Protection against polio can be achieved by either live-attenuated Sabin vaccine or killed Salk vaccine. The shared feature of both vaccines is their ability to induce which of the following immune responses?
Activated CD8+ cytotoxic T lymphocyte effectors in circulation
Activated CD8+ cytotoxic T lymphocyte effectors in gut
Memory CD8+ T lymphocytes
Neutralizing antibodies in the circulation
Neutralizing secretory IgA antibodies in the gut
