CU2-MEDIATED COMPLEX-FORMATION BETWEEN POLYACRYLIC-ACID (PAA) AND BOVINE SERUM-ALBUMIN()

Cu2+-mediated complex formation between polyacrylic acid (PAA) and neg atively charged bovine serum albumin (BSA) was studied in neutral wate r in the presence of Cu2+. Depending on the concentration of Cu2+, the reaction between PAA-Cu2+ complexes and BSA appeared to follow one of two possible paths. At low Cu2+ concentrations (n(Cu)/n(AA) < 0.15), a further increase in BSA concentration led to the breakdown of the co mplex as in mechanism I: [GRAPHICS] At higher Cu2+ concentrations (n(C u)/n(AA) > 0.15), a further increase in BSA concentration led to the f ormation of non-stoichiometric polycomplexes (mechanism II): [GRAPHICS ] The immunogenic properties of ternary mixtures of BSA-Cu2+-PAA were investigated and the relationship between immunogenicity and complex f ormation in solution was analyzed. The addition of Cu2+ to solutions o f PAA with BSA gave rise to a considerable increase in BSA-specific im munogenicity. Data obtained from the analysis of the immunogenicity of BSA-Cu2+-PAA mixtures formed using different ratios of the components suggested that (1) the highest immunogenic activity is exhibited by s table ternary complexes, and (2) immunoactive polyelectrolyte complexe s have a non-stoichiometric composition. We thus propose a novel metho d, based on Cu2+ mediated complex formation, to enhance protein-specif ic antibody responses.