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Fabiano Oliveira,
Bourama Traoré,
Regis Gomes,
Ousmane Faye,
Dana C Gilmore,
Somita Keita,
Pierre Traoré, Clarissa Teixeira,
Cheick A Coulibaly,
Sibiry Samake,
Claudio Meneses,
Ibrahim Sissoko,
Rick M Fairhurst,
Michael P Fay,
Jennifer M Anderson,
Seydou Doumbia,
Shaden Kamhawi,
Jesus G Valenzuela
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ABSTRACT: Immunity to sand fly saliva in rodents induces a T(H)1 delayed-type hypersensitivity (DTH) response conferring protection against leishmaniasis. The relevance of DTH to sand fly bites in humans living in a leishmaniasis-endemic area remains unknown. Here, we describe the duration and nature of DTH to sand fly saliva in humans from an endemic area of Mali. DTH was assessed at 24, 48, 72, and 96 hours post bite in volunteers exposed to colony-bred sand flies. Dermal biopsies were obtained 48 hours post bite; cytokines were quantified from peripheral blood mononuclear cells (PBMCs) stimulated with sand fly saliva in vitro. A DTH response to bites was observed in 75% of individuals aged 1-15 years, decreasing gradually to 48% by age 45, and dropping to 21% thereafter. Dermal biopsies were dominated by T lymphocytes and macrophages. Abundant expression of IFN-γ and absence of T(H)2 cytokines establishes the T(H)1 nature of this DTH response. PBMCs from 98% of individuals responded to sand fly saliva. Of these, 23% were polarized to a T(H)1 and 25% to a T(H)2 response. We demonstrate the durability and T(H)1 nature of DTH to sand fly bites in humans living in a cutaneous leishmaniasis-endemic area. A systemic T(H)2 response may explain why some individuals remain susceptible to disease.Journal of Investigative Dermatology advance online publication, 20 September 2012; doi:10.1038/jid.2012.315.
Journal of Investigative Dermatology 09/2012; · 6.31 Impact Factor
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ABSTRACT: Leishmania vaccines that protect against needle challenge fail against the potency of a Leishmania-infected sand fly transmission. Here, we demonstrate that intradermal immunization of mice with 500 ng of the sand fly salivary recombinant protein LJM11 (rLJM11) from Lutzomyia longipalpis, in the absence of adjuvant, induces long-lasting immunity that results in ulcer-free protection against Leishmania major delivered by vector bites. This protection is antibody independent and abrogated by depletion of CD4(+) T cells. Two weeks after challenge, early induction of IFN-γ specifically to rLJM11 correlates to diminished parasite replication in protected animals. At this time point, Leishmania-specific induction of IFN-γ in these mice is low in comparison with its high level in non-protected controls. We hypothesize that early control of parasites in a T-cell helper type 1 environment induced by immunity to LJM11 permits the slow development of Leishmania-specific immunity in the absence of open ulcers. Leishmania-specific immunity observed 5 weeks after infection in rLJM11-immunized mice shows a twofold increase over controls in the percentage of IFN-γ-producing CD4(+) T cells. We propose LJM11 as an immunomodulator that drives an efficient and controlled protective immune response to a sand fly-transmitted Leishmania somewhat mimicking "leishmanization"-induced protective immunity but without its associated lesions.Journal of Investigative Dermatology advance online publication, 28 June 2012; doi:10.1038/jid.2012.205.
Journal of Investigative Dermatology 06/2012; · 6.31 Impact Factor
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Regis Gomes, Clarissa Teixeira,
Fabiano Oliveira,
Phillip G Lawyer,
Dia-Eldin Elnaiem,
Claudio Meneses,
Yasuyuki Goto,
Ajay Bhatia,
Randall F Howard,
Steven G Reed,
Jesus G Valenzuela,
Shaden Kamhawi
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ABSTRACT: Recombinant KSAC and L110f are promising Leishmania vaccine candidates. Both antigens formulated in stable emulsions (SE) with the natural TLR4 agonist MPL® and L110f with the synthetic TLR4 agonist GLA in SE protected BALB/c mice against L. major infection following needle challenge. Considering the virulence of vector-transmitted Leishmania infections, we vaccinated BALB/c mice with either KSAC+GLA-SE or L110f+GLA-SE to assess protection against L. major transmitted via its vector Phlebotomus duboscqi.
Mice receiving the KSAC or L110f vaccines were challenged by needle or L. major-infected sand flies. Weekly disease progression and terminal parasite loads were determined. Immunological responses to KSAC, L110f, or soluble Leishmania antigen (SLA) were assessed throughout vaccination, three and twelve weeks after immunization, and one week post-challenge.
Following sand fly challenge, KSAC-vaccinated mice were protected while L110f-vaccinated animals showed partial protection. Protection correlated with the ability of SLA to induce IFN-γ-producing CD4(+)CD62L(low)CCR7(low) effector memory T cells pre- and post-sand fly challenge.
This study demonstrates the protective efficacy of KSAC+GLA-SE against sand fly challenge; the importance of vector-transmitted challenge in evaluating vaccine candidates against Leishmania infection; and the necessity of a rapid potent Th1 response against Leishmania to attain true protection.
PLoS Neglected Tropical Diseases 04/2012; 6(4):e1610. · 4.69 Impact Factor
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Xueqing Xu,
Fabiano Oliveira,
Bianca W. Chang,
Nicolas Collin,
Regis Gomes, Clarissa Teixeira,
David Reynoso,
Van my Pham,
Dia-Eldin Elnaiem,
Shaden Kamhawi,
José M. C. Ribeiro,
Jesus G. Valenzuela,
John F. Andersen
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ABSTRACT: LJM11, an abundant salivary protein from the sand fly Lutzomyia longipalpis, belongs to the insect “yellow” family of proteins. In this study, we immunized mice with 17 plasmids encoding L. longiplapis salivary proteins and demonstrated that LJM11 confers protective immunity against Leishmania major infection. This protection correlates with a strong induction of a delayed type hypersensitivity (DTH) response following
exposure to L. longipalpis saliva. Additionally, splenocytes of exposed mice produce IFN-γ upon stimulation with LJM11, demonstrating the systemic induction
of Th1 immunity by this protein. In contrast to LJM11, LJM111, another yellow protein from L. longipalpis saliva, does not produce a DTH response in these mice, suggesting that structural or functional features specific to LJM11
are important for the induction of a robust DTH response. To examine these features, we used calorimetric analysis to probe
a possible ligand binding function for the salivary yellow proteins. LJM11, LJM111, and LJM17 all acted as high affinity binders
of prohemostatic and proinflammatory biogenic amines, particularly serotonin, catecholamines, and histamine. We also determined
the crystal structure of LJM11, revealing a six-bladed β-propeller fold with a single ligand binding pocket located in the
central part of the propeller structure on one face of the molecule. A hypothetical model of LJM11 suggests a positive electrostatic
potential on the face containing entry to the ligand binding pocket, whereas LJM111 is negative to neutral over its entire
surface. This may be the reason for differences in antigenicity between the two proteins.
Journal of Biological Chemistry 09/2011; 286(37):32383-32393. · 4.77 Impact Factor
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Xueqing Xu,
Fabiano Oliveira,
Bianca W Chang,
Nicolas Collin,
Regis Gomes, Clarissa Teixeira,
David Reynoso,
Van My Pham,
Dia-Eldin Elnaiem,
Shaden Kamhawi,
José M C Ribeiro,
Jesus G Valenzuela,
John F Andersen
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ABSTRACT: LJM11, an abundant salivary protein from the sand fly Lutzomyia longipalpis, belongs to the insect "yellow" family of proteins. In this study, we immunized mice with 17 plasmids encoding L. longiplapis salivary proteins and demonstrated that LJM11 confers protective immunity against Leishmania major infection. This protection correlates with a strong induction of a delayed type hypersensitivity (DTH) response following exposure to L. longipalpis saliva. Additionally, splenocytes of exposed mice produce IFN-γ upon stimulation with LJM11, demonstrating the systemic induction of Th1 immunity by this protein. In contrast to LJM11, LJM111, another yellow protein from L. longipalpis saliva, does not produce a DTH response in these mice, suggesting that structural or functional features specific to LJM11 are important for the induction of a robust DTH response. To examine these features, we used calorimetric analysis to probe a possible ligand binding function for the salivary yellow proteins. LJM11, LJM111, and LJM17 all acted as high affinity binders of prohemostatic and proinflammatory biogenic amines, particularly serotonin, catecholamines, and histamine. We also determined the crystal structure of LJM11, revealing a six-bladed β-propeller fold with a single ligand binding pocket located in the central part of the propeller structure on one face of the molecule. A hypothetical model of LJM11 suggests a positive electrostatic potential on the face containing entry to the ligand binding pocket, whereas LJM111 is negative to neutral over its entire surface. This may be the reason for differences in antigenicity between the two proteins.
Journal of Biological Chemistry 07/2011; 286(37):32383-93. · 4.77 Impact Factor
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ABSTRACT: Nitric oxide (NO) and NO-derived reactive nitrogen species (RNS) are present in the food vacuole (FV) of Plasmodium falciparum trophozoites. The product of PFL1555w, a putative cytochrome b(5), localizes in the FV membrane, similar to what was previously observed for the product of PF13_0353, a putative cytochrome b(5) reductase. These two gene products may contribute to NO generation by denitrification chemistry from nitrate and/or nitrite present in the erythrocyte cytosol. The possible coordination of NO to heme species present in the food vacuole was probed by resonance Raman spectroscopy. The spectroscopic data revealed that in situ generated NO interacts with heme inside the intact FVs to form ferrous heme nitrosyl complexes that influence intra-vacuolar heme solubility. The formation of heme nitrosyl complexes within the FV is a previously unrecognized factor that could affect the equilibrium between soluble and crystallized heme within the FV in vivo.
Experimental Parasitology 01/2011; 127(1):1-8. · 2.12 Impact Factor
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Clarissa Teixeira,
Regis Gomes,
Nicolas Collin,
David Reynoso,
Ryan Jochim,
Fabiano Oliveira,
Amy Seitz,
Dia-Eldin Elnaiem,
Arlene Caldas,
Ana Paula de Souza,
Cláudia I Brodskyn,
Camila Indiani de Oliveira,
Ivete Mendonca,
Carlos H N Costa,
Petr Volf,
Aldina Barral,
Shaden Kamhawi,
Jesus G Valenzuela
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ABSTRACT: Sand flies deliver Leishmania parasites to a host alongside salivary molecules that affect infection outcomes. Though some proteins are immunogenic and have potential as markers of vector exposure, their identity and vector specificity remain elusive.
We screened human, dog, and fox sera from endemic areas of visceral leishmaniasis to identify potential markers of specific exposure to saliva of Lutzomyia longipalpis. Human and dog sera were further tested against additional sand fly species. Recombinant proteins of nine transcripts encoding secreted salivary molecules of Lu. longipalpis were produced, purified, and tested for antigenicity and specificity. Use of recombinant proteins corresponding to immunogenic molecules in Lu. longipalpis saliva identified LJM17 and LJM11 as potential markers of exposure. LJM17 was recognized by human, dog, and fox sera; LJM11 by humans and dogs. Notably, LJM17 and LJM11 were specifically recognized by humans exposed to Lu. longipalpis but not by individuals exposed to Lu. intermedia.
Salivary recombinant proteins are of value as markers of vector exposure. In humans, LJM17 and LJM11 emerged as potential markers of specific exposure to Lu. longipalpis, the vector of Leishmania infantum chagasi in Latin America. In dogs, LJM17, LJM11, LJL13, LJL23, and LJL143 emerged as potential markers of sand fly exposure. Testing these recombinant proteins in large scale studies will validate their usefulness as specific markers of Lu. longipalpis exposure in humans and of sand fly exposure in dogs.
PLoS Neglected Tropical Diseases 01/2010; 4(3):e638. · 4.69 Impact Factor
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ABSTRACT: Immunity to a sand fly salivary protein protects against visceral leishmaniasis (VL) in hamsters. This protection was associated with the development of cellular immunity in the form of a delayed-type hypersensitivity response and the presence of IFN-gamma at the site of sand fly bites. To date, there are no data available regarding the cellular immune response to sand fly saliva in dogs, the main reservoirs of VL in Latin America, and its role in protection from this fatal disease. Two of 35 salivary proteins from the vector sand fly Lutzomyia longipalpis, identified using a novel approach termed reverse antigen screening, elicited strong cellular immunity in dogs. Immunization with either molecule induced high IgG(2) antibody levels and significant IFN-gamma production following in vitro stimulation of PBMC with salivary gland homogenate (SGH). Upon challenge with uninfected or infected flies, immunized dogs developed a cellular response at the bite site characterized by lymphocytic infiltration and IFN-gamma and IL-12 expression. Additionally, SGH-stimulated lymphocytes from immunized dogs efficiently killed Leishmania infantum chagasi within autologous macrophages. Certain sand fly salivary proteins are potent immunogens obligatorily co-deposited with Leishmania parasites during transmission. Their inclusion in an anti-Leishmania vaccine would exploit anti-saliva immunity following an infective sand fly bite and set the stage for a protective anti-Leishmania immune response.
PLoS Pathogens 06/2009; 5(5):e1000441. · 9.13 Impact Factor
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ABSTRACT: Neutrophils are the first cells to migrate to the site of tissue damage. Recent work has addressed Leishmania survival and entry into macrophages through the infection of neutrophils that are recruited as a normal response to sandfly bites. New findings indicate that Leishmania is able to escape from neutrophils and 'silently' enter macrophages, a modification of the 'Trojan horse' model. Neutrophil depletion impaired disease progression, indicating an important role for neutrophils in leishmaniasis.
Trends in Parasitology 05/2009; 25(4):145-7. · 5.14 Impact Factor
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Regis Gomes, Clarissa Teixeira,
Maria Jânia Teixeira,
Fabiano Oliveira,
Maria José Menezes,
Claire Silva,
Camila I de Oliveira,
Jose C Miranda,
Dia-Eldin Elnaiem,
Shaden Kamhawi,
Jesus G Valenzuela,
Cláudia I Brodskyn
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ABSTRACT: Visceral leishmaniasis (VL) is a fatal disease for humans, and no vaccine is currently available. Sand fly salivary proteins have been associated with protection against cutaneous leishmaniasis. To test whether vector salivary proteins can protect against VL, a hamster model was developed involving intradermal inoculation in the ears of 100,000 Leishmania infantum chagasi parasites together with Lutzomyia longipalpis saliva to mimic natural transmission by sand flies. Hamsters developed classical signs of VL rapidly, culminating in a fatal outcome 5-6 months postinfection. Saliva had no effect on the course of infection in this model. Immunization with 16 DNA plasmids coding for salivary proteins of Lu. longipalpis resulted in the identification of LJM19, a novel 11-kDa protein, that protected hamsters against the fatal outcome of VL. LJM19-immunized hamsters maintained a low parasite load that correlated with an overall high IFN-gamma/TGF-beta ratio and inducible NOS expression in the spleen and liver up to 5 months postinfection. Importantly, a delayed-type hypersensitivity response with high expression of IFN-gamma was also noted in the skin of LJM19-immunized hamsters 48 h after exposure to uninfected sand fly bites. Induction of IFN-gamma at the site of bite could partly explain the protection observed in the viscera of LJM19-immunized hamsters through direct parasite killing and/or priming of anti-Leishmania immunity. We have shown that immunity to a defined salivary protein (LJM19) confers powerful protection against the fatal outcome of a parasitic disease, which reinforces the concept of using components of arthropod saliva in vaccine strategies against vector-borne diseases.
Proceedings of the National Academy of Sciences 07/2008; 105(22):7845-50. · 9.68 Impact Factor
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ABSTRACT: Nitric oxide (NO) has diverse biological functions. Numerous studies have documented NO's biosynthetic pathway in a wide variety of organisms. Little is known, however, about NO production in intraerythrocytic Plasmodium falciparum. Using diaminorhodamine-4-methyl acetoxymethylester (DAR-4M AM), a fluorescent indicator, we obtained direct evidence of NO and NO-derived reactive nitrogen species (RNS) production in intraerythrocytic P. falciparum parasites, as well as in isolated food vacuoles from trophozoite stage parasites. We preliminarily identified two gene sequences that might be implicated in NO synthesis in intraerythrocytic P. falciparum. We showed localization of the protein product of one of these two genes, a molecule that is structurally similar to a plant nitrate reductase, in trophozoite food vacuole membranes. We confirmed previous reports on the antiproliferative effect of NOS (nitric oxide synthase) inhibitors in P. falciparum cultures; however, we did not obtain evidence that NOS inhibitors had the ability to inhibit RNS production or that there is an active NOS in mature forms of the parasite. We concluded that a nitrate reductase activity produce NO and NO-derived RNS in or around the food vacuole in P. falciparum parasites. The food vacuole is a critical parasitic compartment involved in hemoglobin degradation, heme detoxification and a target for antimalarial drug action. Characterization of this relatively unexplored synthetic activity could provide important clues into poorly understood metabolic processes of the malaria parasite.
Experimental Parasitology 05/2008; 120(1):29-38. · 2.12 Impact Factor
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ABSTRACT: Abstract
Background
In the life cycle of Leishmania within the alimentary canal of sand flies the parasites have to survive the hostile environment of blood meal digestion, escape the blood bolus and attach to the midgut epithelium before differentiating into the infective metacyclic stages. The molecular interactions between the Leishmania parasites and the gut of the sand fly are poorly understood. In the present work we sequenced five cDNA libraries constructed from midgut tissue from the sand fly Lutzomyia longipalpis and analyzed the transcripts present following sugar feeding, blood feeding and after the blood meal has been processed and excreted, both in the presence and absence of Leishmania infantum chagasi .
Results
Comparative analysis of the transcripts from sugar-fed and blood-fed cDNA libraries resulted in the identification of transcripts differentially expressed during blood feeding. This included upregulated transcripts such as four distinct microvillar-like proteins (LuloMVP1, 2, 4 and 5), two peritrophin like proteins, a trypsin like protein (Lltryp1), two chymotrypsin like proteins (LuloChym1A and 2) and an unknown protein. Downregulated transcripts by blood feeding were a microvillar-like protein (LuloMVP3), a trypsin like protein (Lltryp2) and an astacin-like metalloprotease (LuloAstacin). Furthermore, a comparative analysis between blood-fed and Leishmania infected midgut cDNA libraries resulted in the identification of the transcripts that were differentially expressed due to the presence of Leishmania in the gut of the sand fly. This included down regulated transcripts such as four microvillar-like proteins (LuloMVP1,2, 4 and 5), a Chymotrypsin (LuloChym1A) and a carboxypeptidase (LuloCpepA1), among others. Upregulated midgut transcripts in the presence of Leishmania were a peritrophin like protein (LuloPer1), a trypsin-like protein (Lltryp2) and an unknown protein.
Conclusion
This transcriptome analysis represents the largest set of sequence data reported from a specific sand fly tissue and provides further information of the transcripts present in the sand fly Lutzomyia longipalpis . This analysis provides the detailed information of molecules present in the midgut of this sand fly and the transcripts potentially modulated by blood feeding and by the presence of the Leishmania parasite. More importantly, this analysis suggests that Leishmania infantum chagasi alters the expression profile of certain midgut transcripts in the sand fly during blood meal digestion and that this modulation may be relevant for the survival and establishment of the parasite in the gut of the fly. Moreover, this analysis suggests that these changes may be occurring during the digestion of the blood meal and not afterwards.
BMC Genomics. 01/2008;
