Antigen-mediated release of eosinophil growth stimulating factor from Trichinella spiralis sensitized spleen cells: a comparison of T. spiralis stage-specific antigen preparations.

When non-adherent, Trichinella spiralis-sensitized mouse spleen cells were challenged in vitro with T. spiralis antigens, an eosinophil growth factor (Eo-GSF) was released into the culture medium. This factor was assayed by its ability to initiate eosinophil production in liquid cultures of syngeneic, non-adherent marrow cells obtained from unsensitized mice. Extracts of each parasite stage as well as excretory-secretory (ES) products of adult and muscle larva stages were compared for their ability to stimulate spleen cells to release Eo-GSF. All stages and ES products had this ability but most of the preparations had unique dose-optima and there was a very wide range with regard to the optimum dose (in microgram protein/ml): (i) preadult stage, 1 x 10(-5); (ii) muscle stage ES products, 1 x 10(-3); (iii) muscle stage, 1 x 10(-2); (iv) adult stage, 1 x 10(-2); (v) adult ES products, 1 x 10(-1); and (vi) newborn stage, 1.0. When the Eo-GSF-containing conditioned media derived from spleen cell cultures exposed to the optimum dosages were tested on the same population of marrow cells, three potency groups were identified. The rank order of potency was: muscle stage ES products greater than preadult, newborn and adult stages greater than muscles stage and adult ES products. Preliminary experiments revealed that this ranking was not maintained with regard to the release of neutrophil and macrophage growth factors by these preparations.