MoD 1 Flashcards
(32 cards)
What are the effector molecules of apoptosis called?
Caspases
Which molecules are normally sequestered in mitochondria, but when released into the cytosol activate caspases?
Apoptosis initiating factor (AIF) and cytochrome C
Why is the Erythrocyte sedimentation rate (ESR) faster during an acute phase reaction?
Erythrocytes are normally negatively charged and repel one another. When an inflammatory process is present there is an increase in the amount of fibrinogen in the blood, causing the erythrocytes to stick together and sink faster.
What is found microscopically in acute inflammation?
Neutrophil polymorphs
What is granulation tissue composed of?
Capillary loops and myofibroblasts
What are the steps of neutrophil emigration?
Axial stream
- -> Margination into plasmatic zone
- -> Adhesion to endothelial cells (pavementing)
- -> Emigration as they pass through the basal lamina into the adventitia and surrounding tissue
Which compliment factor binds to pathogens for opsonisation?
C3b
Which compliment factors are mediators of inflammation, recruiting phagocytes?
C3a, C5a
Which compliment factors form the membrane attack complex?
C5b, C6-C9
What is the function of Natural Killer cells
Kill foreign and host cells that have low levels of class I MHC+ self peptides. Express NK receptors that inhibit NK function in the presence of high expression of self-MHC
What are the primary lymphoid organs and what is their function
Bone marrow and Thymus, for lymphocyte development and selection
What are the secondary lymphoid organs and their function
Spleen (white pulp), lymph nodes and mucosal surfaces, where the immune response occurs
When foreign antigens are phagocytosed and broken down into peptides, what are they presented upon on the cell surface?
Class II MHC
These are recognised by CD4 helper T cells which become activated
CD8 cytotoxic T cells detect antigens in association with which molecule
class I MHC
What do CD8 cytotoxic T cells secrete when they detect foreign antigen on class I MHC
Perforin which punctures the membrane of the infected cell
Th1 cells are effectors against which pathogens and active which kind of immune response
They are effectors against intracellular bacteria and protozoa. Triggered by IL- 2, Th1 cells promote a cellular immune response by secreting Interferon gamma (IFN-y) and IL-2. This stimulates macrophages and CD8 T cells
Th2 cells are effectors against which pathogens and activate which kind of response
Th2 are effectors against extracellular parasites. Triggered by IL-4, Th2 cells promote a humoral response by secreting IL-4, IL-5, IL-9, IL-10, IL-13. This stimulates B cells, mast cells and eosinophils
What are the main cytokines of the innate immune system?
TNF, IL-1, IL-6, IL-23
Describe Hypersensitivity reaction type I
IgE mediated reaction - anaphylactic
Initial response = degranulation releasing histamine
Late phase reaction = synthesis of lipid mediators such as prostaglandins and leukotrienes from arachidonic acid. Cytokine production by activated T cells. Basophils and eosinophils degranulate.
Describe Hypersensitivity reaction type II
Cytotoxic reaction - antibody mediated, eg blood group incompatibility
Describe Hypersensitivity reaction type III
Immune complex reaction: antigen-antibody complexes are inadequately cleared by the body. These activate compliment causing the degranulation of basophils and neutrophils which damages the surrounding tissue
Describe Hypersensitivity reaction type IV
Delayed type: T cell mediated reaction
Ag-specific T cells release cytokines - recruitment of macrophages (non Ag-specific)
Activated macrophages cause tissue damage
Which inflammatory cells are most predominant in chronic inflammation?
mononuclear cells = macrophages, lymphocytes and plasma cells
Why are macrophages important in chronic inflammation?
Stimulation of the immune system,
Phagocytosis of bacteria and damaged tissue,
Induce angiogenesis granulation tissue formation
