7 research outputs found
Ătude de nouvelles cibles pour le diagnostic de la trypanosomose animale africaine : Expression et purification dâantigĂšnes recombinants de trypanosomes et Ă©valuation de leur potentiel diagnostique Identification des antigĂšnes immunorĂ©actifs sĂ©crĂ©tĂ©s par T. congolense
Trypanosoma congolense, T. vivax, and T. brucei brucei are the causative agents of a devastating disease of livestock, known as African animal trypanosomiasis (AAT) or nagana, occurring in 38 African countries in the sub-Saharan region. Without a vaccine, the control of the disease relies on vector control, chemotherapy, and diagnosis, which is essential for appropriate treatment and follow-up. Serological diagnosis, although applicable in the field according to the test format, has limitations. It lacks antigen standardization, sensitivity and specificity, with rapid diagnostic tests (RDTs) being often inaccessible. The aims of this thesis were to: (i) characterize the diagnostic potential of proteins identified and studied in the host laboratories, (ii) select, from "omics" data, new targets and evaluate their diagnostic potential individually and in combination, and, (iii) identify immunogenic proteins from proteomic and immunoinformatic analysis of the trypanosome secretome. Diagnostic potential of candidate proteins was explored, after their expression and purification, by indirect ELISA with bovine sera from experimental infections and sera from cattle naturally infected by trypanosomes. Individually, the proteins showed low sensitivity. However, combining proteins of equivalent immunoreactivity significantly increased the sensitivity of the tests with a specificity that remained satisfactory. These results constitute a proof of concept of the performance of protein combinations in the diagnosis of AAT. It provides an opportunity to explore new innovative approaches, including the combination of immunogenic peptides of different immunoreactive proteins in the form of chimeras for serological diagnosis. Furthermore, and in consideration of their performance, none of the newly tested proteins could be included individually in an RDT. To find appropriate candidates, we identified trypanosome secreted/excreted proteins by mass spectrometry. Using epitope prediction analysis, we identified approximately 100 putatively immunogenic proteins with multiple epitopes in their sequences. The reactivity analysis of sera from different bovine breeds with the trypanosome secretome showed that the proteins were strongly recognized by the antibodies of the sera used and corresponded mainly to four molecular sizes. At these sizes, a significant number of proteins characterized in silico as immunogenic were detected. These results provide a reliable data for selection of new proteins to be include in serological tests for AAT. They also provide a better understanding of the differences in humoral responses of cattle breeds with different susceptibility to trypanosomosis.Trypanosoma congolense, T. vivax et T. brucei brucei sont les agents responsables dâune maladie dĂ©vastatrice du bĂ©tail, appelĂ©e trypanosomose animale africaine (TAA) ou nagana, qui touche 38 pays africains de la rĂ©gion subsaharienne. En absence du vaccin, le contrĂŽle de la maladie repose sur la lutte anti-vectorielle, la chimiothĂ©rapie et le diagnostic, une Ă©tape indispensable Ă la mise en place des traitements appropriĂ©s et au suivi. Le diagnostic sĂ©rologique, bien quâapplicable sur le terrain selon le format du test, rencontre toutefois des limitations. Il manque de standardisation des antigĂšnes, de sensibilitĂ© et de spĂ©cificitĂ© avec des tests de diagnostic rapide (TDR) souvent peu accessibles. Les objectifs de cette thĂšse Ă©taient de : (i) caractĂ©riser le potentiel diagnostique de protĂ©ines identifiĂ©es et Ă©tudiĂ©es dans les laboratoires dâaccueils, (ii) sĂ©lectionner Ă partir des donnĂ©es « omiques », de nouvelles cibles et Ă©valuer leur potentiel diagnostique individuel et en combinaison, et (iii) identifier les protĂ©ines immunogĂ©niques Ă partir dâanalyse protĂ©omique et immuno-informatique du sĂ©crĂ©tome de trypanosomes. Lâexploration du potentiel diagnostique de protĂ©ines candidates a Ă©tĂ© rĂ©alisĂ©e, aprĂšs leur expression et leur purification, par ELISA indirect avec des sĂ©rums de bovins issus dâinfections expĂ©rimentales et des sĂ©rums issus de bovins infectĂ©s naturellement par les trypanosomes. TestĂ©es individuellement, les protĂ©ines ont montrĂ© une faible sensibilitĂ©. Cependant, la combinaison des protĂ©ines dâimmuno-rĂ©activitĂ© Ă©quivalente a permis dâaugmenter significativement la sensibilitĂ© des tests avec une spĂ©cificitĂ© qui reste satisfaisante. Ces rĂ©sultats constituent une preuve de concept, de la performance des combinaisons de protĂ©ines dans le diagnostic de la TAA. Il offre la possibilitĂ© dâexplorer de nouvelles approches innovantes, notamment lâassociation de peptides immunogĂ©niques de diffĂ©rentes protĂ©ines immunorĂ©actives sous forme de chimĂšres pour le diagnostic sĂ©rologique. Dâautre part, et au regard de leur performance, aucune des protĂ©ines nouvellement testĂ©es ne pourra ĂȘtre incluse de maniĂšre individuelle dans un TDR. Pour trouver des candidats adaptĂ©s, nous avons identifiĂ© des protĂ©ines sĂ©crĂ©tĂ©es/excrĂ©tĂ©es de trypanosomes par spectromĂ©trie de masse. GrĂące Ă une analyse de prĂ©diction dâĂ©pitopes, nous avons identifiĂ© une centaine de protĂ©ines putativement immunogĂ©niques prĂ©sentant plusieurs Ă©pitopes dans leurs sĂ©quences. Lâanalyse de la rĂ©activitĂ© des sĂ©rums provenant de diffĂ©rentes races bovines avec le sĂ©crĂ©tome de trypanosomes a permis de dĂ©tecter des protĂ©ines fortement reconnues par les anticorps des sĂ©rums utilisĂ©s et correspondant principalement Ă quatre tailles molĂ©culaires. Ă ces tailles, un grand nombre de protĂ©ines caractĂ©risĂ©es in silico comme immunogĂ©niques avaient Ă©tĂ© dĂ©tectĂ©es. Ces donnĂ©es fournissent une base de sĂ©lection fiable des nouvelles protĂ©ines Ă inclure dans les tests sĂ©rologiques de la TAA. Elles permettent Ă©galement de mieux comprendre les diffĂ©rences de rĂ©ponses humorales de races bovines prĂ©sentant une susceptibilitĂ© diffĂ©rente aux trypanosomoses
Study of new diagnostic targets for African animal trypanosomosis
Trypanosoma congolense, T. vivax et T. brucei brucei sont les agents responsables dâune maladie dĂ©vastatrice du bĂ©tail, appelĂ©e trypanosomose animale africaine (TAA) ou nagana, qui touche 38 pays africains de la rĂ©gion subsaharienne. En absence du vaccin, le contrĂŽle de la maladie repose sur la lutte anti-vectorielle, la chimiothĂ©rapie et le diagnostic, une Ă©tape indispensable Ă la mise en place des traitements appropriĂ©s et au suivi. Le diagnostic sĂ©rologique, bien quâapplicable sur le terrain selon le format du test, rencontre toutefois des limitations. Il manque de standardisation des antigĂšnes, de sensibilitĂ© et de spĂ©cificitĂ© avec des tests de diagnostic rapide (TDR) souvent peu accessibles. Les objectifs de cette thĂšse Ă©taient de : (i) caractĂ©riser le potentiel diagnostique de protĂ©ines identifiĂ©es et Ă©tudiĂ©es dans les laboratoires dâaccueils, (ii) sĂ©lectionner Ă partir des donnĂ©es « omiques », de nouvelles cibles et Ă©valuer leur potentiel diagnostique individuel et en combinaison, et (iii) identifier les protĂ©ines immunogĂ©niques Ă partir dâanalyse protĂ©omique et immuno-informatique du sĂ©crĂ©tome de trypanosomes. Lâexploration du potentiel diagnostique de protĂ©ines candidates a Ă©tĂ© rĂ©alisĂ©e, aprĂšs leur expression et leur purification, par ELISA indirect avec des sĂ©rums de bovins issus dâinfections expĂ©rimentales et des sĂ©rums issus de bovins infectĂ©s naturellement par les trypanosomes. TestĂ©es individuellement, les protĂ©ines ont montrĂ© une faible sensibilitĂ©. Cependant, la combinaison des protĂ©ines dâimmuno-rĂ©activitĂ© Ă©quivalente a permis dâaugmenter significativement la sensibilitĂ© des tests avec une spĂ©cificitĂ© qui reste satisfaisante. Ces rĂ©sultats constituent une preuve de concept, de la performance des combinaisons de protĂ©ines dans le diagnostic de la TAA. Il offre la possibilitĂ© dâexplorer de nouvelles approches innovantes, notamment lâassociation de peptides immunogĂ©niques de diffĂ©rentes protĂ©ines immunorĂ©actives sous forme de chimĂšres pour le diagnostic sĂ©rologique. Dâautre part, et au regard de leur performance, aucune des protĂ©ines nouvellement testĂ©es ne pourra ĂȘtre incluse de maniĂšre individuelle dans un TDR. Pour trouver des candidats adaptĂ©s, nous avons identifiĂ© des protĂ©ines sĂ©crĂ©tĂ©es/excrĂ©tĂ©es de trypanosomes par spectromĂ©trie de masse. GrĂące Ă une analyse de prĂ©diction dâĂ©pitopes, nous avons identifiĂ© une centaine de protĂ©ines putativement immunogĂ©niques prĂ©sentant plusieurs Ă©pitopes dans leurs sĂ©quences. Lâanalyse de la rĂ©activitĂ© des sĂ©rums provenant de diffĂ©rentes races bovines avec le sĂ©crĂ©tome de trypanosomes a permis de dĂ©tecter des protĂ©ines fortement reconnues par les anticorps des sĂ©rums utilisĂ©s et correspondant principalement Ă quatre tailles molĂ©culaires. Ă ces tailles, un grand nombre de protĂ©ines caractĂ©risĂ©es in silico comme immunogĂ©niques avaient Ă©tĂ© dĂ©tectĂ©es. Ces donnĂ©es fournissent une base de sĂ©lection fiable des nouvelles protĂ©ines Ă inclure dans les tests sĂ©rologiques de la TAA. Elles permettent Ă©galement de mieux comprendre les diffĂ©rences de rĂ©ponses humorales de races bovines prĂ©sentant une susceptibilitĂ© diffĂ©rente aux trypanosomoses.Trypanosoma congolense, T. vivax, and T. brucei brucei are the causative agents of a devastating disease of livestock, known as African animal trypanosomiasis (AAT) or nagana, occurring in 38 African countries in the sub-Saharan region. Without a vaccine, the control of the disease relies on vector control, chemotherapy, and diagnosis, which is essential for appropriate treatment and follow-up. Serological diagnosis, although applicable in the field according to the test format, has limitations. It lacks antigen standardization, sensitivity and specificity, with rapid diagnostic tests (RDTs) being often inaccessible. The aims of this thesis were to: (i) characterize the diagnostic potential of proteins identified and studied in the host laboratories, (ii) select, from "omics" data, new targets and evaluate their diagnostic potential individually and in combination, and, (iii) identify immunogenic proteins from proteomic and immunoinformatic analysis of the trypanosome secretome. Diagnostic potential of candidate proteins was explored, after their expression and purification, by indirect ELISA with bovine sera from experimental infections and sera from cattle naturally infected by trypanosomes. Individually, the proteins showed low sensitivity. However, combining proteins of equivalent immunoreactivity significantly increased the sensitivity of the tests with a specificity that remained satisfactory. These results constitute a proof of concept of the performance of protein combinations in the diagnosis of AAT. It provides an opportunity to explore new innovative approaches, including the combination of immunogenic peptides of different immunoreactive proteins in the form of chimeras for serological diagnosis. Furthermore, and in consideration of their performance, none of the newly tested proteins could be included individually in an RDT. To find appropriate candidates, we identified trypanosome secreted/excreted proteins by mass spectrometry. Using epitope prediction analysis, we identified approximately 100 putatively immunogenic proteins with multiple epitopes in their sequences. The reactivity analysis of sera from different bovine breeds with the trypanosome secretome showed that the proteins were strongly recognized by the antibodies of the sera used and corresponded mainly to four molecular sizes. At these sizes, a significant number of proteins characterized in silico as immunogenic were detected. These results provide a reliable data for selection of new proteins to be include in serological tests for AAT. They also provide a better understanding of the differences in humoral responses of cattle breeds with different susceptibility to trypanosomosis
Diagnosis of African animal trypanosomiases: advantages, limitations and new improvement ways
Les trypanosomiases animales dâorigine africaine repreÌsentent typiquement une maladie tropicale neÌgligeÌe. Elles sont causeÌes par des parasites sanguicoles du genre Trypanosoma transmis par des insectes heÌmatophages, de manieÌre cyclique par les mouches tseÌ-tseÌ pour Trypanosoma congolense, T. vivax et T. brucei brucei, qui causent la nagana, de manieÌre meÌcanique pour T. evansi, agent de la surra, et enfin par transmission sexuelle pour T. equiperdum, qui cause la dourine. La nagana est preÌsente dans 38 pays dâAfrique subsaharienne ouÌ elle peut affecter de nombreuses espeÌces animales, sauvages et domestiques. PreÌs de 55 millions de bovins vivent sous risque trypanosomien, sans compter les petits ruminants. Ces maladies deÌteÌriorent la condition physique de lâanimal, induisant une forte baisse de productiviteÌ. Dans les cas les plus seÌveÌres, et en lâabsence de traitement, la mort survient en quelques semaines. Lâimpact socio-eÌconomique est estimeÌ aÌ 4,75 milliards de dollars de pertes annuelles, ce qui fait de ces maladies lâun des obstacles majeurs au deÌveloppement de lâeÌlevage en Afrique. Le controÌle de ces maladies se heurte aÌ lâabsence de vaccin, aÌ des traitements dont les moleÌcules sont peu nombreuses et contre lesquelles se deÌveloppent de plus en plus de reÌsistances de la part des parasites, et enfin aÌ un diagnostic, moleÌculaire ou seÌrologique, dont la robustesse demande aÌ eÌtre grandement ameÌlioreÌe. Les signes cliniques ne sont pas speÌcifiques, le diagnostic parasitologique est souvent peu sensible, et les meÌthodes moleÌculaires ne sont pas applicables sur le terrain. Les meÌthodes dâimmunodiagnostic sous forme de tests de diagnostic rapide sont les seules adapteÌes au terrain, mais les rares tests existants sont treÌs peu accessibles (disponibiliteÌ, prix), et manquent de speÌcificiteÌ et/ou de sensibiliteÌ. Ici, nous traiterons des limites et des avantages comparatifs des meÌthodes actuelles de diagnostic et proposerons de nouvelles pistes dâameÌlioration de ces dernieÌres pour un meilleur controÌle de la maladie.The animal trypanosomiases of African origin are a rather typical example of a neglected tropical disease. They are caused by blood parasites of the Trypanosoma genus transmitted by haematophagous insects, cyclically by tsetse flies for Trypanosoma congolense, T. vivax and T. brucei brucei, which cause nagana, mechanically by T. evansi, the agent of surra, and finally by T. equiperdum, adapted to sexual transmission, which causes dourine. Nagana affects 38 African countries in the sub-Saharan region with 55 million cattle at risk, not counting small ruminants. These diseases deteriorate the animalâs physical condition, leading to a sharp drop in productivity; in the most severe cases, and in the absence of treatment, the animal dies within a few weeks. The socio-economic impact is estimated at US$ 4.75 billion in annual losses, making these diseases one of the major obstacles to livestock development in Africa. The control of these diseases is hampered by the lack of vaccines, a handful of molecules for treatment against which parasites are increasingly developing resistance, and finally, molecular or serological diagnostics whose robustness needs to be greatly improved. Clinical signs are not specific, parasitological diagnosis is often not very sensitive, and molecular methods are not applicable in the field. Immunodiagnostic methods in the form of rapid diagnostic tests are the only ones suitable for the field, but the few existing tests are poorly available and lack specificity and/or sensitivity. Here we address the advantages and limitations of current diagnostic methods and propose new ways of improving them for better disease control
Les mĂ©thodes de diagnostic des trypanosomiases animales africaines : avantages, limites et nouvelles pistes dâamĂ©lioration
International audienceThe animal trypanosomiases of African origin are a rather typical example of a neglected tropical disease. They are caused by blood parasites of the Trypanosoma genus transmitted by haematophagous insects, cyclically by tsetse flies for Trypanosoma congolense, T. vivax and T. brucei brucei, which cause nagana, mechanically by T. evansi, the agent of surra, and finally by T. equiperdum, adapted to sexual transmission, which causes dourine. Nagana affects 38 African countries in the sub-Saharan region with 55 million cattle at risk, not counting small ruminants. These diseases deteriorate the animalâs physical condition, leading to a sharp drop in productivity; in the most severe cases, and in the absence of treatment, the animal dies within a few weeks. The socio-economic impact is estimated at US$ 4.75 billion in annual losses, making these diseases one of the major obstacles to livestock development in Africa. The control of these diseases is hampered by the lack of vaccines, a handful of molecules for treatment against which parasites are increasingly developing resistance, and finally, molecular or serological diagnostics whose robustness needs to be greatly improved. Clinical signs are not specific, parasitological diagnosis is often not very sensitive, and molecular methods are not applicable in the field. Immunodiagnostic methods in the form of rapid diagnostic tests are the only ones suitable for the field, but the few existing tests are poorly available and lack specificity and/or sensitivity. Here we address the advantages and limitations of current diagnostic methods and propose new ways of improving them for better disease control.Les trypanosomiases animales dâorigine africaine repreÌsentent typiquement une maladie tropicale neÌgligeÌe. Elles sont causeÌes par des parasites sanguicoles du genre Trypanosoma transmis par des insectes heÌmatophages, de manieÌre cyclique par les mouches tseÌ-tseÌ pour Trypanosoma congolense, T. vivax et T. brucei brucei, qui causent la nagana, de manieÌre meÌcanique pour T. evansi, agent de la surra, et enfin par transmission sexuelle pour T. equiperdum, qui cause la dourine. La nagana est preÌsente dans 38 pays dâAfrique subsaharienne ouÌ elle peut affecter de nombreuses espeÌces animales, sauvages et domestiques. PreÌs de 55 millions de bovins vivent sous risque trypanosomien, sans compter les petits ruminants. Ces maladies deÌteÌriorent la condition physique de lâanimal, induisant une forte baisse de productiviteÌ. Dans les cas les plus seÌveÌres, et en lâabsence de traitement, la mort survient en quelques semaines. Lâimpact socio-eÌconomique est estimeÌ aÌ 4,75 milliards de dollars de pertes annuelles, ce qui fait de ces maladies lâun des obstacles majeurs au deÌveloppement de lâeÌlevage en Afrique. Le controÌle de ces maladies se heurte aÌ lâabsence de vaccin, aÌ des traitements dont les moleÌcules sont peu nombreuses et contre lesquelles se deÌveloppent de plus en plus de reÌsistances de la part des parasites, et enfin aÌ un diagnostic, moleÌculaire ou seÌrologique, dont la robustesse demande aÌ eÌtre grandement ameÌlioreÌe. Les signes cliniques ne sont pas speÌcifiques, le diagnostic parasitologique est souvent peu sensible, et les meÌthodes moleÌculaires ne sont pas applicables sur le terrain. Les meÌthodes dâimmunodiagnostic sous forme de tests de diagnostic rapide sont les seules adapteÌes au terrain, mais les rares tests existants sont treÌs peu accessibles (disponibiliteÌ, prix), et manquent de speÌcificiteÌ et/ou de sensibiliteÌ. Ici, nous traiterons des limites et des avantages comparatifs des meÌthodes actuelles de diagnostic et proposerons de nouvelles pistes dâameÌlioration de ces dernieÌres pour un meilleur controÌle de la maladie
Novel axonemal protein ZMYND12 interacts with TTC29 and DNAH1, and is required for male fertility and flagellum function
Male infertility is common and complex, presenting a wide range of heterogeneous phenotypes. Although about 50% of cases are estimated to have a genetic component, the underlying cause often remains undetermined. Here, from whole-exome sequencing on samples from 168 infertile men with asthenoteratozoospermia due to severe sperm flagellum, we identified homozygous ZMYND12 variants in four unrelated patients. In sperm cells from these individuals, immunofluorescence revealed altered localization of DNAH1, DNALI1, WDR66 and TTC29. Axonemal localization of ZMYND12 ortholog TbTAX-1 was confirmed using the Trypanosoma brucei model. RNAi knock-down of TbTAX-1 dramatically affected flagellar motility, with a phenotype similar to the sperm from men bearing homozygous ZMYND12 variants. Co-immunoprecipitation and ultrastructure expansion microscopy in T. brucei revealed TbTAX-1 to form a complex with TTC29. Comparative proteomics with samples from Trypanosoma and Ttc29 KO mice identified a third member of this complex: DNAH1. The data presented revealed that ZMYND12 is part of the same axonemal complex as TTC29 and DNAH1, which is critical for flagellum function and assembly in humans, and Trypanosoma. ZMYND12 is thus a new asthenoteratozoospermia-associated gene, bi-allelic variants of which cause severe flagellum malformations and primary male infertility