Sequence diversity of cytotoxic T cell antigens and satellite marker analysis of Theileria parva informs the immunization against East Coast fever in Rwanda
Rattachement africain : Malawi, Zambie, Rwanda, gb. Niveau de preuve : code pays fourni par la source.
Le résumé fourni par la source
Abstract Background East Coast fever (ECF) caused by Theileria parva is endemic in Rwanda. In this study, the antigenic and genetic diversity of T. parva coupled with immunization and field challenge were undertaken to provide evidence for the introduction of ECF immunization in Rwanda. Methods Blood collected from cattle in the field was screened for T. parva using ELISA and PCR targeting the p104 gene. Tp1 and Tp2 gene sequences were generated from field samples and from Gikongoro and Nyakizu isolates. Furthermore, multilocus genotype data was generated using 5 satellite markers and an immunization challenge trial under field conditions using Muguga cocktail vaccine undertaken. Results Out of 120 samples, 44 and 20 were positive on ELISA and PCR, respectively. Antigenic diversity of the Tp1 and Tp2 gene sequences revealed an abundance of Muguga, Kiambu and Serengeti epitopes in the samples. A further three clusters were observed on both Tp1 and Tp2 phylogenetic trees; two clusters comprising of field samples and vaccine isolates and the third cluster comprising exclusively of Rwanda samples. Both antigens exhibited purifying selection with no positive selection sites. In addition, satellite marker analysis revealed that field samples possessed both shared alleles with Muguga cocktail on all loci and also a higher proportion of unique alleles. The Muguga cocktail (Muguga, Kiambu and Serengeti) genotype compared to other vaccine isolates, was the most represented in the field samples. Further low genetic sub-structuring (FST = 0.037) coupled with linkage disequilibrium between Muguga cocktail and the field samples was observed. Using the above data to guide a field immunization challenge trial comprising 41 immunized and 40 control animals resulted in 85% seroconversion in the immunized animals and an efficacy of vaccination of 81.7%, implying high protection against ECF. Conclusions Antigenic and genetic diversity analysis of T. parva facilitated the use of Muguga cocktail vaccine in field conditions. A protection level of 81.7% was achieved, demonstrating the importance of combining molecular tools with field trials to establish the suitability of implementation of immunization campaigns. Based on the information in this study, Muguga cocktail immunization in Rwanda has a potential to produce desirable results.
Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.
Le contrôle bibliographique ouvert
DOI retrouvé dans Crossref DOI retrouvé ; titre concordant.
- Titre Crossref
- Sequence diversity of cytotoxic T cell antigens and satellite marker analysis of Theileria parva informs the immunization against East Coast fever in Rwanda
- Date Crossref
- 07/09/2020
- Éditeur
- Springer Science and Business Media LLC
- Type
- journal-article
Ce recoupement confirme des métadonnées liées au DOI. Il ne confirme ni la méthode ni les conclusions de l’étude, et il ne compte pas comme une seconde source scientifique indépendante.
Où se fait cette recherche
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Centre of Ticks and Tick-borne diseases Malawi (code pays fourni par la source)Institution
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University of Zambia Zambie (code pays fourni par la source)Université ou école supérieure
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Rwanda Agriculture Board Rwanda (code pays fourni par la source)Organisme public
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Global Alliance for Livestock Veterinary Medicines pays non établi dans la noticeOrganisation à but non lucratif
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Lilongwe Private Bag A130 Lilongwe, Malawi (pays nommé en fin d’affiliation)Organisation à but non lucratif
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School of Veterinary Medicine Department of Biomedical Sciences Lusaka, Zambie (pays nommé en fin d’affiliation)Université ou école supérieure
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International Development Research Centre Nairobi, Kenya (pays nommé en fin d’affiliation)Structure de recherche
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Acre Africa Kigali, Rwanda (pays nommé en fin d’affiliation)Institution
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Rwanda Agricultural Board Kigali, Rwanda (pays nommé en fin d’affiliation)Institution
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LMK Medical laboratories and consultancies Kampala, Ouganda (pays nommé en fin d’affiliation)Institution
Centre of Ticks and Tick-borne diseases (Malawi), University of Zambia (Zambie) et Rwanda Agriculture Board (Rwanda), avec 7 autres affiliations. Pays d’affiliation : Malawi, Zambie, Rwanda, Kenya, Ouganda.
Une affiliation ne permet pas de déduire la nationalité d’un auteur.