Dataset Information

The Leishmania HSP20 is antigenic during natural infections, but, as DNA vaccine, it does not protect BALB/c mice against experimental L. amazonensis infection.

ABSTRACT: Protozoa of the genus Leishmania are causative agents of leishmaniasis, an important health problem in both human and veterinary medicine. Here, we describe a new heat shock protein (HSP) in Leishmania, belonging to the small HSP (sHSP) family in kinetoplastids. The protein is highly conserved in different Leishmania species, showing instead significant divergence with sHSP's from other organisms. The humoral response elicited against this protein during Leishmania infection has been investigated in natural infected humans and dogs, and in experimentally infected hamsters. Leishmania HSP20 is a prominent antigen for canine hosts; on the contrary, the protein seems to be a poor antigen for human immune system. Time-course analysis of appearance of anti-HSP20 antibodies in golden hamsters indicated that these antibodies are produced at late stages of the infection, when clinical symptoms of disease are patent. Finally, the protective efficacy of HSP20 was assessed in mice using a DNA vaccine approach prior to challenge with Leishmania amazonensis.

SUBMITTER: Montalvo-Alvarez AM

PROVIDER: S-EPMC2288687 | biostudies-literature | 2008

REPOSITORIES: biostudies-literature

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The Leishmania HSP20 is antigenic during natural infections, but, as DNA vaccine, it does not protect BALB/c mice against experimental L. amazonensis infection.

Montalvo-Alvarez Ana M AM Folgueira Cristina C Carrión Javier J Monzote-Fidalgo Lianet L Cañavate Carmen C Requena Jose M JM

Journal of biomedicine & biotechnology 20080101

Protozoa of the genus Leishmania are causative agents of leishmaniasis, an important health problem in both human and veterinary medicine. Here, we describe a new heat shock protein (HSP) in Leishmania, belonging to the small HSP (sHSP) family in kinetoplastids. The protein is highly conserved in different Leishmania species, showing instead significant divergence with sHSP's from other organisms. The humoral response elicited against this protein during Leishmania infection has been investigate ...[more]

PMID: 18401455

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Project description:Cutaneous leishmaniasis remains both a public health and a therapeutic challenge. To date, no ideal therapy for cutaneous leishmaniasis has been identified, and no universally accepted therapeutic regimen and approved vaccines are available. Due to the mesenchymal stromal cell (MSC) immunomodulatory capacity, they have been applied in a wide variety of disorders, including infectious, inflammatory, and allergic diseases. We evaluated the potential effects of bone marrow MSC therapy in a murine model of cutaneous leishmaniasis. In vitro, coculture of infected macrophages with MSC increased parasite load on macrophages in comparison with controls (macrophages without MSCs). In vivo, BALB/c mice were infected with 2?×?106Leishmania amazonensis (Josefa strain) promastigotes in the footpad. 7 and 37?days after infection, animals were treated with 1?×?105 MSCs, either intralesional (i.l.), i.e., in the same site of infection, or intravenously (i.v.), through the external jugular vein. Control animals received the same volume (50?µL) of phosphate-buffered saline by i.l. or i.v. routes. The lesion progression was assessed by its thickness measured by pachymetry. Forty-two days after infection, animals were euthanized and parasite burden in the footpad and in the draining lymph nodes was quantified by the limiting dilution assay (LDA), and spleen cells were phenotyped by flow cytometry. No significant difference was observed in lesion progression, regardless of the MSC route of administration. However, animals treated with i.v. MSCs presented a significant increase in parasite load in comparison with controls. On the other hand, no harmful effect due to MSCs i.l. administered was observed. The spleen cellular profile analysis showed an increase of IL-10 producing T CD4+ and TCD8+ cells in the spleen only in mice treated with i.v. MSC. The excessive production of IL-10 could be associated with the disease-aggravating effects of MSC therapy when intravenously administered. As a conclusion, in the current murine model of L. amazonensis-induced cutaneous disease, MSCs did not control the damage of cutaneous disease and, depending on the administration route, it could result in deleterious effects.

Project description:Background: Photosensitizers (PS), like porphyrins and phthalocyanines (PC) are excitable by light to generate cytotoxic singlet oxygen and other reactive oxygen species in the presence of atmospheric O2. Photodynamic inactivation of Leishmania by this means renders them non-viable, but preserves their effective use as vaccines. Leishmania can be photo-inactivated after PS-sensitization by loading via their endocytic uptake of PC or endogenous induction of transgenic mutants with delta-aminolevulinate (ALA) to accumulate cytosolic uroporphyrin I (URO). Here, PS-sensitization and photo-inactivation of Leishmaniaamazonensis was further examined in vitro and in vivo for vaccination against cutaneous leishmaniasis (CL). Methods and Results:Leishmania amazonensis promastigotes were photodynamically inactivated in vitro by PC-loading followed by exposure to red light (1-2 J/cm2) or ALA-induction of uroporphyrinogenic transfectants to accumulate cytosolic URO followed by longwave UV exposure. When applied individually, both strategies of photodynamic inactivation were found to significantly, albeit incompletely abolish the MTT reduction activities of the promastigotes, their uptake by mouse bone marrow-derived macrophages in vitro and their infectivity to mouse ear dermis in vivo. Inactivation of Leishmania to completion by using a combination of both strategies was thus used for the sake of safety as whole-cell vaccines for immunization of BALB/c mice. Different cutaneous sites were assessed for the efficacy of such photodynamic vaccination in vivo. Each site was inoculated first with in vitro doubly PS-sensitized promastigotes and then spot-illuminated with white light (50 J/cm2) for their photo-inactivation in situ. Only in ear dermis parasites were photo-inactivated beyond detection. Mice were thus immunized once in the ear and challenged 3 weeks later at the tail base with virulent L. amazonensis. Prophylaxis was noted in mice photodynamically vaccinated with doubly photo-inactivated parasites, as indicated by a significant delay in the onset of lesion development and a substantial decrease in the parasite loads. Conclusion: Leishmania doubly PS-sensitized and in situ photo-inactivated as described proved to be safe and effective when used for one-time immunization of ear dermis, as indicated by its significant protection of the inherently very susceptible BALB/c mice against CL.

Project description:In mammals, resident dermal macrophages (MÎ¦s) are subverted by Leishmania (L.) amazonensis amastigotes as host cells permissive for parasite multiplication. These Leishmania are living within a communal parasitophorous vacuole (PV) and are expected to trigger unique MÎ¦ transcriptional signatures. We performed a transcription profiling of mouse MÎ¦s harboring amastigotes to get insights into their reprogramming as host cells for parasite multiplication. BALB/c mouse bone marrow-derived MÎ¦s were either loaded or not with four amastigotes on average. Twenty four hours later, when amastigotes multiply, total RNA from MÎ¦ cultures was prepared, amplified and hybridized onto Affymetrix Mouse430_2 GeneChipsÂ®. The outcome recorded a total of 1,248 probe-sets showing significant differential expression. Comparable fold-change values for a handful of genes were obtained between Affymetrix technology and the more sensitive RTqPCR method. Ingenuity Pathway Analysis softwareÂ® pinpointed the up-regulation of the sterol biosynthesis pathway (P-value = 1.31e-02) involving several genes (1.95 to 4.30 fold-change values), and the modulation of various genes involved in polyamine synthesis and in pro/counter-inflammatory signaling. Our findings suggest that amastigotes exploit the MÎ¦ lipid and polyamine pathways to multiply efficiently, and induce a counter-inflammatory environment to expand their dermis niche. Experiment Overall Design: Mice, MÎ¦s and amastigotes: Experiment Overall Design: Swiss nu/nu and BALB/c mice were used (following National Scientific Ethics Committee guidelines) for L. amazonensis (LV79 strain, MPRO/BR/1972/M1841) amastigote propagation and to prepare bone marrow-derived MÎ¦s, respectively. Amastigotes were added at a multiplicity of 4 amastigotes per MÎ¦. Parasite-harboring MÎ¦s (>98%; samples I1, I2 and I3) and parasite-free ones (samples UI1, UI2 and UI3) were cultured at 34Â°C (LV79 permissive temperature) for 24h. Experiment Overall Design: Real-time quantitative PCR: Experiment Overall Design: Total RNA from various biological samples including those used for hybridization experiments were reverse transcribed into cDNA using random hexamers (Roche Diagnostics) and Moloney Murine Leukemia Virus Reverse Transcriptase (Invitrogen Life Technologies). RTqPCR was performed using LightCycler-480 system (Roche) with primers designed with LightCycler Probe Design 1.0 software.Target genes primer sequences, amplicon melting temperatures and amplification efficiencies are available upon request. Gene expression analysis using qBase program allowed determining the normalized relative quantities between parasite-free and parasite-harboring MÎ¦s.

Dataset Information

The Leishmania HSP20 is antigenic during natural infections, but, as DNA vaccine, it does not protect BALB/c mice against experimental L. amazonensis infection.

Publications

The Leishmania HSP20 is antigenic during natural infections, but, as DNA vaccine, it does not protect BALB/c mice against experimental L. amazonensis infection.

Similar Datasets

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