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)

Immunological study of individuals (aged 4 to 70 years) living in an area of Mali hyperendemic for onchocerciasis revealed an 83% prevalence of skin microfilariae (mf). Microfilariae counts from skin snips were highly age-dependent. Screening for concomitant helminth infections showed a low prevalence of hookworms and Mansonella (Dipetalonema) perstans, but neither schistosomiasis nor bancroftian filariasis. Immunological results revealed strong correlation between radioallergosorbent test (RAST) and skin test (5 and 50 ng adult O. volvulus extract), between RAST and total IgE, and between IFAT and ELISA. A negative correlation exists between mf counts and skin tests and between mf counts and RAST; the lowest median values were obtained in the group with high mf counts. Skin sensitizing antibodies were detected in most locally born children aged 4-5 years. Intradermal tests showed a high rate of sensitization to O. volvulus antigen in mf-negative children, whereas ELISA and IFAT values were significantly lower in these children than in mf-positive children. Increasing concentrations of circulating IgE antibodies were found in children aged 4-11 years by RAST, and, in individuals aged 12-19 years (age group for which mf counts sharply increase), skin testing revealed a state of anergy. In long lasting infections (adults greater than 20 years) skin reactivity was comparable to that of young children or was depressed. ELISA and IFAT achieved similar results in each age group.
 ...
PMID:Seroepidemiological investigations of onchocerciasis in a hyperendemic area of West Africa. 389 85

The effects of Onchocerca volvulus infection on immunoglobulin levels have been studied in subjects from three localities with different onchocerciasis prevalence rates. Infestation by O. volvulus provoked a 200-500% rise in total serum IgE levels. Immunoglobulins G, M. and A were increased less dramatically. To study further the IgE response, radioallergosorbent test (RAST) systems were developed using total extract of O. volvulus and Onchocerca supernatant (excretory-secretory) antigens. Both antigen preparations reacted with more than 80% of the onchocerciasis sera from the hyperendemic village, but the reactions were not proportionate to skin microfilarial density. There were also positive reactions with sera of some individuals whose skin biopsies showed no microfilariae, indicating prior exposure to the parasite. European control sera tested under similar conditions reacted only slightly in the RAST system. The developed RAST systems may thus be used for determining prior exposure to O. volvulus.
 ...
PMID:Serum immunoglobulin E levels in onchocerciasis: the development of a radioallergosorbent test for Onchocerca volvulus infection. 400 65

Crude phosphate-buffered extracts of adult Onchocerca volvulus from savanna (Mali) and rain forest (Cameroon) areas were comparatively analysed using biochemical and immunological methods. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing revealed only minor differences between the two extracts. Out of 42 bands detectable by SDS-PAGE at least 21 were identified as glycoproteins by their affinity to concanavalin A. High resolution analysis using two dimensional gel electrophoresis (2D-G) showed marked differences in the polypeptide patterns of the two extracts. Some of the over 100 polypeptides demonstrable by Coomassie blue staining (especially at pIs between 4.3 and 5.6 and mol. wts over 64kD) were clearly different when the two extracts were compared. Antigenic differences between the two extracts could be detected by crossed immunoelectrophoresis using a rabbit anti-O. volvulus hyperimmune serum. The comparison by tandem crossed immunoelectrophoresis demonstrated clearly the existence of at least three antigenic differences, four partial identities and 13 antigenic identities between the extracts. For the identification of O. volvulus antigens serologically recognized by infected patients, we combined the 2D-G with an immunoblotting technique using a pool of highly reactive onchocerciasis sera from Mali. IgG binding antigens were then identified by incubating the blot membrane with this serum pool and with 125I-labelled protein A followed by autoradiography. IgE binding antigens were detected using a 125I-labelled anti-human IgE antiserum. Whilst the overall antigenic patterns were similar, there were, however, clear differences between the antigen preparations which gives further evidence for antigenic diversity of O. volvulus from savanna and rain forest areas.
 ...
PMID:Immunochemical comparison between worm extracts of Onchocerca volvulus from savanna and rain forest. 401 3

It is not clear what role immediate hypersensitivity immune responses have in the pathogenesis of human onchocerciasis, but it is certain that these responses are prominent both in the course of natural infection and during the Mazzotti reactions that follow treatment with diethylcarbamazine. In humans, the levels of total serum IgE associated with onchocerciasis are as high or higher than those associated with almost any helminth infection, although specific IgE antibodies to Onchocerca volvulus appear to be a small and still poorly characterized fraction of the total serum IgE. Evidence about the relationship of these prominent IgE responses in patients with onchocerciasis to the onchocercal skin disease that manifests as pruritus and papular eruptions is conflicting, but in a guinea pig model of ocular pathology induced by onchocerca microfilariae evidence for the pathogenetic importance of IgE and immediate hypersensitivity is much less equivocal. The suggestive findings from this model make it imperative to carry out similar studies of Onchocerca-affected human eyes to determine whether immediate hypersensitivity responses play a similar critical role in the pathogenesis of the ocular lesions in humans.
 ...
PMID:Immediate hypersensitivity responses in the immunopathogenesis of human onchocerciasis. 407 Sep 17

A radioallergosorbent test (RAST) was developed to detect IgE antibodies against adult Onchocerca volvulus antigens coupled to CnBr-activated Sepharose. Twenty-four out of 25 (96%) onchocerciasis sera were reactive. The lower limit of sensitivity was estimated to be at approx. 3 ng/ml IgE antibodies. Tests of sera from patients with non-filarial helminth infections showed much less cross-reactivity with RAST than with an enzyme-linked immunosorbent assay (ELISA) detecting IgG and IgM antibodies against the same antigen preparation. At a specificity comparable to that of RAST, the sensitivity of ELISA was only 61%. A heterologous antigen, prepared from female Dipetalonema viteae worms, was comparatively evaluated with O. volvulus. In RAST and ELISA, onchocerciasis sera were less reactive than against the O. volvulus antigen. Since sera from patients with non-filarial helminth infections were more reactive in RAST and almost equally reactive in ELISA using the D. viteae antigen, sensitivity was 83% for RAST and only 22% for ELISA (compared at the specificity identical to that of the O. volvulus RAST).
 ...
PMID:IgE antibodies in human onchocerciasis. Application of a newly developed radioallergosorbent test (RAST). 611 43

The present study reports the presence of Onchocerca volvulus specific IgE in the sera obtained from onchocerciasis patients. About 70% of onchocerciasis patients showed a raised level of O. volvulus specific IgE compared to patients infected either with other human filarids (Loa loa, Wuchereria bancrofti, Brugia malayi) or with other helminths (Schistosoma mansoni, Ascaris lumbricoides, Fasciola hepatica). The O. volvulus specific IgE level was significantly higher in patients exhibiting 'gale filarienne' than in microfilaremic patients or in endemic controls. The total IgE level was significantly raised in the serum samples of all groups of subjects from endemic areas compared to European controls. There was no significant increase in the level of IgE in the onchocerciasis sera when O. volvulus antigen was replaced by the antigens from various helminths in the present assay system (radioallergosorbent test). However, there was a clear evidence of the presence of cross-reacting allergens in the crude extracts from adults of O. volvulus and Dipetalonema viteae (a rodent filarial parasite) because there was a significant reduction in IgE level in onchocerciasis sera following absorption with either O. volvulus or D. viteae sorbents. Moreover, the IgE antibodies in onchocerciasis patients sera recognized the allergens which were present in the somatic extracts of O. volvulus and D. viteae as revealed by radiolabelled anti-IgE.
 ...
PMID:Detection of IgE antibodies in onchocerciasis. Possibility of using allergens from Dipetalonema viteae extracts that cross-react with allergenic determinants in crude extracts of Onchocerca volvulus. 618 3

Reaginic antibodies to antigens from the human parasite Strongyloides stercoralis were studied by histamine release from basophils in 15 patients with chronic uncomplicated strongyloidiasis and in 12 controls (six North Americans with no evidence of parasitic diseases, two patients with Schistosoma mansoni, two with hookworm, one with Ascaris lumbricoides, and one with Onchocerca volvulus). All of the patients had antibodies to the somatic larval antigens, and 14 of 15 patients also had antibodies to the excretory/secretory products of S. stercoralis larvae. None of the controls had a positive response to any of the antigens tested. These findings indicate that patients with chronic strongyloidiasis have parasite-specific IgE antibodies and that S. stercoralis larval allergens may have a potential role in the immunodiagnosis of strongyloidiasis.
 ...
PMID:Specific allergic sensitization to Strongyloides antigens in human strongyloidiasis. 618 84

A Dipetalonema viteae extract was separated by gel filtration on ACA 34 Ultrogel into four fractions (A, B, C and D). The allergenic activity of the D. viteae extract and its various fractions was assayed by the passive cutaneous anaphylaxis (PCA) test in rats using mouse sera obtained from Balb/c mice transplanted with D. viteae. The PCA reaction showed that fraction B was the most potent allergenic fraction of the D. viteae extract. By the radioallergosorbent test (RAST) the use of fraction B coupled to CNBr-activated paper discs showed elevated binding of IgE antibodies in onchocerciasis human sera. A comparative study demonstrated the efficiency of the above fraction in the RAST technique in distinguishing between Onchocerca volvulus-infected patients and those infected with other human filarial worms or other helminth parasites. The binding of IgE to fraction B was confirmed by the radioimmunoelectrophoresis and radio-double diffusion methods using an 125I anti-human IgE. Since D. viteae antigens are more readily obtainable than those of O. volvulus, a further purification of fraction B to improve its specificity for the detection of IgE antibodies in human onchocerciasis is warranted.
 ...
PMID:Detection of IgE antibodies in onchocerciasis using a semi-purified fraction from Dipetalonema viteae total antigen. 660 Jul 14

To explore the relative species specificities of the IgE and IgG antibody responses to helminth infections in man, we studied four pools of sera from patients infected with Wuchereria bancrofti, Brugia malayi, Onchocerca volvulus or Ascaris lumbricoides and ten individual sera from patients with onchocerciasis. IgE antibodies were detected by radioallergosorbent test (RAST) analysis and IgG antibodies by a Staphylococcus protein A radioimmunoassay (Staph A-RIA). Analysis of the binding curves with four different immunosorbents (prepared from antigens of B. malayi, O. volvulus, Dipetalonema viteae and A. lumbricoides) in the RAST and the binding curves with these same four antigens in the Staph A-RIA confirmed the relative species specificities for both the IgE and IgG antibody responses. Then determination of these antibody levels after specific absorption of the sera with both homologous and heterologous antigens showed that in all instances there was significantly less cross-reactivity with heterologous parasite antigens (i.e. higher species specificity) in the IgE antibody response to filarial infection than in the corresponding IgG antibody response. Such findings imply that efforts toward developing techniques for specific immunodiagnosis of filarial infections are likely to be particularly successful if focused on the IgE antibody response of exposed individuals.
 ...
PMID:IgE antibodies are more species-specific than IgG antibodies in human onchocerciasis and lymphatic filariasis. 719 27

The effect of the microfilaricidal drug ivermectin on the antibody response to a detergent extract of adult Onchocerca volvulus (OvAg) and a number of specific recombinant peptides was examined. Three of the peptides were combined in a serodiagnostic 'cocktail' and the effect of ivermectin on the diagnostic performance of this assay was assessed. Immunoglobulin (Ig) G1 serum levels in response to OvAg significantly decreased following ivermectin treatment. The antibody response to only one recombinant peptide (OvMBP29) was significantly affected, with IgG levels decreasing following treatment. Levels of total IgE increased following treatment. No correlation was observed between initial antibody level (or change in antibody level) and any adverse reaction to treatment. The serodiagnostic 'cocktail' was 100% sensitive before and after the use of ivermectin. A serodiagnostic assay using specific recombinant peptides can be used to evaluate infection in the absence of dermal microfilariae in areas where ivermectin is used.
 ...
PMID:The effect of ivermectin treatment on the antibody response to antigens of Onchocerca volvulus. 757 Aug 44


<< Previous 1 2 3 4 5 6 Next >>