Comparison of three techniques for the ex vivo elimination of T cells from human bone marrow

The high incidence of graft-vs-host disease (GVHD) in allogeneic bone marrow transplantation (BMT) is a significant cause of morbidity and mortality, despite pharmacological prophylactic regimens. Laboratory technologies have been developed to eliminate the immunocomponent T-lymphocyte, the proposed effector cell in the GVHD reaction. In this study, three techniques for the ex vivo purging of T cells from human bone marrow (BM) were compared. BM treatment groups consisted of T-cell depletion by the monoclonal antibodies OKT3 and OKT11A plus complement (MoAb+C), soybean agglutination followed by sheep erythrocyte rosette depletion, or triple rosetting with neuraminidase-treated sheep erythrocytes. Mean final cell yields were 37.2 ± 4.0%, 2.8 ± 0.8%, and 2.5 ± 1.3%, respectively, while final yields of BM progenitor cells, assayed in the double-layer soft-agar CFU-c assay, were 28.5 ± 6.5%, 3.9 ± 2.1%, and 10.5 ± 3.8%, respectively. The three techniques were comparably efficient in elimination of mitogenic responses to irradiated allogeneic lymphoblastoid cells and cytotoxic lymphocyte responses of the BM. Immunofluorescence after T-cell depletion showed greater than 97.5% of all OKT3-positive cells to be eliminated by each technique. Despite the fact that all three techniques were effective in T-cell depletion, treatment with anti-T-cell MoAbs + C proved less labor-intensive and resulted in higher cell yields.