Specific monoclonal antibodies against embryonic chicken adipose tissue cell membranes and their application against developing adipocytes

Abstract

Use of anti-adipocyte monoclonal antibodies (MAb) for reduction of fat mass in chickens was investigated in two experiments. Reduction of adipose tissue mass was obtained only in Experiment II. In Experiment I, 132 fertilized broiler chicken eggs were injected with 23 []g control mouse IgG or MAb against chicken adipocyte plasma membranes. Control IgG or MAb was injected into the allantoic age was observed when a mixture of three MAb at 0, 0.05, 0.1, 0.2, or 0.4 mg was injected at circulation at 14 or 17 d of embryogenesis. Sixty-six uninjected fertilized eggs were a negative control. Hatched chicks were randomly placed in replicate brooder pens and fed ad libitum. Body weight and feed intake were periodically measured. Approximately half of the chicks were killed at 2 weeks of age and heart, liver, bursa, and spleen weights were collected. At 2 and 6 weeks of age whole body, femoral, pectoral, and abdominal adipose weights were collected. In Experiment II, a dose-related reduction of relative abdominal depot mass at 6 weeks of 15 d of embryogenesis. Hatch rate was significantly reduced at the 0.4 mg dose. Subsequently, 180 eggs at 15 d of embryogenesis were an uninjected control or were injected with 0.2 mg of either a control mouse IgG or MAb against chicken adipocyte plasma membranes. At 2 weeks of age, femoral and pectoral adipose tissues, major organs, and total body weights were not affected by MAb injection. Abdominal fat pad mass as a percentage of body weight was reduced (P [] 0.05) > 28% by 6 weeks of age. Neither femoral nor pectoral adipose proportions of body weight were significantly affected. Growth rate, feed intake, and total body weight at 6 weeks of age were not significantly affected. Anti-adipocyte MAb injections at 15 d of embryogenesis significantly reduced (P < 0.05) relative abdominal adipose tissue mass by 6 weeks of age, while total body weight and feed intake were not affected. A dose-dependent reduction of adipose tissue mass was observed later in life after the embryo was exposed to monoclonal antibodies against adipocyte cell membranes.