Human peripheral blood mononuclear cells (PBM's) cultured in serum free medium (II): Lymphocyte-macrophage interaction and related morphological changes.

Morphological descriptions of the attachments between lymphocytes and macrophages are made in serum free cultures. Dynamic morphological processes related to these attachments are explored in live cells using an inverted microscope and the phase technique. The May Grunwald-Giemsa stain and scanning and transmission electron microscopy are also described for the same population of cells. Immunoglobulins were detected in the cells by the immunoflourescence technique. Following lymphocyte-macrophage attachments, the macrophages shrink and round up and subsequently, their cytoplasm becomes laden with immunoglobulin. The membrance surface of interacting macrophages gradually changes from the ruffled appearance characteristic of a monocyte to a blebbed structure. The blebs seem to be related to an exocytotic process, which is most probably immunoglobulin secretion.