102. Swollen Finger Flashcards
What defines the innate immune system?
It is in-born and operates throughout life
What defines the adaptive immune system?
It changes in response to the pathogens it encounters and is characterised by the development of immunological memory such as B cells and antibody production
What are cytokines?
Small soluble proteins involved in cell-cell signalling
What does autocrine mean?
Actions of secretions are on the cell secreting the substance
What does paracrine mean?
Acts on adjacent cells
What does endocrine mean?
Acts on cell and organs at remote sites
What are chemokines?
Subgroup of cytokines that recruit phagocytes and cause leukocyte extravasation, movement out of circulation to tissue site
What do monocytes differentiate into in tissues?
Macrophages
What is the most abundant cell of the innate immune system?
Neutrophils
Which cells release histamine?
Mast cells
Basophils
Eosinophils
Which cell types release histamine?
Granulocytes
What PRR (pattern recognition receptor) mediates phagocytosis?
Complement receptors
Beta-glucan
Fc
Which PRR (pattern recognition receptor) mediate inflammatory response?
TLR’s (toll like receptors)
CLR’s (C-type lectin receptors)
RLR’s (RIG-I-like receptors)
What are the signs of inflammation?
Swelling - Tumor Redness - Rubor Heat - Calor Pain - Dolor Loss of function
What are the 3 complement pathways?
Classical Pathway
Alternative Pathway
Mannose binding lectin pathway
What do all three complement pathways result in?
Formation of the Membran attack complex (MAC)
What complement proteins form the membrane attack complex (MAC)?
C5b-9
Where are complement proteins produced?
In the liver
Once a dendritic cell has encountered an antigen where does it migrate to?
Paracortex of lymph node
What do dendritic cells do in the local lymph node?
They present the antigen to T-cells
What are the two types of T-cells?
T helper (CD4+) T cytotoxic (CD8+)
What do CD4+ (T helper) cells respond to?
MHC2+ Antigen presentation
What do CD8+ (T cytotoxic) cells respond to?
MHC1+ Antigen presentation
What activates B cells?
T helper (CD4+) cells presenting antigens Macrophages presenting antigens
What happens when CD4+ Th1 cells are activated?
They proliferate and secrete IL2 which self stimulates to secrete IFN-gamma and TNF-alpha
What does IFN-gamma do?
Increases macrophages ability to lyse phagocytosed pathogens
What happens when CD8+ (T cytotoxic) cells are activated?
Produce cytolytic enzymes which are injected into the cell to trigger apoptosis
What happens when CD4+ Th2 cell are activated?
They self stimulate with IL4 secretion which causes B cell proliferation
What happens when B cells are activated?
They differentiate into effector and memory cells
What are plasma cells?
The effector B cells once they have been activated and are circulating in the blood producing antibodies
What does humoral immunity involve?
CD4 Th2 cells, B cells and abs
What does cellular immunity involve?
CD4 Th1 cells and macrophages
What is affinity maturation?
Random mutations in V-region genes leading to changes to DNA sequence affecting affinity (antigen binding ability)
What is class switching?
Recombination of Ig gene segments
Constant region = heavy chains but there is a change in the variable region so there is the same antigen specificity
What chemical factors are involved in vasodilation and increase vascular permeability in inflammation?
Histamine NO Substance P Bradykinin Leukotrienes IL1 TNF IFN-gamma
