Luciferase Immunoprecipitation System Research Articles

Detection and monitoring PLA2R autoantibodies by LIPS in membranous nephropathy

Autoantibodies against the M-type phospholipase A2 receptor (PLA2R) are specific markers for primary membranous nephropathy (MN). Quantification of PLA2R autoantibodies is an important, noninvasive tool that facilitates the diagnosis and monitoring of primary MN. In this report we describe a highly quantitative luciferase immunoprecipitation systems (LIPS) assay for detecting PLA2R autoantibodies. For these studies, a cDNA fragment encoding the first 858 amino acids of PLA2R protein was cloned to generate N-terminal antigen fusion constructs with Gaussia luciferase (Gluc) and Nano luciferase (NanoLuc) reporters. Following transfection, crude cell extracts containing the recombinant PLA2R-luciferase fusion proteins were tested by LIPS on healthy controls, subjects with other kidney disease and subjects with MN. LIPS testing with both reporters detected robust PLA2R autoantibody levels in a subset of patients with primary MN and demonstrated 100% sensitivity compared to ELISA and/or Western blotting. The PLA2R-NanoLuc LIPS assay demonstrated 100% specificity matching the ELISA, but the specificity of the PLA2R–Gluc LIPS assays was slightly lower (97%). Further analysis revealed that autoantibody levels determined by PLA2R-NanoLuc LIPS correlated well with urinary protein excretion (R=0.79) and disease activity and was very sensitive for detecting clinical relapse. These results highlight the potential utility of the LIPS PLA2R-NanoLuc assay for diagnosis and management of MN.

Seroprevalence of Toxoplasma gondii in free-ranging and feral cats on Amami Oshima Island, Japan.

On Amami Oshima Island, free-ranging and feral cats are harmful to wildlife populations. In this study, the seroprevalence of Toxoplasma gondii in these cats was examined using a newly developed Gaussia luciferase immunoprecipitation system assay. Of 1,363 cats, 123 cats (9.0%) was positive for T. gondii. The prevalence was significantly different in different areas; among cats in the rural area, where many wild animals live, including endangered species, T. gondii infection was more prevalent than in the urban area of the island. This finding indicates a possible risk to wildlife of infection from free-ranging and feral cats. Therefore, management of cats is important for wildlife conservation.

Ganglionic acetylcholine receptor autoantibodies in patients with autoimmune diseases including primary biliary cirrhosis

Objectives: Autonomic dysfunction is closely associated with autoimmune diseases (AID) including primary biliary cirrhosis (PBC). The objective of this study was to determine the prevalence of anti-ganglionic (nicotinic) acetylcholine receptor (gAChR) antibodies in patients with AID.Methods: We determined the presence of gAChR antibodies in serum samples from 146 patients (systemic lupus erythematosus [SLE] = 32; rheumatoid arthritis [RA] = 43; systemic sclerosis [SSc] = 38; PBC= 33) without information regarding autonomic symptoms, as well as 34 patients with other neurological diseases [OND], and 73 healthy controls [HC]. We specifically analyzed sera for anti-gAChRα3 and -β4 antibodies using the luciferase immunoprecipitation system (LIPS) assay.Results: LIPS assay detected anti-gAChRα3 and -β4 antibodies in the sera from patients with SLE (12.5%, 4/32), RA (18.6%, 8/43), SSc (13.2%, 5/38), PBC (9.1%, 3/33), OND (2.9%, 1/34), and HC (0.0%, 1/73). There were no significant correlations between the levels of anti-gAChRα3 and -β4 antibodies, and the total titers of autoantibodies in AID.Conclusions: The results demonstrated a significant prevalence of anti-gAChR antibodies in patients with AID, which is independent of the production of other autoantibodies in patients with autoimmune diseases. These anti-gAChR antibodies could mediate the autonomic dysfunction involved in the autoimmune mechanisms of AID.

Anti-HIV Antibody Responses and the HIV Reservoir Size during Antiretroviral Therapy.

BackgroundA major challenge to HIV eradication strategies is the lack of an accurate measurement of the total burden of replication-competent HIV (the “reservoir”). We assessed the association of anti-HIV antibody responses and the estimated size of the reservoir during antiretroviral therapy (ART).MethodsWe evaluated anti-HIV antibody profiles using luciferase immunoprecipitation systems (LIPS) assay in relation to several blood-based HIV reservoir measures: total and 2-LTR DNA (rtPCR or droplet digital PCR); integrated DNA (Alu PCR); unspliced RNA (rtPCR), multiply-spliced RNA (TILDA), residual plasma HIV RNA (single copy PCR), and replication-competent virus (outgrowth assay). We also assessed total HIV DNA and RNA in gut-associated lymphoid tissue (rtPCR). Spearman correlations and linear regressions were performed using log-transformed blood- or tissue-based reservoir measurements as predictors and log-transformed antibody levels as outcome variables.ResultsAmong 51 chronically HIV-infected ART-suppressed participants (median age = 57, nadir CD4+ count = 196 cells/mm3, ART duration = 9 years), the most statistically significant associations were between antibody responses to integrase and HIV RNA in gut-associated lymphoid tissue (1.17 fold-increase per two-fold RNA increase, P = 0.004) and between antibody responses to matrix and integrated HIV DNA in resting CD4+ T cells (0.35 fold-decrease per two-fold DNA increase, P = 0.003). However, these associations were not statistically significant after a stringent Bonferroni-adjustment of P<0.00045. Multivariate models including age and duration of ART did not markedly alter results.ConclusionsOur findings suggest that anti-HIV antibody responses may reflect the size of the HIV reservoir during chronic treated HIV disease, possibly via antigen recognition in reservoir sites. Larger, prospective studies are needed to validate the utility of antibody levels as a measure of the total body burden of HIV during treatment.

Vertical transmission of hepatitis C virus-like non-primate hepacivirus in horses.

Non-primate hepacivirus (NPHV), a recently discovered hepatotropic virus infecting horses, is phylogenetically the closest known homologue of hepatitis C virus (HCV). The main route for acquiring HCV infection in childhood is vertical transmission. However, nothing is known about the natural mode of transmission for NPHV. To investigate the possibility of vertically transmitted NPHV infection in horses, 20 Thoroughbred broodmares and their foals were monitored during foaling season 2015 until 6 months post-partum. Prepartal serum was taken from the mares, and during foaling umbilical cord blood and colostrum samples were collected. Postnatal serum samples were taken from the foals after delivery. In addition, serum was taken at 3 and 6 months after foaling from all mares and foals. Samples were analysed for the presence of NPHV RNA by quantitative real-time PCR and for the presence of anti-NPHV NS3 antibodies by luciferase immunoprecipitation system. Identified NPHV isolates were sequenced and phylogenetic analysis of the viral glycoproteins was used to track the course of naturally occurring infections and the circulation of distinct isolates within the herd. At parturition, 16 mares were seropositive, including four viraemic mares. Vertical transmission occurred in one of these four mare-foal pairs. Interestingly, NPHV isolates of newly infected foals and mares after 3 and 6 months cluster in their respective pasture herds suggesting another horizontal route of transmission.

Lack of KIR4.1 autoantibodies in Japanese patients with MS and NMO.

Objectives:To examine anti-KIR4.1 antibodies by 2 different assays in Japanese patients with multiple sclerosis (MS) or neuromyelitis optica (NMO).Methods:One hundred sixty serum samples from 57 patients with MS, 40 patients with NMO/NMO spectrum disorder (NMOSD), and 50 healthy controls (all were Japanese) were tested with ELISA using a synthetic peptide of the first extracellular portion of human KIR4.1. In addition, we attempted to detect anti-KIR4.1 immunoglobulin G in the serum by the luciferase immunoprecipitation systems (LIPS) with the full length of human KIR4.1 produced in a human cell line, which is highly sensitive to single or multiple epitopes.Results:We failed to detect antibodies to the peptide fragment KIR4.183–120 in any case of MS and NMO/NMOSD using ELISA. Antibodies to the recombinant full length of KIR4.1 protein were detected in only 2 patients with MS and none in the patients with NMO/NMOSD by the LIPS assay.Conclusions:We developed 2 different methods (ELISA and LIPS) to measure autoantibodies to KIR4.1 in serum. We detected anti-KIR4.1 immunoglobulin G at a very low frequency in Japanese patients with MS or NMO/NMOSD. Serologic testing for human KIR4.1-specific antibodies is unlikely to improve the diagnosis of MS or NMO/NMOSD in Japanese patients.

Insights from the ganglionic acetylcholine receptor autoantibodies in patients with Sjögren’s syndrome

Objective: It is not known whether autonomic neuropathy is a feature of Sjögren’s syndrome (SS) or whether it is related to circulating antiganglionic acetylcholine receptor (gAChR) antibodies. The goal of the present study was to investigate the autonomic dysfunction in patients with SS and the associations between autonomic dysfunction, anti-gAChR antibodies, and clinical features of SS.Methods: (1) The first observational study tested for the presence of gAChR antibodies in the serum samples from 39 patients with SS (absent information regarding autonomic symptoms) and healthy volunteers. (2) In the second study, serological and clinical data from 10 Japanese patients diagnosed with SS were reviewed. These patients showed autonomic dysfunction, and luciferase immunoprecipitation systems (LIPS) test was conducted to detect anti-α3 and anti-β4 gAChR antibodies. (3) In the final analysis, we combined the data of seropositive SS patients with autonomic symptom from the first study with all of the patients from the second study, and analyzed the clinical features.Results: (1) The LIPS assay revealed that anti-gAChRα3 and anti-gAChRβ4 antibodies were detected in the sera from patients with SS (23.1%, 9/39). Five of nine SS patients had autonomic symptoms. (2) Anti-α3 and anti-β4 gAChR antibodies were also detected in 80.0% (8/10) of patients with SS with autonomic symptoms. Six of the ten patients were diagnosed as having SS after neurological symptoms developed. These seropositive patients had predominant and severe autonomic symptoms and were diagnosed with autonomic neuropathy. (3) Thirteen of fifteen SS patients with autonomic symptoms (86.7%) were seropositive for anti-gAChR antibodies, and we confirmed sicca complex, orthostatic hypotension, upper and lower gastrointestinal (GI) symptoms, and bladder dysfunction at high rates.Conclusion: The present results suggest the possibility of anti-gAChR antibodies aiding the diagnostics of SS with autonomic dysfunction.

Immunoproteomics technologies in the discovery of autoantigens in autoimmune diseases.

Proteomics technologies are often used for the identification of protein targets of the immune system. Here, we discuss the immunoproteomics technologies used for the discovery of autoantigens in autoimmune diseases where immune system dysregulation plays a central role in disease onset and progression. These autoantigens and associated autoantibodies can be used as potential biomarkers for disease diagnostics, prognostics and predicting/monitoring drug responsiveness (theranostics). Here, we compare a variety of methods such as mass spectrometry (MS)-based [serological proteome analysis (SERPA), antibody mediated identification of antigens (AMIDA), circulating immune complexome (CIC) analysis, surface enhanced laser desorption/ionization-time of flight (SELDI-TOF)], nucleic acid based serological analysis of antigens by recombinant cDNA expression cloning (SEREX), phage immunoprecipitation sequencing (PhIP-seq) and array-based immunoscreening (proteomic microarrays), luciferase immunoprecipitation systems (LIPS), nucleic acid programmable protein array (NAPPA) methods. We also review the relevance of immunoproteomic data generated in the last 10 years, with a focus on the aforementioned MS based methods.

Ganglionic acetylcholine receptor autoantibodies in patients with Guillain-Barré syndrome

ObjectivesAlthough standardized autonomic tests are useful for diagnosing autonomic failure in patients with Guillain-Barré syndrome (GBS), they cannot be used as predictive markers. Thus, serological markers may correctly identify patients with GBS who are at risk for autonomic dysfunction. MethodsWe validated a luciferase immunoprecipitation system that detects IgG antibodies in patient serum that specifically bind to the α3 or β4 subunits of ganglionic neuronal nicotinic acetylcholine receptors (gAChR). We then used luciferase-conjugated ligands specific to antibodies against two gAChR subunits to test 79 sera samples from patients with GBS, 34 from subjects with other neurological diseases (OND), and 73 from healthy controls (HC). 1) In the first analysis, patients were classified into two groups according to the presence or absence of autonomic symptoms (AS). We compared the frequency of the anti-gAChR antibodies between these two groups (AS+ and AS−). 2) In the second analysis, furthermore, patients were classified depending on the presence or absence of anti-glycolipid antibodies (AGA). We compared the frequency of the anti-gAChR antibodies between the four categories of GBS (AS+/AGA+, AS+/AGA−, AS−/AGA+, and AS−/AGA−), OND, and HC. ResultsEight subjects with GBS were positive for α3 subunits, while one was positive for β4 subunits. Anti-α3 and -β4 gAChR antibodies were also detected in 13.6% of AS+ GBS group in the first analysis. Two of 35 patients in AS−GBS group were seropositive for the anti-gAChR antibodies and AGA in the second analysis. Patients with GBS that were positive for serum antibodies to the α3 and/or β4 subunits of gAChRs showed a range of clinical features including AS and AGA. ConclusionsPatients with GBS may have circulating antibodies against gAChR, which may contribute to the autonomic dysfunction associated with this disease.

Identification and Validation of Loa loa Microfilaria-Specific Biomarkers: a Rational Design Approach Using Proteomics and Novel Immunoassays.

ABSTRACTImmunoassays are currently needed to quantify Loa loa microfilariae (mf). To address this need, we have conducted proteomic and bioinformatic analyses of proteins present in the urine of a Loa mf-infected patient and used this information to identify putative biomarkers produced by L. loa mf. In total, 70 of the 15,444 described putative L. loa proteins were identified. Of these 70, 18 were L. loa mf specific, and 2 of these 18 (LOAG_16297 and LOAG_17808) were biologically immunogenic. We developed novel reverse luciferase immunoprecipitation system (LIPS) immunoassays to quantify these 2 proteins in individual plasma samples. Levels of these 2 proteins in microfilaremic L. loa-infected patients were positively correlated to mf densities in the corresponding blood samples (r = 0.71 and P < 0.0001 for LOAG_16297 and r = 0.61 and P = 0.0002 for LOAG_17808). For LOAG_16297, the levels in plasma were significantly higher in Loa-infected (geometric mean [GM], 0.045 µg/ml) than in uninfected (P < 0.0001), Wuchereria bancrofti-infected (P = 0.0005), and Onchocerca volvulus-infected (P < 0.0001) individuals, whereas for LOAG_17808 protein, they were not significantly different between Loa-infected (GM, 0.123 µg/ml) and uninfected (P = 0.06) and W. bancrofti-infected (P = 0.32) individuals. Moreover, only LOAG_16297 showed clear discriminative ability between L. loa and the other potentially coendemic filariae. Indeed, the specificity of the LOAG_16297 reverse LIPS assay was 96% (with a sensitivity of 77%). Thus, LOAG_16297 is a very promising biomarker that will be exploited in a quantitative point-of-care immunoassay for determination of L. loa mf densities.

A modified application of the luciferase immunoprecipitation systems for detecting antibodies to the G protein-coupled receptors

Title A modified application of the luciferase immunoprecipitation systems for detecting antibodies to the G protein-coupled receptors Author(s) Mukaino, Akihiro; Higuchi, Osamu; Nakane, Shunya; Maeda, Yasuhiro; Sakai, Waka; Nakamura, Hideki; Matsuo, Hidenori; Kawakami, Atsushi Citation Acta medica Nagasakiensia, 60(2), pp.69-76; 2016 Issue Date 2016-01 URL http://hdl.handle.net/10069/36171 Right NAOSITE: Nagasaki University's Academic Output SITE

Lack of Evidence for Molecular Mimicry in HIV-Infected Subjects.

Previous studies in HIV patients have reported autoantibodies to several human proteins, including erythropoietin (EPO), interferon-α (IFN-α), interleukin-2 (IL-2), and HLA-DR, as potential mediators of anemia or immunosuppression. The etiology of these autoantibodies has been attributed to molecular mimicry between HIV epitopes and self-proteins. Here, the Luciferase Immunoprecipitation System (LIPS) was used to investigate the presence of such autoantibodies in HIV-infected adults. High levels of antibodies to HIV proteins such as capsid (p24), matrix (p17), envelope (gp41), and reverse transcriptase (RT) were detected using LIPS in both untreated and anti-retroviral-treated HIV-infected individuals but not in uninfected controls. LIPS readily detected anti-EPO autoantibodies in serum samples from subjects with presumptive pure red cell aplasia but not in any of the samples from HIV-infected or uninfected individuals. Similarly, subjects with HIV lacked autoantibodies to IFN-α, IL-2, HLA-DR and the immunoglobulin lambda light chain; all purported targets of molecular mimicry. While molecular mimicry between pathogen proteins and self-proteins is a commonly proposed mechanism for autoantibody production, the findings presented here indicate such a process is not common in HIV disease.

Specific detection of peste des petits ruminants virus antibodies in sheep and goat sera by the luciferase immunoprecipitation system

Peste des petits ruminants (PPR) is a contagious and often fatal transboundary animal disease affecting mostly sheep, goats and wild small ruminants. This disease is endemic in most of Africa, the Middle, Near East, and large parts of Asia. The causal agent is peste des petits ruminants virus (PPRV), which belongs to the genus Morbillivirus in the family Paramyxoviridae. This genus also includes measles virus (MV), canine distemper virus (CDV) and rinderpest virus (RPV). All are closely related viruses with serological cross reactivity.In this study, we have developed a Luciferase Immunoprecipitation System (LIPS) for the rapid detection of antibodies against PPRV in serum samples and for specific differentiation from antibodies against RPV.PPR and rinderpest (RP) serum samples were assayed by PPR-LIPS and two commercially available PPR cELISA tests. The PPR-LIPS showed high sensitivity and specificity for the samples tested and showed no cross reactivity with RPV unlike the commercial PPR cELISA tests which did cross react with RPV. Based on the results shown in this study, PPR-LIPS is presented as a good candidate for the specific serosurveillance of PPR.

No evidence of antibodies against GAD65 and other specific antigens in children with autism

BackgroundThe presence of autoantibodies has been proposed as evidence for a role of autoimmunity in autism. This report investigates the prevalence of autoantibodies in children with autism using the luciferase immunoprecipitation systems (LIPS) immunoassay technology. A panel of autoantibody targets against several known and candidate neurological autoantigens, autoimmune-associated autoantigens and viruses was employed. MethodsSerological analysis was performed on typically developing children (n=55), developmentally delayed children without autism (n=24) and children diagnosed with autism (n=104). Autoantibodies were measured against glutamic acid decarboxylase-65 (GAD65), a CNS autoantigen proposed to be associated with autism and against Ro52, glial fibrillary acidic protein, tyrosine hydroxylase, aquaporin-4, and gamma-enolase, the mouse mammary tumor virus and the xenotropic murine leukemia virus. Antibody levels and seropositivity prevalence were analyzed for statistically significant differences between the three groups. ResultsThe majority of the children (98%) were seronegative for all targets in the antigen panel. No GAD65 seropositive children were detected in the cohort. Several low level seropositive sera against several of the protein targets were identified in isolated children in each of the three groups, but there was no difference in prevalence. ConclusionUsing this panel of antigens and a sensitive, robust assay, no evidence of unusual immunoreactivity was detected in children with autism, providing evidence against a role of autoimmunity against several previously implicated proteins in autism spectrum disorder pathogenesis. General significanceThe idea that autoantibodies represent an underlying cause or are biomarkers for autism pathophysiology is not supported by this report.

Genetic and serological surveillance for non-primate hepacivirus in horses in Japan

Non-primate hepacivirus (NPHV) is a recently discovered homolog of the hepatitis C virus in horses. The frequency and distribution of NPHV infections among horses in Japan is unknown. In this study, serum samples from 453 horses across Japan were screened for NPHV RNA using real-time RT-PCR and anti-nonstructural 3 protein (NS3) antibodies using the Gaussia luciferase immunoprecipitation system assay. In order to monitor the course of NPHV infection in horses, we examined 31 stored samples (9 adult horses and 22 young horses) obtained one year ago and compared the results to the recent data. Stored sera from 7 mare–foal pairs were also examined. The NS3 region sequences of 14 NPHV strains from NPHV RNA positive serum samples were determined and analyzed phylogenically. Of the 453 serum samples tested, 33.55% were positive for anti-NS3 antibody and 13.68% were positive for NPHV RNA. We found a higher rate of NPHV RNA detection in serum obtained from young horses (1–2 years of age) than that of adults, in two geographically distinct areas. We observed higher variation in the course of infection over one year in young horses than in adult horses. The foals were infected with NPHV after the weaning period. Phylogenic analysis revealed that while NPHV NS3 genes isolated in Japan clustered with sequences previously classified as NPHV, but the genetic diversity of the Japanese NPHV strains we detected was not correlated with their geographic origin. In conclusion, Japanese horses exhibit a high prevalence of NPHV. Young age appears to be a risk factor for such viral infection in Japan, although the infectious route was not determined.

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

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.

Clinical features of autoimmune autonomic ganglionopathy and the detection of subunit-specific autoantibodies to the ganglionic acetylcholine receptor in Japanese patients.

Autoimmune autonomic ganglionopathy (AAG) is a rare acquired channelopathy that is characterized by pandysautonomia, in which autoantibodies to ganglionic nicotinic acetylcholine receptors (gAChR) may play a central role. Radioimmunoprecipitation (RIP) assays have been used for the sensitive detection of autoantibodies to gAChR in the serum of patients with AAG. Here, we developed luciferase immunoprecipitation systems (LIPS) to diagnose AAG based on IgGs to both the α3 and β4 gAChR subunits in patient serum. We reviewed the serological and clinical data of 50 Japanese patients who were diagnosed with AAG. With the LIPS testing, we detected anti-α3 and -β4 gAChR antibodies in 48% (24/50) of the patients. A gradual mode of onset was more common in the seropositive group than in the seronegative group. Patients with AAG frequently have orthostatic hypotension and upper and lower gastrointestinal tract symptoms, with or without anti-gAChR. The occurrence of autonomic symptoms was not significantly different between the seropositive and seronegative group, with the exception of achalasia in three patients from the seropositive group. In addition, we found a significant overrepresentation of autoimmune diseases in the seropositive group and endocrinological abnormalities as an occasional complication of AAG. Our results demonstrated that the LIPS assay was a useful novel tool for detecting autoantibodies against gAChR in patients with AAG.

SP140L, an Evolutionarily Recent Member of the SP100 Family, Is an Autoantigen in Primary Biliary Cirrhosis.

The SP100 family members comprise a set of closely related genes on chromosome 2q37.1. The widely expressed SP100 and the leukocyte-specific proteins SP110 and SP140 have been associated with transcriptional regulation and various human diseases. Here, we have characterized the SP100 family member SP140L. The genome sequence analysis showed the formation of SP140L gene through rearrangements of the two neighboring genes, SP100 and SP140, during the evolution of higher primates. The SP140L expression is interferon-inducible with high transcript levels in B cells and other peripheral blood mononuclear cells. Subcellularly, SP140L colocalizes with SP100 and SP140 in nuclear structures that are devoid of SP110, PML, or p300 proteins. Similarly to SP100 and SP140 protein, we detected serum autoantibodies to SP140L in patients with primary biliary cirrhosis using luciferase immunoprecipitation system and immunoblotting assays. In conclusion, our results show that SP140L is phylogenetically recent member of SP100 proteins and acts as an autoantigen in primary biliary cirrhosis patients.

Strongyloidiasis as a Cause of Chronic Diarrhea, Identified Using Next-Generation Strongyloides stercoralis-Specific Immunoassays

A 63-year-old-male Vietnam War veteran noted a 6-month history of watery diarrhea. A colonoscopy 6 months prior to presentation was significant for colonic mucosa with inflammation, sheets of eosinophils, and an acellular structure, which was suspicious for a parasite. Initial laboratory testing on presentation revealed an elevated eosinophil count, prompting an investigation for a parasitic infection. Three stool microscopy examinations were negative for parasite ova and larvae, but the patient had a positive Strongyloides immunoglobulin-G antibody on an enzyme-linked immunosorbent assay (ELISA). Confirmation of S. stercoralis infection was achieved using a Strongyloides-specific luciferase immunoprecipitation systems (LIPS) assay. Accurate diagnosis of Strongyloides infection is particularly crucial for patients who are currently immunocompromised or will be immunosuppressed with medications, as immunosuppression can lead to accelerated autoinfection and systemic dissemination, which, if untreated, carries a fatality rate of nearly 100 %.

Detection of antibodies to varicella-zoster virus in recipients of the varicella vaccine by using a luciferase immunoprecipitation system assay.

A high-throughput test to detect varicella-zoster virus (VZV) antibodies in varicella vaccine recipients is not currently available. One of the most sensitive tests for detecting VZV antibodies after vaccination is the fluorescent antibody to membrane antigen (FAMA) test. Unfortunately, this test is labor-intensive, somewhat subjective to read, and not commercially available. Therefore, we developed a highly quantitative and high-throughput luciferase immunoprecipitation system (LIPS) assay to detect antibody to VZV glycoprotein E (gE). Tests of children who received the varicella vaccine showed that the gE LIPS assay had 90% sensitivity and 70% specificity, a viral capsid antigen enzyme-linked immunosorbent assay (ELISA) had 67% and 87% specificity, and a glycoprotein ELISA (not commercially available in the United States) had 94% sensitivity and 74% specificity compared with the FAMA test. The rates of antibody detection by the gE LIPS and glycoprotein ELISA were not statistically different. Therefore, the gE LIPS assay may be useful for detecting VZV antibodies in varicella vaccine recipients. (This study has been registered at ClinicalTrials.gov under registration no. NCT00921999.).