5 Immunopathology Flashcards
What are the general principles of the immune response? (7).
Multilayer. Network of pattern recognition. Communication. Multiple mechanisms. Adaptive response. Self-regulation. Limitation of host damage.
What are the major components of the innate immune system? (5).
Pattern recognition receptors. Antimicrobial peptides. Cells. Complement components. Cytokines.
What do pattern recognition receptors recognise?
Pathogen associated molecular patterns (PAMPs) and Danger associated molecular patterns (DAMPs).
What are the two groups of PRRs?
Cell surface and intracellular receptors.
Fluid-phase soluble molecules.
What are TLR’s and what do they do?
Toll-like receptors.
Transmembrane proteins that trigger cytokine synthesis and secretion.
What are NLRs and RLRs and what do they do?
Nod-like receptors, Rig-like receptors.
Regulate inflammatory/apoptotic response.
What are CLR’s? 3 examples.
C-type lectin receptors. Fluid phase molecules.
Mannan-binding Lectin.
Surfactant protein A and D.
What do CLRs do?
Recognise microbial carbohydrates and bind to Carbohydrate-Recognition Domains.
Role in neutralisation of pathogens and recruitment of adaptive response.
Give some examples of antimicrobial peptides: (7).
Defensives. Cathelin. Protegrin. Granulsyin. Histamine. Secretory leukoprotease inhibitor. Probiotics.
What does IL1 do? (innate) (3).
Increases coagulation and inflammation.
Increases acute phase protein production by hepatocytes.
Tells hypothalamus to induce fever.
What does TNF do? (innate) (4)
Increases coagulation and inflammation.
Increases acute phase protein production by hepatocytes.
Tells hypothalamus to induce fever.
Increases activation of neutrophils.
What does IL6 do? (innate) (2).
Increases proliferation of B lymphocytes.
Increases production of acute phase proteins by hepatocytes.
What does IL23 do? (innate)
Increases IL17 production by T lymphocytes.
How are epithelial cells involved in innate immunity?
Produce anti-microbial peptides - e.g. lung epithelial cells produce surfactant proteins that bind and promote clearance of invading lung microbes.
What is the central feature of the adaptive immune system?
Unique antigen receptors on each lymphocyte that can trigger clonal expansion. Allows high specificity.
What are the primary lymphoid organs and what do they do?
Bone marrow. Thymus.
Lymphocyte development and selection.
What are secondary lymphoid organs? (3).
White pulp of spleen.
Lymph noes.
Mucosal surfaces.
What is the range of antigenic variability? How many genes do we contain? How is this limitation overcome?
10 to the 9
30,000
V(D)J recombination.
What is the structure of T and B cell receptors?
Two heavy chains linked by disulphide bridges with a light chain either side. Variable regions are on the end of the Y, constant at the base. Fab and Fc regions.
Describe the mechanism of antigen presentation
Antigens are internalised, broken down to peptides, associated with Class 2 molecules, brought to cell surface. If they are foreign, helper T cells recognise them and produce cytokines.
What are histocompatibility antigens also known as? Which genes are they coded by?
Human leukocyte antigens.
MHC.
Name the three types of Class 1 HLAs.
HLA-A
HLA-B
HLA-C
Name the three types of Class 2 HLAs.
HLA-DP
HLA-DQ
HLA-DR
What are the functions of MHC proteins.
Present antigenic peptides to T cells.
MCH Class 1 to cytotoxic T cells
MHC Class 2 to helper T cells
What are the functions of the different types of lymphocytes?
Tk: cellular immunity. Kill.
Th: secrete cytokines which control response.
Suppressor: dampen down immune response
How does binding of antibodies to antigens inactivate them?
Neutralisation (blocks binding site). Agglutination. Precipitation of dissolved antigens. ALL enhance phagocytosis.
Activation of complement system.
How do cytotoxic T cells work?
Binds to infected cell. Perforin enzyme allows entrance of apoptosis promoting enzymes into the infected cell.
What does Th1 response favour? (3).
Cytotoxic activation.
B cell IgG opsonisation for phagocytosis.
Macrophage activation.
What does a Th2 response favour? (3).
Eosinophil activation to kill parasites.
Mast cell and basophil activation to regulate vascular permeability.
B cell immunoglobulin production for direct antibody killing and opsonisation.
What does IL4 do? (adaptive) (4).
Increases IgE response.
Th2 proliferation.
Decrease macrophage response.
Increase mast cell proliferation.
What does IL5 do? (adaptive) (2).
Increase IgA response.
Increase eosinophil activation and proliferation.
What does IL17 do? (adaptive) (3).
Increase chemokine production by endothelia.
Increase macrophage production of cytokines.
Increase G-CSF and GM-CSF.
Define immunosuppression.
A natural or artificial process that turns off the immune response.
Define immunodeficiency.
Lack of an efficient immune system.
Without an inflammatory response you are more susceptible to: (2)
Pneumococcus.
HSV.
Without macrophages/neutrophils, you are more susceptible to: (3)
CGD.
Staphylococcus.
Aspergillus.
Without T cells (SCID) you are more susceptible to:
Opportunistic infections.
Without complement you are more susceptible to:
Meningococcus.
Without TNF or IL-1 you are more susceptible to:
Mycobacterium.
Without B cells you are more susceptible to:
Recurrent sino-pulmonary infections.
