Canine antibodies against formaldehyde-dog serum albumin conjugates: Induction, measurement, and specificity

Formaldehyde-dog serum albumin (F-DSA) conjugates were prepared as soluble haptenized proteins. The F-DSA reacted with rabbit anti-DSA. Change in electrophoretic migration of F-DSA as compared with DSA demonstrated conjugation. The more rapid migration toward the anode of F-DSA implied deletion of positive charges on DSA by conjugation with formaldehyde. F-DSA was antigenic for dogs when given intravenously as solution or subcutaneously in Freund's complete adjuvant. Intravenously administered formaldehyde resulted in an anti-F-DSA response, presumably caused by F-DSA forming in vivo. Canine IgG and IgA antibodies were measured by enzyme-linked immunosorbent assay. Canine anti-F-DSA has specificity for neither formaldehyde nor DSA alone, as determined by inhibition analysis, indicating that the antigenic determinant of F-DSA for dogs is a combination of formaldehyde and a new antigenic determinant formed on DSA. Immediate-type hypersensitivity occurred transiently in dogs immunized intravenously with formaldehyde or F-DSA. Finally, exposure of DSA to formaldehyde either in vivo or in vitro results in alteration of DSA molecules and an immune response to that altered DSA as well as to commercial DSA. Such results have previously been seen with formaldehyde in rabbits or with glutaraldehyde by other investigators.