disease and the immune system Flashcards
what is an antigen
a molecule that triggers an immune response when detected by the body
what is a phagocyte
a type of white blood cell
whats a lyzozome
enzymes that come from lysosomes
what type of cell is a t cell
white blood cell
what do t cells have on their surface and why
receptor proteins that bind to complementary antigens presented by phagocytes
what do T helper cells do
release chemical signals to activate and stimulate phagocytes and cytotoxic t cells
what to cytotoxic T cells do
kill abnormal and foreign cells
what type of cells are B cells
white blood cells
what are B cells covered with
antibodies
what is clonal selection
after antibodies bind to antigens substances from helper t cells activate B cells
what do activated B cells divide into
plasma cells
what do plasma cells secrete
monoclonal antibodies
the specificity of an antibody depends on what
its variable regions which form the antigen binding sights
what is the cellular immune response made up of
t cells and other immune system cells they interact with
whats the humoral immune response made up of
B cells, clonal selection and production of monoclonal antibodies
what is the primary immune response like- why
slow and weak - there arent many b cells to bind with
what gets left over after the primary immune response
memory cells
what is the secondary immune response like
quick and strong
why is the secondary immune response faster
memory B cells can divide into plasma cells fast and memory t can divide fast enough to kill cell carrying antigen
what do vaccines contain
antigens that cause your body to produce memory cells against a particular pathogen
describe what herd immunity means
vaccines protect individuals who have had them and reduce occurance of disease
how can vaccines be taken
injected or oral
whats a disadvantage of taking vaccines orally
they can be broken down by enzymes
antigens on the surface of pathogens activate what kind of response
primary immune response
when does antigenic variation occur
when a pathogen changes their surface antigen
what can antigenic variation be difficult for
vaccinations
what is active immunity
when your immune system makes its own antibodies after being stimulated by an antigen
what is natural active immunity
when u become immune after catching a disease
what is artificial natural immunity
when you become immune after youve been given a vaccination
what is passive immunity
when you have been given antibodies made by a different organism
what is natural passive immunity
when a baby gets antibodies from mother in placenta and breast milk
whats artificial passive immunity
when u become immune after being injected with antibodies from someone else
which type of immunity requires exposure to antigen
active
which type of immunity takes a while for protection to develop
active
which type of immunity produces memory cells
active
which type of immunity provides longer term protection
active immunity
what is a monoclonal antibody
antibodies produced from a single group of genetically identical B cells
what special antigens do cancer cells contain
tumour markers
what do monoclonal antibodies do to cancer cells
bind to tumour markers
what can antibody-antigen complexes for tumour markers do
allow anti-cancer drugs to only accumulate in one area
what does the application area of a pregnancy test contain
antibodies for hCG bound to a blue bead
what happens to the pregnancy test when someone urinates on it
and hCG will bind to antibodies
how does a positive pregnancy test result show
hCG carried up stick to immobilised area concentrating it
what can the ELISA test be used to test for
pathogenic infections, allergies or anything that an antibody can be made for
what is the first step of the ELISA test
add test sample from patient to a beaker
what is the second step of the ELISA test
wash the sample to remove any unbound test sample
whats the 3rd step of the ELISA test
add antibody complementary in shape to antigen and then wash any unbound antibody
what is the 4th step
add a second antibody- which has enzyme attached complementary in shape to first antibody
whats the 5th step of ELISA test
add colourless substrate sample
whats a positive result for ELISA test
is liquid goes from colourless to a colour then antigen is present
what are some ethical issues with monoclonal antibodies
antibodies require mice to produce them
why might testing vaccines on people be an ethical issue
volunteers might put themselves at unescesary risk of contracting the disease
what happens when u contract aids
the immune system deteriorates until it fails
what cells does HIV invade and are hosted in
it invades helper T cells
when do people with HIV develop AIDS
when number of helper T cells reach a critically low level
what is in the centre of a virus
genetic material and some proteins
what encloses the genetic material in a virus
the capsid
whats the membrane of a virus called
the envelope
what sticks out of a virus and whats their job
attachment proteins - attach to host helper t cell
where does HIV replicate
inside the helper T cells
Are phagocytes specific or non specific
Non- specific
Are lymphocytes specific or non specific
Specific
Where are phagocytes found
In blood and tissues
What kind of response is phagocytosis
Non specific
Describe the stages of phagocytosis
Debris or chemicals released by pathogens attract phagocytes
Receptor binding points on surface of phagocyte attach to antigens
Phagocyte changes shape and moved around pathogen and engluf
Pathogen is contained within a phagosome
Lysosome will fuse to pathogen and release its contents
Lytic enzyme hydrolyses pathogen
Where do t cells mature
Thymus
What kind of response involved t cells
Cell mediated
Describe a cell mediated response
Antigens are positioned on cell surface
Helper t cells attach to antigens
This activates helper t cells to divide by mitosis
Helper t cells differentiate into other cells
Describe how HIV is replicated
Attachment proteins attach to receptors on helper T
RNA enters cell
Reverse transcriptase converts RNA to DNA
Viral proteins produced
Virus assembled and released
What are the 4 different species that can be recognised as non self
Pathogens
Cells from other organisms of same species
Abnormal body cells
Toxins
Describe the role of antibodies in producing a positive result in ELISA TEST
Antibodies attach to complementary antigen
Antibody with enzyme attached
Antibody attaches to antigen
Colour changes
What is the role of antibodies in stimulating phagocytosis
Bind to antigen
Causes clumping
