Viruses & Dat Flashcards
Explain how an ELISA test works
1) Antibodies to PSA placed in test plate
2) Blood from patient added. PSA will bind to antibody if present. Wash plate remove unbound antigens.
3) Antibody with enzyme attached added which will only bind to first antibody if PSA present. Wash plate
4) Colourless substrate added
5) Enzymes converts colourless substrate to coloured if enzyme present, hence, if PSA is present
Explain How Agglutination works
Each antibody has 2 binding sites. Each antibody binds to an antigen on a different pathogen to make a lattice like structure of antigen-antibody complex. This immobilises the pathogen and render a toxin harmless and makes it easier to engulf and destroy the pathogens during phagocytosis
Explain how the Cellular Response works
T cells become activated when antigen is being displayed on surface of own body cells (A.P.C) after phagocytosis. T helper cell with comp. Shaped receptor is activated and releases chemicals which stimulates:
Cytotoxic cells to divide by mitosis which destroy infected body cells which show the antigen on the surface
T memory cells will stay for secondary response if same antigen encountered
More helper T cells to stimulate B cells to produce antibodies in Humoral Response
Explain how the Humoral Response works
B cell with the receptor of comp. Shape to the antigen will become activated (stimulated from chemicals from T helper Cells). Activated B cell divide mitosis to produce genetically identical cells by clonal selection.
Some are Plasma Cells that secrete antibodies called monoclonal antibodies
A few are memory cells which don’t produce antibodies and remain for secondary response.
Antibodies produced bind to the antigen forming antigen - antibody complex and destroy antigen by agglutination
What are monoclonal antibodies?
A large No. Of one type of antibody produced by a clone of plasma cells
What are the uses of Monoclonal antibodies?
Targeting Medication : A therapeutic drug can be attached to the antibody and as the antibody will only bind to a specific antigen, the drug will be carried directly to specific cells for the drug to work on
medical diagnosis - ELISA test
Give 2 ways in which pathogens cause disease agent entering the body of their host?
They produce toxins
Damage the cells and tissues
What is an antigen?
A molecule that triggers an immune response leading to antibody production
Define pathogen
An organisms that causes disease in another organism e.g. Bacteria/Fungi/Viruses
What are the methods the body uses to prevent the entry of pathogens?
- Mucus- Stomach acid- Enzymes
How are pathogens able to cause disease?
Release toxins
What do pathogens do?
- Destroy host cells- Produce toxins
What are antibodies?
Proteins that bind to antigens to kill pathogens
What is the structure of an antibody?
- Antibodies are proteins with a specific primary, secondary and tertiary structure- Antibodies have a variable region and a constant region which are joined by a hinge and held together by disulphide bridges- The antibodies tertiary structure is responsible for the specific variable region which allows the antibody to form antibody-antigen complexes with its complementary antigen
What happens in a secondary immune response?
- The same pathogen with the same antigen infects you- The immune response is faster and stronger because you already have the memory B and T-cells which can divide and carry out the humeral and cellular responses in order to kill pathogens (T) and produce antibodies (B) - Because the pathogen has less time to replicate you feel no symptoms - Antigenic variation and various pathogen strains can prevent this
