Drugs and the Immune Response Flashcards
What is the inflammatory response?
Events in the response to a pathogen or noxious substance
What is the innate response?
Macrophages and antigen presenting cells recognise pathogen associated molecular patterns and release cytokines to trigger the specific response
How does the innate response result in swelling?
Arterioles dilate and blood flow becomes static. The stasis of blood increases venule permeability and therefore the exudation of fluid into the tissues
What is induction in the specific response?
Antigen is presented to T cells which triggers clonal expansion in T and B cells
Describe the humoral specific response
The Fab portions of the immunoglobulin bind to antigens and the Fc portion activates cascades by binding to neutrophils and macrophages
What does IgE do?
Binds to mast cells and basophils and triggers histamine release
What do immunoglobulins do?
Stimulate phagocytosis and direct natural killer cells and stimulate complement sequences
Describe the cell mediates response
Stimulation of cytotoxic T cells to kill virally infected cells and stimulate helper T cells to activate macrophages, lymphocytes and proliferation of other T cells
Describe anaphylactic hypersensitivity and its causes
The release of histamine triggered by non-pathogenic material. Can be caused by pollen, house dust, morphine, penicillin, etc
Describe antibody mediated cytotoxic hypersensitivity
Antibodies are directed against cells.
Haemolytic anaemia - reduction in erythrocytes caused by sulfonamides or antibacterial agents
Thrombocytopenia - reduction in platelets caused by cardiac controlling drugs and digoxin
Describe complex mediated hypersensitivity
Antibodies react with soluble agents and attach to mast cells. Caused by penicillins, lupus erythematosus
Results in rashes, swollen joints, fever
Describe cell mediated hypersensitivity
T lymphocytic response
Involved in transplant rejection, rheumatoid arthritis, type I diabetes, multiple sclerosis and skin reactions to drugs and chemicals
Where are histamines found in abundance?
Lungs, skin and GI tract
Which leukocytes are histamines found in and how are they stored?
Mast cells and basophils
Stored in granular complexes with heparin
Decribe the release of histamines
A receptor mediated interaction between and antigen and IgE results in a rise of intracellular calcium and therefore calcium dependent exocytosis of the histamines
What is the role of H1 histamine receptors?
Increases vascular permeability, smooth muscle contraction and vasodilation
What is the role of H2 histamine receptors?
Increases gastric acid secretion and heart rate
What is the role of H3 histamine receptors?
Inhibits neurotransmitter release
Name the antagonistic drugs for H1 receptors
Diphenhydramine
Promethazine
Cetirizine
Fexofenadine
Why does diphenhydramine and promethazine cause lethargy?
They have a high affinity for muscarinic receptors and so has a sedative effect
What are the two types of eicosanoids?
Prostanoids and leukotrienes
What are examples of prostanoids?
Prostaglandins
Thromboxane
Prostacyclin
What effects do prostanoids have on the body?
Vasodilation
Potentiates histamines and bradykinin
Produces fever
Bronchoconstriction
What effects does platelet aggregating factor have on the body?
Vasodilation
Hyperalgesia
Chemotaxis
Vascular permeability
