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Description
Flashcards by Kyla Michie, updated more than 1 year ago
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Created by Kyla Michie
almost 7 years ago
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| Question | Answer |
| What are the cell mediated aspects of the immune system? | Phagocytes; Neutrophils, Eosinophils, Basophils, Mast Cells, Macrophages and Monocytes and Dendritic cells. Lymphocytes: T Cells, B cells and NK cells. |
| What are the four Humoral mediated aspects of the immune system? | Antibodies Complement System Proteins Cytokines Acute Phase proteins |
| What are the three main cells involved in mediating an allergic response? | Mast Cells, Basophils and Eosinophils. |
| Explain the function of all Phagocytes. | They ingest pathogens and debris via phagocytosis. Also ingest dead and dying apoptotic cells. Important sources of cytokines. |
| How abundant are Macrophages and where do they migrate to? | They comprise 5% of all circulating Leukocytes and migrate into peripheral tissues and differentiate into Macrophages. |
| What do macrophages do and what are they involved in? | They: Limit inflammation Are Long Lived Are Involved in: Tissue Repair Antigen Presentation |
| What do neutrophils do and how abundant are they? | They circulate in the blood Comprise 50-70% of all circulating Leukocytes Are Short lived And are rapidly recruited into inflamed, damaged and infected tissues. |
| Where are dendritic cells found in both 'immature' and 'mature' states and what is their role? | Immature - Peripheral tissues Mature - Secondary Lymphoid tissues They phagocytose antigens and play a key role in antigen presentation. |
| Where are Mast Cells found and what do they do? | They reside in tissues and protect mucosal surfaces and Mediate an allergic response. |
| Where are Basophils and Eosinophils founds and what is their role? | They circulate in the blood and are recruited to the site of infection by inflammatory signals. They are the main defence system against large pathogens and also mediate allergic responses. |
| Explain how Mast Cells, Basophils and Eosinophils work in mediating an allergic response. | The granulocytes release chemicals such as histamine, heparin and cytokines which cause acute inflammation. They are the defence mechanism against large pathogens that cannot be phagocytosed. |
| What is the main role of B cells? | B cells are responsible for the production and secretion of antibodies to defend against extracellular pathogens. |
| What are the two types of T cells and what are their roles? | T Helper Cells: Key regulators of the immune system T Killer (Cytotoxic) Cells: Kill virally infected host cells. |
| What are NK cells and what are their roles? | NK (Natural Killer) cells are large granular lymphocytes that kill tumour and virally infected host cells. |
| What are antibodies and antigens and what do they do? | Antibodies aka immunoglobulins are proteins that are produced in response to an antigen. An antigen is anything that can stimulate an immune response. They provide defence against extracellular pathogens. |
| Explain the complement system i.e. How many? Where produced? Role? | They are a family of approximately 30 proteins. Produced in the liver and then circulate the blood as inactive precursors. Can enzymatically cleave and activate others in a cascade. Play a critical role in inflammation. |
| What are cytokines, when are they produced and what do they do? | Diverse collection of small proteins and peptides Produced in response to infection, inflammation and tissue damage Modulate behaviour of cells Short half life Can act locally or systemically |
| What is the function of an interferon? | Anti-Viral activity |
| What is the function of Tumour Necrosis Factor a (TNFa) | A pro-inflammatory cytokine |
| What is the function of a Chemokine? | Control and direct cell migration |
| What is the function of an Interleukin? | Various Functions |
| Where are acute phase proteins produced? | The liver |
| What are the three functions of Acute Phase Proteins? | Diagnosis Enhance Phagocytosis Complement system activation |
| What is the innate immune system and how rapid is its response? | The innate immune system is the natural general response to every different pathogen. Has a rapid response (minutes to hours). |
| What are the two distinct methods of communication in the innate immune system? | Direct contact: Receptor : Ligand e.g MHC:TCR Indirect: Production and secretion of cytokines e.g. Interleukins |
| What are the 4 cells of the innate immune system that are used in response to pathogens? | Macrophages Mast Cells NK Cells Neutrophils |
| What are the three phases of the innate immune system in response to a pathogen? | 1. Recognition Phase 2. Activation Phase 3. Effector Phase |
| Explain the recognition phase. | Pathogens express 'signature' molecules not found in human cells - "Pathogen associated molecular patterns" PAMPs |
| Name the four Pattern-recognition receptors to their matching PAMPs. | TLR4 - LPS Dectin 1 - Beta-glucans NOD2 - Muramyl dipeptide TLR7 - ssRNA |
| What do macrophages produce when they engulf apoptotic bodies? | Anti-inflammatory cytokines IL-10 Pro-inflammatory mediators and present antigens on their surface |
| Define and explain "Macrophage Power" and how it is increased. | Macrophage power = Killing ability It is enhanced by cytokines produces by NK cells. Increases production of toxins, microbicidal activity and antigen presentation. |
| What do mast cells produce and how do they identify pathogens? | They produce inflammatory mediators. They identify pathogens by the PRR on their surface through degranulation to release the mediators and gene expression to replace them. |
| What three* pro-inflammatory mediators do Macrophages, Mast cells and NK cells produce. | Nitric Oxide, Prostaglandins and Histamines Cytokines - TNFa, Interleukins, Interferons Chemokines |
| What do Nitric Oxide, Prostaglandins and Histamines cause in the body? | Vasodilation Permeability Pain Smooth Muscle Contraction |
| What do Cytokines cause in the body? | Permeability Endothelial cell division |
| What do Chemokines cause in the body? | Leukocyte recruitment and activation |
| Name the three killing methods of Neutrophils. | Phagocytosis Degranulation NETs |
| What is phagocytosis and how exactly does it work? | In infected tissues, pathogens release signals that attract Neutrophils. Neutrophils use their PRRs to bind and encapsulate pathogens. They then kill the pathogens via Anti-microbial proteins or NADPH oxidase dependant mechanisms. |
| What is Degranulation and how does it work? | Degranulation is the release of anti-bacterial proteins from neutrophils granules into the extracellular matrix. Directly kills extracellular pathogens but can cause tissue damage. |
| What are NETs and how do they work? | Neutrophils release 'NETs' of their DNA into the environment which immobilize pathogens and prevent them from moving, thus facilitating their Phagocytosis. |
| What can occur as a result of increased levels of TNFa? | IBS, psoriasis, arthritis, asthma, cancer, infectious diseases and others are related to linked levels of TNFa.4 |
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Complete the following table
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| What are the three complement pathways? | Mannose-binding Lectin Pathway Alternative Pathway Classical Pathway |
| What is inactive C3 cleaved into? | Active C3a and Active C3b |
| What is opsonisation and what is an example of an oponin? | Opsonisation is a ay of identifying the invading particle to the phagocyte. E.g C3b |
| What are C3a and C5a known as and what do they do? | Anaphylatoxins which promote inflammation. They activate Mast Cells. |
| Name four examples of Secondary Lymphatic tissue. | Tonsils and adenoids Lymph nodes Large Intestine (Peyers patches) Appendix |
| What is the adaptive immune system and how quick is the response? | It is the learned response to millions of different pathogens and is able to recognise and respond to them. The response is slow and can take days. |
| What are the cells that need to be able to: Recognise Find Activate and Respond to a pathogen? | T Cells and B Cells |
| Why is the adaptive immune system so slow? | Its response is individual to each pathogen and it is responsible for creating immunological memory. |
| How many antigenic epitopes can T and B Cells bind to? | One - T and B Cells only express one antigen receptor which can only bind to once specific antigenic epitope. |
| Which of these is a T Cell and which is a B Cell? | |
| Each heavy and light chain region on a B cell has a variable and constant region. What are the 5 different antibodies and their heavy chains. | • IgM : m heavy chain • IgG: g heavy chain • IgA : a heavy chain • IgE : e heavy chain • IgD : d heavy chain |
| Where are Mature Dendritic cells, pathogens, antigens and debris trapped? | 2nd Lymphoid Tissues |
| How do T and B cells enter 2nd Lymphoid tissues? | Trans endothelial migration |
| What are the two signals that B Cells require to be activated? | BCR + Antigen T cell help |
| T cells can only recognise antigens presented by __________? | MHC proteins/HLAs |
| What are the two classes of MHC and where are they expressed? | MHC class I - expressed on ALL nucleated cells. Present peptide antigens to cytotoxic T cells. MHC class II - Expressed only on professional Antigen Presenting Cells. Present peptide antigen to helper T cells |
| CD8+ and CD4+ are proteins expressed to what cells respectively? | CD8 goes with T cytotoxic cells to form CD8+ T cells. CD4 goes with T helper cells to form CD4+ T Cells. |
| What can active B cells differentiate into? | Plasma Cells (effector B cells) |
| What is IgG? How abundant is it? What can it do? | IgG is the most abundant antibody in Plasma. It can actively transport across the placenta. It has 4 subtypes: IgG1-4 |
| What is IgA? How abundant is it? What can it do? | 2nd most abundant Ig type Monomeric form – blood Dimeric – breast milk, saliva, tears, mucosal secretions |
| What is IgD? How abundant is it? What can it do? | It has extremely low levels in blood. Unknown function. Is surface bound. |
| What is IgE? How abundant is it? What can it do? | Extremely low levels normally Produced in response to parasitic infection and allergic responses |
| What is IgM? How abundant is it? What can it do? | Surface bound monomer = BCR 1st Ig type produced during an immune response (present only in plasma/secretion) |
| How do antibodies activate the complement pathway? | Through C+C2+C4, which activates when it comes into contact with stable forms of IgM. |
| How do phagocytes bind to opsonised pathogens? | Phagocytes express Fc receptors that bind to the constant region of Igs. |
| What are memory cells and when are they produced? | Memory cells (Memory Th/Tc/B) are generated during the initial response to an antigen. They are small long lived cells that are primed and ready to respond to the same antigen. |
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