What are the two types of Lymphocytes?
Lymphocytes are produced from _______ in _______.
homopoietic stem cells, bone marrow
Lymphocytes that have matured but not yet received their antigens are called...
Where does each type of lymphocyte mature?
B-cells mature in bone
T-cells mature in thymus
What are the characteristics of a Naive lymphocyte
- They are fully mature
- Have not received their antigens yet (they don't know their purpose of being)
Naive lymphocytes receive their antigens from
secondary lymphatic organs
What are some secondary lymphatic organs?
- Lymph nodes
What are the primary lymphatic organs?
- Bone marrow
(Where the B & T cells mature)
When T-cells mature, the must first pass through the _______ of the thymus to undergo ________.
cortex, positive selection
In positive selection, the receptors of lymphocytes are checked for _______.
Explain what that means.
- ability to bind to antigens
What happens to a lymphocyte that fails positive selection?
it is tagged for apoptosis
What happens to a lymphocyte that passes positive selection?
It passes through the cortex to medulla of the thymus for negative selection.
In negative selection, lymphocytes are checked for
"self" antigens (if will it bind to cells the body needs)
The ability of the body to deal with a certain amount of lymphocytes that may attach to cells the body needs is called
What happens to lymphocytes that fail negative selection?
Tagged for apoptosis
What happens to a lymphocyte that passes negative selection?
It is released to pick up its antigen from secondary lymphatic organs
The process of positive and negative selection results in a
True or False
Naive lymphocytes have been activated.
B-cells go through negative and positive selection _______ in _______.
locally, bone marrow
T-cells go through negative and positive selection in
True or False
T-cells traveling from bone marrow to the thymus are mature.
The binding of a lymphocyte to an antigen is called
T-cell receptor binding requires an
Antigen Presenting Cell (APC)
What kind of cells can be APCs?
What is MHC?
Major Histocompatibility complex
A group of genes found on the surfaces of cells that help the immune system recognize foreign substances.
How are APCs created?
- a neutrophil or b-cell finds an antigen
- engulfs antigen
- presents that antigen on its surface along with MHC
- MHC+Antigen then bind to t-cell receptor
Once a t-cell is activated, it initates
cell mediated immunity
Cell mediated immunity is when a specific t-cell...
proliferates and differentiates
What is t-cell proliferation and differentiation also known as?
What are the four types of t-cells