203 L13 Flashcards
Hypersensitivity
When you first encounter an antigen that’s called a ——– immune response. The response is fairly —– and —-. — and —- —– lymphocytes are produced.
If you see that antigen again it’s called a ——– immune response. The – and — —– lymphocytes enable much —— and —— protection.
Usually the immune response is helpful but sometimes the ——– immune response can be harmful to the —– which is what kind of underlies the ——— reaction.
When you first encounter an antigen that’s called a primary immune response. The response is fairly weak and short. B and T memory lymphocytes are produced.
If you see that antigen again it’s called a secondary immune response. The T and B memory lymphocytes enable much faster and stronger protection.
Usually the immune response is helpful but sometimes the secondary immune response can be harmful to the host which is what kind of underlies the hypersensitivity reaction.
Are the symptoms immediate for Type 1 hypersensitivity reaction or type 2?
Type 1
An allergic reaction is like an overzealous ——- response to a normally innocuous ——- called ——–.
——– are involved in these reactions
In individuals that have a predisposition to having —– they have this abnormal response to an ——–. The individual becomes ———- as part of their ——– immune response. If they see that —— again they have a ——– immune response that gives rise to all of the features associated with the —— reaction.
An allergic reaction is like an overzealous immune response to a normally innocuous antigen called allergens.
Genes are involved in these reactions
In individuals that have a predisposition to having allergies they have this abnormal response to an allergen. The individual becomes sensitized as part of their primary immune response. If they see that allergen again they have a secondary immune response that gives rise to all of the features associated with the allergic reaction.
Activation of adaptive immune system
In response to a pathogen ——– cells ———– a microbe in a process called ————. The ——– cell changes different ——– molecules on its surface and becomes ———. They then ———- to areas of the body where there are ———. In addition to ——- the cells start to express more —- molecules on their surface to present a ——– from the degraded bacteria on their surface. They then come into contact with —– – cells (not activated) which have —– receptors on their surface. If these ——- receptors are activated they will ——- and drive the ——- immune system by activating different —- cells
This process is the same for when an allergen is presented instead of a pathogen
In response to a pathogen dendritic cells phagocytose a microbe in a process called macropinocytosis. The dendritic cell changes different adhesion molecules on its surface and becomes premigratory. They then migrate to areas of the body where there are lymphocytes (e.g. lymph node). In addition to migration the cells start to express more MHC (major histocompatibility complex) molecules on their surface to present a peptide from the degraded bacteria on their surface. They then come into contact with naive T cells (not activated) which have antigen receptors on their surface. If these antigen receptors are activated they will proliferate and drive the adaptive immune system by activating different T cells
Name the immune cell described below:
Multilobed nuclei
First responders to infection so have receptors on their surface that recognise microbes. When they detect the microbes they are activated. They can degranulate and release contents that kill microbes
Most abundant but short lived.
Phagocytosis
Neutrophils
Name the immune cell described below:
Called granulocytes together
Smaller
Contribute to the secondary immune response
Degranulation
Basophils and eosinophils
Name the immune cell described below:
In the circulation for a day
Phagocytosis and cytokine production
Differentiate into macrophages when they have migrated to the peripheral tissues
Monocytes
Name the immune cell described below:
Innate immune cells
Contribute to secondary immune response and hypersensitivity reactions
Produce cytokines (pro cytokines during acute inflammatory response)
Are plastic = can change their phenotype depending on their environment (e.g. pro inflammatory or anti inflammatory)
Antigen presenting cells (APC)
Macrophages
Name the immune cell described below:
B cell that makes antibodies
In type 1 hypersensitivity reaction they produce iGE antibody
Plasma cell
Name the immune cell described below:
Innate immune cell
Recognise autoantibodies (antibodies against their own self antigens)
Cover the surface of tissues during autoimmune disease
Target cells for destruction by releasing granules
Natural killer cells
Name the immune cell described below:
Primary and secondary response
Long lived
Degranulation and cytokine production
Mast cells
Name the immune cell described below:
Antigen presenting cells
Phagocytosis
Cytokine production
Bridge between innate and adaptive immune response
Dendritic cells
Name the immune cell described below:
Drive adaptive immune response
B and T cells
——— are the primary immune system ——- of type —, — and —- ——— reactions. They have —- heavy chains and — light chains, —– antigen binding sites and —– effector function controlling region.
They are split into —- domains;
—— —— domain referred to as —– regions. They have a highly ——– amino acid sequence which equips the —— with limitless ability to recognise different ——.
——— region referred to as the —- region. The —– —– sequence doesn’t change. this region engages with the —- system. This region can activate ———- as a response of binding to the microbe. There are —- receptors on the —– immune cells which can recognise this region and activate the immune cells.
Antibodies are the primary immune system mediators of type 1, 2 and 3 hypersensitivity reactions. They have 2 heavy chains and 2 light chains, 2 antigen binding sites and 1 effector function controlling region.
They are split into 2 domains;
Antigen binding domain referred to as Fab regions. They have a highly variable amino acid sequence which equips the antibodies with limitless ability to recognise different allergens.
constant region referred to as the Fc region. The amino acid sequence doesn’t change. this region engages with the immune system. This region can activate complement as a response of binding to the microbe. There are Fc receptors on the innnate immune cells which can recognise this region and activate the immune cells.
Heavy chain isotypes - differences in Fc regions
There are – different types of heavy chain isotypes.
Different isotypes of antibodies have different —– and are located in different —– compartments
Type 1 hypersensitivity reaction involves —–.
Type 2 and 3 hypersensitivity reactions involve —– and —-.
The —– receptors on the — cells are specific for each class of antibody.
The Fc —– receptor recognises IgE and the Fc —- receptor recognises IgG.
This means that the —- region engages with different parts of the —– system and drives different —– responses. Therefore you activate different parts of the —– system to eliminate the —– making it a better response.
There are 5 different types of heavy chain isotypes.
Different isotypes of antibodies have different functions and are located in different tissue compartments
Type 1 hypersensitivity reaction involves IgE.
Type 2 and 3 hypersensitivity reactions involve IgG and IgM.
The Fc receptors on the immune cells are specific for each class of antibody.
The Fc epsilon receptor recognises IgE and the Fc gamma receptor recognises IgG.
This means that the Fc region engages with different parts of the immune system and drives different immune responses. Therefore you activate different parts of the immune system to eliminate the allergen making it a better response.
