Expression of Heat Shock Protein 70 (HSP70) and Astacin Genes of Strongyloides stercoralis as well as HSP70 and HSP17.1 Genes of S. ratti in Adult and Larval Stages of S. stercoralis.

Background: Uncovering the roles and characteristics of pathogenesis-related molecules can help us develop novel management methods in parasitology. In this study, we studied the expression levels of Strongyloides stercoralis heat shock protein70 (HSP70) (Sst-hsp-70) and astacin (Sst-ast) as pathogenesis-related genes as well as the expression of S. ratti HSP70 and HSP17.1 (Sra-hsp-70, Sra-hsp-17.1) in the larvae and adult stages of S. stercoralis. Methods: A hyperinfection isolate of S. stercoralis from Gilan Province, northern Iran was cultivated on nutrient agar. After a couple of days, parasites in different stages of life were collected, and total RNA was extracted. The expression levels of astacin and HSP genes were compared by real-time PCR. Results: Statistically higher expression levels of Sst-ast, Sst-hsp-70, and Sra-hsp-70 genes in L3 larvae than in adults were observed. However, the expression level of Sra-hsp-17.1 was non-significantly lower in the larval stage than in adult worms. Conclusion: Higher expression levels of Sst-ast, Sst-hsp-70, and Sra-hsp-70 genes in the larval stages of S. stercoralis suggest the potential role of these enzymes in parasite cutaneous invasion and pathogenesis. However, higher expression of Srahsp-17.1 in adult forms is probably involved in resistance and survival mechanisms. The similarity in gene expression between S. stercoralis and S. ratti can provide helpful hints to better understand strongyloidiasis from various perspectives, including pathogenesis, proper diagnosis, and targeted treatment.

Production of recombinant 14-3-3 protein and determination of its immunogenicity for application in serodiagnosis of strongyloidiasis.

BACKGROUND: Strongyloides stercoralis is the fourth most important intestinal nematode worldwide. The parasite load and larvae count are often low, thus conventional methods are not sufficiently sensitive to detect the infection. In this study we developed an immunoglobulin G-based enzyme-linked immunosorbent assay (ELISA) method to detect antibodies against S. stercoralis 14-3-3 protein in patients' sera. METHODS: S. stercoralis RNA was extracted and following complementary DNA synthesis, the 708-bp fragment of 14-3-3 protein was amplified by polymerase chain reaction and cloned into the pET28a+ expression vector. The 30-kDa recombinant 14-3-3 protein was expressed in Escherichia coli BL21 (DE3) cells and purified by affinity chromatography. Finally, its immunoreactivity was assessed by indirect ELISA and western blotting. RESULTS: The S. stercoralis 14-3-3 gene was successfully amplified and cloned into an expression vector. The 30-kDa recombinant protein was purified by affinity chromatography. An ELISA developed in-house detected infected patients' sera with 96% sensitivity. CONCLUSIONS: We concluded that the recombinant 14-3-3 protein has enough sensitivity and specificity for detection of strongyloidiasis in human sera and could be applied for serodiagnosis.