A student asks why some vaccinations are given orally and some are given by injection. What response by the professor is best?
◦ Different routes allow the speed of onset of the antigen to be varied, with the intravenous route being the fastest.
◦ Some individuals appear to be unable to respond to an antigen by a specific route, thus requiring the availability of different routes for the same antigen.
◦ Antigen-presenting cells are highly specialized and thus require stimulation by different routes.
◦ Each route stimulates a different lymphocyte-containing tissue, resulting in different types of cellular and humoral immunity.