vaccines, disease and monoclonal antibodies. Flashcards
what are the types of vaccines?
live attenuated
inactivated
what do vaccines do?
produce long term immunity
cause memory cells to be created.
stronger secondary response.
generally harmless.
antigenic variation
the variation due to major changes in the antigens of pathogens causes the vaccines to not trigger an immune response.
too many antigens on cell surface membrane makes it difficult to produce vaccine which ould prompt the immune system quickly enough.
antigenic concealment
this occurs when the pathogen hides from the immune system by living inside cells.
or when it coats itself in host proteins or by parisiiting immune cells such as macrophages and T cells (e.g. HIV) by remaining in parts of the body witch are difficult for vaccines to reach. e.g. small intestine.
live attenuated vaccines
whole pathogens
weakened - antigens can be recognised
stronger and longer primary immune response
unsuitable for people with weak immune system
e.g. MMR measles mumps and rubella
inactivated vaccines
whole pathogens witch have been killed
do not contain living pathogens and can not cause disease.
not as strong or long lasting (kinda sucks in comparison)
booster may be required or redose ( you better not fear needles)
some people may have allergic reactions which can leangthen the immune response
e.g. polio.
Herd immunity
sufficiently large proportion of the pop has been vaccinated and are therefore immune.
those who are not immunised are protected
it is important as it allows those who cannot be vaccinated to be protected
the proportion of people to reach ‘sufficient’ differs per disease.
Eradicating disease
some pathogens are simply complicated. this means that a vaccine has not been developed.
too few in the community have been vaccinated.
Unstable political situations.
lack of public health facilities.
active immunity
antibodies are produced
specific immune response is triggered
naturally or artificially acquired
produces memory cells for long term immunity.
promary response one or two weeks, the antibodies increase in numbers. much faster in secondary response.
passive immunity
no antibodies produced
no memory cells
artificial
injection or transfusion of the antibodies
used when you do not have time to get active immunity.
natural passibe immunity occurs when foetuses recieve antibodies across placenta.
babies receive the initial breast milk from mothers.
passive vs active immunity
active - passive
antibodies produced by body: yes - no
time for antibodies to produce: 1-2 weeks - immediate
presence of memory cells: yes - no
induced by:
natural exposure to pathogen - antibodies reciebed from another organism.
artificial: vaccination - antibodies manifactured and injected or transfused into organism (monoclonal antibodies delivered by blood transfusion)
HIV some facts
unable to survice outside of human body
transmitted by direct exchange of body fluids
HIV structure
2 RNA strands
protiens
protien coat (caspid)
viral envelope consisting of a lipid bilayer and glycoprotiens
HIV what does it do to T-cells.
infects helper T cells
lymphocytes usually seek out and destroy pathogens
HIV repeatedly changes it’s protien coat.
HIV replication
viral RNA enters cell
ciral reverse transcriptase enymes produce a DNA copy of the viral RNA
the DNA copy is inserted into the chromosome of the cell.
each time the cell divides, it coppies the viral DNA
the infected cells remain normal as viral DNA is inactive.#
Viral DNA becomes active later in time.
takes control of the helper T cells
more HIV particles are produced.
Kills the helper T cells
as a result, thousands of HIV particles are released which infect other helper T cells.
reduces the number of helper T cells.
B cells no longer activated
no antibodies are produced
reduced ability to fight off infections ( eventially leads to AIDS)
