6. Immunity with memory Part 3 Flashcards
What is the function of B cells?
Are responsible for the ‘Humoral Immune Response’, which is the specific production of antibodies that are dispatched in the humors (fluids) of the body to stick onto specific antigen that has triggered the response.
What are plasma cells?
Clones of activated B cells that are responsible for making and releasing antibodies.
What are B memory cell (Bm)?
Clones of activated B cells that are metabolically inactive but last a long time (years) in a person’s body, conferring lasting immunity on that person.
What is the function of cytotoxic T cells (Tc)?
Are involved in the cell-mediated immune response, where they find cells which have foreign antigens and kill them, by releasing enzymes which cause the cell to kill itself (apoptosis).
What is the function of helper T cells (Th)?
When selected, release interleukin which stimulates B cells and interleukin that stimulates Cytotoxic T cells to become very active.
What is the function of suppressor T cells (Ts)?
Like helper T cells, these cells regulate the activity of Cytotoxic T cells, but their action is to slow down the Tc cells, preventing them from launching too vigorous of an attack.
What are Natural Killer cells and what is their function?
Are large granular lymphocytes that are very similar to Tc cells in how they interact with target cells, however, they are part of the second line of defence and are non-specific in their action.
-They circulate in the body all the time and kill cells that do not have the normal MHC1 markers that identify cells as ‘self’, but when they do find such cells, they do not become more metabolically active as Tc cells do.
List 5 types of leucocytes:
- Phagocytes
- Neutrophils
- Macrophages
- Dendritic cells
- Mast cells
List 7 types of lymphocytes:
- B cells (Plasma cells, B memory cells)
- T cells (Cytotoxic T cells, Helper T cells, Suppressor T cells, T memory cells)
- Natural killer cells
What is the structure and location of mast cells and what is their function?
- Contain granules of protein called histamine
- Mature mast cells are embedded in connective tissues of the body such as skin, mucous membranes, and the connective tissues that surround blood vessels.
- When mast cells are activated, they ‘degranulate’ releasing their histamine into the bloodstream, causing the blood vessels to dilate and become ‘leaky’ (this is important in a local inflammation response as it assists phagocytes and other immune cells getting to the site of infection)
How do allergies develop?
- IgE antibodies stimulate mast cells in an allergic response.
- Plasma cells are not ‘meant’ to produce many IgE antibodies.
- When they produce too many, it may lead to hypersensitivity (an allergy) to a specific antigen.
Describe how monoclonal antibodies are used in the treatment of cancer:
- Monoclonal antibodies are synthesised in a laboratory and have an antigen-binding site specific for an antigen expressed on the surface of the cancer cells in a patient undergoing treatment.
- Because the antibodies are specific to an antigen found only in cancer cells, the antibodies will seek and bind to the cancer cells, when injected in the body.
- These monoclonal antibodies are given a ‘payload’ that will kill the cells (Eg. They carry a radioactive compound or chemotherapy drug)
- Because they specifically target cancer cells, the highest doses of radiation or chemotherapy will be delivered to cancer cells.
- This means that much lower doses can be given to the patient (overall), which means that it will have fewer side effects, while still being an effective treatment for the cancer cells.
List the things involved in the cell-mediated immune response:
- Tc cells
- Th cells
- Paracrine signaling between leucocytes
What are cytokines and how do they act?
- Are the signaling molecules of leucocytes
- May be transported in the blood or lymph but only act very locally, where the target cell needs to be close to the cell producing the cytokine
What is autocrine signaling?
When a cell signals itself.
