Isolation of an eosinophil chemotactic lymphokine as a natural mediator for eosinophil chemotaxis from concanavalin A-induced skin reaction sites in guinea-pigs.

An intradermal injection with 20 micrograms concanavalin A (Con A) induce a marked tissue eosinophilia peaking at 24 h after the injection in guinea-pigs. Two different eosinophil chemotactic factors (ECFs) were isolated from the Con A-induced skin reaction sites. A non-dialysable ECF with mol. wt of about 70,000 closely resembled delayed ECF-a, which had been isolated from active cutaneous anaphylactic skin lesions and confirmed to be a product of T lymphocytes by antigenic stimulation, by virtue of the antigenicity, the chromatographic profiles on Sephadex G-100 and on DEAE-Sephadex, affinity to Con A-Sepharose, and other physicochemical properties. The activity of the factor paralleled the intensity of tissue eosinophilia, suggesting that the factor may function for the tissue eosinophilia as a natural mediator. Although another ECF with a low mol. wt (dialysable) was isolated from the same skin lesions, the dialysable factor may not contribute to the tissue eosinophilia because the activity of the factor paralleled the intensity of tissue basophilia but not that of eosinophilia.