Antibodies and Gene Rearrangement Flashcards
What is adaptive immunity
It has memory and changes with both time and persistence of antigen.. The secondary response is stronger and more rapid that the primary response.
B cells
B lymphocytes begin in the bone marrow and mature in secondary lymphatic organs such as the spleen and lymph nodes. They produce antibodies and form the humoral (soluble) arm of the adaptive response
Function of the B cells
They produce antibodies and form the humoral (soluble) arm of adaptive response
What is the B cell receptor
A membrane bound IgM molecule that is associated with intracellular molecules that transmit an activation signal via phosphorylation.
What is primary naive response of B lymphocytes
The 1st immunisation with antigen which results in a rise in antigen specific low affinity IgM in blood peaking at 2 weeks post immunisation then diminishes rapidly.
How did T cells originate
T lymphocytes begin as immature lymphocytes that home to the Thymus gland where they mature into functional T cells.
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Function of T cells
Provide cellular adaptive immunity
What is the T cell receptor
The antigen receptor on T lymphocytes. It is an immunoglobin like surface molecule that is coded for by a separate gene locus. The TcR is associated with a number of surface molecule.
B and T
What are you born with
Massive repertoire of B and T lymphocytes. Each lymphocyte represents a different antigen specifity randomly produced by rearrangement of the genes coding for the antigen receptors.
What do B and T lymphocytes each have
Each with unique antibody randomly generated with stacastic repertoire. It generates as many combinatios in hopes of having right antibody (gene recombination)
True or false, all B and T cells are born with the same specifity
False, all born with different specifity, as they interact with different antigens - cross-reactivity.
Where are antibodies formed from
Repeated protein units called Ig domains.
What is the Ig fold
An Ig domain consists of two anti-parallel B-sheets made up on 7 or 9 B strands.
and what does it contain approx
What is the Ig protein domain fold called
B-barrel with ~ 110 amino acids
How is the structure of Ig protein important
It contains a stable shape which is soluble. The loops at the end are not constrained, which can allow amino acid sequences to change without changing the overalll stability of the protein fold.
What is the blue section and what is its function
It is a disulphide covalent bond which keeps the sheets of the Ig protein fixed.
What does the Fc region do in the antibody protein structure
- Helps antibodies connect to the innate immune response.
- This region interacts with cell surface receptors called Fc receptors and some proteins of the complement system.
- This allows antibodies to activate the immune system.
What does the hinge region of the antibody protein structure do
Provides a degree of flexibility which enables the antibody to bind to multiple targets at various distances - which helps when the antibody might not be in the right place.
