Introduction To Immunology Flashcards
What is meant by innate defence ?
First line of defence
Not improved by further exposure
What is meant by adaptive defence ?
Second line of defence
Response adapts and improves with each exposure
Specificity memory
Improved by further exposure
Examples of 3 physical barriers
Skin, epithelia
Movement cilia
Trading mucus
Examples of biochemical barriers (4)
Low pH sweat
Vaginal secretions
Stomach sectretions
Lysozyme in secretions (damages bacterial cell wall)
Phagocytosis
Involves engulfing and destroying the pathogen
Lysosome fusion
Opsonin
Substance that coats cell/bacteria and enhances the ability of phagocytes to phagocytose the particle.
Opsonisation
Process of coating cell/bacteria with an opsonin
Interferons function
Their main function is to interfere with the replication of the viruses within infected cells.
Interfere with viral proliferation
When is interferon produced ?
When host cells become infected by a virus, they may produce interferons.
What is cell lysis ?
Lysis is the breaking down of the membrane of a cell.
What are the 3 things that destroy bacteria ?
Lysis
Phagocytes
Opsonisation
What is involved in the secondary response ?
IgG
What are plasma cells ?
Cells which produce antibodies
Function of oestrogen in pregnancy
Stimulates IgA and IgG secretions which inhibit T cells which could reject the foetus.
What are cytokines ?
Cytokines are signaling proteins that help control inflammation in your body.
They allow your immune system to mount a defense if germs or other substances that can make you sick enter your body.
Too many cytokines can lead to excess inflammation and conditions like autoimmune diseases.
What are chemokines ?
They attract cells along a gradient of low to high chemical concentration
Function of neutrophils
Neutrophil phagocytosis is activated by interaction with bacteria, either directly or after bacteria have been coated (opsonized) to make them more ingestible
Function of eosinophils
Eosinophils release pro-inflammatory mediators to provide immunity against parasites.
Where are mast cells found ?
Tissues (skin & mucosa)
Function of mast cells and basophils
Both mast cells and basophils release pro-inflammatory mediators.
They play a role in allergy response
Function of macrophages
A key role of tissue macrophages is the maintenance of tissue homeostasis through clearance of cellular debris, especially following infection or inflammation
Dendritic cells function
The function of dendritic cells is activation of naive T lymphocytes to initiate adaptive immune responses.
These cells are like the spies. They notice if there is an invader and then present evidence of the invader to T cells in the lymph nodes.
What is the function of antibodies ?
In host defence, antibodies target, neutralize and remove infectious organisms and toxins from the circulation and tissues, often through recruitment of innate host effector mechanisms such as complement, phagocytes and mast cells (by binding to specific surface receptors on these cells).
Results of phagocyte defects
Cause deep skin infections, abscesses and osteomyelitis
Results of defective antibodies
Producers experience infections with pyogenic (‘pus-forming’) bacteria
Results of T lymphocyte deficiency
Causes infection with fungi, protozoa and intracellular microorganisms.
Function of NK cells
Natural killer (NK) cells are effector lymphocytes of the innate immune system that control several types of tumors and microbial infections by limiting their spread and subsequent tissue damage.
Function of T cells
T cells control your body’s immune system response and directly attack and kill infected cells and tumor cells.
Function of B cells
B cells make antibodies. Antibodies are proteins that target viruses, bacteria and other foreign invaders.
