Lutzomyia longipalpis Saliva or Salivary Protein LJM19 Protects against Leishmania braziliensis and the Saliva of Its Vector, Lutzomyia intermedia

Leishmaniasis, caused by parasitic protozoa Leishmania, is transmitted by bites of female sand flies that, during blood-feeding, inject humans with parasites and saliva. Sand fly saliva has been investigated as a potential vaccine candidate. It was previously shown that immunization with Lutzomyia longipalpis saliva or salivary proteins protects against cutaneous and visceral leishmaniasis. In the present study, we evaluated if immunization with Lu. longipalpis saliva or DNA plasmid coding for a specific sand fly salivary protein (LJM19) can protect hamsters against L. braziliensis plus another sand fly saliva. Immunization with saliva or LJM19 DNA plasmid induced a mononuclear cell infiltrate which can be a marker of protection. The immune response induced by immunization with these insect molecules was able to protect animals against L. braziliensis infection as shown by the significant reduction in lesion size, parasite load in the ear and draining lymph node. These data show the important role of immune response against sand fly saliva components, suggesting the possibility to develop vaccines using a single component of saliva against Leishmania transmitted by different vectors

DNA vaccination with KMP11 and Lutzomyia longipalpis salivary protein protects hamsters against visceral leishmaniasis

It was recently shown that immunization of hamsters with DNA plasmids coding LJM19, a sand fly salivary protein, partially protected against a challenge with Leishmania chagasi, whereas immunization with KMP11 DNA plasmid, a Leishmania antigen, induced protection against L. donovani infection. In the present study, we evaluated the protective effect of immunization with both LJM19 and KMP11 DNA plasmid together. Concerning the protection against an infection by L. chagasi, immunization with DNA plasmids coding LJM19 or KMP11, as well as with both plasmids combined, induced IFN-γ production in draining lymph nodes at 7, 14 and 21 days post-immunization. Immunized hamsters challenged with L. chagasi plus Salivary Gland Sonicate (SGS) from Lutzomyia longipalpis showed an enhancement of IFN-γ/IL-10 and IFN-γ/TGF-β in draining lymph nodes after 7 and 14 days of infection. Two and five months after challenge, immunized animals showed reduced parasite load in the liver and spleen, as well as increased IFN-γ/IL-10 and IFN-γ/TGF-β ratios in the spleen. Furthermore, immunized animals remained with a normal hematological profile even five months after the challenge, whereas L. chagasi in unimmunized hamsters lead to a significant anemia. The protection observed with LJM19 or KMP11 DNA plasmids used alone was very similar to the protection obtained by the combination of both plasmids.This research was supported by FAPESB, CNPq and CAPES. CB, AB, CIO and MB-N are senior investigators of CNPq-Brasil. RAAS received a fellowship from CNPq.Peer reviewe

Experimental infection of dogs with Leishmania and saliva as a model to study Canine Visceral Leishmaniasis

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2014-02-18T19:23:15Z No. of bitstreams: 1 Costa DJ Experimental infection....pdf: 1604899 bytes, checksum: a78c2e529c64a3400dcb92cae6906a2a (MD5)Made available in DSpace on 2014-02-18T19:23:15Z (GMT). No. of bitstreams: 1 Costa DJ Experimental infection....pdf: 1604899 bytes, checksum: a78c2e529c64a3400dcb92cae6906a2a (MD5) Previous issue date: 2013Fundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, BrasilUniversidade Federal do Maranhão. Laboratório de Imunofiosiologia. Departamento de Patologia. Maranhão, BrasilUniversidade Federal do Maranhão. Laboratório de Imunofiosiologia. Departamento de Patologia. Maranhão, BrasilUniversidade Estadual do Maranhão. Departamento de Patologia. Maranhão, BrasilUniversidade Federal do Piauí. Departamento de Morfofisiologia Veterinária Centro de Ciências Agrárias. Piauí, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, Brasil / Instituto de Investigação em Imunologia. São Paulo, SP, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil / Instituto de Investigação em Imunologia. São Paulo, SP, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil / Instituto de Investigação em Imunologia. São Paulo, SP, BrasilFundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Instituto de Ciências da Saúde. Salvador, BA, Brasil / Universidade Federal do Piauí. Departamento de Morfofisiologia Veterinária Centro de Ciências Agrárias Piauí. Piauí, BrasilBACKGROUND: Canine Visceral Leishmaniasis (CVL) is a zoonotic disease caused by Leishmania infantum, transmitted by the bite of Lutzomyia longipalpis sand flies. Dogs are the main domestic reservoir of the parasite. The establishment of an experimental model that partially reproduces natural infection in dogs is very important to test vaccine candidates, mainly regarding those that use salivary proteins from the vector and new therapeutical approaches. METHODOLOGY/PRINCIPAL FINDINGS: In this report, we describe an experimental infection in dogs, using intradermal injection of Leishmania infantum plus salivary gland homogenate (SGH) of Lutzomyia longipalpis. Thirty-five dogs were infected with 1×10(7) parasites combined with five pairs of Lutzomyia longipalpis salivary glands and followed for 450 days after infection and clinical, immunological and parasitological parameters were evaluated. Two hundred and ten days after infection we observed that 31,4% of dogs did not display detectable levels of anti-Leishmania antibodies but all presented different numbers of parasites in the lymph nodes. Animals with a positive xenodiagnosis had at least 3,35×10(5) parasites in their lymph nodes. An increase of IFN-γ and IL-10 levels was detected during infection. Twenty two percent of dogs developed symptoms of CVL during infection. CONCLUSION: The infection model described here shows some degree of similarity when compared with naturally infected dogs opening new perspectives for the study of CVL using an experimental model that employs the combination of parasites and sand fly saliva both present during natural transmission