Preparation of a monoclonal antibody directed against the receptor for murine colony-stimulating factor-1

Studies were undertaken to produce monoclonal antibodies directed against the murine receptor for macrophage colony-stimulating factor (M-CSF or CSF-1). Sprague-Dawley rats were injected with lysates prepared from a murine myelomonocytic cell line (RAW cell line) that has high levels of M-CSF receptors. Spleen cells from immunized animals were fused with murine plasmacytoma cells and expanded. Supernatants from these cells caused inhibition of 125I-CSF binding to either RAW cells or normal murine marrow cells. Antibody-producing cells were cloned by limiting dilution and by colony growth in agar. The antireceptor antibodies appear specific as they neutralize colony formation by M-CSF but have little or no effect on colony growth in response to the other hemopoietic growth factors granulocyte CSF (G-CSF), granulocyte-macrophage CSF (GM-CSF), interleukin-3 (IL-3) or erythropoietin. These antibodies should aid in defining the role of M-CSF in hemopoiesis in vivo.