EOSINOPHILS, IGE AND HELMINTHIASIS

Basically, mammalians' defence against worms lies upon antibody-depend ent cell cytolysis (ADCC), that involves activated eosinophils and spe cific immunoglobulins E attached to the targets. Eosinophils are produ ced by the bone marrow under the regulation of interleukin 5 (IL-5), t hat also activates them. They are attracted towards the parasites by c hemotactic factors, namely helminthic antigens, C5a and eosinophilic c hemotactic factor of anaphylaxis that is released by mast cells. Cytot oxic effects are due to the release of cationic proteins from the eosi nophil granules. Specific IgE are produced by B cells activated by int erleukin 4. IL-4 and IL-5 are secreted by T helpers 2 cells (Th2). The differentiation of this T cell subset is induced by allergens and hel minthic antigens. Large amounts of total IgE observed in helminthiasis are due to a non-specific stimulation of B cells, caused by a direct contact between B cells and T cells through CD 23 receptor.