Changes in the expression of cell surface sialoglycoproteins during transition of human monocytes into macrophages

Cell surface sialoglycoproteins of human mononuclear phagocytes in different maturation stages were labelled by the periodate/borohydride method and separated by SDS-polyacrylamide gel electrophoresis. The main surface glycoproteins of peripheral blood monocytes had molecular masses of 115 and 95 kDa. During in vitro transition into adherent macrophages, the monocyte-characteristic surface glycoproteins disappeared. Most of the changes in the surface glycoprotein pattern occurred during the first 24 h and after 96 h the changes were completed. The major sialoglycoproteins of the macrophage cell surface had molecular masses of 130 and 55 kDa. The macrophage cell surface showed further changes when cultured in the presence of synovial fluid (10%). These results may reflect the in vivo maturation of monocytes into tissue macrophages. In synovium, tissue-derived factors may also take part in differentiation.