Immune Response Flashcards
What are the 2 types of immune response?
Innate (non-specific)
Adaptive (specific)
What external features are there of the innate immune response?
Acid (found on the skin, digestive and reproductive tracts) Mucous (found in the respiratory tract) Enzymes (found in the eyes and saliva) Chemicals (found in sweat) Skin is also a physical barrier
What internal features are there of the innate immune response?
Phagocytes Anti-microbial proteins Mast cells NK-cells Complement pathway (All found in the blood)
What are the types of phagocytes and their differences?
Nuetrophils:
Undergo phagocytosis once then die (—> pus)
Monocytes:
Can undergo phagocytosis many times (—> PAPC’s)
Differentiate into macrophages and DC’s
What are the stages of phagocytosis?
Ingestion of pathogen opsonised (coated in antibodies)
Form phagosome + fusion of phagosome with lysosome
Lysosome releases hydrolytic enzymes and ROS
Exocytosis of digested pathogen
What are the features of Anti-microbial proteins?
Lytic enzymes (disrupt the cell membrane) found near inflamed or cut skin
What are the features of mast cells?
Coated in Immunoglobulin E (IgE) which detects allergens
Contain granules of:
Histamine (increase permeability + causes vasodilation of capillaries)
Heparin (Anticoagulent)
Chemiotaxis for eosinophils and nuetrophils
What are the features of NK-cells?
Found in blood and lymph
Coated in an antibody for Major Histocompatability Complex 1 (MHC1)
An abnormal/absent MHC1 will mean an abnormal cell
The NK-Cell releases perforins forming pores within the membrane of the pathogen which granzymes can enter and cause apoptosis
What are the 2 types of adaptive immune response?
Humoral
Cell-mediated
How does the humoral immune response occur?
B-cells are coated in specific antibodies
When antibodies bind to antigens —> immune response
B-cells replicate themselves into memory B-cells and effector B-cells
What do memory and effector B-cells do?
Memory: retain the antigen for a secondary response if infected by the same pathogen again
Effector: produce more free antibodies and B-cells
What do antibodies do in response to antigens?
Agglutination (bind to each other and antigens)
Neutralisation (prevent Mitosis or growth by blocking molecules and signals)
Opsonisation (mark pathogens for phagocytosis)
How does the cell-mediated immune response occur?
PAPC’s (B-cells, Macrophages, DC’s) produce MHC2 which binds to antigens and flags T-cells
What are the types of T-cells?
NK Suppressor Memory Helper Cytotoxic
How do T-cells respond when an antigen has been flagged?
Helper T-cells bind to the antigen and clones itself producing helper T-cells, memory T-cells, suppressor T-cells
Helper T-cells also secrete cytokines calling cytotoxic T-cells
When the pathogen has been destroyed, suppressor T-cells release inhibitory cytokines to suppress the immune response
