MODIFICATION OF ACCESSORY ACTIVITY OF PERITONEAL-CELLS FROM FASCIOLA-HEPATICA INFECTED-RATS

The effect of Fasciola hepatica excretory-secretory antigen (ESA) was studied in the modulation of the accessory functions of peritoneal cel ls (PC) of rats infected with the parasite. PC rats infected with F. h epatica 7 and 14 days previously showed a marked decrease in phagocyti c activity against Candida tropicalis (P < 0.007 and P < 0.004, respec tively). The same effect was observed when the assay was carried out w ith PC from animals injected 7 days before with ESA(P < 0.001) includi ng PC previously treated in vitro with ESA. To investigate the effect of ESA on the antigen presenting ability, PC of animals infected befor e transfer to syngeneic normal rats were stimulated in vitro with eith er F. hepatica whole antigen (FhWA), ESA or human serum albumin (HSA). Delayed type hypersensitivity (DTH) response to the different antigen s studied over a 35 day period was negative in rats transferred with s ensitised PC. When these animals were immunised with the corresponding antigen the DTH response became positive. A similar result was obtain ed in PC receptors from ESA inoculated rats and in vitro stimulated wi th FhWA or HSA. These data suggest that the alterations observed in th e functions of peritoneal cells may, in part, be due to the effect of the F. hepatica ESA.