八八▲▲ Posite sample Negative smple Postie sample crane sumr RIG. 3. Nonspecific antibodies that do not bind to the antigen are washed away FIG 4. An enzyme labeled (eg alkaline phosphatase or horse- radish peroxidase) secondary antibody is incubated with the ample and binds tightly to the sample antibod 洗涤清除非特异性抗体 加入酶标抗抗体洗涤清除非特异性抗体 加入酶标抗抗体