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

The development of an onchocercal chorioretinopathy from the first detectable signs to a full blown oncho fundus is not fully understood. We investigated the intraocular humoral immune response against Onchocerca volvulus, human S-antigen, IRBP and crude retinal extract (using an ELISA) by examining paired aqueous humour and serum samples obtained from onchocerciasis patients (without [n = 10] and with ocular symptoms [n = 8]) and endemic controls [n = 14] from Sierra Leone (West Africa). A local intraocular anti-retinal IgG antibody production could not be demonstrated in onchocerciasis patients, whether they had ocular symptoms or not. A significantly higher level of O. volvulus antibodies and IgG was measured in the aqueous of onchocerciasis patients with ocular involvement, as compared to patients without ocular symptoms (Mann-Whitney ranksum test; p less than 0.001 and p less than 0.02 respectively). Since interleukin-6 (IL-6) plays an essential role in the differentiation of B cells into immunoglobulin producing plasma cells, we therefore measured this cytokine in paired aqueous and serum samples. Elevated IL-6 levels were found in the aqueous of two out of eight onchocerciasis patients tested. In view of these findings it seems improbable that retinal autoimmunity is a major factor in the pathogenesis of onchocercal chorioretinopathy. The high intraocular levels of antibodies against the parasite suggest a direct involvement of the parasite in the pathogenesis of onchocercal chorioretinopathy.
 ...
PMID:Analysis of aqueous humour in ocular onchocerciasis. 203 8

Living adult males and microfilariae of the cattle filarial parasite Onchocerca gibsoni were externally labelled with radioactive iodine using the iodogen and Bolton-Hunter procedures. Characterization of labelled surface proteins by sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis revealed clear cut differences in the two life cycle stages. In addition, the two radiolabelling procedures yielded some differences in the profiles of radiolabelled surface proteins for both adults and microfilariae. Immunoprecipitation analysis revealed a number of labelled antigens recognized by antibodies in human onchocerciasis serum pools, thereby demonstrating the usefulness of O. gibsoni as a model in Onchocerca volvulus vaccine studies. The reactivity of microfilarial antigens extended to antibodies from other human nematode infections, whereas male surface antigens, particularly those of low molecular weight, were Onchocerca specific. This indicates that O. gibsoni can provide a convenient source of specific diagnostic antigen.
 ...
PMID:Surface antigens of male worms and microfilariae of Onchocerca gibsoni. 204 May 68

The isolation and characterization of a recombinant cDNA clone (OV7) expressing an antigen present in Onchocerca volvulus infective larvae and adult stages is described. Using chimpanzee antiserum generated against irradiated infective larvae, we isolated a cDNA clone from a lambda gt11 cDNA expression library derived from adult O. volvulus mRNA. The open reading frame encodes 131 amino acids corresponding to a 15.2-kDa protein. Affinity purified antibodies which bound specifically to OV7 fusion polypeptide recognized a single antigen with an apparent molecular weight of 17,000 in extracts of L3, L4 and adult worms. Immunoelectron microscopy established that the antigen encoded by this clone is present in the hypodermis and the basal layer of the cuticle of L3 and female adult worm, and in the egg shell around developing microfilariae. Since the OV7 fusion polypeptide is onchocerca-specific and is recognized specifically by sera from onchocerciasis patients, and sera from non-patent but infected chimpanzees, and not by sera from patients with other filarial parasites, it may have potential as an antigenic component in a test for detection of non-patent and patent infections of O. volvulus. The OV7 amino acid sequence contains residues that have a probable homology with the cysteine proteinase inhibitor superfamily.
 ...
PMID:Characterization of an Onchocerca volvulus cDNA clone encoding a genus specific antigen present in infective larvae and adult worms. 205 41

Onchocerciasis (river blindness) is a major blinding disease in Africa, Central America, and South America. Loss of vision can be due to corneal change, optic atrophy, or chorioretinal disease. It has been suggested that autoimmunological reactions resulting from crossreactivity between parasite antigens and components of eye tissues contribute to development of ocular pathology. Using sera collected from onchocerciasis patients as a screening reagent, a cDNA clone (Ov39) has been isolated from a lambda gt11 expression library of Onchocerca volvulus. This antigen exhibits immunological crossreactivity with a component of retinal pigment epithelium cells (RPE). Antiserum raised against this recombinant peptide immunoprecipitates a 22,000 Mr antigen of adult O. volvulus and recognizes a 44,000 Mr component of bovine RPE by Western blotting. A 44,000 Mr antigen of cultured human RPE metabolically labeled with 35S-methionine can be immunoprecipitated with the same antiserum. An antigen of the same size is recognized by a rabbit antiserum raised against whole O. volvulus extract. Immunocytochemical studies on cryostat sections of the bovine eye using the antirecombinant sera localizes this antigen to the RPE.
 ...
PMID:Immunological crossreactivity between a cloned antigen of Onchocerca volvulus and a component of the retinal pigment epithelium. 205 76

Cellular immune responses were tested in vitro using peripheral blood mononuclear cells from 203 individuals resident in an area of Sierra Leone where onchocerciasis is hyperendemic, and 32 individuals (Gambians) with no history of contact with Onchocerca volvulus. Mean reactivity to the mitogen, Concanavalin A, did not differ between these two groups, but responses to PPD were markedly lower in those with onchocerciasis. Proliferative responses to adult female O. volvulus antigen in the latter group were generally low although elevated reactivity was found in certain sub-groups. Higher responses were evident in infected 10-14 year olds, and there was an association between elevated reactivity to O. volvulus antigens and acute reactive dermatological signs, with individuals in the latter group also carrying higher dermal microfilarial loads. A sub-group presenting with lymphadenopathy showed the strongest associations of these three parameters. These results suggested the requirement for a threshold density of dermal microfilariae for induction of acute reactivity. The presence of immunosuppressive factors in soluble O. volvulus antigen was indicated by the ability to suppress, at low concentrations, the cellular responses to PPD of a proportion of individuals.
 ...
PMID:Immunological studies on onchocerciasis in Sierra Leone. 1. Pretreatment baseline data. 207 81

Previous studies in the forest area of Sierra Leone have shown that transmission of Onchocerca volvulus takes place many kilometers away from large breeding rivers and sometimes in open farmland. To determine where and when people in a forest village were most likely to be infected, catches of Simulium damnosum s.l. were carried out every week for 12 months, at five sites in and near a village where onchocerciasis was mesoendemic. The number of flies caught per man a day at open farm sites was significantly higher than the number caught at riverside sites. Infective flies were caught only in farmland and only during the early rainy season. The combined Annual Transmission Potential for the five sites was 129 larvae per man per year. Isoenzyme electrophoresis and morphology of biting flies identified the S. sanctipauli/soubrense subcomplex as the most common vector species. Simulium yahense and S. squamosum were sometimes present. It was concluded that the classical riverside monitoring sites do not represent high risk areas for the transmission of onchocerciasis in a forest village sited well away from the main S. damnosum s.l. breeding sites. The highest risk areas are in open farmland.
 ...
PMID:The transmission of onchocerciasis at a forest village in Sierra Leone. I. Simulium damnosum s.l. biting densities and infection with Onchocerca volvulus at five representative sites. 207 37

The objective of this work is to evaluate the palpation sensitivity of onchocercomata for the diagnosis of onchocerciasis in individuals residents of the locality of Nueva Costa Rica, Mapastepec, in the south endemic area of the state of Chiapas, Mexico. Every one of the 243 individuals who voluntarily participate in this study was interrogated and physical examined for the detection of nodules. The positivity and the worm burden to the Onchocerca volvulus infections was estimated by the presence of one or more microfilariae in any of the for skin snips taken from both suprascapular and gluteal regions, and by the mean of the Dmf/mg of each skin snip. From the total number of individual studied, 131 (53.9%) were positives to microfilariae and 37 (15.2%) to onchocercomata. Only 23 (17.6%) of the microfilariae positive individuals carried nodules. The distribution of positive individuals to nodules in relation to age, was similar in all the age groups. In relation to the intensity of the infection was found that, the mean of the Dmf/mg of all individuals was 6.67, there was not significant differences (p greater than 0.001) between males and females; being the Dmf/mg of 6.35 and 6.99, respectively. The age group between 21 and 30 years old showed the higher mean of Dmf/mg than the rest of the groups (p greater than 0.001). However, there was a high microfilariae positivity in the oldest groups than in the young. The prevalence for onchocerciasis in this locality, estimated by the positivity to either microfilariae or nodules, was 59.9 per cent. It is concluded that, the onchocercomata detection sensitivity for the diagnosis of onchocerciasis was very low, probably due to the nodulectomy activity of the onchocerciasis control program, which has been operating since 1930 and therefore, there are an important number of individuals positive to microfilariae without detectable nodules.
 ...
PMID:[The correlation between onchocercomas and positivity for microfilaria in onchocerciasis]. 208 42

Immunoelectroblotting and enzyme-linked immunosorbent assay were used to identify non-cross-reacting antigenic components of Dracunculus medinensis and the filarial worms Onchocerca volvulus, Loa loa, Wuchereria bancrofti, Brugia malayi, and Mansonella ozzardi. Parasite specific serodiagnostic ELISA systems for onchocerciasis and dracunculiasis were devised based on these findings. Phosphate buffered saline extracts of adult worms were passed through a column of monoclonal antibodies to phosphorylcholine (PC). Crude and PC-depleted extracts were reacted on ELISA plates with individual sera from subjects infected with a range of nematodes. Binding of total antibody (Ig) or IgG class antibody and IgG4 subclass antibody was revealed using goat antihuman-Ig-phosphatase conjugate, or appropriate mouse monoclonal antihuman-Ig-type-specific reagents, followed by goat antimouse-Ig-phosphatase conjugate. Specificity of ELISA was improved by restricting reaction to the host's IgG4 antibody subclass, and/or by removing PC determinants from crude antigens. In parallel immunoelectroblots, crude and PC-depleted extracts probed with pooled sera showed potentially useful diagnostic antigens, including a 12 kDa protein from D. medinensis and 14, 18, and 27 kDa proteins from O. volvulus. Two Onchocerca specific ELISA systems non-reactive with antibodies to D. medinensis were devised.
 ...
PMID:Specific and cross-reacting antibodies in human responses to Onchocerca volvulus and Dracunculus medinensis infections. 213 30

The Falcon assay screening test-enzyme-linked immunosorbent assay (FAST-ELISA) and the enzyme-linked immunoelectrotransfer blot (EITB) technique were used to test human sera with Dracunculus medinensis adult worm antigen in order to assess their potential value in the immunodiagnosis of dracunculiasis. The human sera used were from patients with prepatent and patent D. medinensis infections or from patients infected with other nematodes (Onchocerca volvulus and Loa loa) or trematodes (Schistosoma mansoni and S. haematobium), as well as uninfected Nigerian and Puerto Rican normal controls. In the FAST-ELISA, the sera from prepatent and patent dracunculiasis patients gave the highest absorbance values relative to normal human sera. The highest cross-reactivity was observed with onchocerciasis sera; no cross-reactivity was seen with sera from individuals with loiasis or schistosomiasis mansoni or haematobia. By the EITB, sera from dracunculiasis patients specifically recognized a 16 kDa protein (Dm 16) and antibodies to Dm 16 disappeared 2 months after worm extraction. Recognition of Dm 16 occurred from the late prepatent stage. A 17 kDa protein (Dm 17) was also recognized by dracunculiasis sera, but antibodies to Dm 17 disappeared more slowly and were present 1 year after recovery. The 16 kDa and 17 kDa antigens of D. medinensis may be useful in the immunodiagnosis of dracunculiasis.
 ...
PMID:Immunodiagnosis of dracunculiasis by Falcon assay screening test-enzyme-linked immunosorbent assay (FAST-ELISA) and by enzyme-linked immunoelectrotransfer blot (EITB) technique. 214 63

Antibodies to phosphorylcholine and carbohydrate determinants responsible for much of the cross-reactivity among nematodes are subclass restricted in humans and absent in the IgG4 subclass. Total IgG and IgG4 antibody responses to Onchocerca volvulus were examined by enzyme immunoassay and by immunoblot. Significant background IgG reactivity was detected in both assays in US control sera and sera from patients with intestinal nematode infections, but background reactivity was negligible in the IgG4 assays. IgG4 antibodies were detected by enzyme immunoassay in 17 of 18 Nigerian onchocerciasis serum samples and in 2 of 9 endemic control serum samples. Cross-reactive IgG4 antibodies were present in serum pools from patients infected with other filariae. IgG4 antibodies recognized a restricted subset of O. volvulus antigens in immunoblots relative to IgG. These results confirm the previously reported enhanced specificity of IgG4 antibody assays for filariasis and extend the observation to include onchocerciasis. Whereas IgG4 subclass antibody serology is more specific than measurement of total IgG antibodies for onchocerciasis, cross-reactivity among filariae limits the utility of this approach.
 ...
PMID:IgG4 subclass antibody serology for onchocerciasis. 217 25


<< Previous 1 2 3 4 5 6 7 8 9 10