CYTOKINE PRODUCTION IN HUMAN MIXED LEUKOCYTE REACTIONS PERFORMED IN SERUM-FREE MEDIA

The mixed leukocyte reaction (MLR) is an in vitro test commonly perfor med in a serum-containing medium (SCM), and used to study,allorecognit ion and cellular immunity accompanied by cytokine release. We investig ated the possibility of performing the MLR test in serum-free media (S FM) by comparing human leukocyte proliferation and cytokine release in MLRs performed in SFM and SCM. Of the four SFM tested, only Biotarget -1 was as effective as SCM in supporting leukocyte proliferation and I L-2 secretion. Both phenomena were observed only in allogeneic combina tions. The levels of IL-1, IL-6, and TNF alpha in allogeneic MLR combi nations in SFM were half those in SCM cultures; the kinetics of their release were the same. With the exception of IL-2, a high degree of sp ontaneous release of the other three cytokines analyzed was observed i n responder cells, in irradiated stimulator cells, and in autologous c ombinations cultured in both SCM and SFM. It appears that unlike IL-2, the cytokines IL-1, IL-6, and TNF alpha are nonspecifically produced in MLR and cannot serve as sensitive indices of HLA disparity. (C) 199 8 Elsevier Science B.V. All rights reserved.