Adaptive Immunity - Antibodies Flashcards
What happens during lymphoid haemopoiesis
lyymphoid precursors in the bone marrow become committed to becoming either T cells or B cells.
Pre-T cells migrate to the Thymus to mature
pre-B cells mature and arise form the bone marrow into the circulation
B cell pregenitors in the bone marrow develop into B cells
When the membrane bound antigen receptor (immunoglobulin) binds to the specific antigen they become plasma cells that secrete immunoglobulins
Recap of Primary and secondary Lymphoid Tissue
Where are cells located, what they do - definition
Primary Lymphoid tissues (yellow) - where cells are made
Bone marrow: all immune cells arise from bone marrow including B cells
Thymus: T cells
Secondary Lymphoid tissues (blue) - where cells work
spleen ( fighting infections come from inside e.g. sepsis, blood borne)
Lymph nodes etc (fighting disease come from outside e.g. water, airborne )
Circulatory system
lymph
blood
where are immunoglobulins (antibodies) found
body fluids, tissues and cells
in B lymphocytes in the intracellular compartment
plasma, serum, interstitial fluid
on phagocytic cells
structure of immunoglobulin molecule
2 heavy and 2 light chain, joined by disulphide bonds
in this structure there are variable and constant regions
Lymphocytes antigen receptor
B cells receptor and T cell receptors
B cells receptor
-Antibodies (immunoglobulins)
-membrane-bound and secreted forms
T cells receptors
-Alpha-beta or gamma-delta
-remain membrane-bound
what are the classes and subclasses of immunoglobuin?
DAGEM
IgD, IgA, IgG, IgE, IgM
IgG1, IgG2, IgG3, IgG4 (but 4 does not activate complement)
IgA1 - secretion IgA2 - active component in mucosal surface
what does each class of immunoglobulin do?
Which Ig class is the primary immune response to an antigen
IgM (IgG later)
Which Ig class is the secondary immune response to an antigen
IgG, IgA or IgE
what are the types of T cells
There are two main types of T-cells:
Helper T-cells stimulate B-cells to make antibodies and help killer cells develop. Th1 - cell mediated cells. Th2 help with antibodies and allergy
Killer T-cells or cytotoxic T-cells directly kill cells that have already been infected by a foreign invader.
T supressor cells - supress the immune system
what are the 3 ways of activating B cells
T-independent, repeating antigens, typical B cells response via B-cell antigen receptor binding to antigen
Difference between B and T lymphocyte
what is somatic hypermutation?
The immune system makes Ig molecules to antigens it hasn’t come across yet. This helps variable regions to modify for a better fit to it’s specific antigen. Shuffling of genes to produce antibodies.
