The Immune Response Flashcards
(21 cards)
What are the main stages of the immune response
1.phagocytosis
2. T-Cells
3. B-Cells
4. Antibody production
What is a phagocyte
A macrophage, a typed of white blood cell that carries out phagocytosis
Where are phagocytes found
In the blood and in tissues
Explain phagocytosis
A phagocyte recognises the foreign antigens on a pathogen
The cytoplasm of the phagocyte moves round the pathogen engulfing it - endocytosis
The pathogen is now contained in a phagocytic vacuole in the cytoplasm of the phagocyte
A lysosome fuses with the phagocytic vacuole and the lysozymes break down the pathogen
The phagocyte the presents the pathogens antigens on its surface to activate other immune system cells, the phagocyte is acting as an antigen presenting cell
The waste products are released from the cell - exocyosis
Tell me about stage 2 of the immune response
This is the T-Cell, this is another white blood cell it has receptor proteins on its surface that bind to complementary antigens presented to it by phagocytes. This activates the T-cell, there are different types of T cells
What is cell mediated immunity
When a T cell binds to an antigen the T cell is stimulated to divide and produce clones
What are the different types of t helper cells
Cytotoxic T cells
T helper cells
Memory cells
Explain what a cytotoxic T cell is
The bind to virally infected cells and produce proteins called perfoins which make holes in the cell surface of infected cells and kill them they destroy cancer cells
Explain what a t helper cell is
Helps other cells destroy infected cells
What are memory cells
They are t-cells that remain in lymph nodes and respond rapidly to future infection with the same antigen
Tell me about b cells
They are a type of white blood cell which are covered in antibodies, each b cell has a different shaped antibody on its membrane so it binds to different antigens. When the antibody on the surface if b cell meets a complementary shaped antigen it binds to it, the substances releases from the T cell helps activate b cells this process is called clonal selection, the activated b cell divides into plasma cells
What is an antibody
A y shaped protein, 4 polypeptide chains joined by a disulfirame bridge, they have a tertiary structure
Each chain has a variable and constant region
Each antigen has 2 identical antigen binding sites, they are specific and bind to one type of antigen only
What is clonal selection
The immune system can. Are 10^15 different types of antibody
A few b cells that can make each type of antibody are produced
When these cells encounter an appropriate antigen they divide and form clones
The clones (plasma cellls) produce antibody’s which are specific to one antigen
How do antibodies help destroy pathogens
The antibodies bind to the antigens on the surface of the pathogen, because of the 2 antigen binding sites, each antibody binds to two pathogens
The pathogens clump together which is agglutination
Phagocytes are attracted to the climbs and ingest and destroy them
What are monoclonal antibodies
Identical copies of an antibody produced by plasma cells
What happens when an antibody binds to an antigen
Antigen-antibody binding complex
Explain what a cellular response is
T cells and other immune system cells which interact with phagocytes
Explain the humoral response
B cells and clonal selection and the production of monoclonal antibodies
Tell me about the primary response
When an antigen enters the immune system for the first time it activates the immune system. The primary response is slow because there are no many b cells that can make the antibody needed to bind to it, eventually the body produces the right amount of antibody’s to overcome the infection, the infected person will show symptoms. Then memory cells are produced which remain in the body for a long time
Tell me about the secondary response
When the same pathogen enters the body again the immune system will produce a quicker stronger immune response as memory cells are activated and divide into plasma cells that produce the right antibody to the antigen. Memory T cells are activated and divide into the correct type of T cells to kill the cell carrying antigen no symptoms are shown
