0408 Principles of innate immunology Flashcards
• Innate immune system comprises barriers, specialised cells and circulating proteins that effect an immediate response to pathogens • Four main types of pathogen recognition receptors • Inflammation can be both beneficial and harmful to the host
Which immune system is characterised by specificity inherited in the genome?
Innate immunity
Which immune system is characterised by an immediate trigger response and which is characterised by a delayed, signal response.
Innate immunity = immediate response. Adaptive immunity = signal response
Which immune system recognizes broad classes of pathogens and which recognizes specific types of pathogens
Innate immunity = broad classes of pathogens. Adaptive immunity = specific types of pathogens
Which immune system is able to discriminate between closely related molecular structures
Adaptive immune system
Which immune system is encoded in multiple gene segments
Adaptive immune system
Describe some of the barriers of the innate immune system
Epithelial barriers are the first line of define: skin, epithelial cells on gut, lungs and eyes/nose. Other physical barriers include mucus (lungs,nose,throat). Fatty acids, antibacterial peptides and enzymes (stomach,etc)
What are the 2 broad categories of viruses that cause disease in humans (think molecular level)
DNA (e.g. parvovirus, hperpesvirus) and RNA viruses (e.g.retroviruses, coronaviruses)
What are macrophages? Describe their general role
Macrophages are phagocytes derived from monocytes.
Roles:
• Phagocytosis - engulf and then digest, cellular debris and pathogens
• Anitgen presenting cell- display antigens with MHC
• Cytokine production - Rounding other cells e.g. neutrophils
Where do you find macrophages?
Damaged tissues – monocytes from the circulation enter damaged tissue and change to macrophages
What are neutrophils? Describe their general role
Neutrophils are white blood cells formed from bone marrow.
Role
• Phagocytosis - engulf and then digest, cellular debris and pathogens
Where do you find neutrophils
Circulation – floating in the plasma of systemic circulation. They move to damaged tissue through the endothelium of vessels
What are dendritic cells? Describe their general role
Dendritic cells are specilized antigen-presenting cells. Their main function is to process antigen material and present it on the cell surface to the T and B cells
What are dendritic cells? describe their general role
Dendritic cells are antigen presenting cells. They are present in external tissues. Once activated they move to lymph nodes to activate T, NK and B cells
What are eosinophils and mast cells? Describe their general role
Eosinophils and Mast cells are both components of plasma what are involved in the activation of an allergy response. Eosinophils are involved in protection against anti-body coated parasites and mast cells contain heparin and histamine
Where do you find Eosinophils and Mast cells
Systemic circulation – floating in plasma
What are natural killer cells? Describe their general role
NK cells are lymphocytes of the innate immune system. They protect us from infected cells and tumours by detecting MHC absence or abnormality on infected cell surfaces, triggering cytokine release, causing lysis or apoptosis.
What do dead neutrophils form?
Pus
Name the 2 (professional) antigen presenting cells in the innate immune system
Dendritic cells and macrophages
What are pathogen-associated molecular patterns (PAMPs)
PAMPs are molecules associated with groups of pathogens. PAMPs are proteins, nucleic acids or lipids which we don’t have, or which have modifications to them that make them dissimilar to ours
What are the 4 main types of recognition receptors
TLRs (toll-like receptors), C-type lectin receptors, NLRs (nucleotide-binding oligomerization domain receptors) and RLRs (RIG-I like receptors)
Which of the 2 types of receptors are found in the cell surface and which are found in the cytosol?
Surface= TLRs and C-type lectin receptors
Cytosol= NLRs and RLRs
Which 2 types of receptors recognize PAMPs and DAMPs
TLRs and NLRs
What are damage-associated molecular pattern molecules (DAMPs)
DAMPs are molecules released by stressed cells undergoing necrosis that act as danger signals to promote and exacerbate the inflammatory response
Describe the role of Toll-like receptors (TLRs)
TLRs are cell surface protein receptors responsible for defence against microbial infection. They recognize PAMPs and DAMPs and initiate the signal cascade to activate proinflammatory cytokines
Describe the role of C-type lectin receptors (CLRs)
CLRs are cell surface protein receptors the recognize microbial polysacharaides. They bind to carbohydrates released/attached to pathogens and activate the signal cascade to activate proinflammatory cytokines
Describe the role of NLRs (nucleotide-binding oligomerization domain receptors) ?
NLRs are cytosolic protein receptors that recognize peptidoglycans in bacterial walls. They detect intracellular PAMPs and DAMPs and cooperate with TLRs to regulate inflammatory and apoptosis response
Describe the role of RLRs (RIG-I-Like Receptors) ?
RLRs are cytosolic protein receptors that recognize intracellular virus replication. They sense double stranded RNA, an intermediate in virus replication and produce interferons in infected cells.
List the 3 pathways compliment proteins use to converge on activation of C3 convertase
Classical, alternative and lectin pathway
What are the 2 activated forms of C3 and what is each form responsible for ?
C3a= enhancing inflammation. C3b = opsonization (promote macrophage phagocytosis) and initiating the membrane attack complex (lysis)
