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Innate Immunity
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- 1what is the innate immune system?your first line of defence
- 2is it specific?no
- 3what follows innate immunity?adaptive immunity, which is specific and can involve memory
- 4name some routes of entry through mucosal surfaces by pathogens and how they are transmitted- airway - inhaled droplets
- GI tract - contaminated food or water
- GU tract - direct contact - 5what pathogen is transmitted via inhaled droplets?- the influenza virus - influenza
- Neisseria meningiditis - meningococcal meningitis - 6what pathogens are transimtted via contaminated food or water?- salmonella typhi - typhoid fever
- rotavirus - diarrhoea - 7what pathogen is transmitted via direct contact to the GU tract?- treponoma pallidum - syphilis
- 8name some routes of entry via the external epithelia and how they are transmitted- external surface via physical contact
- wounds and abrasions via minor skin abrasions or punctures
- insect bites via mosquitos/ticks - 9name a pathogen that is transmitted via physical contact of the external surfaceTinea Pedis - athletes foot
- 10name a pathogen transmitted via wounds?- Bacillus anthracis - anthrax
- Clostridium tetani - tetanus - 11name a pathogen transmitted via insect bites- flavivirus - yellow fever
- plasmodium - malaria
-borrelia - lyme disease
-burgdorferi - 12name some mechanical barrier to infection- tight junctions between cells prevent access
- movement of mucus by cillia
- air and fluid flow across epithelium - 13name chemical barrier to infection- fatty acids on skin
- enzymes: lysozyme in saliva, sweat and tears
- low pH in stomach
- antibacterial peptides: defensins, cryptidins - 14name microbiological barriers to infection- Normal flora compete for nutrients and attachment (biofilms), and also produce antibacterial substances (colicins).
- 15what are the three phases of response to initial infection?1. innate immunity (immediate) 0-4 hours
2. Early induced response (early 4 - 96 hours)
3. Adaptive immune response (late >96 hours) - 16what is the immediate response recognised by ?- preformed, nonspecific effectors
= removal of infectious agent - 17what is the early induced response recognised by?recruitment of effector cells
= recognition and activation of effector cells - 18what does the late response do?transport of antigen to lymphoid organs
= recognition by naive B cells, and clonal expansion of effector cells - 19Once across an epithelial barrier, what are microorganisms recognised and ingested by?mononuclear phagocytes, or macrophages.
- 20list some Bactericidal effects and agents produced by phagocytes• Acidification: pH 3-4, bactericidal
• Toxic oxygen derived products: superoxide, hydrogen peroxide, hydroxyl radical
• Toxic nitrogen oxides: Nitric Oxide
• Peptides: defensins and other cationic proteins
• Enzymes: Lysosyme,acidhydrolases
• Competitors: Lactoferrin, vitamin B12 binding protein. - 21what cell are platelets derived from?megakaryocytes
- 22what cell are All cellular elements of blood, rbc, platelets, white cells derived from?same progenitor - hematopoietic stem cell
- 23difference between monocyte and macrophage?monocyte - circulates in blood
macrophage - differentiated monocytes in the tissue - 24role of macrophages?-phagocytosis and killing of microorganisms
- activation of T cells and initiation of immune response - 25list the granulocytesAlso called polymorphonuclear (PMN) leucocytes due to shape of nuclei
Neutrophils, eosinophils, basophils, mast cells - 26neutrophil rolephagocytosis and killing of microorganism
- 27most important and numerous cell of innate immunityneutrophil
- 28how long to neutrophils spend in circulation?Short time spent in circulation, around 12 hours, once in tissue survive for maybe only 2 days.
- 29what is neutropenia?low numbers of neutrophils, may be genetic or the result of medication including chemotherapy
- 30what is Chronic granulomatous disease- failure in respiratory burst, superoxide production limited, antibacterial activity impaired
- 31what is alpha 1-antitrypsin deficiency?elastase from neutrophils not adequately inhibited, excessive tissue damage during inflammation- pulmonary emphysema
- 32role of eosinophils- killing of antibody coated parasites through release of granule contents
- evolutionarily important in parasite defence - 33what do the eosinophil granules contain?Granules contain histamine and others
- 34how long do eosinophils survive in circulation?Circulate for 12 hours, survive in tissues for 3 days
- 35what is eosinophilia?(increase, more than 500 per microlitre blood) seen in parasitic infections of gut, some vascular diseases, Hodgkin’s Disease, Addison’s Disease
- 36when is eosinopenia often seen?when glutocorticoids are used
- 37function of basophils?- similar and complementary to eosinophils and mast cells
- 38when basophils are activated what do they secrete?Upon activation secrete histamine, proteoglycans, leucotrienes, some cytokines including IL-4 (potentially important for IgE and allergy)
- 39what is the least common granulocyte?basophil
- 40function of mast cellwhen activated release a number of substances that effect vascular systems. Most well known due to IgE mediated triggering in allergies.
- 41name the different types of lymphocyte- small lymphocyte
- plasma cell
- natural killer cell
- dendritic cell - 42what do small lymphocytes differentiate into?either B or T cells
• Within these populations lie the adaptive immune response
- B cells producing antibody,
- T cells becoming cytotoxic T cells (CD8) or helper T cells (CD4). - 43function of natural killer cells- kills cells infected with certain viruses
- large granular lymphocytes that can recognise virally infected cells non- specifically - 44function of dendritic cells- activation of T cells and initiation of adaptive immune response.
- potentially the most important immune cell, bridges the innate and adaptive immune responses.
- Specialised in antigen uptake and antigen presentation - 45what do virus infected cells release?IFN alpha and beta which warns nearby unaffected cells so they can make themselves less susceptible to infection
- 46what kind of things do IFN alpha and beta promote?- induce resistance to viral replication in all cells
- increase MHC class 1 expression and antigen presentation in all cells
- activate NK cells to kill virus-infected cells - 47what is the difference between NK cells and CD8 (cytotoxic) T cells?- The key difference between NK and CD8 T cells is that NK cells are not antigen specific.
- Also they do not require to undergo the lengthy clonal expansion of T cells in lymph nodes when virus is detected
NK cells protect you in first few days of infection until T cells are activated, the virus replication is kept at bay by NK cells. - 48how can NK cells detect a 'loss of self'?1. interaction of nk cell with healthy unaffected cell = no killing of cell
2. interaction of nk cell with target cells in which MHC class 1 expression is lost
= killing of virus infected cell in which MHC class 1 expression is inhibited
3. interaction of nk cell with healthy cell in the presence of anti-MHC class 1 antibody
= anti MHC class 1 antibody prevents interaction between the inhibitory reception and the MHC class 1 - 49what is the complement?- Heat labile component of plasma that act in concert with
antibodies to kill some bacteria
• Comprises a large number of distinct plasma proteins
• Three distinct activation pathways exist that trigger the complement cascade. - 50what are the Three distinct activation pathways ?- classical pathway
- lectin pathway
- alternative pathway - 51describe the classical pathwayantibody binds to specific antigen on pathogen surface
- initiated by activation of the C1 complex
- C3 is cleaved into c3a and c3b to its active form - 52lectin pathwaymannose-binding protein binds to pathogen surface
- uses a structure very similar to c1
comprising MBL MASP-1 and MASP-2. - 53alternative pathwaypathogen surface creates local environment conductive to complement activation
- caused by spontaneous hydrolysis of serum c3, which then bind factor B allowing cleavage by factor D into Ba and Bb.
-The resulting soluble C3 convertase cleaves C3 to C3b, which binds to membranes. - 54what are the possible outcomes after complement activation?1. recruitment of inflammatory cells
2. opsonisation of pathogens, facilitating uptake and killing by phagocytic cells
3. lysis and death of pathogens - 55describe the C3b complement proteinmembrane binding protein and opsonin
- c3b bound to cell surface acts to increase phagocytosis - 56C3apeptide mediator of inflammatory cells (floats away and encourages other immune cells to come help)
- 57c5apeptide mediator of inflammatory cells
- assists in phagocytosis of c3b covered bacteria - 58what does the membrane attack complex do?- punches holes in the membrane of the bacteria
- direct lysis
- contents of bacterial cell leak out - 59what prevents the final assembly of the MAC to stop the lysis happening on healthy host cells?CD59
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- (Cells) Physiology Fichas sobre Innate Immunity, creado por hazel wilkie el 01/05/2017.
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- hazel wilkie
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