Characterization and localization of antigens for serodiagnosis of human paragonimiasis

Abstract

Paragonimiasis is a foodborne trematode infection that affects 23 million people, mainly in Asia. Lung fluke infections lead frequently to chronic cough with fever and hemoptysis, and are often confused with lung cancer or tuberculosis. Paragonimiasis can be efficiently treated with praziquantel, but diagnosis is often delayed, and patients are frequently treated for other conditions. To improve diagnosis, we selected five Paragonimus kellicotti proteins based on transcriptional abundance, recognition by patient sera, and conservation among trematodes and expressed them as His-fusion proteins in Escherichia coli. Sequences for these proteins have 76–99% identity with amino acid sequences for orthologs in the genomes of Paragonimus westermani, Paragonimus heterotremus, and Paragonimus miyazakii. Immunohistology studies showed that antibodies raised to four recombinant proteins bound to the tegument of adult P. kellicotti worms, at the parasite host interface. Only a known egg antigen was absent from the tegument but present in developing and mature eggs. We evaluated the diagnostic potential of these antigens by Western blot with sera from patients with paragonimiasis (from MO and the Philippines), fascioliasis, and schistosomiasis, and with sera from healthy North American controls. Two recombinant proteins (a cysteine protease and a myoglobin) showed the highest sensitivity and specificity as diagnostic antigens, and they detected antibodies in sera from paragonimiasis patients with early or mature infections. In contrast, antibodies to egg yolk ferritin appeared to be specific marker for patients with adult fluke infections that produce eggs. Our study has identified and localized antigens that are promising for serodiagnosis of human paragonimiasis.

Cerebral paragonimiasis: Clinicoradiological features and serodiagnosis using recombinant yolk ferritin

“…westermani exceptionally grows into an egg-laying adult in the CNS. Consequently, cross-reactivity against yolk ferritin might be decreased as other larval helminths invading the CNS do not express yolk ferritin [ 34 ]. Since there is a positive correlation between serum and CSF levels of specific IgG antibodies against rPwYF (r = 0.59, S2A and S2B Fig ), we surmise that specific IgG antibody levels in CSF may reflect those of serum.…”

Parasite OMICS, the grand challenges ahead

“…One of the challenges for global elimination of some parasitic infections such as onchocerciasis is the lack of highly sensitive, specific, and accurate diagnostic tools to detect adult female worms, and thus inform mass drug administration programs. Multi-omics profiling have provided datasets that could be mined for identification of candidates for improved diagnostics (Bennuru et al, 2016); indeed, some studies have mined the data for candidates for serodiagnosis (McNulty et al, 2015), and subsequent studies have fully characterized candidates for different infections (Curtis et al, 2021;Greene et al, 2022).…”

A clinical review of human disease due to Paragonimus kellicotti in North America

“…They were able to match genes to previously identified antigen targets for potential diagnostic research focused on targets present across these four Paragonimus species, making these antigens attractive targets to detect infection regardless of the species of Paragonimus (Rosa et al, 2020). Furthermore, Curtis et al tested five proteins as potential diagnostic antigens and found that patient IgG4 against cysteine protease-6 and IgG against myoglobin-1 were both 100% sensitive and 100% specific for Paragonimus in relation to controls and other helminth infections, but did not differentiate between P. kellicotti and P. westermani infection (Curtis et al, 2021). IgG against cystatin-2 was 100% specific for P. kellicotti, but was poorly sensitive at 24% (Curtis et al, 2021).…”

“…Furthermore, Curtis et al tested five proteins as potential diagnostic antigens and found that patient IgG4 against cysteine protease-6 and IgG against myoglobin-1 were both 100% sensitive and 100% specific for Paragonimus in relation to controls and other helminth infections, but did not differentiate between P. kellicotti and P. westermani infection (Curtis et al, 2021). IgG against cystatin-2 was 100% specific for P. kellicotti, but was poorly sensitive at 24% (Curtis et al, 2021). Nanocomposix Incorporated has successfully completed a Phase I study of a nanoparticle-based rapid diagnostic test for Paragonimus based on the cysteine protease-6 and myoglobin-1 antigens (Small Business Innovation Research, 2019).…”

“…Furthermore, Curtis et al . tested five proteins as potential diagnostic antigens and found that patient IgG4 against cysteine protease-6 and IgG against myoglobin-1 were both 100% sensitive and 100% specific for Paragonimus in relation to controls and other helminth infections, but did not differentiate between P. kellicotti and P. westermani infection (Curtis et al ., 2021). IgG against cystatin-2 was 100% specific for P. kellicotti , but was poorly sensitive at 24% (Curtis et al ., 2021).…”