Different types of response to foreign antigens by leech leukocytes

We used morphological and immunocytochemical approaches to characterize and to show the behavior of cells involved in leech inflammatory responses. Le eches were injected with bacterial lipopolysaccharide, fluoresceinated yeas ts, sulfate spheres and ciliates (Protozoa). Shortly after injection, migra ting cells appeared in the area of injection. The response of the cells occ urred in relation to the injected micro or macro antigens. Each injection f irst provoked a migration of cells towards the non-self material. Afterward s, different responses (degranulation, phagocytosis, encapsulation, melaniz ation) occurred, The migrating cells involved in these series of processes have a similar behavior and are characterized by CD markers of macrophages, NK cells and granulocytes, which are typical of many invertebrates and ver tebrates. (C) 2000 Harcourt Publishers Ltd.