TITLE:
Proposal for a new evaluation of phagocytosis using different sizes of fluorescent polystyrene microspheres
AUTHORS:
Riyo Enomoto, Makoto Imamori, Ayoumi Seon, Kozue Yoshida, Aya Furue, Hirofumi Tsuruda, Eibai Lee-Hiraiwa
KEYWORDS:
Macrophage; Phagocytosis; Polystyrene Microsphere; Total Surface Area
JOURNAL NAME:
Advances in Biological Chemistry,
Vol.3 No.6,
December
19,
2013
ABSTRACT: To investigate phagocytosis, peritoneal-resident and
J774.1 macrophages were incubated with fluorescent polystyrene microspheres
measuring 1.0 μm in diamter at 200 particles per cell. The amount of phagocytized
microspheres increased with incubation time, and both cell types had similar
phagocytic activity. Further, we investigated the phagocytosis of different
sizes of microspheres by J774.1 macrophages. To adequately evaluate
phagocytosis, varying amounts of different sizes of microspheres were added to
J774.1 cells, and their phagocytic activities were evaluated. When the
microspheres were added at a density of 20 particles per cell, few small microspheres
(3 μm in diameter) could not be
evaluated because of cytotoxicity. Thus, the amount of different sizes of microspheres
added is important for precisely evaluating phagocytic activity. When the
amount of different sizes of microspheres added was standardized to provide a
set amount of total surface area, phagocytosis of these microspheres could be
adequately evaluated and compared. To determine the effects of phagocytosis on
cell viability and proliferation, cells incubated with different sizes of
microspheres were assayed using a cell counting kit. We found that phagocytosis
had no effect on cell viability or proliferation and was independent of
particle size. Furthermore, cells already phagocytized microspheres retained
their phagocytic activity.