vaccines – Chemistry Flashcard

what was the first live natural viral vaccine? who developed it? how?
variolation which was sometimes successful, sometimes induced lethal smallpox. this was developed by jenner who noticed that milkmaids infected with coxpox got less smallpox
how did the crude coxpox vaccine that jenner developed induce a smallpox immunity?
cowpox and smallpox share some surface antigens and immunization with cowpox induces antibodies against surface antigens for both cowpox and smallpox (cross-reactive antibodies)
how can’t jenner’s strategy be applied to most pathogenic viruses? what do most viral vaccines today consist of?
most pathogenic viruses have no “safe” immunologic counterpart. most viral vaccines today consist of killed, inactivated, or live attenuated virus
what are live attenuated viral vaccines? how are they made?
viruses mutated to the point of being unable to grow in human cells, therefore no longer pathogenic in humans. they are usually made by growing the pathogenic viruses in cells from a non-human species and selecting for variants that grow better to fit the non-human host and less fit for human hosts
what are examples of live attenuated viral vaccines?
measles, mumps, oral polio, yellow fever, influenza, chicken pox, rotavirus
what are the adavantages of live attenuated viral vaccine?
better immunity b/c the vaccine actually produces a limited infection, the attenuated virus can be spread to others and also immunized, and the “herd immunity” phenomenon where people w/out immunity are largely protected b/c the majority of the population is immune (reservoir is reduced)
what are 2 disadvantages to using a live attenuated viral vaccine?
1) live attenuated viral vaccines can cause disease in immunodeficient individuals/people they are in contact with: VAPP – vaccine associated polio is the reason why OPV is no longer recommended. varicella is contraindicated in children on a high corticosteroid dose, CA, leukemia, lymphoma, or non-HIV immunodeficiency. rotavirus is given w/precautions for altered immmunocompetence. 2) the live attenuated viral vaccine might revert to the wild type or pathogenic virus
how are killed virus vaccines made?
viral particles are chemically treated (formalin), heated or irradiated
what are examples of the killed virus vaccine?
influenza, rabies, salk polio vaccine
what are the advantages of killed viral vaccines?
safe and do not cause disease (even in immunosuppressed pts)
what are the disadvantages of killed viral vaccines?
virus must be administered in large amounts (b/c no replication), risk of incomplete inactivation, and there is no replication of the virus – therefore immunity may not be as “good” (though current killed virus polio vaccine is “good”)
what are subunit vaccines? how are they made? how do they work?
these are usually derived from a viral antigenic surface structure made by recombinant techniques and will induce neutralizing host antibody
what is an example of a subunit vaccine?
hep B and HPV (which protects against 6,11,16, and 18 as well as “helps” protect against genital warts, precancerous cervical lesions and cervical cancer)
what are the 3 kinds of bacterial vaccines?
whole bacteria, toxins, and caspular polysaccharides
are there live attenuated bacterial vaccines?
yes, but very few. BCG for TB, whose efficacy varies in different populations/not used in the USA and salmonella (which is defective in an LPS synthesis enzyme)
what was the prototype for killed bacterial vaccines (whooping cough)? what was a problem with DTP vaccine? what has been done to fix it?
bordetella pertussis, which when given with a tetanus & diptheria toxid, the presence of the bordetella vaccine caused a stronger immune response/bad rxn to the toxoids. now an “acellular” bordetella preparation is used, which is composed of toxoid, filamenous hemaggutinin, peractin, and fimbrial antigen (enough to create an immunity).
how are toxoids made? what disases are there toxoids for?
the toxin activity is destroyed (formalin) but it retains sufficient antigenic activity to protect against disease. there are toxoids for both tetanus and diptheria
how do capsular antigen vaccines work? since the antibody response is usually T-independent and since babies don’t make good T-independent immune responses, what is done to include T cells in this response/what is the benefit of T involvement?
bacterial capsules contain strain/species specific antigens (polysaccharides) as well as block alt complement activation. capsular antigen vaccines are designed to be complement-fixing anti-capsular antibodies. the polysaccharide is usually conjugated with a carrier protein to stimulate T cells in babies b/c otherwise their T-independent antibody response is not developed enough for the vaccine to be effective. T cells allow there to be class switching and a memory response to the vaccine to be mounted
what are currently available capsular vaccines?
strep. pneumoniae, neisseria meningitidis, and hemophilus influenzae.
what diseases are conjugated vaccines effective in reducing the incidence/severity of?
childhood meningitis and pneumonia
why does conjugating the polysaccharide antigen to protein carriers do?
this improves the vaccine by allowing more chance of class switching from IgM to IgG, higher antibody titer levels, better memory generation, longer lasting immunity, and higher efficacy in younger children
since purified bacteria protein vaccines induce poor immunity, what is added to them to increase their efficacy? how do they work?
adjuvants, which are substancs that induce non-specific inflammation. strong immune responses require some degree of inflammation, inducing IL-12/IFN-gamma which helps class switching to IgG. the adujvants also cause the soluble antigens to aggregate, clear slower, increasing phagocytosis which leads to better processing/presentation to T cells
how many sexually active woment by age 50 are estimated to have HPV?
80%
which kinds of HPV does the HPV vaccine protect against?
6, 11, 16, 18 (quadrivalent)
who is the HPV vaccine recommended for?
females 9-26 (routine recommendation for girls 11-12)
what does the HPV vaccine prevent against?
HPV-induced cervical cancer, cervical precursor/precancerous lesions (dysplasia), vaginal/vulvar cancer precursors, anogenital warts
is the HPV vaccine recommended for men?
not yet, efficacy studies are stil ongoing
what is the most effective age for the zoster vaccine? what does it prevent?
60-69 (people in this age range still have pretty strong immune systems), the zoster vaccine prevents shingles in 50% of vaccinated individuals and post-herpetic neuralgia in 67% of vaccinated individuals – but it does not treat shingles or post-herpetic neuraliga
why is there a rumor about the MMR vaccine causing autism? is it true?
there was a study in 1998 where a small sample size (12) study was done that suggested the MMR vaccine caused bowel problems leading to impaired nutrient absorption causing autism. the study was retracted by 10 of the 13 authors, and no one has replicated the study
what is problematic with non-immunized pts of mothers refusing to get the MMR vaccine?
they are a risk to themselves and other contacts with suppressed immune systems

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