1. Specific Host Defenses : Adaptive Immunity ACQUIRED or SPECIFIC IMMUNITY

2. Two major kinds of defense Innate immunity Acquired immunity

5. Types of Acquired Immunity Acquired Immunity

12. Humoral Response to T Independent Antigens Cell growth division, and differentiation in a lymph node Clone of many effector cells secreting antibodies ER ER ER ER Selection of B cells Triggering of the B cell

13. Humoral Response to T Dependent Antigens

18. PRIMARY RESPONSE (initial encounter with antigen) Antigen Antigen receptor on a B cell Antigen binding to a B cell Memory B cell Antibody molecules Plasma cell Cell growth, division, and differentiation SECONDARY RESPONSE (can be years later) Cell growth,division, & further differentiation Larger clone of cells Plasma cell Antibody molecules Later exposure to same antigen Memory B cell Clone of cells

21. Antibody Response After Exposure to Antigen

24. Acquired Immunity: Ag-Specific Responses

25. T Lymphocytes: Cell Mediated Immunity Figure 24-16: T lymphocytes and NK cells

27. T Cells Only Recognize Antigen Associated with MHC Molecules on Cell Surfaces

30. APC = e.g., Macrophage TCR Peptide Antigen CD4 CD4 T Cell MHC Class II

32. Central Role of Helper T Cells

36. The big picture…Integration of innate and adaptive immunity Courtesy: Abbas and Litchman; Basic Immunology