Final answer:
A polio vaccine must stimulate both the cell-mediated and humoral responses to provide comprehensive protection, as the virus can cause irreversible damage to neurons which the body cannot replace, making prevention through vaccination crucial.
Step-by-step explanation:
The polio vaccine needs to stimulate both a cell-mediated and a humoral response because while the body cannot replace most neurons, it can prevent the onset of the disease by ensuring that both the immune system cells directly target infected cells (cell-mediated immunity), and also by producing antibodies that bind to the virus and neutralize it before it can infect cells (humoral immunity).
Cell-mediated immunity involves T cells that can detect and destroy infected cells.
On the other hand, humoral immunity refers to the production of antibodies by B cells. Antibodies can neutralize pathogens before they infect cells, vital in preventing poliovirus replication in the gastrointestinal tract and its potential spread to the nervous system.
By stimulating both immune responses, a vaccine offers comprehensive protection. For polio, which can lead to paralysis even with the regeneration limitation of neurons, prevention through vaccination is vital.