Immunogenicity of glutaraldehyde treated homologous monomeric albumin in rabbits

Previous studies (Onicaˇ et al., 1978) have shown that glutaraldehyde polymerized homologous albumin is immunogenic in rabbits. The reaction mixture consisted of high proportion of polymeric and oligomeric molecules, but a small quantity of monomeric ones. The present investigation shows that the monomeric fraction isolated from the reaction mixture is altered in comparison with untreated monomeric albumin. The modification produced in the homologous monomeric albumin by glutaraldehyde conferred to the molecule immunogenic properties, due to the presence of new antigenic sites (haptenic determinants). Glutaraldehyde treatment induced similar haptenic determinants on albumins of different origins as shown by the cross-reactivity between glutaraldehyde treated human and rabbit albumin, which precipitate both with human and rabbit antibodies. Rabbit antibodies were shown to be specific both for the glutaraldehyde modified monomeric albumin and the “aged” fraction which exist in albumin stored either in dry state (commercial albumin) or in solution at 37°C. The same antibodies failed to react with freshly prepared albumin. Our data strongly suggest that the glutaraldehyde treatment alter the monomeric albumin in a similar way asin vitro “ageing” does.