Enrichment of MLR-activated human suppressor cells by discontinuous density-gradient centrifugation.
6-day allogeneic mixed lymphocyte cultures (MLR) were fractionated on a four-step discontinuous Percoll gradient. The various fractions were added as regulatory cells to freshly established micro-MLRs between the original or third-party cell donors. Unspecific suppressor activity was highly enriched in gradient fraction III (density 1.069--1.062 g/ml), consisting mainly of blast-like cells. Suppressor cells were non-adherent T cells as determined by their spontaneous rosette formation with sheep erythrocytes and their susceptibility to lysis by anti-T-cell globulin plus complement. Mitomycin C treatment diminished their inhibitory capacity. In addition, gradient fraction III was also enriched with alloantigen-activated memory cells. By contrast, unprimed alloreactive cells were recovered from gradient fraction IV (density greater than or equal to 1.070 g/ml), consisting mainly of small, resting lymphocytes.
D000328:Adult; D002455:Cell Division; D002499:Centrifugation, Density Gradient; D006801:Humans; D007700:Kinetics; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000502:physiology*; D016685:Mitomycin; D008937:Mitomycins / Q000494:pharmacology; D012397:Rosette Formation; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
D008937:Mitomycins; D016685:Mitomycin