Immunological manipulation of adiposity

Although hormonal regulators of adiposity are available they as yet have not been licensed for use. Withdrawal periods and delivery systems are still potential problems in maximizing their effectiveness. Immunization techniques, on the other hand, suffer none of the problems of withdrawal periods or requirement for frequent injection/implantation. As such they are clearly perceived as safe, economic and should have a positive animal welfare image. They are, however, not without their problems. Active immunization in particular involves an autoimmune response and this is typically difficult to evoke and virtually impossible to regulate. In addition, the fact that antibodies may have immunoneutralizing and immunoenhancing properties may explain the apparently contradictory results obtained in various studies as, for example, in the case of immunization against somatostatin. As our knowledge of immune responsiveness and its control increases, however, the possibilities for immune intervention should increase considerably. We may then be faced with ethical rather than practical limitations as to how far we should manipulate growth and body composition.