Newly introduced BAS method in immunoperoxidase staining was compared with PAP
method and the advantages and disadvantages of BAS method were discussed. Various
dilutions of primary antisera of IgG, αFP, lysogyme, HSV Ⅱ and GFA were applied to
the surgical biopsy specimens of inflammatory reaction, hepatocellular carcinoma, gastric
adenocarcinoma, cervical dysplasia and astrocytoma, respectively, and each specimen was
stained with PAP or BAS method.
The ratio of specific staining background staining was higher in BAS method, where
dilutions of the primary antisera were 4-16 times those applied in PAP method. The
high dilution titers in BAS method was thought to be due to strong binding activity
between biotin and avidin, and also due to lattice-like structure of ABC containing many
peroxidase molecules.
The main disadvantage of BAS method is endogenous avidin binding activity which
can be overcome by pretreatment with avidin and biotin.
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