ELISPOT - 101 (Jan/12/2011 )

Hi, could anyone explain to me why is each spot in an ELISPOT assay generated by just one cell, why can't it be more than one? And how can ELISPOT, but not ELISA, still assay for the cytokine of interest that are instantly consumed by the cells?

1. One cell generates one spot becuse the cell is attached to the membrane (which absorbs cytokines secreted by cell)
2. Yep, ELISPOT is not a perfectly precise quantification method, but if cytokines are absorbed (see (1)) the quantifiaction is OK. Anyway,the spot size and density is proportional to the cytokine production of the cell of interest