The fungal spores are a major cause of seasonal and perennial allergic disease affecting approximately 30 percent of atopic individuals. Since sensitization to multiple fungi is common, the ultimate choice of allergens for diagnosis and treatment of mold sensitivity will depend upon the identification of individual allergens. The characterization of the individual fungal allergens is made more critical by prior studies suggesting cross-reactivity among allergens from many genera. The investigator has proposed to study the allergenic composition and relationships of selected aerobiologically and immunologically significant Fungi Imperfecti, especially dark spore formers. Fungi will be established in the laboratory under defined culture conditions. Extracts will be prepared from spores and mycelia. Clinical, biochemical, molecular biological and immunological investigations will follow in order to identify, purify and fully characterize the allergens. Allergenic proteins will be recognized by binding of the IgE present in sensitive patients' sera. The allergen profile of each fungus will be determined on the basis of allergenic composition of spore and mycelial extracts of at least three strains. General cross-reactivity of mold pairs will be recognized by ELISA-inhibition. Individual cross-reacting allergens present in various genera will be identified by immunoblotting and immunoprint inhibition. Further efforts will be focused on characterizing one or more major, including cross-reactive, allergens and on establishing homologies using physicochemical and immunological criteria, amino acid sequence data, monoclonal antibodies and molecular cloning. Eventually, this study will determine the allergenicity of purified allergen(s) among the patients. The availability of major cross-reactive allergens in pure and standardized states will greatly improve the diagnosis and treatment of allergies to the Fungi Imperfecti.