Comparison of methods for removal of nonspecific inhibitors of arbovirus hemagglutination.

Human sera were treated with kaolin, acetone, and dextran sulfate to determine the best method for removing nonspecific hemagglutination inhibitors. Results indicated that on surveys for group A, group B, and some group C arbovirus HI antibodies, dextran sulfate treatment of sera could be used effectively. This method, however, has limited usefulness for detecting HI antibody for a number of arboviruses, particularly some members of the Bunyamwera supergroup since nonspecific inhibitors for these antigens were not completely removed. HI antibodies in sera drawn early after dengue and Venezuelan equine encephalitis infection were detected more readily after dextran sulfate treatment than after kaolin treatment. Kaolin, but not dextran sulfate, was shown to remove antibody from IgM fractions of sera.