The CC chemokine eotaxin is a selective chemoattractant for guinea pig eosinophils, first purified from bronchoalveolar lavage fluid in a guinea pig model of allergic airway inflammation. We have now isolated the gene and cDNA for a human counterpart of eotaxin. The gene maps to chromosome 17 and is expressed constitutively at high levels in small intestine and colon, and at lower levels in various other tissues. The deduced mature protein sequence is 66% identical to human monocyte chemoattractant protein-1, and 60% identical to guinea pig eotaxin. Recombinant human eotaxin produced in insect cells induced a calcium flux response in normal human eosinophils, but not in neutrophils or monocytes. The response could not be desensitized by pretreatment of eosinophils with other CC chemokines, suggesting a unique receptor. In this regard, we show that human eotaxin is a potent and highly specific agonist for CC chemokine receptor 3, a G protein-coupled receptor selectively expressed in human eosinophils. Thus eotaxin and CC chemokine receptor 3 may be host factors highly specialized for eosinophil recruitment in inflammation, and may be good targets for the development of selective drugs for inflammatory diseases where eosinophils contribute to pathogenesis, such as asthma.

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Mikulicz's disease is quite different from SS clinically and histopathologically. MD is suggested to be an IgG4-related systemic disease.

Following the 1st IUIS/WHO Collaborative Study of monoclonal anti-IgG subclass antibodies, a panel of WHO Specificity Reference Reagents (SRR) was established [Jefferis, R., et al. (1985) Immunol. Lett., 10, 223]. At the time, the hope was expressed that further reagents particularly for IgG2, and other allotypic specificities would become available which could be applied in a wide range of assay protocols. The 2nd study reports the evaluation of nineteen anti-subclass and seven anti-allotype monoclonal antibodies. The anti-IgG1 antibody HP6187 was equivalent in performance to the SRR. Others, that were not of the mouse IgG1 isotype, may be useful for particular applications. The anti-IgG2 antibody HP6200 could be a valuable addition to the WHO SRR; it is specific for an epitope in the Fab region but does not have the light chain bias of HP6014. Antibodies of putative allotype specificity exhibited the claimed specificity when used within protocols similar to those employed by the originating laboratory. It appears to be inherent in the nature of the epitopes (allotopes) recognized that it will take several years before reagents applicable to a wide range of techniques will become available.

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