Is restimulation of cells always necessary for cytokine secretion?

For detection of antigen-specific T cells, specific restimulation is usually necessary, because only antigen-specific restimulation will induce cytokine secretion in the responding cells.

Some cytokine-secreting cells can also be isolated directly ex vivo, for example, in acute infections. However, in these cases, it is not possible to draw conclusions regarding the specificity of the secreting cells.