Inflammation and Immune Response Flashcards
What are some features of innate immunity?
Is the first line of defence, inborn, distinguishes self from non-self, however, unable to distinguish between pathogens
What are some of the components of innate immunity?
Epithelial cells Neutrophils and macrophages NK cells Complement proteins Cytokines
What are the components of adaptive immunity?
B and T lymphocytes
What is the humoral response?
(part of adaptive immunity) Results in the production of antibodies directed against an antigen. Involve B lymphocytes
What is the cell-mediated response?
(part of adaptive immunity) Leads to the destruction of infected body cells, include cytotoxic and helper T cells
What are the central immune structures?
Bone marrow and thymus. Where immune cells are produced and mature
What are the peripheral immune structures?
Lymph nodes, spleen. Where immune cells interact with antigens
What kind of cells are CD4+?
Helper T cells
What kind of cells are CD8+?
Cytotoxic T cells
What does CD stand for?
Clusters of differentiation
What is the difference between NK cells and cytotoxic T cells?
NK cells do not need to recognise a specific antigen before being activated, they are programmed to automatically kill foreign cells.
Cytotoxic T cells have to be activated by a specific antigen in order to become cytotoxic
What does MHC I do?
Allows the body to differentiate between normal and infected cells. Expressed on almost all cells
What does MHC II do?
Allows appropriate interactions among immune cells. Expressed only on a few cell types including macrophages, B cells, helper T cells
What are cytokines?
Are proteins that form a communication link between immune cells and other tissues and organs of the body
What cells do cytokines primarily act on?
Activated helper T cells and macrophages
Why are cytokines secreted for only a brief time?
This ensures that excessive immune responses do not occur
What can excessive production of cytokines lead to?
Serious adverse effects such as septic shock and some kinds of cancer
What is a complement?
A group of proteins that circulate in the blood and, when activated, bind and destroy any foreign cell
What does the complement system do?
Mediates innate and adaptive immunity and therefore enables the body to produces an inflammatory response, lyse foreign cells, and increase phagocytosis
How is complement controlled?
Uncontrolled activation is prevented by inhibitor proteins, which prevent the membrane attack complex from forming, and the instability of the activated proteins
What is the result of inadequate immune response?
Immunodeficiency
What is the result of excessive immune response?
Allergic reactions and/or autoimmune diseases
How are normal responses self-limited?
Antigen elimination, the products of response (eg cytokines and antibodies) having a short life span and being secreted for brief periods after antigen recognition
What is tolerance?
An aspect of self-regulation, is the ability of the immune system to be non-reactive to self-antigens (ie protects an individual from harmful autoimmune responses)
What are the characteristics of acute inflammation?
Short duration, characterised by the exudation of fluid and plasma components, and emigration of neutrophils into extravascular tissues
What are the characteristics of chronic inflammation?
Longer duration, associated with the presence of lymphocytes and macrophages, proliferation of blood vessels, fibrosis and tissue necrosis
What are the stages of acute inflammation?
Immediate vascular changes, influx of inflammatory cells, widespread effects of inflammatory mediators
Explain the immediate vascular changes (acute inflammation)
Initiated by brief vasoconstriction of small blood vessels, followed by vasodilation of the arterioles and venules that supply the area
Results in the area becoming congested causing redness (erythema) and warmth
Explain the influx of inflammatory cells in acute inflammation
eg neutrophils from the microcirculation and their activation to eliminate the injurious agent
Done by the means of phagocytosis and the release of enzymes by neutrophils and macrophages
Explain acute inflammation in terms of inflammatory mediators
Produces a fever and other systemic signs and symptoms
Plasma-derived mediators for increasing vascular permeability
Cell-derived mediators for increasing vascular permeability, vasodilation, pain, fever, etc
What are the two type of chronic inflammation?
Non-specific chronic inflammation and granulomatous inflammation
Explain non-specific chronic inflammation
Involves accumulation of macrophages and lymphocytes at the site of injury
Macrophages infiltrate the inflamed site and accumulate, therefore, leading to fibroblast proliferation with subsequent scar formation which replaces the normal connective tissue of the involved structures
Explain granulomatous inflammation
Involves formation of granulomas (1-2mm lesions) in which there is a massing of macrophages surround by lymphocytes
These modified macrophages aka epitheloid cells
They can clump in a mass, forming a multinucleated giant cell that attempts to surround the foreign agent
Dense membrane of connective tissue encapsulates and isolates the lesion
What is granulomatous inflammation associated with?
Asbestos, silica, and microorganisms causing TB, syphilis etc, all of which are poorly digested and not easily controlled by other inflammatory mechanisms
