Enhancement of Eosinophil Leukocyte Chemotaxis by a Factor in Normal Human Serum (SEF)

Abstract

An activity in normal human serum is described which enhances the migration of eosinophils towards neutrophil-derived eosinophil chemotactic factor (ECF). The serum-enhancing factor (SEF), in contrast to the inhibitors in serum, is expressed primarily during weak chemotaxis, acts in a cell-directed fashion, increases the chemokinesis of eosinophils and, in the presence of ECF, enhances chemotaxis in a synergistic fashion. SEF is found in sera of several mammalian species, affects human and guinea pig eosinophils, and it is heat-labile (56°C). On Sephadex column chromatography, SEF has a molecular weight of ∼800,000 daltons. In some sera, a second activity with a molecular weight of ∼200,000 daltons is eluted. SEF does not enhance eosinophil migration once the cells have been deactivated in vitro by their chemotactic factor. Because of its wide distribution, SEF may play an important modulating role both in in vitro assay systems and in vivo.

The presence of eosinophil‐activating mediators in sera from individuals with Schistosoma mansoni infections

“…mass and the other of 10 kDa. A substance of approximately 800 kDa has been described in human serum and plasma which causes enhancement of the chemotactic response of eosinophils in vitro [33]. The activity in the 10-kDa region resembles ECEF in mol.…”

Eosinophil chemotactic factor (ECF) in blister fluid of dermatological diseases

“…The several eosinophil chemotactic factors of larger molecular weight mentioned in the introduction could have contributed to this finding, as well as the larger products from mast cells (Boswell, Austen & Goetzl, 1978) and PMNs (Czarnetzki et al, 1976a). Enhancing factors in serum such as aj macroglobulin (Czarnetzki & Feldmann, 1978) could, furthermore, have increased the biological activity of these factors in the void volume of the G 25 column. The lack of ECF in some lesions despite the presence of eosinophils (Table 2) speaks for the involvement of other eosinophil chemotactic factors and thus for the activation of several immunological mechanisms.…”