Changes in the surface antigen profile ofSchistosoma mansoniduring maturation from cercaria to adult worm

Publisher Website
Google Scholar
Abstract
Antigenic proteins on the surfaces of different developmental stages of Schistosoma mansoni were radio-iodinated by the lodogen-catalysed method and identified by immunoprecipitation with a panel of antisera. The sera comprised specific immune serum from mice harbouring a chronic schistosome infection or vaccinated with γ-irradiated cercariae; serum from rabbits immunized with adult schistosome tegumental outer membranes or a partially purified Mr32K glycoprotein from adult worm membranes; and a monoclonal antibody recognizing an Mr20 K antigen on the surface of schistosomula. The Mr38–32 K glycoproteins were the major antigens identified in surface-labelled cercariae and their probable association with the glycocalyx is discussed. Schistosomula transformed from cercariae either mechanically or by penetration of host skin in vitro, expressed a similar pattern of surface antigens to that identified for cercariae, but low molecular weight antigens of Mr20, 17 and 15 K were also detected. The Mr38–32 K glycoproteins, although present on newly transformed schistoso mula, were progressively replaced with time, by a single dominant glycoprotein (Mr 32 K) expressing identical epitopes to those on the Mr 38–32 K complex. Moreover, the data confirm that the Mr 32 K glycoprotein persists on the tegument after in vivo maturation and is conserved, together with Mr 20 and 15 K antigens, through to the adult stage. New antigens (Mr 97 and 25 K) were also detected during in vivo maturation and were present in late-stage schistosomes recovered from infected hosts. In addition, the enzyme alkaline phosphatase is expressed on the surfaces of 3-week-old liver worms as a dominant antigen (Mr 65 K); this feature may be related to nutritional and/or physiological processes in the tegument of this metabolically active stage of development.