The Immune System Flashcards
(15 cards)
Antigens
Molecules that generate an immune response by lymphocyte cells when detected in the body
2 differences between specific and non-specific immune responses
Non=Immediant, same for all pathogens
Specific=Lag time, B&T lymphocytes complementary to pathogen
Cell-mediated response
-Response involving T cells
- Antigens of the destroyed pathogen are placed on the cell surface of phagocyte, making it an antigen-presenting cell
- Helper T cells are attracted to APC
- Once the hT cell is attached, the activated hT cell divides by mitosis and makes large numbers of clones
- The cloned hT cells then:
-Activate B cells
-Stimulate macrophages
-Become memory cells
- differentiate into cytotoxic T cells-release perforin, which pierces holes in the membrane of infected cells, leading to cell death
Humoral response
Involves B cells & antibodies
1. B cells collide with helper T cell receptor
2. Activating B cells to divide rapidly by mitosis to make a large number of cells
3. These differentiate into plasma cells and memory B cells
4. Plasma cells produce antibodies
How antibodies destroy pathogens
- Agglutination- antibodies are flexible so bind multiple antigens together. Making it easier for phagocytes to locate and destroy the pathogens
2.
Primary vs secondary immune response
Primary: Slow, takes time for specific plasma cells to be activated
-Shows symptoms
-Memory cells produced
Secondary: Fast, presence of memory cells
-Stronger than primary, more plasma cells, quicker
-Unlikely to show symptoms
Passive vacines
Given antibodies via injection or received from the mother
-No immune response
-Short term
-Instant protection
-No memory cells
Active vaccines
Exposure to antigens on the pathogen surface
-Immune response
-Long lasting
-Takes time to develop
-Memory cells made
Herd immunity
Most of the population is vaccinated against a pathogen, breaking the chain of infection. So the pathogen is unable to pass from person to person, therefore pathogen disappears
Antibodies
Binds to antigens forming antigen-antibody complex
-Large Y-shaped proteins
-Produced by plasma cells
Memory cells
-Remain in the body for months/years
-Enable a faster response to the same antigen in the secondary immune response
-Greater antibody production as B memory cells can differentiate immediately
How we make monoclonal antibodies
- Immune response stimulated using the antigen
- Specific B cells are harvested
- B cell is fused with a myeloma (tumour) cell
- Hybridoma makes a large number of clones
- Clones produce antibodies, which are collected
- These are then used to treat diseases
Elias test
- Antigen for the pathogen being tested is immobilised to the bottom of the beaker
- Add a sample of blood; if antibodies are present, they bind to the antigens fixed to the beaker
- Wash to remove unbound antibodies
- Add the second antibody with enzyme, which binds to the first antibody
- Add solution; if the solution changes colour, the secondary antibody has bound. Indicating the blood sample is infected with the pathogen
Direct monoclonal antibody therapy
Antibodies attach to cancer cells and prevent chemicals from binding to cancer cells, which enables uncontrolled division. Therefore, prevent cancer growing
Indirect monoclonal antibody therapy
Specific antibodies for cancer cell antigens have a drug attached to them. The drug is delivered directly to the cancer cells and kills them
