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

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Microorganisms and Disease
The influenza vaccine is administered each year because

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

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Microorganisms and Disease
Which of the following characteristic of the Rotavirus was important for the construction of the Rotashield vaccine?

A limited number of capsule types
The ability of monkey Rotavirus strains to cause serious illness (diarrhea) in human beings
The possession of a segmented RNA genome
The ability of the Rotavirus to be transmitted faster

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Microorganisms and Disease
The "A" subunit of diphtheria toxin

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

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