated Epithelium and the Follicular Cortex -- 3.6.5 Immunoglobulins -- 3.7 Lymphocyte-Differentiating Hormones -- 3.8 Development of the Immune Responses -- 3.8.1 Early Immune Responses -- 3.8.2 Antibody Isotype Switching and Hypersensitivity Reaction -- 3.8.3 Allograft Rejection -- 3.9 Conclusions -- Acknowledgments -- References -- 4 B Cells, the Bursa of Fabricius and the Generation of Antibody Repertoires -- 4.1 Introduction -- 4.2 The Generation of Avian Antibody Repertoires -- 4.2.1 Immunoglobulin Light Chains.

4.2.2 Immunoglobulin Heavy Chains -- 4.2.3 Generation of Ig Molecules by V(D)J Recombination -- 4.2.4 Generation of Ig Diversity by Somatic Gene Conversion -- 4.2.5 Implications of Gene Conversion for Allelic Exclusion -- 4.3 The Development of Avian B Cells -- 4.3.1 Pre-Bursal B Cell Development -- 4.3.2 Colonization of the Bursa by B Cell Progenitors -- 4.3.3 Colonization of Lymphoid Follicles in the Bursa -- 4.3.4 Growth of Bursal B Cells in Bursal Follicles -- 4.3.5 Development of the Bursa after Hatch -- 4.3.6 Development of Peripheral B Cell Populations -- 4.3.7 Activation of Peripheral B Cells -- 4.3.8 Plasma Cell Development -- 4.3.9 Cytokines in Chicken B Cell Development and Activation -- References -- 5 Avian T Cells: Antigen Recognition and Lineages -- 5.1 Introduction -- 5.2 TCR Structure and Lineages -- 5.2.1 Somatic DNA Recombination -- 5.2.2 Organization of TCR Clusters -- TCRα/δ Cluster -- TCRβ Cluster -- TCRγ Cluster -- 5.3 CD3 Signaling Complex -- 5.3.1 Mammalian CD3 -- 5.3.2 Chicken CD3γ/δ and CD3ε -- 5.3.3 ζζ Homodimer -- 5.3.4 TCR Complex: Structural Models -- 5.3.5 TCR Signal Transduction -- 5.4 CD4 and CD8 -- 5.5 Co-Stimulatory Molecules -- 5.6 T Cell Lineages -- 5.7 Perspectives -- References -- 6 Structure and Evolution of Avian Immunoglobulins -- 6.1 The Basic Structure of Immunoglobulins -- 6.2 Avian Immunoglobulins -- 6.2.1 Avian IgM -- 6.2.2 Avian IgY (IgG) -- 6.2.3 Avian IgA -- 6.2.4 Lack of Avian Homologs of IgD and IgE -- 6.2.5 L Chains -- 6.2.6 Genomic Organization of the IgH Locus -- Avian Ig allotypes -- 6.3 Ig Half-Life -- 6.4 Natural Antibodies -- 6.5 Maternal Antibodies -- 6.6 Fc Receptors -- 6.6.1 Chicken Polymeric Ig Receptor -- 6.6.2 Chicken FcRn Homolog -- 6.6.3 Chicken Fc Receptor Cluster -- 6.6.4 ggFcR -- 6.6.5 CHIR-AB1 -- 6.7 Avian Antibody Responses -- 6.8 The Chicken Egg as a Source of Antibodies.

6.9 Avian Antibodies as Tools for Research -- References -- 7 Innate Immune Responses -- 7.1 Introduction -- 7.2 Constitutive Barriers -- 7.2.1 Active Responses (Chemical) -- Acute Phase Proteins -- Host Defense Acute-Phase Proteins -- Inhibitors of Serine Proteinases (Serpins) -- Transport Proteins with Antioxidant Activity -- C-Reactive Protein -- Serum Amyloid A -- α1-Acid Glycoprotein -- Haptoglobulin -- Hemopexin -- Fibrinogen (FB) -- Fibronectin -- Ceruloplasmin -- Transferrin-Ovotransferrin -- Collagenous Lectins -- Mannan-Binding Lectin -- Ficolins -- Surfactants: SP-A and SP-D -- Other Collectins -- 7.2.2 Antimicrobial Peptides -- 7.2.3 The Complement System -- Classical Pathway -- Lectin Pathway -- Alternative Pathway -- C3: The Key Complement Component -- 7.2.4 Regulation of the Complement System -- Complement Opsonization and Phagocytosis -- Membrane Attack Complex -- Anaphylatoxins -- 7.3 Cells of the Innate Immune System -- 7.3.1 Natural Killer Cells -- Potential NK Cell Receptor Families -- Phenotype of Chicken NK Cells -- NK Cell Function -- 7.3.2 Heterophils -- 7.4 Pattern Recognition Receptors -- 7.4.1 Cell-Associated Pattern Recognition Receptors -- 7.4.2 Avian Toll-Like Receptors -- Background -- The Avian TLR Repertoire -- TLR1/6/10-Related Molecules -- TLR2 -- TLR3 -- TLR4 -- TLR5 -- TLR7 and TLR8 -- TLR9 -- Avian TLR without Mammalian Orthologs: chTLR15 and chTLR21 -- TLR Signaling Pathways in Chickens -- Cytosolic PRR -- NLRs -- RLRs -- 7.4.3 General Considerations in Pattern Recognition -- References -- 8 The Avian MHC -- 8.1 Introduction -- 8.2 The Classical Chicken MHC is Small, Simple and Rearranged -- 8.3 The Classical Chicken MHC Encodes Single Dominantly Expressed Classical Class I and II Molecules.

8.4 The Properties of Single Dominantly Expressed Class I and II Molecules Can Explain Responses to Pathogens and Vaccines -- 8.5 The Presence of a Single Dominantly Expressed Class I Molecule is Due To co-Evolution with Tap and Tapasin -- 8.6 The Chicken MHC Provides Insights Into the Primordial MHC and the Subsequent Evolution of the MHC -- References -- 9 Avian Antigen-Presenting Cells -- 9.1 Introduction -- 9.1.1 Antigen Presentation -- 9.1.2 Dendritic Cells -- 9.1.3 Macrophages -- 9.1.4 Development of Myeloid Cells -- 9.1.5 Sources for Avian Macrophages and Dendritic Cells -- 9.2 Avian Myeloid Cell Lines -- 9.2.1 Cell Surface Markers for Avian Myeloid Cells -- Characterization of Macrophages and DC in Tissue Sections -- Functional Properties of Chicken Macrophages -- 9.2.2 Macrophage Migration -- 9.2.3 Phagocytosis -- Respiratory Burst Activity -- 9.2.4 Nitric Oxide Production: A Readout System for Avian Macrophage Activation -- 9.2.5 Cytokine Response of Avian Macrophages -- 9.3 Functional Properties of Chicken DCs -- 9.3.1 Maturation from Antigen Sampling to Antigen Presenting -- 9.4 Migration -- 9.5 Concluding Remarks -- References -- 10 Avian Cytokines and Chemokines -- 10.1 Definitions -- 10.2 Description of Avian Cytokine and Chemokine Families -- 10.3 The Interleukins -- 10.3.1 The IL-1 Family -- 10.3.2 T Cell Proliferative Interleukins -- 10.3.3 Th1 Interleukins -- 10.3.4 Th2 Interleukins -- 10.3.5 The Th1-Th2 Paradigm -- 10.3.6 The Interleukin-10 Family -- 10.3.7 The Interleukin-17 Family -- 10.3.8 Other Interleukins -- 10.4 The Interferons -- 10.4.1 Type I IFN -- 10.4.2 Type II IFN -- 10.5 The Transforming Growth Factor-β Family -- 10.5.1 The Tumor Necrosis Factor Super-Family -- 10.5.2 Colony-Stimulating Factors -- 10.6 Chemokines -- 10.6.1 XC and CX3C Chemokines -- 10.6.2 CC Chemokines -- 10.6.3 CXC Chemokines -- 10.7 Receptors.

10.7.1 Class I Receptors.