AN ANTI-ADIPOCYTE MONOCLONAL-ANTIBODY IS CYTOTOXIC TO PORCINE PREADIPOCYTES IN-VITRO AND DEPRESSES THE DEVELOPMENT OF PIG ADIPOSE-TISSUE

A mouse monoclonal antibody of the IgG2b subclass was raised against p orcine adipocyte plasma membranes. This antibody did not cross-react i n immunocytofluorescence with any tested celltype or tissue other than porcine adipocytes. Complement-mediated cytotoxicity was demonstrated in primary cultures of porcine stromal-vascular cells. When the antib ody and complement were added to already differentiated cultures, the treatment resulted in elimination of lipid-filled preadipocytes, where as an early treatment of cultures prevented the appearance of these ce lls. In vivo, injection of newborn pigs with 1 mg/kg of monoclonal ant ibody on d 2 and 5 of life produced a more than 20% reduction of subcu taneous and leaf fat lipids at 35 d of age, whereas the lipid content of the longissimus muscle remained unaffected. These results demonstra te that early systemic treatment of pigs with a specific anti-adipocyt e antibody reduces the fat mass. In addition to their potential in viv o use, monoclonal antibodies directed against adipose determinants may be useful tools for studying adipocyte lineage.