Chapter 16

• Innate immunity: already exist in the body, and attacks anything deemed “other”
• Adaptive immunity: Developed response based on exposure to a foreign invader
• Five attributes of adaptive immunity: Specificity, Inducibility, Clonality,Unresponsiveness to self, and Memory
• Specificity: Adaptive immunity acts against a specific antigen
• Inducibility: Specific pathogen activates/induces adaptive immunity cells
• Clonality: Replication of immunity cells
• Unresponsiveness to self: Does not act against normal body cells
• Memory: Adapts and responds faster to subsequent encounters with the same pathogen/toxin
• B lymphocytes: Mature in the bone marrow and produce antibodies
• T lymphocytes: Mature in the thymus and is part of the cell-mediated immune responses
• Antibody mediated immunity (humoral): B lymphocyte produces antibodies that bind to antigens on microbes, marking them for destruction by phagocytic cells or complement proteins.
• Cell mediated immunity: T lymphocytes directly attack infected host cells through cytotoxicity or activate other cells such as macrophages and natural killer cells.
• Lymphatic System: Composed of lymphatic vessels, cells, tissues and organs and screens the tissues for foreign molecules
• Lymphatic vessels: One-way system that conducts lymph from tissues and returns it to the circulatory system
• Lymphatic Primary Organs: Red bone marrow and Thymus
• Lymphatic Secondary Organs: Lymph nodes, Spleen, Tonsils, Mucosa-associated lymphoid tissue
• Antigen: Surface molecules on pathogen
• Epitopes: specific regions of a protein that can be recognized by an antibody
• Allergens: substances that cause an allergic reaction in the body
• Exogenous antigens: Toxins and other components of microbes
• Endogenous antigens: Produced by microbes that reproduce inside a body’s cells
• Autoantigens: Derived from normal cellular processes
• Major histocompatibility complex: Antigens bind in the antigen-binding groove and position antigen epitopes for presentation of immune cells
• MHC Class 1: All except Red blood cells
• MHC Class 2: Antigen-presenting cells
• Antigen processing: Antigens processed so MHC proteins can display epitopes.
• Endogenous: All cells using type 1 MHC
• Exogenous: APC’s only using type 2 MHC
• T Cells have T cell receptors(TRCs) on their surface.
• Clonal deletion of T cells: Failure to recognize MHC, Recognize autoantigen (apoptosis), Some “Self-recognizing(Tr cells), and Recognize MHC and foreign epitopes(protective T cells)
• B cells receptors don‘t require MHC proteins, are unique to each B-cell and have two antigen-binding sites
• Plasma Cell: When B-cell is activated and releases antibodies
• Antibodies: Y shaped protein molecules that bind to specific antigens
• Roles of Antibodies: Activation complement and inflammation, Neutralization, Opsonization, Agglutination, Antibody-dependent cellular cytoxicity
• Cytokine Network: Complex web of signals among cells of the immune system
• Interleukins: Signals among leukocytes
• Interferons: Antiviral proteins that may act as cytokines
• Growth factors: Proteins that stimulate stem cells to divide
• Tumor necrosis factor: Secreted by macrophages and T cell to kill tumor cells and regulate immune responses and inflammation
• Chemokines: Chemotactic cytokines that signal leukocytes to move