5 Function of Splenic Compartments . . . . . . . . . . . . . . . 45 5. 1 Splenic White Pulp Compartments during Primary T Cell-Dependent Antibody Responses against Protein Antigens . . . . . . . . . . . . . . . . . . . . . . . . . 46 5. 1. 1 Priming of CD4+ Helper T Cells by Dendritic Cells in the PALS . . . . . . . . . . . . . . . . . . . . 46 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 5. 1. 1. 1 5. 1. 2 Interaction of Primed CD4+ T Cells with Antigen-Specific B Cells in the PALS and Formation of Extrafollicular Foci . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 5. 1. 2. 1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 5. 1. 3 Formation of Germinal Centres . . . . . . . . . . . . . . . . . . . 50 5. 1. 3. 1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5. 1. 4 Localisation of Memory B Cells in the Marginal Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 5. 1. 4. 1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5. 2 Function of the Marginal Zone during Primary Antibody Responses against T Cell-Independent Type 2 Antigens . . . . . . . . 57 5. 2. 1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Function of the Red Pulp . . . . . . . . . . . . . . . . . . . . . . . . . 59 5. 3 5. 3. 1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 5. 4 Role of the Spleen in CD8+ Cytotoxic T Cell Responses . . . . . . . . . . . . . . . 61 5. 4. 1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 The Spleen, Natural Killer Cells 5. 5 and Gamma/Delta T Cells . . . . . . . . . . . . . . .. . . . . . . . . 62 5. 5. 1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 6 Recirculation of Lymphocytes Through the Spleen . . 65 6. 1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 7 The Role of Cytokines and Chemokines in the Development of Splenic Compartments . . . . . . 69 7. 1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 8 Unsolved Problems of Human Splenic Structure and Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 VI 8. 1 Arterial Blood Supply to the Splenic Follicles and to the Perifollicular Zone. . . . . . . . . . . . . . . . . 73 . . . . 8. 1. 1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 8.