Monoclonal antibodies to XXXX brain acetylcholinesterase: selective enzyme inhibition, differential affinity for enzyme forms, and cross-reactivity with other mammalian cholinesterases.

@entity19 @entity1219 @entity840 @entity95 @entity4360 @entity35
Eleven unique monoclonal IgG antibodies were raised against @entity95 brain acetylcholinesterase ( @entity4360 , EC 3.1.1.7), purified to electrophoretic homogeneity by a two-step procedure involving immunoaffinity chromatography. The apparent dissociation constants of these antibodies for @entity95 @entity4360 ranged from about 10 nM to more than 100 nM (assuming one binding site per catalytic subunit). Species cross-reactivity was investigated with crude brain extracts from @entity95 , @entity35 , @entity19 cat, @entity840 , and human. One antibody bound @entity95 @entity4360 exclusively; most bound @entity4360 from three or four species; two bound enzyme from all species tested. Identical, moderate affinity for @entity35 and @entity19 brain @entity4360 was displayed by two antibodies; two others were able to distinguish between these similar antigens. Nine of the antibodies had lowered affinity for @entity4360 in the presence of 1 M @entity1219 , but two were salt resistant. Analysis of mutual interferences in @entity4360 binding suggested that certain of the antibodies were competing for nearby epitopes on the @entity4360 surface. One antibody was a potent @entity4360 inhibitor (IC50 = 10(-8) M), blocking up to 90% of the enzyme activity. Most of the antibodies were less able to bind the readily soluble @entity4360 of detergent-free brain extracts than the @entity4360 which required detergent for solubilization. The extreme case, an antibody that was unable to recognize nearly half of the "soluble" @entity4360 , was suspected of lacking affinity for the hydrophilic enzyme form.
