The human macrophage system: activity and functional morphology

Macrophages of humans could be extracted in large numbers from the connective tissue using a newly developed, not particularly difficult method. These macrophages were compared with the peritoneal macrophages of mice using light-, scanning and transmission electron-microscopic methods. The sterility of the cell suspension and the high yield of macrophages has allowed the first in vitro study of histiocytes to take place, in contrast to the classic 'microexudate-coated surface method'. The activity of the human in comparison with peritoneal murine macrophages has been evaluated using numerous histochemical and immunological techniques. These methods prove a modulation of the macrophage activity of healthy humans and mice under exemplary conditions of extremely strenuous physical exercising, in accordance with earlier experimental findings on animals alone. The degenerative changes which occur under these experimental conditions in the skeletal muscular system show an invasion of cells of the immune system, which are integrated into an explanation of the increased activity of macrophages. These results find their place in a new theoretical concept supporting the general validity of the co-operation of macrophages and other cells of the immune system in pathological degeneration and regeneration processes in the skeletal muscular system. It has been shown that the increased activity of human and murine macrophages brought about by extreme strenuous physical exercising, insofar as one is able to order them into a progressive scheme of stress happenings, fit very well into the concepts of the 'alarm reaction' phase. The activity of macrophages proves to be sensitive to the mediators of tumours of mesenchymal origin, with respect to the initial stage of phagocytosis, to the further biochemical deterioration, to the cytotoxicity and to the amount of cells; this, however, is not able to halt the rapid growth of sarcoma in a long term experiment. The proof of a weakened migration of macrophages in sarcoma-bearing animals raises the interest in those substances which are able to positively modulate the migration activity. On the one hand the migratory performance of macrophages in sarcoma-bearing animals in a short-term experiment was increased by the introduction of an anabolic steroid hormone. On the other hand, however, a different degree of success was registered for the further parameters of macrophage activity during short- and long-term experimental investigations.(ABSTRACT TRUNCATED AT 400 WORDS)