12.6 Specific Immune System Flashcards
What’s an advantage and disadvantage of the specific immune response (active/acquired immune response)
advantage: if the same pathogen enters the body again, the body is really quick at responding with memory cells
disadvantage: it can take up to 14 days for the first response to battle the pathogen
What’s the structure of antibodies
y-shaped glycoproteins called immunoglobulins; these bind to a specific antigen on a pathogen;
2 identical polypeptide chains known as HEAVY chains and 2 LIGHT chains held by disulphide bridges;
antibodies bind to proteins with a ‘lock and key’ mechanism;
binding site is 110 amino acids on the heavy and light chains (called VARIABLE region);
hinger region allows antibody to be flexible so it can bind to 2 antigens.
through what 3 ways do antibodies defend the body
- neutralisation
- acting as anti-toxins
- agglutination
what’s neutralisation
antibodies called anti-toxins can bind to toxins produced by pathogens; this prevents the toxins affecting human cells, so toxins are neutralised.
what’s agglutination
each antibody has 2 binding sites so can bind to 2 pathogens; the pathogens become clumped together. Phagocytes can then phagocytose the pathogens at once. Antibodies that do this are known as agglutinins.
How do antibodies prevent pathogens binding to human cells
antibodies bind to antigens on pathogens so they may block the cell surface receptors the pathogen needs to bind to the human cell. The pathogen can’t bind to host cells as a result.
What’s the 2 different of lymphocytes
T lymphocytes (mature in Thymus gland) and B lymphocytes (mature in bone marrow)
What are the types of T lymphocytes
killer, memory, helper, regulator
what do T killer lymphocytes do
produce perforin which perforates the pathogen, therefore, destroying it
what do T memory lymphocytes do
if they meet the same pathogen again, it rapidly divides to form T killer cells
what do T regulator cells do
ensures the body recognises ‘self’ antigens; prevents autoimmune response
what do T helper cells do
they have CD4 receptors which bind to antigens on APCs; produce interleukins (type of cytokines) to act as a signalling molecule.
what are examples of B lymphocytes
effector, memory, plasma cells
What do B memory lymphocytes do
immunological response; rapid response when a similar or same pathogen is encountered a second time
what do plasma cells do
produce antibodies for a certain antigen/pathogen; can produce 2000 a second into the bloodstream
what do B effector cells do
divide to form plasma cell clones
what are the 2 types of specific response the immune system can produce
cell mediated and humoral
what’s cell mediated immunity and what does it fight against
involves highly specialised cells that target pathogens inside cells. Fights infections and early cancers. Where T-lymphocytes respond to cells in an organism that have changed in some way
What do T-lymp. do in cell mediated immunity
it has receptors on its surface which bind to antigens presented by APCs when they have complementary shapes; this activates the T-lymp.
What’s the process of cell mediated immunity
- (from non specific response) macrophages engulf and digest pathogens in phagocytosis, process the antigens from the surface to from APCs.
- receptors on some of the T helper cells fit the antigens; these produce interleukins, stimulates T cells to divide; from identical clones to carry same antigen to bind to pathogen.
- the cloned T cells may:
- develop into T memory cells
- produce interleukins for phagocytosis/B cells to divide
- develop T killer cells
What do cloned T-lymphocytes do in cell mediated immunity
they may:
- develop into T memory cells
- produce interleukins to stimulate phagocytosis
- produce interleukins to stimulate B cells to divide
- stimulate T killer cell development
what’s humoral immunity
response targets pathogens in the body fluids with antibodies on the surface of B-lymphocytes.
When there’s a pathogen complementary to a B-cell antibody, it will engulf it and become an APC.
What is clonal selection in humoral immunity (pt. 1 of humoral process)
A T-helper cell will bind to the B cell APC; at this point the correct antibody is selected for cloning
What’s clonal expansion (pt. 2 of humoral process)
Interleukins produced by the activated T helper cells activate B cells; these B cells replicate through mitosis to make clones of plasma cells (with the correct antibody) and B memory cells
What is the primary and secondary immune response (pt. 3 & 4 of humoral response)
Primary: cloned plasma cells produce antibodies that fit the antigens on the pathogen and disable them (agglutinins/opsonins).
Secondary: cloned B cells develop into B memory cells so if the pathogen reoccurs, the body will be quicker at responding with the correct antibody.
What is an autoimmune disease
When the immune system stops recognising ‘self’ cells and starts to attack healthy body tissue. Can be genetic, or a mild pathogen not being treated properly, T regulator cells not working effectively.
Treatments may be immunosuppressants but they deprive natural body defences.
Examples include type 1 diabetes, lupus
