Microorganisms and Disease
The influenza vaccine is administered each year because

the vaccine is sufficiently toxic to make it necessary to administer only a small amount at any one time
None of these
mutations in the viral hemagglutinin may allow the virus to evade the immune response elicited by previous vaccines
it is a polysaccharide vaccine that does not confer long-term protection

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Microorganisms and Disease
Type III secretion systems are used to inject "effector" proteins directly into a host cell. Salmonella uses a type III secretion system to help the pathogen to

survive the acid pH of the stomach
survive within macrophages
secrete LT (heat labile toxin) and ST (heat stable toxin) into the lumen of the intestine
activate T cells to proliferate and secrete cytokines

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Microorganisms and Disease
Which of the following is common in the disease caused by Coryne-bacterium diphtheriae and Bacillus anthracis?

Both organisms cause skin and respiratory tract infections
Both organisms are gram-positive spore formers
Diphtheria toxin and edema toxin are ADP ribosylating toxins
The most serious disease symptoms are the direct result of toxin action

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Microorganisms and Disease
The "A" subunit of diphtheria toxin

binds host cell receptors found on heart cells
lysis macrophages with the release of cytokines
cause ADP ribosylation of a factor involved in protein synthesis
forms cAMP that leads to fluid accumulation

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