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What is an antigen
Foreign protein that triggers immune respone
What is an antibody
A protein specific to an antigen, released by B cells
Outline phagocytosis
pathogen recognized by phagocyte because it’s foreign
pathogen is engulfed by endocytosis
vesicle fuses with pathogen, forming phagosome
lysosome containing lysozyme fuses with it forming phagolysosome and enzyme hydrolyses pathogen and then it is releases via exocytosis
How does vaccination work?
vaccine contains antigen from pathogen
Macrophage presents antigen on its surface
T helper cell with complementary receptor binds to antigen
T helper cell stimulates B cells to undergo mitosis and secrete antibodies
Describe how B-lymphocytes respond when they are stimulated by antigens
B lymphocyte engulfs antigen and becomes antigen presenting
T helper cell with complementary receptor binds to antigen
T helper cell stimulates B lymphocyte to undergo mitosis and make plasma cells which can secrete antibodies and memory cells which can differentiate into plasma cells and secrete antibodies
Suggest why it is advisable for people to be vaccinated against influenza every year
Influenza mutates so its antigens change
So influenza antibodies need replacing
Describe cell-meditated immunity
T helper cell with complementary receptor binds to antigen on antigen presenting cell
T cell clones by mitosis to:
stimulate phagocytosis and mitosis of B cells, and activate cytotoxic T cells and become memory cells
How are monoclonal antibodies made ?
Why are they called monoclonal ?
mouse injected with vaccine
B cells are collected and fused with tumor cells
forms hybridoma and then antibodies are collected
Monoclonal → made from single group of identical B cells
Give two ways pathogens might cause disease when they enter the body
release toxins
damage / kill cells
Why are antibodies specific ?
It has specific primary structure meaning its tertiary structure is also specific so it is only complementary to one antigen
Describe the replication of HIV
HIV’s attachment proteins bind to host helper T cell
capsid is release and reverse transcriptase and RNA is released into it’s cytoplasm
reverse transcriptase makes complementary DNA strand from RNA
double stranded DNA is made and inserted into human’s DMA
What is herd immunity
Vaccinating a large amount of the population so most of the people are immune and the virus can’t spread
Difference between active and passive immunity
Active is long term while passive is short term
Active takes longer while passive is faster
Active involves memory cells while passive doesn’t
Active involves antibodies from plasma cells while passive involves antibodies from outside source
