Improvement of murine immune functions in vitro by thioproline

Previous studies have shown that several immune functions were improved in mice after the ingestion of a thioproline (thiazolidine-4-carboxilic acid) enriched diet. In the present work, we have studied the in vitro effects of several concentrations of this thiol compound (0.1, 0.5, 1, 2.5 and 5 mM) on the most relevant functions of three pivotal immune cells, namely, macro phages, lymphocytes, and natural killer (NK) cells from BALB/c mice. The re sults show that thioproline stimulates the phagocytic process of macrophage s, increasing the mobility directed to the inflammatory focus (chemotaxis) and the phagocytosis of inert particles. It increases the adherence and the chemotaxis capacities of lymphocytes, their proliferative activity and fav ours the natural cytotoxic activity that could improve the capacity to dest roy malignant cells. Thioproline concentrations of 0.5 and 1 mM were the mo st effective regarding the different functions analysed. These results sugg est that the improvement of immune functions, observed in previous work, af ter thioproline-enriched diet ingestion is due to a direct action of this t hiol compound on immune cells. (C) 1999 Elsevier Science B.V. All rights re served.