Production and characterization of two monoclonal antibodies against human myeloperoxidase

Two monoclonal antibodies against human myeloperoxidase, designated 3-2H3 and 4-2C11, were produced and characterized. Both bound to the native enzyme, but neither bound to the denatured enzyme or to its two denatured subunits. 4-2C11 bound to the three types of leukocyte myeloperoxidase, I, II, and III, as well as to the four types of myeloid leukemia HL-60 cell myeloperoxidase, IA, IB, II, and III. 3-2H3 did not bind to enzyme IB, but bound to the other types of leukocyte and HL-60 cell enzymes. On incubation with myeloperoxidase III, 4-2C11 inhibited the enzyme activity, but 3-2H3 did not. Both antibodies belong to the IgG1 subclass.