GENERATION OF H2O2 BY HUMAN NEUTROPHILS AND CHANGES OF CYTOSOLIC CA2-BINDING PROTEINS (LECTINS OR IMMUNOGLOBULINS)( AND PH OF RAT THYMOCYTES IN RESPONSE TO GALACTOSIDE)

In contrast to plant agglutinins, biological activities of animal/huma n lectins are not well defined yet. Testing a panel of seven mammalian carbohydrate-binding proteins we have found that the dimeric lectin f rom chicken liver (CL-16) was a stimulator of H2O2 release from human neutrophils as well as effector for induction of cytosolic Ca2+ and pH increase in rat thymocytes. Activity of this lectin was comparable to potent galactoside-specific plant lectins such as Viscum album L. agg lutinin. The activities of the tested plant lectins depended significa ntly on their nominal carbohydrate specificity as well as on the sourc e. The results indicate that endogenous lectins may be involved in the regulation of neutrophil and lymphocyte functions by elicitation of s elective biosignaling reactions.