Hapten concentrations in the circulation of animals actively immunized with hapten-protein conjugates
O'Neill, S.P.; Robb, T.E.
Journal of Immunology 116(2): 363-366
1976
ISSN/ISBN: 0022-1767 PMID: 1249418 Document Number: 98324
Animals immunized with hapten-protein conjugates subsequently circulate high concentrations of hapten bound by antibody. The levels of hapten detected are capable of significantly reducing antibody titer in the sera immunized animals. In the case of steroid-protein conjugates, the main source of increased plasma steroid concentration is the immunizing conjugate, although a contribution from increased host secretion may also occur. The results for rabbits immunized with digoxin-BSA indicate that the appearance of circulating digoxin followed the appearance of circulating antibody to digoxin. Appearance of digoxin in circulation appears to coincide with the operation of the immune response and may be related to macrophage activity. Similar conclusions are drawn from results obtained for circulating morphine in the serum of a sheep immunized with morphine-BSA. Injected hapten-protein antigens are probably processed by macrophage to produce low molecular weight haptenic fragments which are maintained in circulation for prolonged periods in the form of antibody-hapten complexes.