Phagocytic activity of macrophages
To evaluate neutral red phagocytosis by peritoneal macrophages, 100 µl
of 0.075% aseptic neutral red solution was added and incubated for 1 h.
The supernatant was discarded and the cells were washed twice with PBS.
Then, 100 µl of cell lysate solution (ethanol 50% and 1% acetic acid
at the ratio of 1:1) was added to a 96-well plate to lyse the cells at
room temperature for 2 h. The optical density at 540 nm was measured by
ELISA reader.