The production and characterization of monoclonal antibodies to the fungus Aspergillus versicolor

Abstract

Fungal exposure measurements in indoor environments require accurate and precise monitoring methods. Such techniques may be based on monoclonal antibodies (Mabs) and enzyme-linked immunosorbent assays (ELISA) and here we report the cross-reactivity patterns of Mabs produced against Aspergillus versicolor. Balb/c mice were immunized with the particulate fraction of homogenized spores and 46 Mabs (35 IgM, nine IgG3, two IgG1) were produced and tested for cross-reactivity against 55 fungal species. None of the Mabs was found to be species-specific for A. versicolor. Several Mabs strongly cross-reacted with most Aspergillus, Penicillium and Eurotium species and some Mabs also cross-reacted with Paecilomyces variotii and several Cladosporium and Stachybotrys species. Our results show that antibody responses in mice against spores of A. versicolor are dominated by highly cross-reactive antibodies of the IgM isotype. The widespread cross-reactivity suggests that the specificity of antibodies to be used for the detection of fungi in environmental samples need to be thoroughly characterized in order to avoid ambiguities in the interpretation of monitoring results. Furthermore, accurate estimates of spore concentrations may require the application of species-specific Mabs in order to avoid bias in result interpretation because of the differential reactivity of cross-reactive Mabs with different fungi.

Practical implications: Producers of monoclonal or polyclonal antibodies for the detection of fungi in environmental or clinical samples need to verify antibody reactivity patterns and accurately report that information to potential users. Furthermore, immunoassays based on mouse or human serum or purified immunoglobulin fractions need to consider antibody cross-reactivity as a potential confounding factor during interpretation of results.