Search

Background: In previous studies, a new Trichinella spiralis serine protease 1.1 (TsSP1.1) was identified in surface proteins of T. spiralis muscle larvae (ML) by proteomics analysis, but its functions in T. spiralis infection are unknown. The aim of this study was to investigate the roles of TsSP1.1 during larval intrusion of gut epithelium. Methods: From January 2019 to March 2021, complete TsSP1.1 cDNA sequence was cloned and expressed in Escherichia coli BL21 at the Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, China. Expression and location of TsSP1.1 in the parasite were investigated using indirect immunofluorescence assay (IIFA) and Western blotting. The in vitro intestinal epithelium cells (IECs) intrusion assay was used to ascertain the roles of TsSP1.1 during larval intrusion of IECs and gut epithelium. Results: TsSP1.1 was a surface and secretory protein, which was expressed at various T. spiralis stages, and principally localized at cuticle, stichosome and embryos of the nematode. rTsSP1.1 accelerated larval intrusion of IECs, whereas anti-rTsSP1.1 antibodies impeded larval intrusion. The acceleration and inhibtion was dose-dependently related to rTsSP1.1 and anti-TsSP1.1 antibodies. Block of the IIL with anti-rTsSP1.1 serum also impeded larval intrusion of gut mucosa. Conclusion: TsSP1.1 participates in T. spiralis intrusion of gut epithelium.

Background: The intraperitoneal injection is a common method for establishing the experimental animal model infected with parasites. The aim of this study was to investigate if the intraperitoneal injection was another route of Trichinella spiralis infection. Methods: From June to July 2015, twenty BALB/c mice were intraperitoneally injected with 300 T. spiralis muscle larvae in Department of Parasitology, Medical College, Zhengzhou University, China. The larvae per gr (LPG) muscle from the infected mice and the reproductive capacity index (RCI) of T. spiralis were calculated Results: Sixty percent (12/20) mice injected were successfully infected at 35 day post injection (dpi), but the muscle larval burden (381.53 larvae per gr) and reproductive capacity index (32.33) in infected mice was lower. Conclusion: A mechanical force indicated as a possible mechanism in successful larval invasion of almost all kind of host tissues. However, the exact migratory route of larvae from peritoneal cavity into small intestine is not clear.

Background: Sparganosis is caused by the invasion of Spirometra sparganum into various tissues/organs. Subcutaneous sparganosis can be diagnosed by biopsy, while visceral/cerebral sparganosis is not easy to be diagnosed. The diagnosis de­pends largely on the detection of specific anti-sparganum antibodies. The specific­ity of the ELISA could be increased by using S. mansoni sparganum excretory–secre­tory (ES) antigens, but it also had the cross-reactions with sera of patients with cysticercosis or paragonimiasis. The aim of this study was to identify early specific diagnostic antigens in S. mansoni sparganum ES proteins.Methods: The sparganum ES proteins were analyzed by two-dimensional electrophore­sis (2-DE) and Western blot probed with early sera from infected mice at 14 days post-infection. The immunoreactive protein spots were characterized by MALDI-TOF/ TOF-MS.Results: A total of approximately 149 proteins spots were detected with isoelectric point (pI) varying from 3 to 7.5 and molecular weight from 20 to 115 kDa and seven protein spots with molecular weight of 23-31 kDa were recognized by the infection sera. Three of seven spots were successfully identified and characterized as the same S. mansoni protein (cysteine protease), and the proteins of other 4 spots were not included in the databases.Conclusion: The cysteine protease from S. mansoni ES proteins recognized by early infection sera might be the early diagnostic antigens for sparganosis.

Background:We have previously reported that a 31 kDa protein was screened from the excretory-secretory (ES) proteins of Tichinella spiralis muscle larvae (ML) by immunoproteomics using early infection sera, and the gene encoding a 31 kDa protein from T. spiralis was cloned and expressed in an E. coli expression system. In this study, the recombinant 31 kDa antigens were used for detection of anti- Trichinella antibodies in serum of experimentally infected mice by ELISA. Methods:Anti-Trichinella IgG antibodies in sera of mice infected with Trichinella were assayed by ELISA with recombinant 31 kDa antigens, and its sensitivity and specificity were compared with ELISA with ES antigen. Results:The sensitivity and specificity of ELISA with recombinant antigens was 96.67% (29/30) and 96.87% (62/64), compared with 100% (30/30) and 98.44% (63/64) of ELISA with ES antigens was (P＞0.05). In heavily, moderately and lightly infected mice (500, 300 and 100 larvae/mouse), anti-Trichinella antibodies were firstly detected by ELISA with recombinant antigens at 8, 12 and 14 dpi, re-spectively; then increased rapidly with a detection rate of 100% respectively at 28, 22 and 30 dpi. While the antibodies were firstly detected by ELISA with ES anti-gens at 10, 8 and 10 dpi, respectively, the antibody positive rate reached 100% at 14, 12 and 22 dpi, respectively. Conclusion:The recombinant 31 kDa antigens of T. spirali had a good sensitivity and specificity for detecting anti-Trichinella antibodies and might be the potential diagnostic antigen for trichinellosis.

Background: The phylogenetic location of Chinese Spirometra sparganum isolates remains unclear. The aim of this study was to explore the phylogenetic location of the Spirometra sparganum isolates from China. Methods: The 28S ribosomal DNA (rDNA) D1 sequences of 14 Spirometra sparganum isolates collected from thirteen locations in China were analyzed by using Neighbor-Joining (NJ), maximum parsimony (MP) and Bayesian inference (BI),respectively. To investigate the deep variance of 28S rDNA D1 region among included species, the secondary structure of 28S rDNA D1 region was also calculated using the program RNA structure. Results: The genus Spirometra as a monophyletic group was evidenced by two inference methods (MP and BI). All sequences within the genus Spirometra had a bulge of a cytosine residue (Bulge C) in the stem 13 of the secondary structure model of 28S rRNA D1 region. Varietal sites in sequences from all thirteen Chinese isolates were appeared in loops. In loops, adenine was the most abundant base(averagely 41.9%) followed by guanine (averagely 30.0%), and cytosine (averagely 15.1%). In stems, the average percentage of G + C (58.3%) was higher than the percentage of A + T (41.7%). Conclusion: The „Bulge C‟ in the stem 13 of the 28S rDNA D1 secondary structure could be as a suitable mark to identify the Spirometra species

Background: Sparganosis is caused by the invasion of Spirometra sparganum into various tissues/organs. Subcutaneous sparganosis can be diagnosed by biopsy, while visceral/cerebral sparganosis is not easy to be diagnosed. The diagnosis de-pends largely on the detection of specific anti-sparganum antibodies. The specific-ity of the ELISA could be increased by using S. mansoni sparganum excretory– secretory (ES) antigens, but it also had the cross-reactions with sera of patients with cysticercosis or paragonimiasis. The aim of this study was to identify early specific diagnostic antigens in S. mansoni sparganum ES proteins. Methods: The sparganum ES proteins were analyzed by two-dimensional electro-phoresis (2-DE) and Western blot probed with early sera from infected mice at 14 days post-infection. The immunoreactive protein spots were characterized by MALDI-TOF/ TOF-MS. Results: A total of approximately 149 proteins spots were detected with isoelectric point (pI) varying from 3 to 7.5 and molecular weight from 20 to 115 kDa and sev-en protein spots with molecular weight of 23-31 kDa were recognized by the infec-tion sera. Three of seven spots were successfully identified and characterized as the same S. mansoni protein (cysteine protease), and the proteins of other 4 spots were not included in the databases. Conclusion: The cysteine protease from S. mansoni ES proteins recognized by early infection sera might be the early diagnostic antigens for sparganosis.