Foundations Of Immunology Flashcards
What are the 2 kinds of immunity?
Innate and Adaptive
What does innate immunity do and how can it be flawed?
Doesn’t distinguish between pathogens but recognises them and acts immediately. Some microbes develop immunity
How does adaptive immunity work? How long does it take to develop?
Distinguishes between pathogens and using antigen markers. Few days to remember but produce memory cellls
What are the three phagocytes and their purpose?
Neutrophils, Monocytes, Macrophage. Engulf and digest pathogens and our own dead cells
What is the role of neutrophils?
They are granulated cells. When a microbe attaches to them, it undergoes endocytosis and forms a phagosome. The granule filled lysosome in the cell fuses with the phagosome and the granules enzymes kill the microbe. The waste is secreted by exocytosis
What are Eosinophils and their role?
Help us combat parasitic infections, allergy and asthma. Have acid granules and enzymes.
What are mast cells?
Has histamine as granules and has IgE receptor which binds to allergens, causing histamine to be released and cause an allergic reaction.
What are basophils?
Least common WBC. No proven function but have granules which are inflammatory mediators and found near site of infection.
What are cytokines?
Proteins secreted by cells under specific stimuli. Communicate many biochemical processes. Important in innate and adaptive immunity
What are the primary lymphoid organs and what happens there?
Thymus and bone marrow. T-cells mature in the thymus (receive receptor). Hematopoeisis occurs in bone marrow
What are the secondary lymphoid organs and what do they all do?
Lymph nodes, spleen, tonsils and mucosal immune system. The sites of lymphocyte action
What are the two lymphocytes?
B and T cells
What occurs at the lymph nodes?
Over 500 in our bodies. Connected by lymph vessels which transport WBC’s. Acts as a filter to eliminate waste from lymph fluid
What occurs in the spleen?
150g fist shaped organ which filters blood and produces leukocytes to fight germs in blood
What are the 2 T-Lymphocytes and their overall function (2)?
Cytotoxic T cells and T-Helper cells. Responsible for cell-mediated immunity and assisting B-cells
Which receptor does cytotoxic T Cells have and how do they function?
CD8+ receptor. Recognises antigens bound to MHC1 and kills abnormal cells directly
How do cytotoxic T Cells kill abnormal/foreign cells?
Once CD8+ has bound to the antigen, perforin form holes in the abnormal cell, and granzymes enter via the holes and induce lysis.
How do T-Helper cells work?
They have CD4+ receptors which bind to cells with MHC11 attached. They bind to B Cells and release cytokines to activate B-Cells.
What are the 4 T-Helper cell types and their functions?
All produce different cytokines for varying situations. TH1 (activate macrophages), TH2 (eosinophils and mast cells), TH17 (mast cells) and Tfh (activate b-cells)
Role of B-Lymphocytes + where are they found?
Produced and mature in bone marrow. Differentiate into memory cells and plasma cells, which generate antibodies specific to pathogen.
What is an antigen?
Any substance that can trigger an immune response.
What is an antibody/immunoglobulin?
A protein produced as an immune response. They have a Y shaped structure which binds to antigens
What are the 5 classes of Immunoglobulin?
IgA, IgE, IgD, IgM, IgG
Where can IgA be found, its role and its structure?
Saliva, tears, mucus, breast milk. Involved in neutralisation. 1-4 Y -antibodies
Where is IgG found, what does it do and it’s prominence?
Found in blood and ECF, controlling infection. Makes up 75% of total antibodies
Where is IgD found and its function?
Found on B cell as receptor - activates B-Cell
What are the three mechanisms of antibody protection?
Neutralisation, opsonization and the complement system
What is neutralisation?
Antibodies (in particular IgA) binding to pathogens, preventing attachment to cell surfaces.
What is opsonization?
Antibodies facilitating the uptake of pathogens by phagocytosis
What is the complement system and where does it occur?
Group of proteins act as a domino effect that leads to production of membrane attack complex on target cells, and destroys them. Takes place on the surface of target cells./
What roles do the products of the complement system partake? (2)
Some products increase blood flow and recruit other WBC’s (neutrophils and macrophages) to the site to enhance the immune response. Some products also induce opsonization
Active vs Passive immunity
Active is when an individuals own immune system is involved with producing antibodies. Passive is when antibodies have been inserted into an individual to induce immunity. E.g. vaccines
IgM role
Involved in early immune response. Activate the complement system
What are platelets formed from?
Megakaryocytes
