IMMUNOELECTROPHORESIS AND THEIR ANALYSIS BY TWO-DIMENSIONAL

SEROLOGY is widely used in the study of the involvement of Aspergillus spp. in a variety of pulmonary diseases. Since the introduction of double-diffusion and electrophoretic techniques in agar, soluble antigens have been obtained in one or other of the following ways. A culture is grown for 4-6 weeks and the supernatant fluid is used as a source of antigens (Longbottom and Pepys, 1964). A variant of this is the addition of toluene to a young culture, causing autolysis in 2-3 days (Pappagianis et al., 1961). Another method 'is the mechanical disruption of young mycelium approximately 3 days old, at the end of the logarithmic phase of growth (Wada, 1960; Azuma et al., 1967; Tran van Ky, Biguet and Vaucelle, 1968; Bardana et al., 1972; Kim and Chaparas, 1978; Hearn and Mackenzie, 1979); this last method has been used here in a search for more specific and reproducible antigens and to investigate the role and the relative immunological importance of the different antigens in the invaded host. Ammonium sulphate (AS) precipitation has been used previously to frac-tionate the culture-filtrate antigens of A. fumigatus (Longbottom, 1964) and two-dimensional immunoelectrophoresis can be used to assess antigenic varia-tion and individual IgG antibody response (Longbottom, 1978). The method has been used here to study the distribution of mycelial antigens precipitable by increasing concentrations of AS and to determine their reactivity against test sera. Two different batches of antigen have been analysed by the use of a serum raised against culture-filtrate antigens and a selected human serum. With selected antigenic preparations the IgG-antibody variation in individual sera has been examined; concurrently the detection of some recurring antigen-antibody interactions has been made possible. Finally, the procedure has proved useful for studies on the chemical nature of the antigens, by lectin-bind-ing with concanavalin A