Anti-choline acetyltransferase fragments antigen binding (Fab) for immunohistochemistry

The preparation of fragments antigen binding (Fab) from serum of rabbits immunized against human brain choline acetyltransferase (CAT) is described. Ant-CAT Fab fragments were less potent than anti-CAT immunoglobulin (IgG) in inhibiting mammalian CAT activity and did not precipitate CAT activity. They proved, however, far superior to anti-CAT IgG for the immunohistochemical staining of CAT in mammalian neurons.