SERUM-FREE CULTURING OF ADULT SCHISTOSOMA-MANSONI IN DIALYSIS BAGS FOR THE PRODUCTION OF EXCRETORY SECRETORY ANTIGENS/

Antigenic excretory/secretory (E/S) products from Schistosoma mansoni are potentially important in the development of diagnostic assays used to detect circulating antigens in schistosomiasis. The E/S products t o be used as antigen(s) for this development must, by necessity, be fr ee of exogenous proteins. The ability to extend serum-free in vitro cu lture of adult worms is, therefore, essential. Adult worms were perfus ed from mice, washed in serum-free RPMI-1640 with antibiotics, and pla ced in sterile dialysis bags, molecular weight cut-off 10 kDa, at a co ncentration of 100 worms in 1 ml of serum-free, supplemented RPMI-1640 . Each bag was then placed in a flask of supplemented RPMI-1640 with 1 0% fetal calf serum in a humidified incubator at 37 C, 7% CO2. At days 1, 3, 5, 8, and 12, worms were collected; E/S culture medium was anal yzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Wor m survival rates were 85% after I day in culture, dropping gradually t o 65% on day 8, and then to 38% on day 12. Silver stain for total prot ein and immunoblot exposed to positive human infection serum showed E/ S culture media from days 3 and 5 having the least complex banding pat tern. The quantitative specific activity of E/S, as measured by antige n-limiting Falcon assay screening test system-enzyme-linked immunosorb ent assays against human infection serum, indicates E/S antigenicity c losely follows the attrition of worms and, therefore, may be directed against the release of somatic antigens by dead worms. Culturing S. ma nsoni in dialysis tubing is useful in deriving E/S products.