Effects of irradiation and tunicamycin on the surface glycoproteins Schistosoma mansoni

Abstract

The cercarial glycocalyx and schistosomulum surface contains a number of glycoproteins which are expressed in very variable amounts within a parasite population. Tunicamycin inhibits glycoprotein synthesis of schistosomula if the parasites are incubated for 24 hr with the drug (10 micrograms ml-1). An unexpected increase in lectin binding to the parasite surface was observed but no other changes were detected. Schistosomula treated in this way did not develop in the host past the lung stage. Ultraviolet irradiation (400 microW min cm-2) also inhibited glycoprotein synthesis. Synthesis of other proteins, and in particular heat shock proteins, were also inhibited. Sera from mice (NIH strain) infected with irradiated cercariae contained antibodies which bound to normal schistosomula with lower affinity than to irradiated parasites. This is evidence that irradiation modifies the surface and secreted glycoproteins of schistosomula, so they are processed in a different way to normal glycoproteins by the host's immune system. The effects of irradiation on heat shock protein synthesis may allow the parasite to release a variety of proteins and glycoproteins in abnormal conformations. This may explain the enhanced immunogenicity of irradiated cercariae.

Schistosoma japonicum: proteomics analysis of differentially expressed proteins from ultraviolet-attenuated cercariae compared to normal cercariae

“…Furthermore, our group has found that recombinant SjHSP70 could activate dendritic cells and enhanced their antigen presentation capacity (data not shown), same as described by Srivastava 2002), indicating level change of HSP70 in UVAC might be related to the induced higher immune protection and provide new clues for the development of vaccine against schistosomiasis. HSP60 and HSP90 proteins are showed to be downregulated in UV-irradiated cercariae, which is consistent with the postulation of Kusel et al that the synthesis of heat shock proteins is inhibited in UV-irradiated cercariae, which causes the parasite to release a variety of proteins and glycoproteins with an abnormal conformations (Kusel et al 1989).…”

Schistosoma mansoni: Antiparasitic effects of orally administeredNigella sativaoil and/orChroococcus turgidusextract

“…The damage to the tegument along the worm's body would have impaired the functioning of the tegument and also destroyed the defense system of the worm, so that it could easily be attacked by the host's immune system [63]. Kusel et al [31] reported some of the functions of glycoproteins in the parasite surface acting as a physical or immunochemical barrier against the host's immune system. Therefore, the tegmental alteration in S. mansoni worms after treatment with black seed oil and/or algal extract could have exerted an intense effect on the meta-bolic activities of the parasite and in turn expose the tegument to the host's immune attack.…”

Ultrastructure alterations of adult male Schistosoma mansoni harbored in albino mice treated with Sidr honey and/or Nigella sativa oil

“…Also, Ro15-5458 and R-354 were recorded to cause tegumental damage of S. mansoni in the form of vacuolation (Fawzi, 1999;Taha, 2007). Kusel et al (1989) reported some of the functions of glycoproteins in parasite surface: act as receptors for growth substances, as a physical or immunochemical barrier to cells and antibodies of the host immune system and maintain the structure of the surface membrane. Therefore, the tegumental changes induced by Sidr honey and/or black-seed oil in S. mansoni worms could have exerted a profound effect upon the metabolic activities of the parasite.…”