[Immunohistochemical observation on the antigens inducing IgG and IgM antibodies against sparganum]

Seropositivity and identification of paramyosin for sparganosis in the Kangwon and Incheon provinces of the Republic of Korea

Sparganosis is one of the top three tissue-dwelling heterologous helminthic diseases, along with cysticercosis and paragonimiasis, in Korea. Due to a lack of effective early diagnosis and treatment methods, this parasitic disease is regarded as a public health threat. This study evaluated reactivity, against sparganum extracts, of sera from inhabitants of Cheorwon-gun, Goseong-gun and Ongjin-gun in Korea. The sera from 836 subjects were subjected to enzyme-linked immunosorbent assay and immunoblot analysis. The sera from 18 (5.8%) and 15 (5.1%) inhabitants in Cheorwon-gun (n = 312) and Goseong-gun (n = 294), respectively, exhibited highly positive reactions to the sparganum antigen, whereas only two (0.9%) inhabitants in Ongjin-gun (n = 230) showed positivity. We sought antigenic proteins for serodiagnosis of positive sera by immunoproteomic approaches. Total sparganum lysates were separated by two-dimensional electrophoresis and then subjected to immunoblot analysis with mixed sparganosis-positive sera. We found seven antigenic spots and identified paramyosin as an antigenic protein by liquid chromatography-mass spectrometry. By two-dimensional (2D)-based mass analysis and immunoblotting against sparganosis-positive sera, paramyosin was identified as a candidate antigen for serodiagnosis of sparganosis.

Human sparganosis, a neglected food borne zoonosis

Human sparganosis is a food borne zoonosis caused by the plerocercoid larvae (spargana) of various diphyllobothroid tapeworms of the genus Spirometra. Human infections are acquired by ingesting the raw or undercooked meat of snakes or frogs, drinking untreated water, or using raw flesh in traditional poultices. More than 1600 cases of sparganosis have been documented worldwide, mostly in east and southeast Asia. Sporadic cases have been reported in South America, Europe, and Africa, and several cases have been described in travellers returning from endemic regions. Epidemiological data suggest that the increased effect of sparganosis on human health is because of greater consumption of raw meat of freshwater frogs and snakes. This Review provides information about the Spirometra parasites and their lifecycles, summarises clinical features, diagnosis, and treatment of human sparganosis, and describes geographical distribution and infection characteristics of Spirometra parasites in host animals.

Production of polyclonal antibodies against the tegument of sparganum (plerocercoid of Spirometra mansoni) and its immunolocalization

In a previous study, the author developed a method for separation of the tegument of spargana (plerocercoids of Spirometra mansoni) from the parenchyme using urea. The present study, as a next step, was performed to evaluate which molecules are present in the outer tegument. Two major proteins, 180 and 200 kDa, are present in the tegument and we could make polyclonal antibodies against these molecules. Their immunolocalization was processed and the outermost layer of the spargana showed strong positive staining. Conclusively, we could confirm that the 180 and 200 kDa molecules might be tightly bound membrane proteins in the tegument of spargana.

Isolation and partial characterization of cysteine proteinase from sparganum

A proteolytic enzyme was purified from the tissue extract of spargana (plerocercoids of Spirometra erinacei) by DEAE-Trisacryl M ion exchange chromatography and thiopropyl-sepharose affinity chromatography resulted in a 21-fold purification. The proteinase activity was assayed with a synthetic fluorescent substrate, carbobenzoxy-phenylalanyl-7-amino-4-trifluoromethyl-coumarin. SDS-polyacrylamide gel electrophoresis of the purified materials revealed a single 28,000 dalton band. Inhibitor profiles of the band indicated that it belonged to cysteine endopeptidases. It exhibited identical pH curves with optimum at pH 5.5, and 50% activity from pH 4.7 to 8. It could completely degrade collagen chains to three identical products. It also showed some activity on hemoglobin. Furthermore, the band on immunoblots was reactive to the sera of sparganosis patients. These results suggest that the proteolytic enzyme belongs to cysteine proteinase which plays a role in the tissue penetration. Also it may be used as the antigen for diagnosis of active sparganosis.

Immunohistochemical localization of 36 and 29 kDa proteins in sparganum

Antigenic proteins of 36 and 29 kDa were localized in Spirometra mansoni plerocercoid (sparganum) immunohistochemically by avidin biotin complex (ABC) staining. When polyclonal antibodies such as BALB/c mouse serum immunized with crude saline extract of sparganum or confirmed sparganosis sera were reacted as primary antibodies, the positive chromogen (3-amino, 9-ethylcarbazole) reactions were recognized at syncytial tegument, tegumental cells, muscle and parenchymal cells and lining cells of excretory canals. A monoclonal antibody (MAb) which was reacting to 36 and 29 kDa proteins in the extract of the worm was localized at the syncytial tegument and tegumental cells. The present results suggested that the potent antigenic proteins of 36 and 29 kDa in sparganum were produced at the tegumental cells and transported to the syncytial tegument.