I. Cytokine Knockouts in Models of Human Disease.- 1. Cytokine Knockouts in Inflammation.- 2. The Use of Cytokine Knockouts to Study Host Defense Against Infection.- 3. The Use of Cytokine Knockouts in Animal Models of Autoimmune Disease.- 4. The Use of Cytokine Knockout Mice in Cancer Research.- 5. The Use of Cytokine Knockout Mice in Neuroimmunology.- II. Cytokine Knockout Mice.- 6. The Role of IL-1 in the Immune System.- 7. IL-1 Receptor Antagonist-Deficient Mice.- 8. A Unique Role for IL-2 in Self-Tolerance.- 9. Molecular Basis for Binding Multiple Cytokines by ?c: Implications for X-SCID and Impaired ?c-Dependent Cytokine Receptor Function.- 10. G-CSF, GM-CSF, and IL-3 Knockout Mice.- 11. IL-4 Knockout Mice.- 12. Role of IL-5 in Immune and Pathological Responses in the Mouse.- 13. IL-6 Knockout Mice.- 14. IL-10 and IL-2 Knockout Mice: Effect on Intestinal Inflammation.- 15. IL-12-Deficient Mice.- 16. IL-13 and Double IL-4/IL-13 Knockout Mice.- 17. IL-15: Insights from Characterizing IL-15-Deficient Mice.- 18. IL-18 and IL-18 Receptor Knockout Mice.- 19. Mice Knockouts for Chemokines and Chemokine Receptors.- 20. IFN-? and IFN-? Receptor Knockout Mice.- 21. Macrophage Migration Inhibitory Factor (MIF)-Deficient Mice.- 22. Osteopontin, a Surprisingly Flexible Cytokine: Functions Revealed from Osteopontin Knockout Mice.- 23. RANKL, RANK, and OPG.- 24. Targeting the TGF-? Pathway In Vivo: Defining Complex Roles for TGF-? Signaling in Immune Function, Wound Healing, and Carcinogenesis.- 25. Physiologic Roles of Members of the TNF and TNF Receptor Families as Revealed by Knockout Models.