Characterization of human monocytes maintained in long-term culture with functional and morphological homogeneity.

We recently reported a method for long-term in vitro culture of human monocytes with maintenance of functional and morphological homogeneity. We have now used microexudate-coated flasks to improve both the plating efficiency and the purity of these cultures. The technique is based on pregrowth of BHK cells that presumably produce large amounts of fibronectin, thus coating the flask with this substance, for which monocytes have receptors. We have further characterized the monocytes obtained with this culture technique by scanning electron microscopy (SEM), transmission electron microscopy (TEM), cytochemistry, surface markers, lectin receptors, and phagocytic functions. All these methods show the cultured cells to consist of a pure, functionally and morphologically homogeneous population of nontransformed monocytes.