Role of immune interferon in the monocytic differentiation of XXXX promyelocytic cell lines induced by leukocyte conditioned medium.

@entity1 @entity558 @entity137 @entity379 @entity3027
@entity558 ( @entity558 ) from lectin-stimulated @entity1 leukocytes contains factors that induce @entity1 promyelocytic cell lines to differentiate along the monocytic pathway. In this report, we show that @entity1 promyelocytic cell lines are also induced to differentiate along this pathway by immune interferon ( @entity379 ). Various preparations of @entity3027 tested did not induce this differentiation. In cultures containing @entity379 , the cells are induced to coordinately express monocyte markers and functions such as monocyte-specific surface antigens, HLA-DR antigens, nonspecific esterase, receptors for the Fc fragment of IgG, and the ability to mediate antibody-dependent cell-mediated @entity137 . Our data indicate that differentiation induced by @entity379 is not secondary to an arrest of growth of promyelocytic cell lines, but rather that a proportion of cells is induced along a programmed pathway of terminal differentiation similar to that of normal monocytes. @entity558 contains @entity379 , but its ability to induce differentiation is greater than expected on the basis of its content of @entity379 . Treatments at 56 degrees C or at pH 2.0, which abolish @entity379 activity, abrogate the differentiation ability of @entity558 . The antiviral activity and the differentiation activity contained in the @entity558 are coeluted from gel filtration and reverse-phase columns. Monoclonal antibodies anti- @entity379 , which completely abrogate the differentiation ability of @entity379 and the antiviral activity in the @entity558 , completely suppress the induction of some monocyte markers by @entity558 , but only reduce the expression of others. When @entity379 is added to @entity558 , promyelocytic cell lines are induced to differentiate to a much greater extent than that induced by either @entity379 or @entity379 -depleted @entity558 alone. These results show that the differentiation activity of leukocyte @entity558 is due to the synergistic effect of @entity379 and other factors not yet identified.
