Defence: Introduction to Immunology PDF

Defence: introduction to immunology     **MLO16.    **Explain the adaptations of different cell types and the processes that enable them to;                              a)     **provide immunity**, and \                             b)    generate nerve impulses. Cytokines transmit information fr...

Defence: introduction to immunology     **MLO16.    **Explain the adaptations of different cell types and the processes that enable them to;                              a)     **provide immunity**, and \                             b)    generate nerve impulses. Cytokines transmit information from one cell to another Granulocytes contain lots of granules, within granules lots of antimicrobial proteins 60% WBCs are neutrophils Dendritic cells bridge innate and adaptive immune responses Dendritic cells migrate to lymph nodes Interferons interfere with immune response and shuts down cell response NK cells provide us with early protection against [virally] infected cells Adaptive immune response provides virus specific antitoxic T cells Cytotoxic T cells (CD8+) recognise pathogen-derived peptides in conjunction with which cell surface molecule? - MHC Class 1 is expressed on every nucleated cell in the body MHC Class II is only expressed on professional antigen presenting cells/dendritic cells The molecules responsible for directing leukocyte migration are known as what? - Chemokines specifically act as a chemo attractant (they are a type of cytokine) very small can infuse across tissues T helper cells recognise MHC class I Cytotoxic T cells recognise Complement directly lyses bacteria via the formation of what? - Membrane attack complex Neutrophils are members of which family of immune cells? - Granulocytes **Which of the following is contained within phagolysosomes?** - Reactive oxygen species - Lysozymes - Nitric oxide - Lactoferrin - Cathe 3 main defences against infection: Passive barriers - Structures that are in place ready to defend the body against external infections etc - Eg. Airway mucosa where the mucus can trap bacteria and viruses so they can't travel any further - Eg. Urination, bacteria is washed away when you urinate Innate immune system - Various specialised cells and proteins - Inflammatory response Adaptive immune system - T cells and B cells Innate immune system: - Neutrophils most common WBC - Neutrophils contain granules which can be released to digest pathogens - Macrophage cells are large and can engulf infection via phagocytosis - Mast cells also contain granules that are triggered by injury and initiate inflammatory response Inflammation: - Redness - Pain - Swelling/oedema - Heat - Vasodilation: blood vessels widen so it is easier to pass through Adaptive immune system - Specific to a particular invader - All cells express an integral membrane protein called MHC (major histocompatibility complex antigen)/HLA (human leukocyte antigen) - MHC is used as a marker/self flag Antibodies - Tiny proteins with a special recognition site - Y shape formed of a heavy chain, light chain, binding site - Antibody recognises an epitope (antigen) as it fits directly in binding site How are antibodies made: - Antigen presented to B cells - B cell engulf antigen/pathogen - Displays MHC Class 2 on CSM surface - B cell is activated and starts to multiply - Clone army of B cell created plasma cell which is much bigger - Secretion of antibody T cells: - MHC Class 2 can fit with different T cell receptors - T cell docks, secreting cytokines - Cytokines trigger B cells to multiply - T cells also activate macroohages - T cell recognises MHC Class 1 on a non self cell - T cell receptor works with CD8 to secrete or degranulate granules by perforins A table with text on it Description automatically generated Multi-layered immune system Anatomic barriers\>microbial proteins\>innate immune cells\>adaptive immunity Stages of an immune response Inflammatory inducers\>sensor cells\>mediators\>target tissues Cellular immunity: - Directed by immune cells - Non-specific (innate) - Phagocytosis - Intracellular Humoral immunity: - Soluble molecules - Highly specific (antibodies) - Neutralising - Extracellular - Humoral factors are soluble molecules that act as antimicrobials  Innate immunes system is non-specific -- only recognises PAMP/DAMP =\> PRRs Moodle recap quiz Q: Which of the following are classic signs of acute inflammation? A: Pain, swelling, redness and heat Q: Which cell(s) is involved in establishing immune memory? A: B-cells Q: What are the roles of T-helper cells? A: Help B cells to function, help killer T cells to function Q: Which of the following cells are involved in inflammation and immunity? A: T-cells, lymphocytes, monocytes, mast cells, macrophages