In vitro functional tests for evaluation of stimulating capacity of cultured human dendritic cells

Basic functional test for evaluation of in vitro cultured human dendritic cells (DC) is primary allogeneic one-way mixed lymphocyte reaction (MLR). In this way, one can evaluate stimulating capacity, which is a basic characteristic of DC. The proliferation of cells is measured through incorporation of 3H-thymidine. Normally proliferation is measured at days 5-7. We studied kinetics of proliferative responses initiated with different stimulating cell suspensions to evaluate differences and possibly reduce time needed to perform this test. Gradual increase in response from days 1 to 7 and a significant difference from controls (peripheral blood mononuclear cells) seen from day 4 was noted if macrophages were used as stimulators. A consistently higher proliferation, compared to controls, was always found already on day 2 when mature DC were used as stimulators. The reaction peaked 2 to 3 days earlier and was also more than two times more intense. This maximal and significantly higher response, consistently seen already after 48 hours, allows us to confirm the presence of mature DC in stimulating suspensions much earlier than previously.