IMMUNO Flashcards
Name the 2 major types of immunity
Innate and Adaptive
What are the 2 roles of the immune system?
- Recognition function
2. Effector function
Describe innate immunity
Innate immunity is a “first line of defence”, which is present at birth and responds rapidly, with no specificity and no memory.
Name 3 examples of innate immunity
- Cells (NK cells, phagocytes, eosinophils)
- Barriers (physical / chemical / biological)
- Soluble factors (lysozyme, complement, cytokines, acute phase proteins)
List 5 characteristics of the adaptive immune system
- Highly specific
- Has memory
- Adpative
- Slow to start
- Recognition of self from non-self
What are the 2 components of the adaptive immune system?
- Humoral
2. Cellular
What is the humoral component of the adaptive immune system made up of?
Antibodies (immunoglobulins) - specific proteins produced against pathogens, from B lymphocytes
What is the cellular component of the adaptive immune system made up of?
B lymphocytes and T lymphocytes
What is an antigen?
Any substance that elicits an immune response
What is an epitope?
A restricted part of the antigen to which an antibody binds
Give some examples/forms in which antigens present in (x6)
- Proteins
- Carbohydrates
- Nucleic Acids
- Lipids
- Drugs e.g. penicillin
- Inorganic molecules (e.g. Nickel)
Name the granulocytes (x3)
- Neutrophils
- Eosinophils
- Basophils
How many percent of blood leucocytes does each make up:
- Neutrophils
- Eosinophils
- Basophils
neutrophils: 60-70%
eosinophils: 2-5%
basophils:
Size of neutrophils
10-20um
Role of neutrophils
Phagocytosis and destruction of pathogens
Mode of action of neutrophils
Adhere to endothelial cells lining blood vessels and squeeze between them to leave circulation and enter tissues
Mode of action of eosinophils
Release of granules upon activation, resulting in the killing of large pathogens that cannot be phagocytosed
What is the function of the mononuclear phagocyte system?
Disposal of microbes and dead body cells through phagocytosis
Where in the body is each found?
- monocytes
- kupffer cells
- mesangial cells
- alveolar macrophages
- microglial cells
- sinus macrophages
- serosal macrophages
- monocytes – blood
- kupffer cells – liver
- mesangial cells – kidney
- alveolar macrophages – lungs
- microglial cells – brain
- sinus macrophages – spleen, lymph nodes
- serosal macrophages – peritoneal cavity
Function of platelets
involved in blood clotting and inflammation
function of antigen presenting cells (APC)
Present antigen to T cells and produce cytokines
Function of endothelial cells
Receptors recognise certain lymphocytes and control lymphocyte traffic and distribution
Name the primary lymphoid organs
Bone marrow and Thymus
Name the secondary lymphoid organs (x6)
- Peyer’s patches
- Lymph nodes
- Spleen
- Waldeyer’s Ring
- Bronchus associated lymphoid tissue
- Lymphoid nodules
CD marker on Helper T cell surface
CD3, CD4
CD marker on Cytotoxic T cell surface
CD3, CD8
How many antigenic determinant is each lymphocyte specific for?
1
Name the 5 classes of immunoglobulins
IgG, IgA, IgM, IgE, IgD
What are the 2 types of light chains?
Lambda
Kappa
Which chain determines the class of antibodies?
Heavy chain
Which heavy chains of immunoglobulin groups fold into 4 globular domains?
IgG, IgA, IgD
VH, CH1, CH2, CH3
Which heavy chains of immunoglobulin groups fold into 5 globular domains?
IgM, IgE
VH, CH1, CH2, CH3, CH4
Which is the most abundant Ig in plasma?
IgG
Name the subclasses of IgG
IgG1
IgG2
IgG3
IgG4
Which class of Ig can pass from mother to child through placenta?
IgG
Which class of Ig is the predominant antibody of secondary response?
IgG
What does IgG do?
IgG is very efficient at triggering complement and phagocytosis via Fc receptors
Name the subclasses of IgA
IgA1
IgA2
Name the two forms in which IgA can be present as
Monomeric
Dimeric
Describe the composition of serum IgA
Monomeric, with 90% IgA1 and 10% IgA2
Describe the composition of secretory IgA
Predominantly dimeric, with 40% IgA1 and 60% IgA2
Which is the major antibody in seromucous secretions?
IgA
Where can IgA be found?
Seromucous secretions e.g. milk, saliva, gut
Which is the class of antibody first encountered by invading bacteria and viruses?
IgA
What is the Fc region of antibody?
Fragment crystallisation region
What is the Fab region of antibody?
Fragment antigen-binding region
Where is IgM present?
Only in plasma
Why is IgM only present in plasma?
It is too large to enter tissues
Which is the predominant antibody of primary response?
IgM
How are the 5 Y shaped units of IgM joined?
J chain and disulfide bridges
What does IgE interact with?
FceRI - binds Fc region of IgE
Where is FceRI expressed?
Mast cells and basophils
What is IgE important for?
Protects against parasitic infections
Where is IgD found?
On the surface of lymphocytes
What does binding of antibody-coated targets to FcR on immune cells result in? (x5)
- Phagocytosis
- Release of activated oxygen species and enzymes
- Release of inflammatory mediators (e.g. histamines)
- Enhanced antigen presentation
- Clearance of immune complexes
List some functions of the complement system (x6)
- Triggering and amplification of inflammatory reactions
- Attraction of phagocytes by chemotaxis
- Clearance of immune complexes
- Cellular activation
- Direct microbial killing
- Important role in the development of antibody responses
3 Pathways in which complement activation can take
- Classical
- Alternative
- Lectin