Isolation of human mononuclear cell subsets by counterflow centrifugal elutriation (CCE): II. Functional Properties of B-lymphocyte-, T-lymphocyte-, and monocyte-enriched fractions

Counterflow centrifugal elutriation (CCE), a technique which separates cells by size and density, was used to separate human peripheral blood mononuclear cells into fractions enriched for T lymphocytes, B lymphocytes, and monocytes. These morphologically and phenotypically distinct fractions were analyzed for their ability to respond in several functional assays. B-Cell-enriched fractions devoid of monocytes did not proliferate nor produce significant quantities of lymphokines in response to antigens. These B cells did proliferate to anti-IgM antibodies but not to anti-IgD antibodies. B-Cell fractions served as stimulators of the autologous mixed-lymphocyte reaction (AMLR). T-Lymphocyte fractions were unable to respond to antigen challenge, but both proliferation and lymphokine production could be restored by the addition of monocytes. Monocyte fractions produced PGE₂, displayed chemotaxis, and functioned as stimulators in the AMLR. Thus, CCE appears to be a useful technique for reproducibly obtaining highly enriched subsets of human peripheral blood mononuclear cells with unique phenotypic and functional properties. These isolated populations can consequently be used to identify the independent and collaborative roles of the cells in immunological events.