Enrichment (and depletion) of human suppressor cells with monoclonal antibodies and immunoglobulin-coated plates

A cell separation method using immunoglobulin (Ig)-coated plates, originally devised for murine spleen cells, was modified and adapted for enrichment (and depletion) of cellular subpopulations from human peripheral blood. For the direct separation of B and T cells, F(ab')2 fragments of anti-human Ig were used to coat the plates. For indirect separation, the cells were first incubated with monoclonal antibodies to cell surface antigens and then separated in plates coated with anti-mouse Ig. Plates were first coated with poly-L-lysine to facilitate the adherence of anti-Ig antibodies, and finally with bovine serum albumin to mask free poly-L-lysine. Cells which did not react with the anti-Ig antibodies or which were nonadherent to the plate were pipetted off; cells which reacted with the anti-Ig antibodies or which were adherent were eluted after incubation with excess serum. T, non-T, T4+, T4-, T8+, and T8- lymphocytes were separated with high viability, purity, and yield. The method was used to study suppressor activity of a patient who was treated by bone marrow transplantation for myelofibrosis. Strong suppressor activity was associated with unfractionated peripheral blood mononuclear leukocytes, monocytes, T, T8+, and T4- cells but not with B, T8-, and T4+ cells.