Sm14 gene expression in different stages of the Schistosoma mansoni life cycle and immunolocalization of the Sm14 protein within the adult worm

Abstract

Sm14 is a 14-kDa vaccine candidate antigen from Schistosoma mansoni that seems to be involved in cytoplasmic trafficking of fatty acids. Although schistosomes have a high requirement for lipids, they are not able to synthesize fatty acids and sterols de novo. Thus, they must acquire host lipids. In order to determine whether Sm14 is present in different stages of the life cycle of the parasite, we performed RT-PCR. Sm14 mRNA was identified in all stages of the life cycle studied, mainly schistosomulum, adult worm and egg. Additionally, we used a rabbit anti-Sm14 polyclonal antibody in an indirect immunofluorescence assay to localize Sm14 in adult worm sections. The basal lamella of the tegument and the gut epithelium were strongly labeled. These tissues have a high flow of and demand for lipids, a finding that supports the putative role of Sm14 as an intracellular transporter of fatty acids from host cells.

Parasitological characteristics of Schistosoma mansoni infection in swiss mice with underlying malnutrition

“…Given that the biological characteristics of the parasite were not affected due to malnourishment, it is important to stress some questions concerning factors that may influence egg-laying. The first aspect is based on the fact the migrating schistosomula possess ability to take up nutrients from the host (Brito et al 2002). Hence, our results suggest malnutrition seem do not affect them.…”

Excretory/Secretory Proteome of the Adult Developmental Stage of Human Blood Fluke, Schistosoma japonicum

“…Therefore, schistosome FABPs, which are capable of binding fatty acids and/or retinoids (59), have been selected by the World Health Organization as one of six antischistosome vaccine candidates (60). This protein has been reported to localize on the subtegumental region and the gut epithelium (61). However, our study indicated it may be excreted or secreted into host serum (Table I); this result strongly argues against the possibility that SjFABP is unlikely to be accessible to the immune system (52).…”

“…If nonspecific adsorption of host proteins by schistosome were to prevail then albumin and hemoglobin would be expected to be the dominant host proteins in our results. This was not the case, raising the possibility that most, if not all, of these host proteins identified in ESPs of S. japonicum were selectively adsorbed by schistosome worms with specific tegument receptors (61,86). Therefore, these findings illustrate a potential molecular mechanism for host-parasite interplay: the schistosome specifically adsorbs host Igs and fibronectins to prevent host immune detections and attacks, while the host tries to stimulate its innate immune reactive molecules (antimicrobial protein CAP18) and acquired immune (Igs and complement C3) systems against schistosome invasion.…”

Current Status of Vaccines for Schistosomiasis

“…Although technically challenging, there is a case for promoting the development of a live, attenuated, cryopreserved schistosomulum vaccine for use against S. japonicum in buffaloes to reduce zoonotic transmis-VOL. 21,2008 CURRENT STATUS OF VACCINES FOR SCHISTOSOMIASIS 229 sion to humans in China (99). If successful, the veterinary vaccine could provide a paradigm for the development of antischistosome vaccines for human use.…”