Human Antibody Response to Thioredoxin Peroxidase-1 and Tandem Repeat Proteins as Immunodiagnostic Antigen Candidates for Schistosoma japonicum Infection

Abstract

Abstract. Schistosomiasis continues to be a public health problem in many tropical and subtropical countries. Improving the diagnostic tools for surveillance and monitoring in areas that have reached elimination level will help hasten the possible elimination of this disease. This study therefore aims to develop enzyme-linked immunosorbent assay through the use of recombinant proteins such as thioredoxin peroxidase-1 (SjTPx-1) and four tandem repeat proteins (Sj1TR, Sj2TR, Sj4TR, and Sj7TR). Cutoff values were calculated using 38 serum samples from healthy Japanese volunteers. Sera from 35 schistosomiasis-confirmed patients, four cured from the disease by chemotherapy, and 15 endemic negative controls were used to assess these antigens. SjTPx-1 and Sj7TR both had 85.71% sensitivity. Furthermore, these antigens were also tested against human sera positive for other parasitic infections and showed no or very minimal cross-reaction. These results suggest the potential defined antigens for development of an accurate diagnostic test for schistosomiasis.* Address correspondence to Shin-ichiro Kawazu, National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, 2-13 Inada-cho, Obihiro, Hokkaido, 080-8555 Japan. E-mail: skawazu@obihiro.ac.jp 675 TPX-1 AND TRPS FOR S. JAPONICUM HUMAN DIAGNOSIS the Guide for Animal Experimentation at Dokkyo Medical University Japan.Human sera. Non-endemic control sera were collected from 38 healthy Japanese volunteers from Tochigi prefecture in May 2003. 22 These subjects were without any risk of contracting S. japonicum infection and had no history of traveling to schistosomiasis-endemic areas. Fifteen endemic control sera and four post-treatment samples (1 year after chemotherapy) were collected from Gonzaga, Cagayan, the Philippines. These individuals were confirmed negative through stool examination. The schistosomiasis-positive serum samples were collected from 35 human patients from Leyte, the Philippines. 23They were diagnosed by the detection of the parasite eggs in their stool. Sera from patients with other parasites, including Trichuris trichiura ( N = 1), Plasmodium falciparum ( N = 4), Plasmodium vivax ( N = 1), and Entamoeba histolytica ( N = 4) were collected from a schistosomiasis-free area in the Philippines. They were diagnosed through either microscopic examination or detection of antibodies by immunofluorescent assay. Paragonimus westermani -positive samples ( N = 11) were taken from Japanese patients and Opisthorchis viverrinipositive sera ( N = 10) were collected from Thailand diagnosed through either clinical manifestations or antibody detection. Blood samples were taken from these subjects after informed consent in their local language were obtained by a medical staff member from each patient or their guardians. This study was done according to the ethical guidelines for epidemiological studies provided by the Ministry of Education, Culture, Sports, Science and Technology and the Ministry of Health, Labor and Welfare o...

Vaccines and diagnostics for zoonotic schistosomiasis japonica

“…Recently, more rapid, sensitive and portable diagnostic assays to detect human antibodies against S. japonicum, have been developed and tested in areas of low endemicity for schistosomiasis japonica in China (Table 3) (3) a time-resolved fluoroimmunoassay (TRFIA), established for detecting Sj14-3-3, as a circulating antigen in serum ; (4) an electrochemical immunosensor array (ECISA) assay (Deng et al 2013) which uses a recombinant S. japonicum calcium-binding protein (SjE16), with SEA, coimmobilized on a disposable 16-channel screenprinted carbon electrode array. So far, a number of candidate antigens have been tested for diagnosing S. japonicum infection; these include Sj23HD ), rSj26GST-Sj32 (Cai et al 2011), SjEFCAB (Lu et al 2012b, SjTPx-1 (Angeles et al 2012) and Sj1TR (Angeles et al 2012), Sj7TR (Angeles et al 2011), SjCHGCS19 (Guo et al 2012), SjLAP , whose characteristics are shown in Table 4. This technique allows the serum-based diagnosis of subjects infected with S. japonicum without the need for sample pretreatment and it can diagnose individuals co-infected with schistosomiasis and TB.…”

Schistosomiasis in Children in the Philippines: Beyond Health Issues

“…Molecular techniques become research milestones in the detection and diagnosis of schistosomiasis because of their high sensitivity. [41][42][43][44] But one of their limitations is that disease severity, such as the level of hepatic fibrosis in intestinal schistosomiasis, may not be characterized. In addition, other accompanying complications affecting other organs may be neglected.…”

Development of Monoclonal Antibodies That Target 1-Cys Peroxiredoxin and Differentiate Plasmodium falciparum from P. vivax and P. knowlesi

“…It has been shown that Prx may have diagnostic value for the detection of Leishmania spp., Echinococcus granulosus , Fasciola gigantica , Taenia spp. [8] and Schistosoma japonicum [9]. 1-Cys peroxiredoxin (1-Cys-Prx) in P. falciparum , the orthologous molecule of human Prx VI, is abundantly expressed in the trophozoite stage of P. falciparum [10] making it a promising candidate as a diagnostic antigen.…”