Microorganisms and Disease
Lactoferrin helps to protect against pathogens by

blocking sebum production
sequestering Iron
facilitating the growth of normal flora
lowering the pH

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Microorganisms and Disease
The influenza vaccine is administered each year because

it is a polysaccharide vaccine that does not confer long-term protection
None of these
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
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 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
survive the acid pH of the stomach

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