The effects of vector control on the antibody response to antigens of<i>Onchocerca volvulus</i>

Bradley, Janette E.; Gillespie, A. J.; Trenholme, Katharine R.; Karam, M

doi:10.1017/s003118200006710x

Cited by 17 publications

(7 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2 Our previous work has indicated that community antibody levels decreased after both vector control and treatment with ivermectin. 6,12 This, when combined with the results shown here, indicates that this test is sensitive to levels of infection within a community and that it will be possible to monitor the increase (or decrease) of these parameters effectively. Perhaps the best method for defining reinfection within a community is to measure incidence of infection, i.e., new infections.…”

Section: Discussionsupporting

confidence: 56%

“…2 Since this test is highly specific, 6,7 infections with other nematodes, frequently coendemic with O. volvulus, especially other human filarial parasites, do not affect the results. We have also shown that responses to this assay decrease in a community after vector control 6 and are beginning to decrease two years post-ivermectin treatment. 8 If antibody detection assays are sensitive to the endemicity/intensity of infection in a community, it may be possible to calibrate the assay and provide a serologic index (SI).…”

mentioning

confidence: 65%

See 1 more Smart Citation

A cocktail of recombinant Onchocerca volvulus antigens for serologic diagnosis with the potential to predict the endemicity of onchocerciasis infection.

Bradley

Atogho²,

Elson³

et al. 1998

The American Journal of Tropical Medicine and Hygiene

View full text Add to dashboard Cite

Abstract. We report here the evaluation of the potential of a serologic test to determine the endemicity of onchocercal infection in hyper, meso, and hypoendemic communities by the detection of antibodies to a cocktail of recombinant antigens. Parasitologic parameters of infection prevalence and intensity were compared with serologic results. Infection prevalence by serology was consistently but not significantly higher than that defined by parasitology. Differences between the communities defined by microfilarial load (CMFL) and a measurement of Onchocerca volvulus-specific antibody levels (serologic index [SI]) were similar. When stratified by age, differences were more significant in the younger age groups. If a sentinel population of 5-15-year-old individuals was used to compare communities, all could be equally ranked by serologic and parasitologic parameters. The SI of the sentinel population gave a better distinction between each community than the SI of the whole and would be sufficiently sensitive to measure the changes in endemicity that would be required for onchocerciasis control programs.An estimated 18 million people are infected by the parasitic filaria Onchocerca volvulus, the causative agent of human onchocerciasis or river blindness. Control of the disease is being attempted world-wide by vector control and/or large scale distribution of ivermectin, a drug effective against the pathogenic microfilarial stage of the parasite. The Onchocerciasis Control Program (OCP) in West Africa has been successful in lowering the risk of blindness due to infection with O. volvulus. Thirty million people in 11 West African countries have been estimated to be protected from damaging ocular legions caused by this parasite. 1 A diagnostic test is urgently required by control programs such as the OCP to both monitor the success at reducing the prevalence of infection or to monitor recrudescence in areas where transmission has been successfully interrupted and vector control ceased.2 The method of parasitologic diagnosis is the examination of skin snips for the presence of microfilariae (mf) collected with punches and, although exquisitely specific, it is not very sensitive, particularly in areas of low transmission. Skin snips are also unable to detect prepatent infection, which would result in a critical delay in the detection of recrudescence of transmission. Consequently, control operations would be instigated later and may require implementation on a much wider scale. Finally, with the increase in the prevalence of blood-borne viruses, the substitution of the skin snip is desirable due to problems of sterilization of the expensive punches.Serologic assays based on antibody detection are one possible alternative method of determining infection by this parasite. There have been a number of reports of tests capable of this (for a review see Bradley and Unnasch 3 ). We have previously reported the development of a serologic test able to detect specific O. volvulus antibodies to a cocktail of three recombinant anti...

show abstract

Section: Discussionsupporting

confidence: 56%

mentioning

confidence: 65%

A cocktail of recombinant Onchocerca volvulus antigens for serologic diagnosis with the potential to predict the endemicity of onchocerciasis infection.

Bradley

Atogho²,

Elson³

et al. 1998

The American Journal of Tropical Medicine and Hygiene

View full text Add to dashboard Cite

show abstract

“…What is clear from these investigations is that the antibody response is strong and diverse, immunoglobulin (Ig)G4 constitutes the predominant IgG subclass and high levels of IgE are present (7–9). Several recombinant O. volvulus antigens also induce this characteristic IgG4/IgE response (10–12). This isotype balance indicates the production of cytokines such as IL‐4 and IL‐13: in fact, cellular studies have demonstrated Th2 cytokine production in infected people (13,14).…”

Section: Introductionmentioning

confidence: 99%

Antibody responses in onchocerciasis as a function of age and infection intensity

Faulkner

Gardon

Kamgno

et al. 2001

Parasite Immunology

View full text Add to dashboard Cite

Onchocerciasis is caused by the filarial nematode Onchocerca volvulus and is a major public health problem in West and Central Africa. With only partial and long-term treatment currently available, there is a need to develop a suitable vaccine. We analysed the antibody response to infective L3 larvae because this stage is thought to be associated with host protective immunity. In addition, we have related our findings to the age, gender and current infection intensity of our participants: variables that may significantly influence antibody production. Interestingly, whilst 90% of our study group were seropositive for adult specific immunoglobulin (Ig)E, only 23% produced L3 specific IgE. This is in contrast to IgG4 where seropositivity was comparable at 96% and 92%, respectively. Furthermore, IgG levels were significantly affected by age and the intensity of infection but unaffected by host gender. This finding is independent for the IgG subclass (IgG1, IgG2, IgG3 and IgG4) and its specificity (L3 versus adult antigen). In summary, we show that L3 larvae induce little specific IgE and the antibody response shows a different isotype balance than that against adult antigens. Both host and parasite variables can influence antibody production in this disease.

show abstract

“…This lack of association was to be expected in the case of OvMBP/lO and OvMBP/l 1 due to their localization in adult and L3 stages, but the localization of OvMBP/29 has yet to be established. An association between exposure to infective larvae and antibody titres to the cocktail of recombinant proteins has been indicated in areas under vector control (Bradley et al 1993b) indicating that differences in exposure to L3 larvae between individuals may account for some of the variation in responses shown here.…”

Section: Discussionmentioning

confidence: 71%

Heterogeneity of IgG antibody responses to cloned Onchocerca volvulus antigens in microfiladermia positive individuals from Esmeraldas Province, Ecuador

Trenholme

Tree

Gillespie

et al. 1994

Parasite Immunology

View full text Add to dashboard Cite

The prevalence of IgG antibodies to three recombinant O. volvulus antigens, OvMBP/10, OvMBP/11 and OvMBP/29 was determined in a group of 94 microfilaria positive (mf+) individuals resident in the hyperendemic onchocercal area of Esmeraldas Province, Ecuador. Clone OvMBP/11 was the antigen most frequently recognized by patients sera followed by OvMBP/10 and OvMBP/29. When a cocktail of the three recombinant antigens was used the proportion of positive sera increased to 100%. Antibody responses to the fusion partner maltose binding protein (MBP) were low in comparison with those to the cloned antigens and no correlation of responses between individual antigens was observed. The relative level of antibody response to each of the clones in the cocktail varied between individuals. The distribution of IgG responses to OvMBP/11 was bimodal and those to OvMBP/29 and OvMBP/10 were positively and negatively skewed, respectively. When the three recombinant antigens were used in combination this variation was minimized and the pattern of responses showed a normal distribution as was also seen to crude O. volvulus antigen. The cocktail of recombinants thus offers excellent diagnostic sensitivity in combination with the parasite specificity demonstrated previously.

show abstract

The effects of vector control on the antibody response to antigens ofOnchocerca volvulus

Cited by 17 publications

References 27 publications

A cocktail of recombinant Onchocerca volvulus antigens for serologic diagnosis with the potential to predict the endemicity of onchocerciasis infection.

A cocktail of recombinant Onchocerca volvulus antigens for serologic diagnosis with the potential to predict the endemicity of onchocerciasis infection.

Antibody responses in onchocerciasis as a function of age and infection intensity

Heterogeneity of IgG antibody responses to cloned Onchocerca volvulus antigens in microfiladermia positive individuals from Esmeraldas Province, Ecuador

Contact Info

Product

Resources

About