Human serum immuno-reactive copper, zinc-superoxide dismutase assayed with an enzyme monoclonal immunosorbent in patients with digestive cancer.

Two types of monoclonal antibodies, N4 and N6, were raised against human copper, zinc-superoxide dismutase (Cu,Zn-SOD). An enzyme-linked immunosorbent assay for Cu,Zn-SOD was developed in sandwich method using these monoclonal antibodies. The measurable assay range was 1.0-100 micrograms/l and the coefficient of variation within and between series were 7.5% and 8.1%. Sera of 154 healthy control subjects displayed a low level (14 micrograms/l) of immunoreactive Cu,Zn-SOD with a logarithmic normal distribution. On the other hand, serum Cu,Zn-SOD levels were significantly elevated in patients with various digestive cancers.