The role of serum in the in vitro assay of lymphocyte-mediated cytolysis.

Serum affects lymphocyte-mediated cytotoxicity in vitro by facilitating cell-cell interactions. Assays using low killer and target cell concentrations in plastic tissue culture dishes and dependent upon rocking to facilitate lysis, require serum lipid to prevent the adhesion of cells to the plastic surface of the dish. This adhesion prevents the cells from freely moving and making the killer-target cell contact essential for lysis. If the assay is performed in microtest plates with high cell concentrations in smaller volumes, rocking is not necessary to promote lysis and serum is not required. In addition, we have observed that glucose facilitates lysis in the absence of serum.