ABSTRACT
The potential anti-tumor activity of human macrophages, grown in macrophage colony stimulating factor (M-CSF), was examined in mice homozygous for the mutation severe combined immune deficiency (scid) bearing xenografts of autologous human melanoma. Injection of scid mice, bearing subcutaneous melanoma xenografts, with the cultured macrophages or with the macrophage culture supernatant, once or repeatedly, resulted in partial to complete regression of tumors. Since a large number of such macrophages (greater than 1 x 10(9)) could be grown in vitro for repeated injection, the scid-human chimera can serve as an in vivo model to examine the role of human macrophages in tumor immunity and to explore the potential of the in vitro cultured macrophages in the therapy of cancer.