Effect of carrageenan on activity of the mononuclear phagocyte system in the mouse.

Injection of 5 mg carrageenan caused hepatosplenomegaly and thymic involution and resulted in temporary blockade of the mononuclear phagocyte system (MPS). Impaired MPS activity was shown by decreased hepatic phagocytosis of i.v. injected colloidal carbon and 51Cr-labelled sheep red blood cells (SRBC). Depression of Kupffer cell activity was dependent on carrageenan dose, route of administration and interval between carrageenan and particle injection. Reduction in hepatic uptake of SRBC was accompanied by increased localization of these cells within the spleen.