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69 Cards in this Set
- Front
- Back
1. What are the properties of B and T cell epitopes?
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B cell:
1. proteins > carbohydrates > fat 2. linear, conformational and discontinuous 3. combine directly with Ab 6-8 amino acids long 4. usually hydrophilic T cell epitopes 1. Protein 2. conformational or linear (ie: not discontinuous) 3. MHC 1: 9 amino acids long, positions 2 and 9 critical 4. MHC II: 12-15 aa long 5. only recognised when presented on MHC molecules 6. often amphipathic helix |
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2. Compare and contrast primary and secondary immune responses.
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PRIMARY INFECTION
- Long period to Ab production 7-10 days - high IgM titre - low IgG titre - low affinity Ab SECONDARY INFECTION - Shorter period to infection 2-4 days - Low IgM titre - High IgG - High Ab affinity |
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3. what are the criteria for a recent infection?
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1. Detection of infection consistent with symptoms
2. 4x or greater rise in Ab titre in paired sera collected 7-10 days apart and tested in parallel 3. Detection of IgM Ab compatible with symptoms and collected within 4 weeks of onset of symptoms |
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What are five groups of agents that cause infectious disease?
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Virus, bacteria, parasite, fungi, helminths, protozoa
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Give an example of a bacteria species.
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Streptococcos pyrogenes
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Give an example of a virus.
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Epstein Barr Virus
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Give an example of a parasite
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Malaria
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What protects you from infectious disease? Give examples of physical barriers:
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PHYSICAL BARRIER, Mechanical, Chemical, Biological
• Skin • Cilia, coughing, sneezing • Mucous secretions • Inner surfaces of respiratory, digestive, reproductive tracts • Flushing of surfaces • Commensal bacteria • pH |
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Describe the innate immune system
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• Rapid, non-specific response to infectious threat
• Recognition by pre-formed, broadly specific effectors • May be associated with inflammation |
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Give examples of innate immunity effectors - which activities are performed by these effectors
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Phagocytosis:
1.tissue macrophages, neutrophils (PMNs) 2. Antimicrobials, microbicidals 3. Complement 4. Natural Killer cells |
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Describe the components of the immune system
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- All white blood cells originate from the pluropotential haemopoetic stem cell (HSC).
1. immunological cells are split in to myeloid cells and lymphocytes. Myeloid cells: neutrophils, eosinophils, basophils, monocytes, macrophages (granulocytes) Lymphocytes: B cells, T cells, NK cells |
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Know the location of immunological tissue around the body
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1':
Bone marrow (all cells) Thymus (T cells) 2': Lymph nodes Spleen Mucosal associated lymphoid tissue - Tonsils - Adenoids - Bronchus - Lymphoid nodules - Peyer's Patch |
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What kinds of cells are involved in immunological
responses? (Initial immune response) |
Innate:
- macrophage recognition - recognition of PAMPs - recognised by PRRs and TLRs - Phagocytosis --> initiation of inflammatory response - cytokine secretion - Complement initiation - activation of adaptive immune response. Adaptive |
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Where are these cells located/found?
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All immunological cells originally arise in the bone marrow
from a pluripotential haemopoietic stem cell (HSC), then circulate in the blood and are recruited to tissue sites of injury |
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What are their basic functions of:
1. neutrophils 2. eosinophil 3. basophil 4. lymphocyte 5. monocyte |
1. phagocytosis, degranulation and NETosis
2. helminth and asthma, secrete cytokines 3. histmamine & allergy 4. NK (innate) --> virus and tumours 5. B cells --> Ab production 6. T cells --> cell mediation (adaptive) |
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Define antigen
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Any substance that can bind to a specific antibody (antibodygenerator) / molecules that are specifically recognised by antigen receptors of either B cells or T cells
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Define immunogen
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Any substance that can elicit an immune response
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Define epitope
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Site on the antigen where the antibody binds or recognises. T cell will recognise a protein, this short protein molecule will bind to an MHC molecule and is recognised by a T cell. B cell epitopes are recnogised directly and are structural motifs on the antigen
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Define hapten
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a small molecule that can only elicit an immune response when bound to a larger carrier molecule
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Define innate immunity
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also known as non-specific immune system and first line of defense,[1] comprises the cells and mechanisms that defend the host from infection by other organisms in a non-specific manner. This means that the cells of the innate system recognize and respond to pathogens in a generic way, but unlike the adaptive immune system (which is only found in vertebrates), it does not confer long-lasting or protective immunity to the host.
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Define adaptive immunity
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pathogen-specific receptors are "acquired" during the lifetime of the organism (whereas in innate immunity pathogen-specific receptors are already encoded in the germline)... The acquired response is said to be "adaptive" because it prepares the body's immune system for future challenges (though it can actually also be maladaptive when it results in autoimmunity)
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Define chemotaxis
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attraction and movement to site of injury
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Innate and adaptive immune responses depend on the
activities of ________________ |
leucocytes
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What are the adaptive immunity receptor characteristics?
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1. encoded multiple gene segments
2. gene arrangement (required) 3. clonal distribution 4. ability to discriminate between even closely related molecular structures |
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What ability does innate immnuity have?
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distinguish self from non self
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What are the receptor characteristics of innate immunity?
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1. specifically inherited in the genome
2. expressed by all cells of a particular type 3. triggers an immediate response 4. recognises a broad class of pathogens 5. interacts with a range of molecular structures of a given type |
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How fast is the onset of innate immunity?
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0-4 hours
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what are the recognition agents in innate immunity?
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preformed, already circulating non specific and broadly specific effectors
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Describe the events of innate immune response
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- 0-4 hours a response is mounted by preformed, non specific or broadly specific effectors
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How fast is a response mounted by 'early induced innate response' ?
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4-96 hours
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What is the 'early induced innate response'?
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- activation in 4 - 96 hours
- recognition of microbial -associated molecular patterns - inflammation and recruitment and activation of effector cells |
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How long does it take for an adaptive immune response?
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more than 96 hours
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What is requires in an adaptive immune response?
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- transport of antigen to lymphoid organs
- recognition by naive B and T cells - clonal expansion and differentiation to effector cells |
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What would happen if there was no adaptive immunity?
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- immunodeficiency diseases
- death occurs in infancy due to overwhelming infection - recurrent infections - no response to innocuous substances - vaccines no use |
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Describe the stages of an infection and response in a skin wound
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1. Infectious agent must adhere to the epithelial cells
2. Local immune response, local healing induced by complement, phagocytes to destroy microorganisms 3*. Local infection of tissues delivers infectious agent to lymph node which initiates immune response. 4. Infection cleared by antibody, T cell macrophages anctivation and cytotoxic t cells. |
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Where do immunological cells arise?
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• All immunological cells originally arise in the bone marrow from a pluripotential haemopoietic stem cell (HSC)
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What are the two types of immunological cells?
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- myeloid
- lymphoid |
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What are exampled of myeloid cells?
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- granulocytes
- macrophages |
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Describe lymphocyte
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Leucocyte in highest
concentration in blood. Lifespan 6-8hrs. Can move into tissues following a chemotactic gradient. Anti-microbial strategies: - Phagocytosis - Degranulation - NETosis |
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What is netosis?
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Release of net web-like structures called neutrophil extracellular traps which trap and kill microbes. this is used in tandem with degranulation and phagocytosis
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Describe the roles of the eosinophil
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Multi-functional.
Mainly respond to helminth infections and asthma. Recruited to inflammatory area. Secrete many inflammatory cytokines |
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Describe the basophil
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- <1% of PB leucocytes.
- Express IgE receptor - Release histamine in response to allergy, - IL-4: ?mediate Th2-type immune response |
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Describe the lymphocyte
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1. Natural killer (NK) cells (innate immunity)
2. Kill virus-infected and tumour cells (intracellular) 2. B cells antibody production 3. T cells cell mediation (both participate in adaptive immunity) |
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Describe the monocyte
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Mature to macrophages
migrate to tissues Phagocytic function |
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What are the roles of B cells?
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B cells:
• Humoral immunity • Antibody production • Act against extra-cellular pathogens |
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What are the roles of T cells?
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• Cell-mediated immunity
• Cellular immune response to intra-cellular pathogens eg viruses • Regulation of B cell responses • CD4 and CD8 major sub-types |
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What is the function of NK cells?
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recognise abnormal cell proteins cell death
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What are the types of lymphocytes?
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- B cells
- T cells - NK cells |
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What is Leucocytosis?
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increase in WBCs stimulated by release of inducingfactors from injured cells
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What is Margination/tethering/adhesion?
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• injured cells display cell adhesion molecules (CAMs) that adhere the phagocytes to the endothelial capillary wall
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What is diapedesis?
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phagocytes pass through capillary wall
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What is chemotaxis?
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attraction and movement to site of injury
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Describe the mobilisation of leukocytes
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• Leucocytosis
• increase in WBCs stimulated by release of inducingfactors from injured cells • Margination/tethering/adhesion • injured cells display cell adhesion molecules (CAMs) that adhere the phagocytes to the endothelial capillary wall • Diapedesis • phagocytes pass through capillary wall • Chemotaxis • attraction and movement to site of injury |
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What is the main determinant in neutrophil migration?
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chemotactic gradient of IL8
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Describe the roles of macrophages
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Forms the mononuclear phagocyte
system • Phagocytosis • May act as antigen-presenting cell (APC) |
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Describe the roles of mast cells?
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Release granule contents upon
activation • Histamine ( vasoactivity) |
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Describe the roles of dendritic cells
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Phagocyte
• Professional antigen-presenting cell (APC) • activation of T cells |
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What are the types of dendritic cells?
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- Classical dendritic cells
- Langerhans cells - Plasmacytoid dendritic cells - follicular dendritic cells |
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What are factors which increase immunogenicity of proteins?
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1- larger the protein the more the immune response
2- intermediate dose 3- subcutaneous is more immunogenic than intraperitoneal, intravenous/intragastric 4- complex composition 5- particulate as opposed to a soluble form 6- denatured as opposed to a native protein 7- very different from self protein 8- slow release adjuvants (pref. bacteria) 9- effective MHC interaction |
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Explain the roles of antibodies in immunity
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Principal functions:
• 1) recognise and bind to extracellular foreign antigen • 2) recruitment and activation of ‘effector molecules’ to eliminate antibody-coated foreign material |
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Name each of the antibody classes and their role in immunity
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6
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Draw a diagram of each of the antibody classes and be able to
identify: • The heavy and light chains • Domains • Hinge region • Presence of J chain |
6
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Know the relative concentrations of the Ig classes in serum and secretions
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6
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Explain how antibodies attach to antigens and Fc receptors
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6
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What role do antibodies and Fc receptors play in immunity?
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6
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Where are the primary immunological tissues in the body?
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6
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Where are the secondary immunological tissues in the body?
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6
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Describe how antigen-antibody connections form
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6
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Describe an illustrate the basic types of antigen-antibody reactions that are employed in a laboratory
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6
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