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PubMed1991

An improved immunomagnetic procedure for the isolation of highly purified human blood eosinophils.

A simple method is described for the isolation of human peripheral blood eosinophils by an immunomagnetic procedure. Superparamagnetic particles were coupled to a monoclonal antibody against CD16, a molecule present on neutrophils but not on eosinophils. A peripheral blood granulocyte preparation, containing neutrophils and eosinophils, was incubated with these anti-CD16 particles. In the magnetic field of a permanent magnet, magnetically labelled neutrophils were then retained on columns with a ferromagnetic matrix. By this negative selection procedure, eosinophils of 99.5% purity were obtained from normal individuals and 99.6% purity from patients with eczema. A comparison was made between the immunomagnetic method and eosinophil isolation after N-formyl-methionyl-leucyl-phenyl-alanine treatment. Even in the case of individuals with very low eosinophil counts, the immunomagnetic method permits the efficient isolation of highly purified and functionally active eosinophils.

Antigens, CD↗

PubMedDate not supplied

Regulation of cytokine expression by human blood basophils.

IL-4 and IL-13 are key immunoregulatory cytokines because of their ability to induce and amplify Th2-type immune responses and by promoting IgE formation. The basophil is a particularly prominent source of IL-4/IL-13, which are rapidly produced upon Fc epsilonRI cross-linking. Cytokine expression by basophils is unique and distinct from other cell types, since: (1) Basophils are the only cell type constitutively expressing IL-4 and IL-13 mRNA. IL-4/IL-13 message and protein are expressed in a very restricted manner, since neither the mRNAs nor the protein products of most proinflammatory Th1-type, and even Th2-type, cytokines or chemokines are expressed; (2) Basophils secrete IL-4/IL-13 also upon IgE-independent activation (IL-3 plus C5a), and they are thereby potentially capable of initiating a Th2 response. Furthermore, we identified an adjuvant from helminths capable of directly inducing IL-4 formation, and (3) IL-4 expression by basophils is resistant to counter-regulatory effectors inhibiting Th2 development. Studies about the regulation of IgE-dependent and -independent IL-4/IL-13 expression by different cytokines, growth factors and chemokines demonstrate that the different basophil effector functions such as chemotaxis, exocytosis, leukotriene C4 formation and cytokine expression are regulated separately. Thus, our study supports a key immunoregulatory role of basophils in the skewing of immune responses to Th2.

Basophils↗