CH12 specific immune system Flashcards
1
Q
What is an antigen
A
- cell markers
- present on all cells
- trigger an immune response, involving production of antibodies
2
Q
What is an antibody
A
- y shaped glycoprotein called immunoglobulins that bind to a specific antigen
- bind with antigens with a ‘lock and key’ mechanism
- forms an antigen-antibody complex
3
Q
What is the structure of an antibody
A
- made up of two heavy chains and two light chains
- chains held together by disulfide bridges and also disulfide bridges are present within polypeptide chains
- binding site is an area of 110 amino acids on both heavy and light chains (variable region which gives specificity)
4
Q
How do antibodies defend the body
A
- antibody acts as an opsonin so complex easy engulfed by pathogens
- most pathogens can no longer effectively invade host cells once part of antigen-antibody complex
- act as agglutinins causing antigen-antibody complexes to clump together
- act as antitoxins
5
Q
Where do b lymphocytes mature
A
Bone marrow
6
Q
Where to t lymphocytes mature
A
Thymus gland
7
Q
T-helper cells
A
- have CD4 receptors on cell-surface membranes which bind to surface antigens on apc’s
- produce interleukins which stimulate activity of B cells (increases antibody production, stimulates production of other types of T cells and attracts and stimulates macrophages to ingest pathogens with antigen-antibody complexes)
8
Q
T killer cells
A
- destroy pathogen carrying antigen
- produce chemical called perforin which kills pathogen by making holes in cell membrane so is freely permeable
9
Q
T memory cells
A
- part of immunological memory
- if meet antigen for a second time, they divide rapidly to form a huge number of clones of T killer cells that destroy pathogen
10
Q
T regulator cells
A
- suppresses immune system acting to control and regulate it
- stop immune response once pathogen has been eliminated
- makes sure body recognises self antigens and doesn’t set up an autoimmune response
11
Q
Plasma cells
A
- release antibodies to a particular antigen
12
Q
B effector cells
A
- divide to form plasma cell clones
13
Q
B memory cells
A
- provide immunological memory
- enable body to provide a rapid response to a pathogen carrying antigen if already been seen before
14
Q
Cell mediated immunity
A
- t lymphocytes respond to cells of organism that have been changed in some way eg, by antigen processing or mutation
- receptors on some t helper cells fit antigens on apc’s and are activated
- produce interleukins, which stimulate more t cells to divide rapidly by mitosis
- cloned t cells: t memory, interleukins to stimulate phagocytosis or b cells to divide or development of t killer cells
15
Q
Humoral immunity
A
- body responds to antigens found outside cells and produces antibodies
- when pathogen enters body, a b cells with complementary antibodies will bind to antigen and engulfs to become an apc
- t helper cells bind to apc, and produces interleukins to activate b cells, which divide by mitosis to give clones of b cells
- clones cells produce antibodies or develop into b memory cells
16
Q
Autoimmune disease
A
- immune system stops recognising ‘self’ cells
- starts to attack healthy body tissue
