Hostname: page-component-7479d7b7d-pfhbr Total loading time: 0 Render date: 2024-07-12T03:41:54.195Z Has data issue: false hasContentIssue false
  • English
  • Français

A preliminary assessment of the feasibility of evaluating promising antifilarials in vitro against adult Onchocerca volvulus

Published online by Cambridge University Press:  06 April 2009

J. C. W. Comley ,
T. M. Szopa ,
G. Strote ,
M. Buttner ,
K. Darge  and
W. Buttner
J. C. W. Comley
Affiliation:
Molecular Sciences Department, The Wellcome Research Laboratories, Langley Court, Beckenham, Kent BR3 3BS, UK
T. M. Szopa
Affiliation:
Biochemistry Department, The London Hospital Medical College, Turner Street, London El 2AD, UK
G. Strote
Affiliation:
Helminthology Department, Bernard Nocht Institute, Bernard Nocht Street 74, D-2000 Hamburg 36, FRG
M. Buttner
Affiliation:
Helminthology Department, Bernard Nocht Institute, Bernard Nocht Street 74, D-2000 Hamburg 36, FRG
K. Darge
Affiliation:
Helminthology Department, Bernard Nocht Institute, Bernard Nocht Street 74, D-2000 Hamburg 36, FRG
W. Buttner
Affiliation:
Helminthology Department, Bernard Nocht Institute, Bernard Nocht Street 74, D-2000 Hamburg 36, FRG
Get access Rights & Permissions [Opens in a new window]

Summary

The suitability of motility indices and tetrazolium-based colorimetric assays for the determination of the viability of adult Onchocerca volvulus after in vitro exposure to potential macrofilaricides has been examined. Experimentation showed that both techniques could be applied to adult O. volvulus, although the variability between individual worms necessitated the use of large experimental groups. The potential of using cut anterior tips of female O. volvulus for screening was also investigated. These were shown to give reasonably consistent motility indices, and drug effects were discernible even after 72 h in vitro culture. Application of these viability criteria to studies on the short-term in vitro survival of intact male and female O. volvulus incubated in Eagles MEM plus serum, under 5% CO2 in air, showed this medium to be suboptimal with a greater than 50 % loss of worm viability within 144 h of nodulectomy. Males isolated by the collagenase technique were shown to be significantly less viable than dissected males, by both motility indices and tetrazolium reduction. The results highlight the need to use either dissected males, or in the case of females, the need to minimize exposure to collagenase solution. A possible mechanism for selecting a more uniformly viable female worm population is discussed. Examination of the in vitro effects of CGP 20376 using these viability criteria/assay systems showed some delayed suppression of worm motility, but after 120 h in vitro CGP 20376 was not macrofilaricidal against male or female O. volvulus. Male worms were also implanted subcutaneously into gerbils. Treatment of these animals with CGP 20376, with autopsy 2 weeks later, resulted in a small macrofilaricidal effect (28% worm death). Some reduction in the motility of living worms recovered from CGP 20376-treated gerbils was also evident. Good survival of control worms recovered 2 weeks post-implantation suggests that male O. volvulus might survive longer subcutaneously. The prospects for undertaking meaningful drug evaluations against O. volvulus in vitro (and in vivo in rodents) is therefore promising, but because of parasite availability will probably be limited to those compounds which have shown potential in other filarial test systems.

Keywords

Onchocerca volvulusviabilitymotilitytetrazolium reductioncollagenase isolationdrug evaluation.
Type
Research Article
Information
Parasitology , Volume 99 , Issue 3 , December 1989 , pp. 417 - 425
Copyright
Copyright © Cambridge University Press 1989

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bennett, J. L. & Pax, R. A. (1986). Micromotility meter: an instrument designed to evaluate the action of drugs on the motility of larval and adult nematodes. Parasitology 93, 341–6.CrossRefGoogle ScholarPubMed
Comley, J. C. W., Rees, M. J., Turner, C. H. & Jenkins, D. c. (1989 a). Colorimetric quantitation of filarial viability. International Journal for Parasitology 19, 77–83.CrossRefGoogle ScholarPubMed
Comley, J. C. W., Townson, S., Rees, M. J. & Dobinson, A. (1989 b)., The further application of MTT-formazan colorimetry to studies on filarial worm viability. Tropical Medicine and Parasitology (in the Press).Google Scholar
Paull, K. D., Shoemaker, R. H., Boyd, M. R., Parsons, J. L., Risbood, P. A., Barbera, W. A., Sharma, M. N., Baker, D. C., Hand, E., Scudiero, D. A., Monks, A., Alley, M. C. & Grote, M. (1988). The synthesis of XTT: a new tetrazolium reagent that is bioreducible to a water-soluble formazan. Journal of Heterocyclic Chemistry 25, 911–14.CrossRefGoogle Scholar
Pax, V. A., Williams, J. F. & Guderian, R. H. (1988). In vitro motility of isolated adults and segments of Onchocerca volvulus, Brugia pahangi and Acanthocheilonema viteae. Tropical Medicine and Parasitology 39, 450–5.Google ScholarPubMed
Satti, M. Z., Vandewaa, E. A., Bennett, J. L., Williams, J. F., Conder, G. A. & Mccall, J. W. (1988). Comparative effects of anthelmintics on motility in vitro of Onchocerca gutturosa, Brugia pahangi and Acanthocheilonema viteae. Tropical Medicine and Parasitology 39, 480–3.Google ScholarPubMed
Scudiero, D. A., Shoemaker, R. H., Paull, K. D., Monks, A., Tierney, S., Nofziger, M. J., Seniff, D. & Boyd, M. R. (1988). Evaluation of a soluble tetrazolium/formazan assay for cell growth and drug sensitivity in culture using human and tumor cell lines. Cancer Research 48, 4827–33.Google ScholarPubMed
Townson, S. (1988). The development of a laboratory model for onchocerciasis using Onchocerca gutturosa: in vitro culture, collagenase effects, drug studies and cryopreservation. Tropical Medicine and Parasitology 39, 475–9.Google ScholarPubMed
Walter, R. D. (1988). In vitro maintenance of Onchocerca volvulus for harvest of excretory and secretory products. Tropical Medicine and Parasitology 39, 448–9.Google ScholarPubMed