vaccines and diseases

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Cards (19)

what are two types of immunity
active
passive
what is a vaccine
a suspension of antigens from a dead or weakened pathogen that stimulate a immune response in body to produce memory cells for immunity
how do vaccines produce long term immunity
produce memory cells that recognise specific antigens and can trigger immune response faster and produce antibodies faster
what does antigenic variation do to vaccines
causes them to be less affective as mutation changes shape of antigen so no longer complimentary to memory cells produced by vaccine so immune response not triggered
what is antigenic concealment
when pathogen hides from immune system by living inside cells or when antigen coats body in host proteins
what is herd immunity
when a sufficiently large proportion of population vaccinated and makes it difficult for pathogen to spread. those not immune protected as unlikely to contract virus as levels in population low
importance of heard immunity
protects those who are unable to be vaccinated
what is active immunity
when antigens enter body and trigger specific immune response and antibodies produced
naturally acquired or through vaccines
produce memory cells that are long live and trigger immune response faster in secondary infection
in primary response to pathogen antibody concentration takes one or two weeks to increase
long lasting
what is passive immunity
person injected with antibodies that kill specific disease
immune response not triggered so memory cells not produced so can not fight of secondary infection
effective for immediate treatment
not long lasting
can be artificial by injection or natural like babies getting antibodies from placenta or breast milk
what does HIV stand for and how is it spread
human immunodeficiency virus it is a retrovirus
spread by exchange of body fluids e.g sex , blood donation , mother to child and sharing needles
structure of HIV 
two RNA strands
reverse transcriptase enzyme
capsid ( protein coat)
attachment proteins
lipid envelope
how does HIV replicate
attachment proteins bind to protein CD4 which is frequently found on helper T cells.
capsid fuses with cell surface membrane
RNA and reverse transcriptase enter cells
reverse transcriptase converts RNA into DNA which then moves into nucleus
HIV uses cell organelles to produce more virus particles
cell releases new HIV particles into blood for further infection
how does HIV affect body
destroys Helper T cells that are used to stimulate b lymphocytes for immune response , so weaken immune system making body more prone to infections as antibodies not produced
development of aids  
after infection of HIV people mainly have flue like symptoms
after several months or year viral DNA replicated by HIV becomes active and destroys helper T cells and antibodies no longer produced
immune system seriously weak and person more prone to infection
uses of monoclonal antibodies
pregnancy test , diagnosing HIV , detecting pathogens and cancers . treating diseases
how do monoclonal antibodies treat cancers
recognises antigens s on cancer cell surface membrane
has complimentary receptors and binds to it
allows immune system to identify cancer or can release treatment to defeat cancer
how are monoclonal antibodies produced
specific antigen injected into mouse
mouse produced lymphocytes which produce antibodies specific to antigen
spleen cells that produce lymphocyte that's wanted removed
cells fused with myeloma cells that are cancerous and fast dividing and produce hybridoma cells which divide
hybridoma cells divide and produce monoclonal antibody
ethics for monoclonal antibodies and vaccines
Against: animal testing on vaccines and monoclonal antibodies seen as unethical
human volunteers are paid and this can cause exploitation and they are at risk of side affects
For: the benefits and lives saved out way the risks
process of Elis test
antigen of interest immobilised in sample
monoclonal antibodies added and bind to specific antigen
apparatus washed to remove unbound antigens
more monoclonal antibodies added that contain colour changing enzymes and these bind to antigens
washed again
complementary substrate added that trigger colour change therefore showing presence of antigen