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 u sing the Moloney murine leukemia virus-based retroviral vector pXT1. B MpXT1 cells resembled mature alveolar macrophages in being adherent an d 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 cel l antigens found in mature macrophages, and low-efficiency phagocytosi s suggested that the cells may be at an intermediate to late stage of myelomonocytic differentiation.