East coast fever: 1. Chemoprophylactic immunization of cattle against Theileria parva (Muguga) and five theilerial strains

Radley, D.E.; Brown, C.G.D.; Burridge, M. J.; Cunningham, M. P.; Kirimi, I.M.; Purnell, R.E.; Young, A. S.

doi:10.1016/0304-4017(75)90005-9

Cited by 166 publications

(79 citation statements)

References 9 publications

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“…The results of these studies are of particular practical significance because of the well-documented antigenic variability among strains of T. parva, which results in incomplete crossprotection against different strains (17). Additional preliminary studies of the antigens described herein have confirmed that the defined epitope regions vary in sequence among parasite strains and are differentially recognized by CD8 T cells (R. Pellé and S. P. Graham, unpublished data).…”

Section: Discussionsupporting

confidence: 56%

“…However, the ability of T. parva to transform host lymphocytes and undergo rapid multiplication in the transformed cells, as well as the limited replicative capacity of the intraerythrocytic piroplasm stage, represent fundamental differences from the corresponding plasmodial stages. Cattle that recover from an initial exposure to T. parva, either spontaneously or as a result of chemotherapy, are solidly immune to homologous and, in certain instances, heterologous challenge (17). The long duration of immunity to East Coast fever also contrasts with immunity to malaria, which develops only after several years of exposure and wanes in the absence of exposure to parasite challenge (9).…”

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confidence: 99%

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Characterization of the Fine Specificity of Bovine CD8 T-Cell Responses to Defined Antigens from the Protozoan ParasiteTheileria parva

et al. 2008

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Immunity against the bovine intracellular protozoan parasite Theileria parva has been shown to be mediated by CD8 T cells. Six antigens targeted by CD8 T cells from T. parva-immune cattle of different major histocompatibility complex (MHC) genotypes have been identified, raising the prospect of developing a subunit vaccine. To facilitate further dissection of the specificity of protective CD8 T-cell responses and to assist in the assessment of responses to vaccination, we set out to identify the epitopes recognized in these T. parva antigens and their MHC restriction elements. Nine epitopes in six T. parva antigens, together with their respective MHC restriction elements, were successfully identified. Five of the cytotoxic-T-lymphocyte epitopes were found to be restricted by products of previously described alleles, and four were restricted by four novel restriction elements. Analyses of CD8 T-cell responses to five of the epitopes in groups of cattle carrying the defined restriction elements and immunized with live parasites demonstrated that, with one exception, the epitopes were consistently recognized by animals of the respective genotypes. The analysis of responses was extended to animals immunized with multiple antigens delivered in separate vaccine constructs. Specific CD8 T-cell responses were detected in 19 of 24 immunized cattle. All responder cattle mounted responses specific for antigens for which they carried an identified restriction element. By contrast, only 8 of 19 responder cattle displayed a response to antigens for which they did not carry an identified restriction element. These data demonstrate that the identified antigens are inherently dominant in animals with the corresponding MHC genotypes.

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Section: Discussionsupporting

confidence: 56%

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confidence: 99%

Characterization of the Fine Specificity of Bovine CD8 T-Cell Responses to Defined Antigens from the Protozoan ParasiteTheileria parva

et al. 2008

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“…The latter issue probably has little relevance to the field situation but has substantial implications for the maintenance of stabilates for large-scale infection and treatment immunization, which depends on heterogeneity for breadth of cover (27). However, variation among tick populations in the specificity of selection for T. parva parasites has major consequences for the population structure of the parasite in the field, since it identifies tick population heterogeneity as a major determinant of parasite diversity.…”

Section: Discussionmentioning

confidence: 99%

Extensive Genotypic Diversity in a Recombining Population of the Apicomplexan ParasiteTheileria parva

et al. 2006

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We evaluated sexual recombination in the apicomplexan parasite Theileria parva using genome-wide marker analysis of haploid sporozoite populations obtained from infected Rhipicephalus appendiculatus ticks. Analysis of 231 parasite clones derived by in vitro infection of bovine lymphocytes revealed 48 distinct combinations of 64 polymorphic marker loci. One genotype accounted for more than 75% of the clones, and the population was highly inbred with respect to this. The occurrence of frequent recombination was evident from reassortment of contiguous markers in blocks, with some recombination occurring within blocks. Analysis of four polymorphic loci encoding antigens targeted by protective cytotoxic-T-lymphocyte responses confirmed that these loci reassort, both within and between chromosomes, suggesting that recombination may influence immune recognition. Marker analysis of a panel of 142 clones derived from the population after an additional passage through a calf and the same tick colony revealed 18 genotypes, with the original dominant genotype accounting for 75% of the population and a higher level of inbreeding with respect to it in the remaining clones. Selected marker analysis of genomic DNA from these stabilates and the two preceding generations of the isolate, each derived from distinct tick colonies, revealed shifts in population structure with each generation, suggesting that the tick vector may impose nonrandom selective pressure on the parasite.

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“…Later Wilde (1967), in an important review of the disease, also questioned this dogma. However, sterile immunity was given further credence in the late 1960s and early 1970s through the use of the T. parva Muguga stock in a very large number of experiments, once triturated tick stabilates became available (Cunningham et al 1973;Radley et al 1975;Radley 1981). This parasite, an example of the causative agent of classical ECF, does not induce carriers (Young et al 1986) and although this characteristic may be rare, it is not unique.…”

Section: Carrier States and Disease Transmissionmentioning

confidence: 99%

Dogmas and misunderstandings in East Coast fever

Dolan¹

1999

Tropical Med Int Health

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SummaryEast Coast fever (ECF) is the most important tick-borne disease in eastern, central and southern Africa and caused an estimated loss of US $186 million in 1989 in the 11 countries where it occurs. It was brought to southern Africa with cattle from Tanzania in 1901 and, over the next 3 years, devastated the cattle that had survived the rinderpest pandemic of the 1890s. Chemical control of ticks using arsenical compounds was introduced in the early 1900s and became the main control measure for both ticks and the diseases they transmit. This method of control has become less reliable over the last 30 years for many reasons, including reduced government spending on livestock and extension, the cost of acaricides, acaricide resistance, poor management of dips and spray races, and poor application of cattle movement control and quarantine. Significant advances in immunization and treatment have been made in the last 30 years, and more robust integrated strategies combining immunization, reduced frequency of chemical control and treatment are being adopted or considered. Throughout its history, ECF has been a source of great anxiety and cost to farmers, and of intense interest to research workers. Many dogmas and misconceptions have become established, some of which still flourish while others took years to demolish. This paper briefly reviews these as well as the history of the disease and explores recent epidemiological findings and their relevance to applying effective control.

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East coast fever: 1. Chemoprophylactic immunization of cattle against Theileria parva (Muguga) and five theilerial strains

Cited by 166 publications

References 9 publications

Characterization of the Fine Specificity of Bovine CD8 T-Cell Responses to Defined Antigens from the Protozoan ParasiteTheileria parva

Characterization of the Fine Specificity of Bovine CD8 T-Cell Responses to Defined Antigens from the Protozoan ParasiteTheileria parva

Extensive Genotypic Diversity in a Recombining Population of the Apicomplexan ParasiteTheileria parva

Dogmas and misunderstandings in East Coast fever

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