Vaccinations Flashcards
what types of antibodies act against pathogens
IgG antibodies
what is the purpose of vaccines
deliver some part or all of a disease organism that imitates the pathogen but is not pathogenic
induces protective immune response
what diseases use live vaccinations
measles, mumps, rubella
what diseases use inactivated vaccines
hepatitis A, influenza, pneumococcal polysaccharide
what diseases use recombinant sub-unit vaccinations
Hepatitis B
what diseases use toxoid vaccinations
tetanus, diptheria
what diseases use conjugate polysaccharide-protein vaccinations
pneumonococcal, meningococcal, HiB
what are live-attenuated vaccines
derived from disease causing virus or bacteria
they are weakened by repeated culturing under stress conditions
they must replicate in the vaccinated person
virus is purified and formulated
what are the advantages of using live vaccines
cheap, adjuvants not necessary
what are the disadvantages of using live vaccines
potential to cause pathology, stability
what are inactivated vaccines
produced by growing bacteria or virus in culture media then inactivating it with heat/chemicals
inactivated vaccines are not alive and cannot replicate; the entire dose of antigen is administered in the injection
vaccines cannot cause disease from infection, even if pt is immunocompromised
first dose does not produce immunity but ‘primes’ the immune system; protective immunity developed after second dose
what are some advantages of inactivated vaccines
generally safer, improved stability
what are some disadvantages of using inactivated vaccines
can be costly, hypersensitivity
what are recombinant sub-unit vaccines
comprised of one antigenic part of the pathogen produced recombinantly (other microbes are programmed to produce the desired antigen component) inactivated subunit vaccine is composed of longer chains of sugar molecules that make up the surface capsule of certain bacteria
what are the antigen components used in recombinant sub-uni vaccines
proteins or surface polysaccharides
what is the immune response to a pure polysaccharide vaccine (recombinant sub-unit)
typically T-cell independant, the vaccines are able to stimulate B-cells without assistance of T-helper cells
DNA vaccines are a type of recombinant vaccine
what are toxoids
forms of chemically altered toxin that are no longer pathogenic
how do toxoid injections work
antibodies produced in the body as a consequence of toxoid administration neutralise the toxic moeity produced during infection rather than act upon the organism itself
toxoids are highly efficacious and safe immunising agents
what are conjugate polysaccharide vaccines
prepared from extracellular fractions (e.g. polysaccharide antigen of cell wall)
polysaccharides often chemically attached to a carrier protein (can be toxoids)
high efficacy and safety
what is a monovalent vaccine
immunises against a single antigen or single pathogen
what is a multivalent vaccine
immunises against two or more strains of the same microorganism or against two or more microorganisms
what is the purpose of stress conditions in the live attenuated vaccine process
they pressure the virus to replicate differently; slower replication and loss of virulence factors
what is the MMR vaccine
passage of live mumps and rubells viruses similar to measles
three separate attenuated viruses are combined in the formulation step
how are inactivated vaccines formulated
whole oathogen is grown and killed (heat/chemical)
how are recombinant sub-unit vaccines made
insert pathogenic gene into host-organism for production
express protective antigen in safe easy-to-grow organism (HepB and HPV in yeast)
purify the antigenic sub-unit and formulate
what is the first stage of conjugate polysaccharide vaccination formulation
surface polysaccharides from pathogen grown and isolated
carrier protein grown separately and purified
what is the second stage of conjugate polysaccharide vaccination formulation
toxins chemically removed from polysaccharide; carrier protein and polysaccharide covalently attached; ‘conjugate’ then purified and formulated
what is the Hib vaccine
haemophilus influenzae type B
conjugated to tetanus toxoid as carrier protein
combined with other vaccines
hib vaccination given to children four times as a result of poor efficacy
what is the pneumococcal conjugate vaccine
pneumonococcus serotypes conjugated to CRM197 as a carrier protein
vaccine contains 13 types of pneumococcus; mixture absorbed on aluminum phosphate and formulated
what is in the formulation of vaccines
active components, adjuvants, antibiotics, stabalisers (MgSO4), preservatives, trace components from production process
what are adjuvants
used in vaccines to keep antigens near site of injection so they can be easily accessed by immune cells
Al(OH)3
AlPO4
what are advantages of adjuvants
enhance immune response, induce protective antibody responses with less antigen, induce broader immune response, overcome weakened immunity
