Crossed immunoelectrophoretic analysis of two antigen extracts of Thermoactinomyces candidus

A pyridine extract antigen and a double-dialysis antigen (DDA) obtained from Thermoactinomyces candidus were analyzed by crossed immunoelectrophoresis. In addition, the heat lability, pronase sensitivity, and isolectric points of the components of the DDA were determined. By using antisera raised against crude pyridine extract antigen, two immunogenic components were resolved by crossed immunoelectrophoresis. A similar analysis of DDA using antisera raised against crude DDA revealed 15 immunogens. All but six components were heat labile, whereas pronase had little effect on the number of resolvable components. Intermediate gel crossed immunoelectrophoresis using antiserum raised to whole spores detected six immunogenic components, four of which were also detected by the anti-DDA serum. A total of 19 bands were obtained when the DDA was subjected to flatbed isoelectric focusing on polyacrylamide gels. The isoelectric points for the various components were found to range from 3.5 to 5.7. Crossed immunoelectrophoresis using isoelectric focusing in the first dimension yielded at least 16 immunogenic components. Six components with isoelectric points falling in the range of 4.5 to 6.4 were found to be resistant to heat. A comparison with antigens obtained from other thermophilic actinomycetes is presented.