[Characterization of exoantigens of Aspergillus fumigatus. Study of factors influencing their quality].

Several methods are available for exoantigen preparation and standardization, but until now there is no agreement about which is the best of them. Moreover an exhaustive analysis of the influence of several experimental conditions on the antigenic composition of exoantigens of Aspergillus fumigatus is badly needed. In this paper the analysis of the influence of the following conditions on this antigenic composition is described (origin of strains, culture media composition, incubation time of mycelial stationary growth in culture media and immunological techniques used to standardize the antigens. Antigenic extracts were obtained from six strains of A. fumigatus from different origin (pathogenic, collection and contaminants) growing in different broth culture media (glucose-asparagine, Sabouraud, dialyzed neopeptone, and Czapek Dox). The culture media were separated from mycelium, dialyzed and freeze-dried. These extracts were used at concentrations of 100 mg/ml. Immunoprecipitation techniques (immunodiffusion, immunoelectrophoresis and crossed-immunoelectrophoresis) were used in this work to evaluate the quality of the extracts. All these methods were performed with human sera from patients with aspergilloma and animal sera (rabbit and goat) experimentally immunized. Averages and standard deviations were calculated for each group and the possible significance of differences between groups was studied using the Student-t test. Analysis of results shows that immunological characteristics of the exoantigens used for diagnosis are independent of the different incubation times studied. It has been confirmed in this study that results depend to a certain degree on the origin of the serum used. The strains kept in collection for several years showed less reactivity than those recently isolated.(ABSTRACT TRUNCATED AT 250 WORDS)