Hostname: page-component-77c89778f8-5wvtr Total loading time: 0 Render date: 2024-07-18T07:41:51.488Z Has data issue: false hasContentIssue false
  • English
  • Français

Antigenic variation in trypanosomes: a computer analysis of variant order

Published online by Cambridge University Press:  06 April 2009

R. J. Kosinski
R. J. Kosinski
Affiliation:
Biology Department, Texas A & M University, College Station, Texas 77843
Get access Rights & Permissions [Opens in a new window]

Summary

African trypanosomes can undergo antigenic variation and evade the host immune response. Whether the antigenic variants arise in an ordered sequence or randomly has been in dispute but has not been statistically tested. The coefficient of concordance (W), a statistic designed to detect similarities between sequences of objects, was applied to the literature data. The tendency towards a reproducible order of variants was strong, although in several of the studies the number of experimental animals was so low that no conclusions could be drawn. A computer model was used to determine whether this degree of order could arise with random generation of variants followed by selection. The model simulated a trypanosome clone with 90 possible variants, widely differing variant-specific growth rates, random variant origin and variant eradication by an anamnestic host immune response. Parameters varied were maximum parasitaemia, growth rate differential between ‘fast’ and ‘slow’ variants, and parasitologist ability to detect minor variants. Random generation and selection by growth rate alone could not produce the degree of variant orderliness reported in the literature. However, experiments with larger numbers of host animals and direct investigation of variant growth rates and competitive interactions are necessary before the random generation-selection hypothesis can be proven or disproven.

Type
Research Article
Information
Parasitology , Volume 80 , Issue 2 , April 1980 , pp. 343 - 357
Copyright
Copyright © Cambridge University Press 1980

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

Cantrell, W. (1958). Mutation rate and antigenic variation in Trypanosoma equiperdum. Journal of Infectious Diseases 103, 263–71.CrossRefGoogle ScholarPubMed
Capbern, A., Giroud, C., Baltz, T. & Mattern, P. (1977). Trypanosoma equiperdum: Étude des variations antigeniques au cours de la trypanosome experimentale du lapin. Experimental Parasitology 42, 6–13.CrossRefGoogle Scholar
Clarkson, M. J. (1976). Trypanosomes. Veterinary Parasitology 2, 9–29.CrossRefGoogle Scholar
Dar, F. K., Paris, J. & Wilson, A. J. (1973). Serological studies on trypanosomes in East Africa. IV. Comparison of antigenic types of Trypanosoma vivax group organisms. Annals of Tropical Medicine and Parasitology 67, 319–29.CrossRefGoogle ScholarPubMed
De Raadt, P. (1974). Immunity and antigenic variation: clinical observations suggestive of immune phenomena in African trypanosomiasis. In Trypanosomiasis and Leishmaniasis, Ciba Fdn Symp. 20 (N.S.), pp. 199–216. Amsterdam: Associated Scientific Publishers.Google Scholar
Doyle, J. J. (1977). Antigenic variation in the hemaprotozoa-with special reference to salivarian trypanosomes. In Immunity to Blood Parasites of Animals and Man (ed. Pino, J., Miller, L. and McKelvey, J.), pp. 31–63. New York: Plenum Press.CrossRefGoogle Scholar
Gray, A. R. (1965 a). Antigenic variation in a strain of Trypanosoma brucei transmitted by Glossina morsitans and G. palpalis. Journal of General Microbiology 41, 195–214.CrossRefGoogle Scholar
Gray, A. R. (1965 b). Antigenic variation in clones of Trypanosoma brucei. I. Immunological relationships of the clones. Annals of Tropical Medicine and Parasitology 59, 27–36.CrossRefGoogle ScholarPubMed
Gray, A. R. (1970). Antigenic variation. In The African Trypanosomiases (ed. Mulligan, H. W.), pp. 113–17. New York: Wiley Interscience.Google Scholar
Gray, A. R. (1972). Variable agglutigenic antigens of Trypanosoma gambiense and their distribution among isolates of the trypanosome collected in different places in Nigeria. Transactions of the Royal Society of Tropical Medicine and Hygiene 66, 263–83.CrossRefGoogle ScholarPubMed
Gray, A. R. (1975). A pattern in the development of the agglutigenic antigens of cyclically transmitted isolates of Trypanosoma gambiense. Transactions of the Royal Society of Tropical Medicine and Hygiene 69, 131–8.CrossRefGoogle ScholarPubMed
Hirumi, H., Doyle, J. J. & Hirumi, K. (1977). African trypanosomiasis: cultivation of animal-infective Trypanosoma brucei in vitro. Science 196, 992–4.CrossRefGoogle Scholar
Inoki, S., Osaki, H. & Nakabayashi, T. (1956). Studies on the immunological variation in Trypanosoma gambiense. Verification of the new variation system by Ehrlich's and in vitro methods. Medical Journal of Osaka University 7, 165–73.Google Scholar
Jones, T. W. & Clarkson, M. J. (1972). The effect of syringe and cyclical passage on antigenic variants of Trypanosoma vivax. Annals of Tropical Medicine and Parasitology 66, 303–12.CrossRefGoogle ScholarPubMed
Kendall, M. G. (1955). Rank Correlation Methods. London: Charles Griffin.Google Scholar
McNeillage, G. J. C. & Herbert, W. J. (1968). Infectivity and virulence of Trypanosoma (Trypanozoon) brucei for mice. II. Comparison of closely related trypanosome antigenic types. Journal of Comparative Pathology 78, 345–9.CrossRefGoogle ScholarPubMed
Miller, J. K. (1965). Variation of the soluble antigens of Trypanosoma brucei. Immunology 9, 521–8.Google ScholarPubMed
Ormerod, W. E. & Venkatesan, S. (1971). The occult visceral phase of mammalian trypanosomes with special reference to the life cycle of Trypanosoma (Trypanozoon) brucei. Transactions of the Royal Society of Tropical Medicine and Hygiene 65, 722–35.CrossRefGoogle Scholar
Osaki, H. (1959). Studies on the immunological variation in Trypanosoma gambiense (serotypes and mode of relapse). Biken's Journal 2, 113.Google Scholar
Russell, H. (1936). Observations on immunity in relapsing fever and trypanosomiasis. Transactions of the Royal Society of Tropical Medicine and Hygiene 30, 179–90.CrossRefGoogle Scholar
Seed, J. R. (1974). Antigens and antigenic variability of the African trypanosomes. Journal of Protozoology 21, 639–46.CrossRefGoogle ScholarPubMed
Seed, J. R. (1978). Competition among serologically different clones of Trypanosoma brucei gambiense in vivo. Journal of Protozoology 25, 526–9.CrossRefGoogle ScholarPubMed
Seed, J. R. & Effron, H. G. (1973). Simultaneous presence of different antigenic populations of Trypanosoma brucei gambiense in Microtus montanus. Parasitology 66, 269–78.CrossRefGoogle ScholarPubMed
Seed, J. R. & Gam, A. A. (1966). Passive immunity to experimental trypanosomiasis. Journal of Parasitology 52, 1134–40.Google Scholar
Seed, J. R., Kemp, W. M. & Brown, R. A. (1977). Antigenic variation in the African trypanosomes: number and sequence. Texas Journal of Science Special Publication No. 2.Google Scholar
Soltys, M. A. (1963). Immunity in African trypanosomiasis. Bulletin of the World Health Organization 28, 753–61.Google ScholarPubMed
Terry, R. J. (1976). Immunity to African trypanosomiasis. In Immunology of Parasitic Infections (ed. Cohen, S. and Sadun, E. H.), pp. 203–21. Oxford: Blackwell Scientific Publications.Google Scholar
Van Meirvenne, N., Janssens, P. G. & Magnus, E. (1975). Antigenic variation in syringe passaged populations of Trypanosoma (Trypanozoon) brucei. I. Rationalization of the experimental approach. Annales de la Societé Belge de Medécine Tropicale 55, 1–23.Google ScholarPubMed
Vickerman, K. (1971). Morphological and physiological considerations of extracellular blood protozoa. In Ecology and Physiology of Parasites (ed. Fallis, A. M.), pp. 58–91. Toronto: University of Toronto Press.CrossRefGoogle Scholar
Vickerman, K. (1978). Antigenic variation in trypanosomes. Nature, London 273, 613–17.Google Scholar
Watkins, J. F. (1964). Observations on antigenic variation in a strain of Trypanosoma brucei growing in mice. Journal of Hygiene 62, 69–80.CrossRefGoogle Scholar
Wilson, A. J. & Cunningham, M. P. (1972). Immunological aspects of bovine trypanosomiasis. I. Immune response of cattle to infection with Trypanosoma congolense and the antigenic variation of the infecting organism. Experimental Parasitology 32, 165–73.CrossRefGoogle Scholar
World Health Organization (1977). Antigenic variation in African trypanosomiasis: a memorandum. Bulletin of the World Health Organization 55, 703–14.Google Scholar