Interaction of a mouse macrophage cell line with homologous erythrocytes.
The interaction of the IC-21 murine macrophage cell line and homologous red blood cells (RBC) was assessed in the absence of exogenous opsonins. These results were used to evaluate this system as a potential model for macrophage-mediated clearance of old or damaged RBC. The binding and ingestion of density-separated and unseparated RBC by IC-21 cells were quantitated in assays that involved both 51Cr-labeled RBC and direct microscopy. The number of unseparated RBC that bound to IC-21 macrophages depended on the number of RBC added. Macrophages phagocytized an appreciable proportion of RBC within 3 hours with the ratio of RBC:macrophage of 10, a point at which the RBC-binding was not rate limiting. The mouse RBC were separated into dense- and less-dense fractions which are presumably enriched for old and young cells, respectively. When these RBC fractions were incubated with the IC-21 macrophage, significantly more of these dense cells were phagocytized. These results show that IC-21 macrophage cell line is a useful model for defining the processes whereby aged or damaged RBC are recognized and removed from circulation by macrophages.
D000818:Animals; D001343:Autophagy; D002448:Cell Adhesion; D002460:Cell Line; D004905:Erythrocyte Aging; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D008264:Macrophages / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010537:Peritoneum / Q000166:cytology; D010587:Phagocytosis