IRON COMPOUNDS AFTER ERYTHROPHAGOCYTOSIS - CHEMICAL CHARACTERIZATION AND IMMUNOMODULATORY EFFECTS

In humans, the lymphomyeloid system has a fundamental role on iron met abolism promoting its recycling due to a continuous removal of effete red blood cells. Additionally, one of the most intriguing aspects of m etalloporphyrins in biology is their effect on the immune system. Howe ver, the process of erythrocyte catabolism is still poorly understood and needs further research. In the present study, we attempt to invest igate the nature and the possible physiologic role of Fe compounds rel eased after erythrophagocytosis during the removal of red blood cells. Monocyte erythrophagocytosis in vitro experiments were done to charac terize chemically the Fe compounds present inside the cells and in the culture supernatants, We tested the probable immunomodulatory functio ns of erythrophagocytosis products over lymphocyte cultures activated in vitro with T mitogens (alpha-CD3). Data obtained from atomic absorp tion spectroscopy confirmed the presence of Fe in the culture supernat ants of monocyte cultures after erythrophagocytosis. Also, high-spin h aem complexes derived from erythrocyte catabolism were detected by ele ctron paramagnetic electronic resonance. Finally, in vitro activated l ymphocyte proliferation experiments indicate the co-mitogenic properti es of monocyte culture supernatants after red blood cells phagocytosis . Thus, the results of the present work provide evidence that culture monocyte supernatants after in vitro erythrophagocytosis contain Fe (I II) high-spin haem complexes and show lymphocyte proliferation co-stim ulatory properties. (C) 1998 Academic Press.