Lymphopoiesis Flashcards
When does the beginning of lymphopoiesis begin and where?
In the foetal liver, first trimester.
Where are B cells produced post neonate?
In the marrow from cell progenitors.
What happens in the marrow during B cell production?
proliferation
maturation of lymphoblast to lymphocyte that express surface immunoglobulin.
What does B cell proliferation produce?
Plasma cells
What is the role of plasma cells?
antibody production
humoral immunity.
Where are T cells produced?
In the marrow
Where do T cells develop?
In the thymus.
What do T cells not produce which B cells do?
Antibodies, immunoglobulins.
What is the role of the T cells?
- production of cytokines
- cell mediated immunity (cytotoxic, helper, suppressor and memory)
What immune response do natural killer cells respond to?
Innate (non-specific) immune response.
How do natural killer cells decide which cells to kill? (2)
- kill by antibody dependent cellular cytotoxicity (ADCC)
- Direct killing of cells ex: virus infected cells or tumours cells without the presence of an antibody.
What hormone is released from the thymus?
Thymosin.
What is the major role of the mature T lymphocyte?
Programmed to recognise one specific type of antigen
What type of immunity are T lymphocytes involved in?
Cell mediated immunity
What is the major role of the B lymphocyte ?
to provide adaptive antibody-mediated immunity ‘humoral immunity’ ex: plasma cells
- each b lymphocyte targets one specific antigen by producing a specific antibody to attach and enable the destruction of a foreign antigen.
What is a speciality in the genes that code for the production of T cells?
These genes that code for the production of B cells (antibodies) - have the facility to slightly change their little segments to give a specific response to whatever threat they come across.
What is produced from every one of the millions of different antigens encountered in life?
That there is one corresponding T and B lymphocyte produced in the body.
What does cell mediated immunity involve?
As T lymphocytes first encounter - become sensitised to antigen.
- macrophages engulf and phagocytose
- clonal expansion.
What needs to happen when a new antigen enters the body?
It needs to be ‘presented’ to the T lymphocyte using APC (diff types incl: macrophages)
What do APC do when presenting?
They transport the most antigenic fragment to their own cell membrane and display it on their surface.
On its journey around the body it will come into contact with the T-lymphocyte that has been processed to target the specific foreign antigen.
What happens when the antigen has been presented to T-lymphocyte by APC?
Clonal expansion of lymphocyte - 4 different types produced.
What are the 4 different types of cells involved in the clonal expansion of the T-lymphocyte?
- memory
- cytotoxic
- helper
- killer
What is the role of memory T-cells?
These cells survive past the initial threat and carry the foreign antigen that has been neutralised.
What is the role of the cytotoxic T cells?
These directly inactivate any cells carrying antigens by attaching themselves to the target cell and releasing powerful toxins = destruction of the target cell carrying the foreign antigen
