CELL BIOLOGY AND FUNCTION OF THE EOSINOPH IL GRANULOCYTE IN IMMUNOLOGICAL INFLAMMATION

In recent years, increasing evidence has accumulated to suggest that t he eosinophil represents a potent cytotoxic effector cell which plays a key role in the pathogenesis of pulmonary diseases as well as other human disorders. Beside contributing to anti-parasitic host defense, e osinophils can prove detrimental to a number of host organs and tissue s via release of their preformed basic proteins as well as de novo gen erated lipid mediators or oxygen radicals. Eosinophil effector functio ns are stimulated by certain lipid mediators and cytokines released by other cells in the course of active disease. In addition to their eff ector functions, eosinophils may have other functions in immune respon ses. Synthesis and expression of class II proteins of the major histoc ompatibility complex (MHC) may enable eosinophils to serve as antigen- presenting cells, i.e. to the antigens that appear at mucosal surfaces . In addition to collaborative interactions with lymphocytes, CD4-expr essing eosinophils may elaborate cytokines that can effect cells withi n their tissue milieu. In conclusion, the evolving understanding of eo sinophils indicates that eosinophils may not only serve as end-stage e ffector cells but also interact cooperatively with other cellular tiss ue elements in related diseases.