B-Cells and T-Cells. Flashcards
What are the two main types of lymphocites? and describe each one of them.
- B-cells: stay in the bone marrow and mature there.
- T-cells: move out of the bone marrow, and mature in the thymus.
explain where B cells stay and mature.
They stay in the bone marrow, and then mature also in the bone marrow.
Explain where T-cells stay and mature.
they move out of the bone marrow, and mature inside the thymus.
Explain the process by which a B-cell clones.
1.The naive B-cells receptors, bind to the complementary antigens on the pathogen.
2.The B-cell internalises the pathogen, and processes the antigen. It then presents the processesd antigen on its surface.
3. A helper T-cell with a receptor complementary to the processed antigen, then binds to the processed antigen.
4. The helper T-cell then releases some chemicals, which stimulate the B-cell to clone.
5. Once the clone of the B-cell is formed, the B cell DIFERENTIATES into two different cells:
Plasma cells, and memory cells.
How long does a plasma cell survive?
It can only survive for a couple days.
what does a plasma cell secrete?
A protein called an antibody.
state what is meant by the term antibody?
an angibody is a protein secreted by a plasma cell, produced by naive B-cells in response to the presence of a specific antigen.
what does an antibody do?
It contributes to the destruction of pathogens.
explain what determines the structure of the antigen binding site.
It is due to the antibodies tertiary structure.
What do the chains in an antibody consist of of, and what are those components held together by?
They consist of amino acids, which are held together by peptide bonds.
Each chain is a polypeptide chain.
what is an antigen-antibody complex?
when an atingen binds to an antigen binding site, we say they form and antigen-antibody complex.
What is a monoclonal antibody?
Antibodies with the same tertiary structure, which are produced from cloned B-cells.
Explain and describe agglutination.
Antibodies have two antigen binding site, which means they are capable of binding two antigens at once.
And so, when monoclonal antibodies encounter a group of pathogens , with complementary antigens. They bind to the antigens , which causes the pathogens to clump together.
What are the effects of agglutination.
- Makes it harder for the pathogens to move throughout the body.
- Makes it easier for phagocytes to locate them, and destroy a large number of pathogens at once.
How long can memory cells survive in our body?
for years, even decades.
How do memory B-cells function in the body?
They remain, in case the same non-self cell , with the familiar antigen, invades again.
If a pathogen does RE-enter, the memory B-cells act the same way as naive B-cells.
Outline and explain the two main differences between the naive B-cell response, and the memory B-cell response.
- Due to the fact that memory B-cell remembers the pathogen , they respons much quicker than naive B-cells.
- Because the memory B-cells, outnumber the naive B-cells. Cloning the memory B-cell, results in more plasma cells per unit of time, thus more antibodies per unit of time.
state what is meant by antigen variability.
The ability of antigens to mutate, and vary their shape, is known as antigen variability.
explain the effect of antigen variability on the memory B-cells response.
Memory B-cells will be useless, because antigen is not complementary to the receptors of the B-cell.
This means no new plasma cells are produced.
Naive B-cells, now have to start all over again, which takes alot more longer.
explain what a primary immune response is.
It is the first time our body encounters a pathogen.
It involves naive Bcells.
explain what a secondary immune response is.
It is when our body re-encounters a pathogen.
-Involves memory B cells.
What do we call the entire process ( including both primary and secondary immune response)?
The Humoral response.
