Measurement of specific IgE and IgG antibodies against Aspergillus fumigatus antigen in patient sera by use of enzyme immunoassays: influence of different procedures of antigen immobilization.

IgG and IgE antibody titers against Aspergillus fumigatus were measured in patient sera by enzyme immunoassays by use of antigens or allergens immobilized to different carriers. Specific-IgG antibodies were measured by a double antibody-layer enzyme immunoassay; specific IgE was determined by Phadezym -RAST (Pharmacia Diagnostics). In both cases antigens and allergens were immobilized in two ways: first by covalent binding to CNBr-activated paper discs and second by spontaneous binding to polystyrene surface of microtiter plates. Much higher IgE-antibody titers were found with allergens immobilized to paper discs when these discs were compared with microtiter plates, which could be explained by a higher allergen-binding capacity of activated paper discs. On the contrary, higher IgG antibody titers were found with antigens bound to microtiter plates when these plates were compared with paper discs. It is concluded that IgG antibodies are directed against antigenic components that are preferentially bound to polystyrene surfaces.