Lymphocytes Flashcards
What are the 2 types of T-Lymphocyte?
- T-helper cells
- Cytotoxic (killer) T-cells
What type of immunity are T-cells involved in?
cell-mediated
What types of cells can T-helper cells respond to? Give 2 examples
Antigen presenting cells
- Phagocytes, that display proteins from pathogens on their cell-surface membrane
- Infected body cells, which display viral proteins
- cells which present non-self antigens
- cancer cells
What is an antigen?
a molecule/protein on the cell-surface membrane that stimulates an immune response
Once stimulated, what are 4 things a T-helper cell can do?
- become a memory cell
- stimulate phagocytes
- stimulate B-cells
- clones itself, and form cytotoxic T-cells
How do cytotoxic T-cells kill pathogens?
By making holes in their cell-surface membranes
Where are T-cells formed? Where do they mature?
formed in the bone marrow
mature in the thymus (gland)
Where are B-cells formed? Where do they mature?
Formed in the bone marrow
Mature in the bone marrow
What are the 2 types of B-cells?
- memory cells
- plasma cells
Outline how T-cells are involved in the specific immune response to a pathogen
- specific receptors bind to the antigens that have been presented on antigen-presenting cells
- this activates the T-helper cells which then divide by mitosis
- These T-helper cells can do 1 of 4 things when activated
What do plasma B-cells do?
They are involved in the production of antibodies into the bloodstream as part of the primary immune response
How do memory cells work?
They remain in the body after infection. If they come into contact with the pathogen again, then they will turn into plasma cells and produce antibodies. Memory cells are part of the secondary immune system
What is meant by the term ‘monoclonal antibodies’?
Many copies of the same antibody produced by clones
What is clonal selection?
The rapid division and cloning of cells needed to produce antibodies. This occurs once the B-cells have been activated by the T-helper cells
