Effects of tuftsin on postsplenectomy sepsis.

Tuftsin is a tetrapeptide within the CH2 domain of the IgG immunoglobulin. Enzymatically cleaved from its parent globulin, it increases the phagocytic activity of macrophages, monocytes, and neutrophils by specific receptor mechanisms. In splenectomized hosts the circulating levels of tuftsin are reduced. Postsplenectomy sepsis is due to impaired clearance of intravascular bacteria; it has been postulated that tuftsin deficiency may contribute to this impairment. In this experiment splenectomized DBA/2 mice were subjected to pneumococcal sepsis. The groups of mice treated with tuftsin and those that received autotransplanted splenic tissue had significantly improved survival rates. We conclude that tuftsin deficiency plays a role in postsplenectomy sepsis and that treatment with synthetic tuftsin protects the splenectomized host against pneumococcal septic death.