Summary
Antisera obtained by the immunization of rabbits with heated polynucleotide-bovine serum albumin (BSA) mixtures prepared in 0.0015 M citrate buffer, pH 5.5 (C buffer) did not react with polynucleotide alone. The amount of antibody precipitated from such antisera by homologous antigen mixtures was greater than the amount precipitated by either native BSA or BSA heat denatured alone in an isotonic phosphate saline buffer, pH 7.4 (P-S buffer). Polynucleotide preadded to such an antiserum caused no reduction in the amount of antibody precipitable by homologous antigen. Mixtures of polynucleotide and BSA heated either separately or together in P-S buffer were less effective in precipitating antibody from such antisera than were homologous antigen prepared in C buffer. Absorption of polynucleotide-BSA antisera with heated BSA removed all cross-reacting antibody for both native and heated BSA, but further antibody precipitation could still be obtained with homologous antigen. Precipitin studies with anti-native BSA and anti-heated BSA showed that heated polynucleotide-BSA mixtures prepared in C buffer were closely related to heated BSA, while simultaneously retaining immunologic features of native BSA. It was concluded that the new antigenic properties found in heated BSA-polynucleotide mixtures were related to changes induced in the protein moiety by virtue of its interaction with polynucleotide, and that this interaction was strictly limited by the ionic strength and pH obtaining at the time of heating.
