Immunology Flashcards
What are the uses of monoclonal antibodies? (5)
- Research
- Diagnosis
- Killing specific cells
- Targeting drugs
- Immuno assays (ELISA)
Ethics of a vaccine? (4)
- Testing on animals/humans
- Side effects
- Compulsory?
- Only available to those who can afford it?
What is a vaccine?
Antigen from dead pathogen
Differences between passive immunity + active immunity? (5)
Passive immunity:
- No exposure to antigen
- Antibody is given (mother, injection) whereas…
- No memory cells produced
- Short term
- Fast acting
Explain how HIV affects production of antibodies when AIDS develop in a person? (3)
- Less antibodies produced
- Destroys TH cells
- Few B cells activated so dont undergo mitosis
State 3 roles of a T Helper Cell?
- Specific TH cell binds to the antigen presenting cell
- Releases cytokines that attract phagocytes to area of infection
- Activates specific complementary B cell
Describe how HIV is replicated ONCE INSIDE TH cells? (4)
- RNA converted into DNA using reverse transcription
- DNA inserted into genome
- DNA transcribed into mRNA
- This is translated into viral/HIV proteins
Describe how a person infected with HIV will develop AIDS (if untreated) and die of secondary infections? (4)
- High viral load leads to increased destruction of TH cells
- Less activation of B cells/ TC cells
- Less production of plasma cells + antibodies
- Less able to destroy pathogens
When is a person/organism infected by a virus such as HIV?
The moment the viral DNA is inserted into the host cells genome
Describe role of antibodies in producing a positive result in an ELISA test? (4)
- Antibody binds to complimentary antigen
- Antibody with enzyme attached is added
- Antibody attaches to antigen
- Substrate added + colour changes
What threatens herd immunity? (3)
- Low vaccine uptake
- Mutation of pathogen
- Vaccine doesn’t produce longterm immunity
Describe the structure of HIV?
Different antibodies from the same organism bind to different antigens. Explain why? (3)
- Variable region of each polypeptide has a different tertiary structure
- Which provides a specific antigen binding site with specific shape
- So only complimentary to specific antigen to form an antigen-antibody complex
Why are some antibodies referred to as monoclonal?
Antibodies produced from a single clone of B cells
What is antigenic variability?
Gene mutations in pathogens that leads to change in tertiary structure of antigen specific to B cell so no longer complimentary so difficult to develop vaccine against
Describe + explain the role of antibodies in stimulating phagocytosis?
Optimisation - Bind to antigen
Agglutination - Antibodies cause clumping or attract phagocytes
Antibody Structure?
Explain how the humoral response leads to immunity? (3)
- B cells specific to antigen reproduce by mitosis
- B cells produce plasma + memory B cells
- Second infection produces antibodies in larger quantities + more rapidly
When a vaccine is given to a person, it leads to the production of antibodies against a disease-causing organism. Describe how? (6)
Describe how HIV is replicated? (5)
- Attachment proteins attach to receptors on TH cell
- RNA enters cell
- RNA in converted by reverse transcriptase to DNA
- Viral protein/capsid is produced
- Virus is assembled + released
What do attachment proteins of HIV do?
Bind to host cells in order to infect them.
What do TH release? What does this do? (2)
Cytokines - attract phagocytes to area of infection
- activate TC
What is cell-mediated immunity? (4)
- Specific TH cell receptor binds to complimentary antigen presented on APC + TH becomes activated
- Cloning of APC by mitosis
- These cloned cells differentiate into different TH like: Cytotoxic killer T cells (TC), Memory TH cells, TH cells
- TH cells locate + destroy infected body cells by releasing perforin which creates holes in cell surface membrane to destroy APC
What type of cells, other than pathogens, can stimulate an immune response?
- Cancer cells
- Cells infected by virus
- Cells from transplants
Describe the non-specfic defence mechanism the body may launch against pathogens? (5)
- Pathogen is engulfed by phagocyte
- Engulfed pathogen enters cytoplasm of phagocyte in a vesicle
- Lysosomes fuse with vesicle releasing digestive enzymes
- These enzymes break down pathogen
- Waste materials are ejected from cell by exocytosis
What are antigens?
Forein protein that stimulates an immune response that results in the production of a specific antibody
Give 2 ways that pathogens cause harm/disease?
1) Produce toxins (proteins) wich directly damages tissues
2) Replicate inside + destroys host cells
NMO is a disease that leads to damage of nerve cells. A person with NMO produces anti-AQP4 antibodies that attack these nerve cells.
Explain why the anti-AQP4 antibodies only damage these cells? (4)
- Antibody has a specific tertiary structure
- has binding site/variable region that is only complimentary to ONE antigen
- Antigen to this antibody is only found on these nerve cells
- So antibody forms an antigen-antibody complex with these nerve cells
What is a monoclonal antibody?
Antibodies produced from a single B cell clone
