Specific immune response Flashcards
(14 cards)
Define cell-mediated response:
Mediated primarily by T cells rather than antibodies secreted by B cells
What are the 2 types of lymphocytes?
T cells: mature in thymus gland + in cell mediated response
B cells: mature in bone marrow + humoral reponse –> produce antibodies
WHat are the specific types of T-cells:
T helper: receptors on cell surface bind to complementary antigens on APC. –> produce interleukins –> stimulate B cells/phagocytes
–> can form memory cells + T killer cells.
T killer: kill abnorma/foreign cells –> produce perforin: holes on cell surface membrane –> freely permeable + cause cell death
T regulator: suppress immune system after pathogen destroyed. –> helps prevent immune system from attacking body cells
T memory: provide long term immunity against specific pathogens: rapid response of body re-infected.
Describe stages of cell-mediated response:
T helper cell complementary receptor to APC bind to antigen. –> clonal selection
T help activated –> divide by mitosis to form clones
–> clonal expansion
Carry out different functions:
Develop into T memory cells
Stimulate phagocytosis –> produce interleukins
Stimulate division of B cells
What is the humoral response?
Involves production of specific antibodies to destroy pathogen.
B-lymphocytes.
Describe the humoral reponse:
B cell with complementary antibody binds toi antigen on pathogen.
B cell engulfs pathogen –> BAPC
Clonal selection: T helper bind to B cell –> activates
Clonal expansion: activated B cell divides by mitosis –> form plasma + memory cell clones
Cloned plasma cell produce + secrete specific antibody –> complementary to antigen on pathogen surface.
–> attach to antigen on pathogen + destroy them.
What are the types of plasma cells made?
Agglutitins: clump pathogens/toxins together –> detected by immune system
Opsonins: Tag pathogen –> easier recognition engulfment
Anti-toxins: counteract toxins released by bacteria
State difference between primary + secondary response:
Primary: when body exposed to pathogen for first time.
–> slow + infected individual experiences symptoms of disease.
Secondary: When body exposed to same pathogen before.
–> faster + stronger –> pathogens destroyed b4 any symptoms appear.
conc of antibodies in secondary > primary
Describe primary immune response:
Antibody production slow after exposure (longer lag phase)
Conc of antibodies slowly increase.
–> very few B cells specific to pathogen’s antigens.
Takes time for B cells to divide to plasma cells to produce correct antibody –> symptoims of disease experienced
B cells –> memory cells: immunity
Describe secondary immune response:
- Production of antibodies much quicker after exposure to pathogen (shorter lag phase)
- Conc of antiobodies increase quickly
- Memory B cells recognise pathogen’s antigens + quickly divide into plasma cells
- Plasma cells secrete larger number of antibodies to quickly destroy pathogen before individual experiences any symptoms
- Memory T cells –> T killer –> destroy pathogen
What are autoimmune diseases?
Give examples:
Body cannto recognise ‘self’ antigens starts attacking them. –> leads to breakdown of healthy tissues.
Type 1 diabetes: immune system attacks insulin-secreting cells (B cells) of pancreas. –> lack of insulin
Lupus: attack in connective tissue –> inflammation
Rheumatoid arthritis: attack cells in joints –> cause pain + inflammation
What are antibodies?
Y-shaped glycoproteins w/ 4 polypeptide chains
2 heavy
2 light
Held together via disulphide bridges
What are the regions in antibody?
Constant: same for all antibodies + binds to receptors (B cells).
**Variable **: Different to each antibody –> shape complimentary to specific antigen
–> part of antibody that binds to antigen
Hinge: allows antobody to be flexible –> can bind to multiple anitgens at once.
State functions of antigens:
Agglutination of pathogens: clumping pathgens = easier phagocytosis
Neutralisation of toxins: when antibodies bind to toxins to inactivate them.
Preventing pathogens from binding: when antibodies bind to pathogens to stop them from infecting body cells
