Eosinophils: Collection, Separation, and Activation

Granulocytes play an important role in the host defense against invading microorganisms such as bacteria and fungi (1 ,2 ). For the killing reaction, these cells have an extensive machinery of cytotoxic effector mechanisms including phagocytosis, production of toxic oxygen metabolites, initiated by a membrane bound nicotinamide adenine dinucleotide phosphate (NADPH)oxidase, and degranulation of cytotoxic proteins (for reviews see 1 ,2 ). Apart from being cytotoxic, these cells are also involved in maintaining inflammatory reactions by the release of cytokines and bioactive lipids such as platelet-activating factor and arachidonic acid metabolites. Uncontrolled activation of neutrophils plays an important role in the pathogenesis of diseases like acute respiratory distress syndrome (ARDS) and septic shock. Syndromes associated with granulocyte dysfunctions can cause severe clinical conditions (1 ,2 ).