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Chapter 19- vaccines. Where we’re going-We’ll learn some terms- active, passive, inactivated, subunit, toxoid, attenuated, and associate these with some vaccines. Learn some newer approaches, and the problems of testing and implementation.
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Chapter 19- vaccines • Where we’re going-We’ll learn some terms- active, passive, inactivated, subunit, toxoid, attenuated, and associate these with some vaccines. • Learn some newer approaches, and the problems of testing and implementation. • I’ll get arrogant about the supremacy of microbiology as a science.
Go Vaccines! Go Micro! We live as long as we do because we: • Treat our water • Treat our sewage • Treat infectious diseases w/ antibiotics • Get vaccinated • It’s ALL microbiology!
You could divide the vaccines into “replicative” and “non-replicative”, except the DNA vaccines would muddle the picture.
German measles- we vaccinate the mom to protect the unborn baby… Note- log scale!
Measles vaccine; we find out that the vaccine needs a booster
Passive Immunity-antibodies raised in someone/something else • Nursing moms & babies- IgA • Anti-venin, anti-toxins- problems with serum sickness (Type III hypersens.) if repeated. • Pooled human immune serum is used as well- Hepatitis A & B
Active Immunity-YOU make the Ab’s or cells • Attenuated: weakened microbe that imparts immunity, but not the disease. • Good humoral and cellular response • Evolution of virulent forms • Immunocompromised people- finding out the hard way! • Requires refrigeration Some examples: BCG, smallpox (many viruses)- MMR,
MORE Active.. • Inactivated- many bacteria, some viruses • Salk polio, Pertussis, Anthrax • Storage and production is easy, • Mainly humoral response- need boosters. • Side-effects- particularly with G- organisms, fever due to LPS. • Flu vaccine is usually inactivated- attenuated one is now available. It’s easier to respond to an epidemic w/ inactivated.
MORE active.. • Purified macromolecules • Bacterial polysaccharides- pneumonia, Hemophilus – T independent response; conjugating Hib to diphtheria toxin boosts response. • Toxoids- purified inactivated toxins- diphtheria, tetanus • Hepatitis B- cloned surface viral antigen
Herd immunity • An unimmunized person surrounded by immunized people is less likely to contact the disease- the immunized people dramatically slow the spread, making contact with an infected person less likely. • Doesn’t work w/ unimmunized subpopulations-say, an unimmunized community. • Important to keep immunization levels up!
And coming to a clinic near you.. • DNA vaccines- A key immunogenic protein is cloned and the DNA put directly into an injection- muscle and dendritic cells take up, express, and present the Ag- good humoral and cell-mediated response.
DNA vaccines- there’s an apparent role for both muscle and dendritic cells in displaying antigen.
Vaccines get political/religious also • Early opposition on religious grounds- “thwarting the will of God” • Still an issue in the attempts to eradicate polio. • Civil rights issues when vaccination becomes unpopular.
Things to know • Basic terms and examples of them- passive, active, attenuated, toxoid, inactivated whole organism, purified molecule, etc. • Advantages and disadvantages of attenuated vs “non-replicative” • DNA vaccines • Herd immunity
Quiz on Wed • Define & give examples of: • Passive immunity-natural, artificial • Attenuated vaccine • Inactivated vaccine • Subunit vaccine • Toxoid • + &- of attenuated vs inactivated • What’s a DNA vaccine?