The antigens of pigeon breeder's disease. VII. Isoelectric focusing studies on unfractionated pigeon dropping extract

Isoelectric focusing (IEF) studies on pigeon dropping extracts (PDE) revealed that it is a complex mixture of components that are acidic in nature. Chromatographically purified antigens PDE(B), PDE₁, and PDE₃ showed multiple bands in IEF, indicating a microheterogeneity of these components, with peak concentrations focusing at pH 6.1, 4.6, and 3,8, respectively. The isoelectric points are compatible with the chromatographic behavior of these antigens on DEAE-cellulose. Crossed immunoelectrofocusing (CRIF) resolved PDE into seven precipitin lines with rabbit antiserum in a pH gradient from 3.5 to 9.5, and into nine precipitable components in a pH gradient from 2.5 to 7.0. The complexity of this antigen source appears to reside in the heterogeneity of immunologically related antigens. A comparison of pigeon breeder's sera by CRIF of PDE revealed a qualitative difference in precipitation patterns obtained with symptomatic and asymptomatic individuals. Sera from all (eight out of eight) of the symptomatic breeders tested precipitated an unidentified component of PDE, whereas none (zero out of four) of the sera from asymptomatic breeders detected this antigen. These results suggest that CRIF of PDE is useful as a diagnostic tool and that some specific component of PDE may be involved in the pathogenesis of the disease.