Sera from Trypanosoma b. gambiense infected patients cross-react with a Trypanosoma cruzi recombinant protein

In previous studies, we and others have shown utility of a 24-kDa #Trypanosoma cruzi recombinant antigen (rTc24) for serological diagnosis of Chagas' disease. Also, this molecule has been proved useful to evaluate cure of chagasic patients who submit to specific treatment. However, in all the studies done so far, the 24-kDa protein was used as a fusion with a Gluthatione-S-transferase (GST) of #Schistosoma japonicum, therefore, parallel assays to determine the anti-GST responses of all sera were required to deduce the GST noise in serological tests. Here, we show the subcloning by polymerase chain reaction of the cDNA encoding the #T. cruzi$ 24-kDa antigen in a vector system (pQE) allowing us to obtain Tc24 recombinant protein as a single molecule. The highly reactivity of chagasic sera from Colombia, Ecuador, Brazil and Bolivia in ELISA against the recombinant antigen is confirmed. However, sera from patients infected with African trypanosomes recognize rTc24 in ELISA and blot. The relevance of these findings in the context of Chagas' disease diagnosis and/or the relationship with African trypanosomes is analyzed. (Résumé d'auteur

Results of vaccination against canine visceral leishmaniasis (Leishmania infantum) in enzootic areas

Protection against canine leishmaniasis was evaluated in dogs living in enzootic areas in the south of France, and vaccinated with a candidate vaccine, LiESP with the adjuvant MDP. A double-blind field study was carried out in a large number of dogs (n = 414) over two years. At the end of the study, infection rate was 0% in vaccinated dogs versus 5.14% in the placebo group. The candidate vaccine induced an effective and lasting immunity against canine leishmaniasis.La protection contre la leishmaniose canine est évaluée chez des chiens vivant en zone d'enzootie dans le sud de la France, vaccinés par un candidat LiESP adjuvé par MDP. Une étude de terrain randomisée en double aveugle est conduite dans une large population de chiens (n = 414), durant une période de deux années. À l'issue de l'étude, le taux d'infection est de 0 % chez les chiens vaccinés et de 5,14 % chez les chiens du groupe placebo. Le candidat vaccinal a induit une immunité efficace, durable contre la leishmaniose canine

Canine leishmaniosis due to Leishmania infantum: immunotherapy trials

As most methods currently available to treat and control canine leishmaniasis have a limited efficacy, researchers are testing immunotherapeutic methods with great interest. Excreted–secreted antigens (ES Ag) of promastigotes of Leishmania infantum cultured in a defined medium were selected. Three Leishmania–infected dogs received two intradermal injections of 25 mg of ES Ag, at 3 weeks interval. This treatment was the first ever in one of the dogs, whereas the other two had previously received a standard treatment with Glucantime® and Zyloric®. Marked clinical improvement was noted as of Day 15 after the first injection, as well as an intense leishmanicide activity in collected monocytes, and a significant decrease of antibody titres. No clinical relapse was recorded over two years later.La plupart des méthodes disponibles aujourd'hui de traitement et de contrôle de la leishmaniose canine sont d'une efficacité limitée, aussi le développement de méthodes immunothérapeutiques est-il d'un grand intérêt. Des antigènes d'excrétion-sécrétion (Ag ES) de promastigotes de Leishmania infantum cultivés en milieu défini sont retenus. Trois chiens leishmaniens en reçoivent 25 μg, 2 fois à 3 semaines d'intervalle, par la voie intra-dermique: un chien est traité pour la première fois selon ce protocole, les 2 autres avaient été traités antérieurement selon un protocole classique à base de glucantime et de zyloric. Une nette amélioration clinique est observée dès J15 après la première injection, ainsi qu'une forte activité leishmanicide des monocytes récoltés et une diminution significative des titres en anticorps. Aucune rechute clinique n'est enregistrée plus de 2 ans plus tard