Immunology Flashcards
What are non-specific defences?
Don’t work against a specific antigen, just work against all pathogens.
Skin - protects sensitive internal organs
Mucosa - thick and cells reproduce rapidly
Saliva with enzymes - protect and flow stops bacteria entering salivary glands
Chemical - stomach acid denatures proteins and protects whilst digesting.
What is acute parotitis?
Usually seen in elderly patients when dehydrated and run down, their salivary flow rate decreases and bugs can enter the parotid gland and it becomes swollen.
What are the two types of non specific immunity?
Humoral immunity and cell mediated
What are some non specific molecular immune defences?
Inflammation - chemicals left by dead cells trigger immune response.
Leads to vasodilation - more blood in the area
Increased permeability - more blood in the area that allows white blood cells to move from the blood system out into the tissues.
What are the macroscopic signs of inflammation?
Calor - heat
Rubor - redness
Tumor - swelling
Dolor - pain
Functio laesi - loss of function
What is the complement cascade?
3 pathways - classical, lectin and alternative pathway that both lead to a final common pathway = producing activated complement.
Stimulated by - inflammation, bacteria, viruses, tissue damage, antibodies
What is the effect of the complement cascade?
Opsonisation - covering a molecule/activated cell in activated complement labelled for phagocytosis
Cell lysis
Inflammation causing more vasodilation, permeability and chemotaxis.
What is hereditary angiodema?
Inherited deficiency of C1 esterase inhibitor leading to no check on the activation of C1 in the classical pathway of the complement system which leads to uncontrolled activation of the complement cascade causing a lot of swelling and leads to problems with airway control.
How do antibodies work?
They are specific to a particular antigen and have a component that binds to an antigen and the effector end of the antibody is able to trigger other immune responses.
Antibodies can cover up an antigen and stop it working or mark an antigen as something significant an attract other cells that can bind to the effector end of the antibody triggering the immune system. The effector end can bind immune cells, complement etc.
What is humoral immunity?
Where B cells produce antibodies specific to an antigen. When a B cell has been triggered by a particular antigen it will be stimulated to replicate to a lot of cells specific to that antigen, if these antigens are encountered again you will have a lot of B cells ready to create a lot of antibodies to that antigen.
What is cell mediated immunity?
T cell receptors recognise antigens on tumour cells/viral cells and non self cells. These activate the T cell that secretes cytokines and cytotoxic chemicals that cause the cell to die, you will get clonal expansion of the cell so you get lots of cells that target that specific antigen.
What is tetanus?
Tetanus is an infection caused by bacteria called Clostridium tetani. When these bacteria enter the body, they produce a toxin that causes painful muscle contractions and locked jaw.
How is tetanus treated
Immunoglobulin - antibodies against C. tetani
No lasting protection with no immunological memory
How do we get long lasting protection from tetanus?
Immunisation of toxoid - has the same antigenicity as the tetanus toxin without the toxic effects.
Lasting protection through active immunity
How can viruses/bacteria be modified for vaccination?
- Killed
Live attenuated
Viral particles
DNA/RNA
What are some examples of auto-immunity?
Bone - RA
Endocrine - DM
GI tract - coeliac
PNS/CNS - multiple sclerosis
Skin - pemphigus
Saliva - Sjogren’s
What allows the immune system to tell self from non-self?
Major histocompatibility complex
How do organs reject each other?
If the graft has a different major histocompatibility complex to the recipient the tissue is recognised as non self and rejected.
What is graft vs host disease?
Commonly seen in treatment of leukemia with haemopoeitic stem cell transplant where the graft cells start to attack the host’s healthy cells.
What oral signs can you see of graft vs host disease?
Dry mouth
Lichenoid reactions
How are autoimmune diseases treated?
Steroids
Methotrexate
Biological response modifiers
