Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A PEG-ELISA was used to demonstrate parasite specific immune complexes in a significant proportion (25/26) of Onchocerca volvulus infection sera from Sierra Leone. The parasite antigen was detected using a peroxidase-conjugated rabbit serum raised to the bovine parasite O. gibsoni. Controls including European control serum, endemic control serum and Rh+ sera gave consistently low readings. Characterization of the parasite component in the immune complexes by Western blotting demonstrated a heat stable antigen of M(r) 46,000. This antigen was not present in the circulating immune complexes (CIC) prepared from patients with Wuchereria bancrofti infection, but a cross-reactive molecule of the same size was weakly recognized in the CIC of Loa loa and Mansonella perstans infected patients. No association between the level of parasite specific CIC and clinical disease was observed in the O. volvulus patients.
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PMID:Identification and characterization of a parasite antigen in the circulating immune complexes of Onchocerca volvulus infected patients. 128 95

This report describes the presence of circulating Onchocerca volvulus antigens (COA) in sera of patients with onchocerciasis. By using a double diffusion immunoelectrophoresis method, COA could be detected in 24 of 77 sera analyzed (31%). In contrast, when more sensitive assays such as the radioimmunoprecipitation-PEG assay or sandwich radioimmunoassay were used to detect COA, about 75% of the sera from O. volvulus-infected patients were found positive; moreover, a highly significant correlation between the two assays was observed. The parasite specificity of the COA was demonstrated directly by identity reaction with a component of O. volvulus somatic antigens. COA was never found when hyperimmune antisera against other parasite antigenic extracts were used instead of anti-O. volvulus hyperimmune serum. However, when anti-O, volvulus hyperimmune serum was used against sera obtained from patients infected with various other helminths we found a cross-reactivity between COA and the circulating antigens of other human filarids (Wuchereria bancrofti, Loa loa, Brugia malayi), but not with other nematode or trematode parasites (Ascaris lumbricoides, Schistosoma mansoni, Fasciola hepatica). Further immunoelectrophoretic studies demonstrated one precipitin are localized in the cathodic region which seemed specific for COA, which raises the possibility of preparing a monospecific hyperimmune serum to circumvent cross-reactivities.
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PMID:Detection of circulating antigens in onchocerciasis. 679 90

A monoclonal antibody of the IgM class recognizing Onchocerca volvulus circulating antigen (COA) was obtained. This monoclonal antibody was used in a radioimmunoprecipitation-PEG assay (RIPEGA) to detect circulating antigen in onchocerciasis patients' sera. COA could be detected in 63 (80%) of the 79 African patient sera tested, and in 126 (76%) of the 164 Indian (Venezuela) sera studied. There was no direct correlation between the presence of COA detected in the patient serum and the level of microfilarodermia. The RIPEGA using this monoclonal antibody detected COA in 91% of children under 10 years old, whereas the microfilarodermia in this group was positive in only 52% of the cases. The specificity of this test is improved compared to the results obtained with polyclonal antibodies. Immunofluorescence studies suggest that the COA might be located in the microfilaria cuticle.
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PMID:Onchocerca volvulus: detection of circulating antigen by monoclonal antibodies in human onchocerciasis. 685 99

Improved methods for diagnosis of onchocerciasis are needed. We have recently identified immune complex-associated parasite antigens in sera from onchocerciasis patients. The goal of this study was to produce monoclonal antibodies to these antigens that might be used in antigen detection assays. Two monoclonal antibodies (OV-1 and OV-5) that bind to parasite antigens in immunoblots of PEG-precipitated immune complexes from human onchocerciasis sera and to corresponding antigens in adult worm extracts and excretory-secretory products were produced. The target epitopes of the monoclonals are heat stable, resistant to trypsin, and destroyed by Pronase. The two monoclonals produce similar but not identical patterns of binding to immunoblots of Onchocerca volvulus adult worm antigen with major bands at 43-47, 58-63, and 70 kDa. OV-1 and OV-5 appear to bind to two distinct but closely related epitopes, neither of which is phosphorylcholine. Immunoelectron microscopy showed that the epitopes recognized by these monoclonals are widely distributed in adult female worms, but concentrated in the uterus and intestine. Antigen assays based on these antibodies detected parasite antigen in 9 of 14 sera from onchocerciasis patients, but significant background signal was detected in some nonendemic human sera. Thus, although this study has provided new information on parasite antigens in sera from onchocerciasis patients, additional work will be needed to achieve the goal of producing a sensitive and specific antigen diagnostic test for onchocerciasis.
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PMID:Onchocerca volvulus: monoclonal antibodies to immune complex-associated parasite antigens. 769 Jul 12