pH-dependent binding of peroxidase-antiperoxidase /PAP/ immune complex to Fc receptors of macrophages.

Rat peritoneal macrophages were incubated at 4 degrees C in media of varying pH-s containing rat peroxidase-antiperoxidase /PAP/ immune complex. Two binding maxima were found at pH 5.5 and 7.0, resp. There was a sharp decrease in binding between 5.5 and 5.0. The peak at pH 7.0 was found to be trypsin-sensitive.