INDUCTION OF ANTIGEN EXPRESSION OF FOLLICULAR DENDRITIC CELLS IN A MONOBLASTIC CELL-LINE - A CONTRIBUTION TO ITS CELLULAR-ORIGIN

Experiments were carried out to elucidate the cellular origin of the dendritic reticulum cell (DRC). The monoblastic cell line THP‐1, the histiocytic cell line U‐937, and the mononuclear cell fraction from peripheral blood (PMC) were stimulated with supernatants from lectin‐stimulated peripheral blood lymphocytes and from stimulated T‐ and B‐cell lines. Differentiation towards DRC was assessed by immunocytochemical demonstration of the DRC‐specific antigen Ki‐M4. Supernatants from isolated peripheral T lymphocytes and from T‐ and B‐cell lines were capable of stimulating THP‐1 to Ki‐M4 antigen expression, whereas U‐937 and the PMC fraction remained negative for this antigen throughout the experiments. These results provide further evidence for a relationship of DRCs with the mononuclear phagocytic cell system and hence for their bone marrow origin. Furthermore, the data suggest that soluble factors of T and/or B cells are involved in mediating the differentiation process of precursor cells to DRC. Copyright © 1990 John Wiley & Sons, Ltd.