Generation of an ovine bone marrow-derived myelomonocyte-like cell line by retroviral-mediated transformation. Immunological characterization and the effect of cytokines and lipopolysaccharides.

A cell line (designated BMpXT1) was generated from sheep bone marrow using the Moloney murine leukemia virus-based retroviral vector pXT1. BMpXT1 cells resembled mature alveolar macrophages in being adherent and esterase positive, in expressing certain cell surface antigens, and in secreting granulocyte-macrophage colony-stimulating factor (GM-CSF) when stimulated by ovine interferon-gamma and lipopolysaccharide (LPS) in combination. The absence of a proliferative response to ovine GM-CSF and macrophage colony-stimulating factor, the absence of other cell antigens found in mature macrophages, and low-efficiency phagocytosis suggested that the cells may be at an intermediate to late stage of myelomonocytic differentiation.