Lipoprotein lipase suppression in 3T3-L1 cells by a haematoprotozoan-induced mediator from peritoneal exudate cells.

Lysates of the haematoprotozoa Trypanosoma brucei or Plasmodium berghei stimulated murine peritoneal exudate cells to release a mediator, which suppressed lipoprotein lipase activity in differentiating 3T3-L1 preadipocytes. The parasite-induced mediator suppressed the activity of cell surface lipoprotein lipase up to 39% in a dose dependent manner. By impairing the activity of cell surface lipoprotein lipase, this mediator acts to inhibit the uptake of fatty acid, and ultimately the accumulation of lipid by the adipocyte. In vivo this defect in triglyceride removal may explain the hypertriglyceridemia commonly observed in haematoprotozoan infections. We suggest that the lipoprotein lipase suppression mediator is produced as a consequence of the immune response to these parasitic protozoa.