Immunosuppression following Thermal Injury through B Cell Activation of Suppressor T Cells

Abstract

Normal human lymphocytes isolated by sedimentation and cotton column adherence were used to develop a reliable assay of immunosuppression of PHA-[phytohemagglutinin]-induced blastogenesis by serum from patients with burn injuries. These lymphocyte cultures contained responder cells (subpopulation x) and regulator cells (subpopulation y). Lymphocytes isolated by gradient centrifugation on sodium metrizoate-Ficoll contained responder cells (x), but no regulator cells (y). Cultures of lymphocytes isolated by this method were stimulated by PHA, but were not suppressed by the addition of patient serum. When lymphocytes were isolated by a cotton column adherence/Lymphoprep centrifugation-double separation, subpopulations (x) and (y) were isolated. Both subpopulations were necessary for suppression to occur, and (y) operates as the regulator of (x) B [bone marrow-derived] cell and T [thymus-derived] cell populations isolated by nylon column adherence or AET [2-aminoethylisothioronium bromide hydrobromide] rosette separation demonstrated that the regulator ability of subpopulation (y) is the result of B cell activation of suppressor T cells.