Differences and similarities of nurse cells in cysts ofTrichinella spiralisandT. pseudospiralis

Abstract

AbstractThe nurse cell in the cyst ofTrichinella spiraliscomprises at least two kinds of cytoplasm, derived from muscle or satellite cells, as indicated by the pattern of staining using regular dye (haematoxylin and eosin, or toluidine blue), alkaline phosphatase (ALP) expression, acid phosphatase (ACP) expression and immunostaining with an anti-intermediate filament protein (desmin or keratin). Muscle cells undergo basophilic changes following aT. spiralisinfection and transform to the nurse cells, accompanied by an increase in ACP activity and the disappearance of desmin. Satellite cells are activated, transformed and joined to the nurse cells but remain eosinophilic. The eosinophilic cytoplasm is accompanied by an increase in desmin and ALP expression but not an increase in ACP activity. Differences in the staining results for ALP or ACP suggest that the two kinds of cytoplasm have different functions.Trichinella pseudospiralisinfection results in an increase of ACP activity at a later stage thanT. spiralis. There is also a difference in the location pattern of ACP in the cyst ofT. spiraliscompared withT. pseudospiralis. InT. spiralis, ACP is diffused within the cell, but inT. pseudospiralis, ACP distribution is spotty corresponding to the location of the nucleus.Trichinella pseudospiralisinfection is accompanied by a slight increase in ALP activity. Activated satellite cells following aT. pseudospiralisinfection exhibit an increase in desmin expression. The present study therefore reveals that nurse cell cytoplasm differs between the twoTrichinellaspecies and between the two origins of cytoplasm in the cyst ofT. spiralis.