Indoor exposure to Streptomyces albus and Aspergillus versicolor elevates the levels of spore-specific IgG, IgG1 and IgG3 serum antibodies in building users - A new ELISA-based assay for exposure assessment.

Moisture-indicative microbes in buildings are associated with a variety of symptoms, ranging from mild irritation to severe clinical illnesses. These symptoms are caused principally by dried, dormant and dead microbe material like spores, mycelium and microbe metabolites, leading to the activation of the immune system and formation of the antigen-specific immunoglobulins. This activation presumably takes place through the respiratory track and is a normal immune reaction against pathogenic invaders. During continuous exposure, a prolonged state of inflammation will follow, and this forms a considerable health risk for a building's occupant. A new ELISA system utilizing spores from two species Streptomyces albus and Aspergillus versicolor as an antigen was developed to reveal the related immunological processes. In 159 persons, microbial exposure was observed to increase the levels of spore-specific IgG, IgG1 and IgG3 serum antibody levels of individuals residing in microbe-dense buildings compared with the control reference buildings. No differences were detected in the levels of S. albus- and A. versicolor-specific serum IgA or IgM levels.