CHARACTERIZATION OF HEMOPOIETIC STEM CELL CHIMERISM IN ANTIBODY-FACILITATED BONE MARROW CHIMERAS

Abstract

A model for bone marrow transplantation that involves preparation of the host with monoclonal antibody against class I or class II antigens instead of irradiation or cytotoxic drugs is described. This allows engraftment and subsequent repopulation of the host by donor tissue. Chimerism has been reported in the peripheral blood of P1 .fwdarw. (P1 .times. P2)F1 mice. The bone marrow and spleen stem cell chimerism of these antibody-facilitated (AF) chimeras are examined by determining, with an isozyme assay, the phenotype of methylcellulose colonies grown from stem cells. A correlation was found between peripheral blood chimerism and the stem cell constitution of both spleen and bone marrow. The peripheral blood chimerism also correlates with the level of chimerism in macrophages derived from peritoneal exudate cells. Assaying the peripheral blood of such chimeras provides an excellent indication of the degree of chimerism at the stem cell level and stands in sharp contrast to the level of chimerism in certain lymphoid compartments.