Lecture 5: Principles of Adaptive Immunity PDF

Lecture 5 Principles of Adaptive Immunity 09/19/2024 Learning Objectives Effector Recap of innate Principles of mechanisms of immunity adaptive immunity immunit...

Lecture 5 Principles of Adaptive Immunity 09/19/2024 Learning Objectives Effector Recap of innate Principles of mechanisms of immunity adaptive immunity immunity Recap of Innate Immune System Physical Chemical Microbiological Innate Immune Adaptive barriers barriers barrier Cells Immunity Epithelial linings Acidic pH Microbiota Macrophages B cells/Antibodies Mucosal linings Enzymes Neutrophils T cells Mucus AMPs NK cells Tears Complement Role of Complement Cascade in Innate Immunity Created in BioRender.com Three Outcomes of Complement Activation Created in BioRender.com Complement System in Opsonization and Phagocytosis PRRs Created in BioRender.com Cellular Locations of PRRs or DAMPs Created in BioRender.com Cellular Locations of PRRs Created in BioRender.com Detection of PAMPs by TLRs Created in BioRender.com TLR Signaling Pathways Created in BioRender.com Inflammation and Neutrophil Recruitment Created in BioRender.com Neutrophil Recruitment Fig. 3.30 The release of TNF- by macrophages induces local protective effects, but TNF- can be damaging when released systemically Fig. 3.31  Interferons induced by viral infection make several contributions to host defense TLR Recognition of viral particles within an infected cell activates the expression Interferon response: and release of type-1 interferons. PKR – inhibits protein These cytokines can bind to a receptor synthesis RIG-1 on the same cell (autocrine signaling) RNase L – destroys RNA in the to limit the viral infection. Type an cell; RNA is a typical interference can also bind to receptors component of many viral on adjacent cells (paracrine signaling), genomes including uninfected cells and NK cells. p53 – induce apoptosis Type-1 interferon signaling in uninfected cells trigger protective mechanisms against viral spread. Type- 1 interferon signaling and NK cells activate the cells, which then destroy infected cells via the actions of perforin and granzymes.  Inhibitory and Activating Receptors of NK Cells Perforins: punches holes in the membrane Granzymes: apoptosis KIRs (killer-cell Ig -like receptors Lectin-like receptors Dendritic cells link innate immunity to adaptive immunity Innate vs. Adaptive Immunity Lymphocytes activated by antigen give rise to clones of antigen- specific effector cells that mediate adaptive immunity The four basic principles of clonal selection Fig. 1.16 and 1.17 Lymphocytes mature in the bone marrow or the thymus and then congregate in lymphoid tissues throughout the body Yellow: Central (or primary) lymphoid organs Blue: Peripheral (or secondary) lymphoid organs Fig. 1.21 The distribution of lymphoid tissues in the body Adaptive immune responses are initiated by antigen and antigen-presenting cells in peripheral lymphoid tissues Circulating lymphocytes encounter antigens in peripheral lymphoid organs Organization of a Lymph Node Mucosal surfaces have specialized immune structures – Organization of the Peyer’s patch in the gut mucosa Checkpoint Questions What are the differences between primary and secondary lymphoid tissue? Explain the role of secondary lymphoid tissue in the adaptive immune response At what locations within lymph nodes are T and B cells activated? How are antigens delivered to MALT? Assigned Readings Chapter 1 1-8, 1-12, 1-13, 1-14, 1-15, 1-16, 1-17 InQuizitive 20240919 Readings