Further environmental factors affecting the antigenicity of Trichophyton rubrum

Biochemical determinations performed on ammonium sulfate soluble and insoluble fractions of crude mycelial extracts ofTrichophyton rubrum indicated that these antigens were either carbohydrates or carbohydrates with peptide side chains. The antigens contained considerable amounts of galactose and mannose.Gel filtration techniques proved to be effective in separating these antigens. One antigen had a molecular weight greater than or equal to 2.0 × 10⁶. A smaller, more reactive antigen was also found; however, the elution time of this antigen varied with the concentration of dextrose in the medium.Quantitative precipitation tests used to differentiate the serological reactivity of crude antigens, recovered from mycelia grown on media containing variable concentrations of dextrose, indicated that the serological reactivity of the crude antigen was inversely proportional to the concentration of the carbohydrate source, with an optimum reactivity occurring with antigens prepared from mycelia grown in low dextrose concentrations.Nitrogen and carbohydrate concentrations performed on whole mycelia and cell free extracts demonstrated that the total nitrogen, soluble nitrogen, total carbohydrate and soluble carbohydrate concentrations were influenced by the concentration of the carbohydrate source. The optimum carbohydrate concentration necessary for the maximum ratio of protein and carbohydrates per gram of mycelium was 15.0 g/l. This is less than the amount used in most Sabouraud's dextrose media formulations. The effect of these environmental factors on the serological reactivity was discussed.Supported in part by NIH Environmental Health Tranining Grant ES00081-02. The help of Mrs. Gary Swecker is gratefully acknowledged for preparing the graphs.