1. Immunoglobulin 2. Complement 3. B cell Receptor 4. T Cell receptors 5. MHC 6. Immune diversityAllelic exclusion, DNA rearrangement in B and T cell, Junctional diversity, Somatic hypermutation, Isotype switching 7. Extracelluar and intracellular antigen presentation 8. T Cell activation 9. B Cell activation 10. T cell and B cell effector functions 11. ADA, Chronic granulomatous disease, Ataxia Telegactesia 12. Autoimmunity