Immunology and Neurobiology Unit 3 KA 6 Flashcards
Specific Cellular Defences against Pathogens
What are Lymphocytes?
Lymphocytes are white blood cells that carry out a specific immune response
What are Lymphocytes made out of?
Lymphocytes are made out of stem cells in bone marrow
What do Lymphocytes respond to?
Lymphocytes respond to specific antigens on invading pathogens
What are Antigens?
Antigens are molecules (often proteins) located on the surface of cells that trigger an immune response
What are the two types of Lymphocytes?
1) T Lymphocytes
2) B Lymphocytes
What does Antigen binding lead to?
Antigen binding leads to repeated lymphocyte division resulting in the formation of a clonal population of identical lymphocytes
What do B Lymphocytes do?
B Lymphocytes produce antibodies against antigens, leading to the destruction of the pathogen
What are Antibodies?
Antibodies are Y-shaped proteins that have receptor binding sites specific to a particular antigen on a pathogen
What happens when Antibodies become bound to the antigens?
When Antibodies bind to antigens, they inactivate the pathogen
How is the antigen-antibody complex destroyed?
The antigen-antibody is destroyed by Phagocytosis
What happens when B Lymphocytes respond to antigens on substances which are harmless to the body?
When B Lymphocytes have a hypersensitive response and respond to antigens on substances which are harmless to the body it causes an Allergic reaction
What do T Lymphocytes do?
T Lymphocytes destroy the infected body cells by recognising antigens of the pathogen on the cell membrane and inducing Apoptosis
What is Apoptosis?
Apoptosis is programmed cell death
What happens to T Lymphocytes when they attach on to the infected cells?
When T Lymphocytes attach on to the infected cells, they release proteins which diffuse into the infected cells causing production of self-destructive enzymes which cause Apoptosis (cell death)
How are the remains of cells removed after they have undergone Apoptosis?
After a cell has undergone Apoptosis, the remains are removed by Phagocytosis
What happens when T Lymphocytes fail to distinguish between the body cells self-antigens and non-self antigens on infected cells?
When T Lymphocytes fail to distinguish between the body cells self-antigens and the non-self antigens on infected cells it leads to Autoimmune diseases as the T Lymphocytes respond to self-antigens
What happens to some of the cloned T and B Lymphocytes that are produced in response to antigens?
Some cloned T and B Lymphocytes that are produced in response to antigens will survive long term as Memory cells
What do Memory cells do after a second exposure to an antigen?
After a second exposure to an antigen occurs, Memory cells will rapidly give rise to a new clone of specific lymphocytes which destroy the invading pathogen before the individual shows symptoms
Primary vs Secondary Immune response:
1) What is the immune response?
2) What is the antibody concentration?
3) Is the response sufficient?
Primary response -
1) No measurable response for the first few days, then antibody production grows steadily
2) Lower antibody concentration
3) Response is not sufficient in stopping the invading pathogen, individual will display symptoms
Secondary response-
1) Rapidly increasing antibody production
2) Higher antibody concentration
3) Response is sufficient in destroying invading pathogen before the individual shows symptoms
What does the human immunodeficiency virus (HIV) do?
HIV attacks and destroys T Lymphocytes which leads to the development of AIDS
What happens to people with AIDS?
People with AIDS have a weakened immune system and are left more susceptible to infections
