Immunology Flashcards
Untreated immune deficiency leads to…
…death from overwhelming opportunistic infection
Primary Immune deficiency disorders
(Born with it)
Bruton’s disease
Congenital thymic aplasia (Di George Syndrome)
SCID - severe combined immune deficiency
What is Bruton’s disease?
Congenital agammaglobulinaemia
Absence of B cells
No germinal centres, small tonsils
Maternal transfer of IgG protects baby for 6-9 months
Treated by gamma-globulin injections
- or patient dies from staph, strep + haemophilus influenzae
Congenital Thymic Aplasia (Di George Syndrome)
Absence of T cells, no secondary antibody response
Patients cannot control viral infections
Fetal thymus transplant required
SCID (severe combined immune deficiency)
T cells do not mature
Adenosine deaminase deficiency
Agammaglobulinaemia
Extreme susceptibility to infection
2 year survival time w/out Bone Marrow transplant
Causes of Secondary immune deficiency
Irradiation
Cytotoxic drugs (suppress immune system)
Glucocorticoids
Acquired Immune Deficiency Syndrome (AIDS)
HIV infecting + killing CD4 T cell = immune deficiency HIV lives inside T cells
3 lines of defence against infection
Physical barriers (skin, mucus membrane)
Innate immune system (consists of phagocytes -phagocytosis)
Adaptive immune system (dependent on antigen receptors on lymphocytes; includes acquired)
Clonal selection
ability to distinguish foreign, harmful antigenic threats (infection) from self - dependent on specific antigen receptors
ability to then amplify that response by selectively expanding the clone of the crosslinked B cell or T cell + protective manner to protect against infection
Primary + secondary response
Function of the Spleen
Control blood-borne infection
T lymphocytes
Arise in bone marrow but mature in the thymus gland
Start immune responses - have antigen specific T cell receptor (CD3)
2 populations of T cells
- T helper
- Cytotoxic T lymphocytes
CD = cluster of differentiation = surface markers distinguishable by specific antibody reagents
B cells
Differentiate into plasma cells + secrete antibodies
Function as a antigen-presenting cells (APCs)
Antigen-presenting cells (APC)
Focus antigen onto the T + B cell antigen receptors causing a more powerful immune response
Antibodies
Classification of antibodies
Immunoglobulin M (IgM)
Immunoglobulin G (IgG)
Immunoglobulin A (IgA)
Immunoglobulin D (IgD)
Immunoglobulin E (IgE)
What are antibodies?
Antibodies are also called immunoglobulins
They co-purify with the globulin fraction of plasma
There are 5 classes
Each class has a specific receptor on its surface called Fc receptor.
For phagocytosis to occur, antibodies crosslinked to antigen bind to Fc Region on phagocyte.
Where is the receptor for IgE found?
On basophils + mast cells
They possess granules containing mediators e.g. histamine
Mediators are released after contact with allergen
Chemokines + Cytokines
Act as chemical messengers
MHC + antigen presentation
MHC is also known as Human Leukocyte Antigens (HLA)
Function of MHC is to present antigen to T cells to distinguish between self + nonself
