TABLE 2.

Binding of ISAV to 4-O-acetylated glycoproteinsa

TreatmentMean (SD) % binding
Guinea pig serumHorse serumBSM
None92 (6.1)65 (16.1)11 (4.1)
PBS100 (0)67 (17.1)13 (6.9)
NaOH11 (4.9)2 (1.6)10 (6.6)
4-O-acetylesterase47 (8.7)36 (9.9)6 (2)
  • a Serum glycoproteins (5 μg/well) were applied to microtiter plates and treated with 0.1 M NaOH (30 min at room temperature), 1.5 mU of recombinant SDAV 4-O-acetylesterase per well (overnight at 37°C), or PBS (overnight at 37°C). ISAV (1.5 mU of esterase/well) was then added and allowed to bind at 4°C. After removal of unbound virus, the wells were washed three times with PBS, and bound virus was detected by addition of 4-methyl umbelliferyl acetate. Hydrolysis of the substrate by the ISAV esterase was monitored with a fluorescence detector.