Development of Ss-NIE-1 Recombinant Antigen Based Assays for Immunodiagnosis of Strongyloidiasis

Abstract

Strongyloides stercoralis is a widely distributed parasite that infects 30 to 100 million people worldwide. In the United States strongyloidiasis is recognized as an important infection in immigrants and refugees. Public health and commercial reference laboratories need a simple and reliable method for diagnosis of strongyloidiasis to identify and treat cases and to prevent transmission. The recognized laboratory test of choice for diagnosis of strongyloidiasis is detection of disease specific antibodies, most commonly using a crude parasite extract for detection of IgG antibodies. Recently, a luciferase tagged recombinant protein of S. stercoralis, Ss-NIE-1, has been used in a luciferase immunoprecipitation system (LIPS) to detect IgG and IgG4 specific antibodies. To promote wider adoption of immunoassays for strongyloidiasis, we used the Ss-NIE-1 recombinant antigen without the luciferase tag and developed ELISA and fluorescent bead (Luminex) assays to detect S. stercoralis specific IgG4. We evaluated the assays using well-characterized sera from persons with or without presumed strongyloidiasis. The sensitivity and specificity of Ss-NIE-1 IgG4 ELISA were 95% and 93%, respectively. For the IgG4 Luminex assay, the sensitivity and specificity were 93% and 95%, respectively. Specific IgG4 antibody decreased after treatment in a manner that was similar to the decrease of specific IgG measured in the crude IgG ELISA. The sensitivities of the Ss-NIE-1 IgG4 ELISA and Luminex assays were comparable to the crude IgG ELISA but with improved specificities. However, the Ss-NIE-1 based assays are not dependent on native parasite materials and can be performed using widely available laboratory equipment. In conclusion, these newly developed Ss-NIE-1 based immunoassays can be readily adopted by public health and commercial reference laboratories for routine screening and clinical diagnosis of S. stercoralis infection in refugees and immigrants in the United States.

Prevalence of parasitic infections among recent immigrants to Chicago

“…Antibody responses to cysticercosis, strongyloidiasis, and toxocariasis were determined using a multiplex bead-based assay (MBA). [51–53] For cysticercosis, 3 recombinant antigens (rGP50, rT24H, and sTs18var1) were used; one recombinant antigen was used for both strongyloidiasis (Ss-NIE-1) and toxocariasis (rTc-CTL-1). Briefly, the antigens were coupled to carboxylated magnetic particles, and then incubated with sera (diluted 1:100 in PBS/0.3% Tween-20/5% milk) for 30 minutes.…”

Multiplex serologic testing within a cross-sectional lymphatic filariasis sentinel site survey in coastal Kenya reveals community-level differences in IgG antibody responses to parasitic diseases and vaccines

“…Recombinant Schistosoma mansoni glutathione-S-transferase (GST) protein was expressed from pGEX 4T-2 plasmid (GE Healthcare, Piscataway, NJ) and purified as previously described [26]. GST fusion proteins that included protein sequences from Brugia malayi [Bm33; [21] and Bm14; [19]], Strongyloides stercoralis [NIE; [27]], and Plasmodium falciparum 3D7 strain [MSP119; [28]] were expressed and purified as previously described. A W. bancrofti Wb123-GST fusion protein was a kind gift from T. Nutman (NIH, Bethesda, MD).…”

Development of Two FhSAP2 Recombinant–Based Assays for Immunodiagnosis of Human Chronic Fascioliasis

“…The antibody detection was also carried out following the procedure previously described. 10,11 The complex of antibody and coupled beads was detected using 50 μL of biotin-XX mouse antihuman IgG 4 (Cat. no.…”

“…5,7,13 This format should allow for simultaneous determination of antibody responses to multiple infections in a single assay run. 11 To summarize, we used a recombinant antigen in two novel high-performance assays for detecting F. hepaticaspecific antibodies. Because these assays use recombinant proteins, negating the need for native parasite materials, they can be more readily adapted for use in public health laboratories.…”