Final answer:
Memory T cells are distinct from naive T cells due to elevated levels of specific coreceptors that enable them to rapidly respond to antigens they have previously encountered, as opposed to the initial response to a pathogen by naive T cells.
Step-by-step explanation:
A memory T cell can be distinguished from a naive T cell on the basis of elevated levels of surface molecules and different functional states.
Unlike naive T cells, which express CD4 or CD8 surface molecules and act as the initial responders to a pathogen, memory T cells are the result of a previous encounter with a pathogen.
These memory T cells retain the specificity for the pathogen's antigen and can rapidly expand upon re-exposure to the same pathogen, thus providing a quicker and more robust immune response. They may also exhibit elevated levels of other surface molecules that are associated with their heightened state of alert and readiness. One critical aspect that differentiates memory T cells from their naive counterparts is the expression of specific coreceptors and an enhanced ability to bind MHC molecules on antigen-presenting cells (APCs) through their T-cell receptors (TCR).