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Lutzomyia longipalpis saliva or salivary protein LJM19 protects against Leishmania braziliensis and the saliva of its vector, Lutzomyia intermedia.

Tavares NM, Silva RA, Costa DJ, Pitombo MA, Fukutani KF, Miranda JC, Valenzuela JG, Barral A, de Oliveira CI, Barral-Netto M, Brodskyn C - PLoS Negl Trop Dis (2011)

Bottom Line: Animals immunized with Lu. longipalpis saliva exhibited smaller lesion sizes as well as reduced disease burdens both at lesion site and in the draining lymph nodes.These alterations were associated with a significant decrease in the expression levels of IL-10 and TGF-β.These findings point out an important role of immune response against saliva components, suggesting the possibility to develop a vaccine using a single component of Lu. longipalpis saliva to generate protection against different species of Leishmania, even those transmitted by a different vector.

View Article: PubMed Central - PubMed

Affiliation: Centro de Pesquisa Gonçalo Moniz, FIOCRUZ, Salvador, Bahia, Brazil.

ABSTRACT

Background: Leishmania transmission occurs in the presence of insect saliva. Immunity to Phlebotomus papatasi or Lutzomyia longipalpis saliva or salivary components confers protection against an infection by Leishmania in the presence of the homologous saliva. However, immunization with Lutzomyia intermedia saliva did not protect mice against Leishmania braziliensis plus Lu. intermedia saliva. In the present study, we have studied whether the immunization with Lu. longipalpis saliva or a DNA plasmid coding for LJM19 salivary protein would be protective against L. braziliensis infection in the presence of Lu. intermedia saliva, the natural vector for L. braziliensis.

Methodology/principal findings: Immunization with Lu. longipalpis saliva or with LJM19 DNA plasmid induced a Delayed-Type Hypersensitivity (DTH) response against Lu. longipalpis as well as against a Lu. intermedia saliva challenge. Immunized and unimmunized control hamsters were then intradermally infected in the ears with L. braziliensis in the presence of Lu. longipalpis or Lu. intermedia saliva. Animals immunized with Lu. longipalpis saliva exhibited smaller lesion sizes as well as reduced disease burdens both at lesion site and in the draining lymph nodes. These alterations were associated with a significant decrease in the expression levels of IL-10 and TGF-β. Animals immunized with LJM19 DNA plasmid presented similar findings in protection and immune response and additionally increased IFN-γ expression.

Conclusions/significance: Immunization with Lu. longipalpis saliva or with a DNA plasmid coding LJM19 salivary protein induced protection in hamsters challenged with L. braziliensis plus Lu. intermedia saliva. These findings point out an important role of immune response against saliva components, suggesting the possibility to develop a vaccine using a single component of Lu. longipalpis saliva to generate protection against different species of Leishmania, even those transmitted by a different vector.

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Cytokines production by lymph node cells from hamsters immunized with LJM19 DNA plasmid in L. braziliensis infection.Hamsters were inoculated three times in the right ear with DNA plasmid LJM19 salivary protein (closed triangle; 9 hamsters per group total) or empty DNA plasmid (CTR – open triangle; 10 hamsters per group total) and were challenged in the left ear with 105 L. braziliensis in the presence of Lu. intermedia SGS. The IFN-γ (A), IL-10 (B) and TGF-β (C) relative mRNA expression was evaluated by Real-Time PCR 5 weeks after the infection. The ratio IFN-γ/TGF-β obtained in A and C for each group was compared (D). Points represent each animal, experiments were repeated three times and were evaluated by Mann-Whitney non-parametric t test. *p<0.05.
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pntd-0001169-g005: Cytokines production by lymph node cells from hamsters immunized with LJM19 DNA plasmid in L. braziliensis infection.Hamsters were inoculated three times in the right ear with DNA plasmid LJM19 salivary protein (closed triangle; 9 hamsters per group total) or empty DNA plasmid (CTR – open triangle; 10 hamsters per group total) and were challenged in the left ear with 105 L. braziliensis in the presence of Lu. intermedia SGS. The IFN-γ (A), IL-10 (B) and TGF-β (C) relative mRNA expression was evaluated by Real-Time PCR 5 weeks after the infection. The ratio IFN-γ/TGF-β obtained in A and C for each group was compared (D). Points represent each animal, experiments were repeated three times and were evaluated by Mann-Whitney non-parametric t test. *p<0.05.

Mentions: In order to investigate the mechanism involved in the protection conferred by LJM19 DNA plasmid immunization, the cytokine expression in draining lymph node cells was evaluated 5 weeks after challenge with L. braziliensis + Lu. intermedia SGS by Real-Time PCR (Fig. 5). There was a significant increase in the IFN-γ expression in LJM19 DNA plasmid immunized group, p = 0.011 (Fig. 5A). However, no differences were found in IL-10 (Fig. 5B) or TGF-β (Fig. 5C) expression in hamsters immunized with LJM19 DNA plasmid compared to control group. Moreover, the ratio of IFN-γ/TGF-β expression was significantly higher (p = 0.011) in LJM19 DNA plasmid immunized hamsters compared with the control group (Fig. 5D). Together, these results suggest that immunization with a defined protein induces a protective immune response, with higher expression of pro-inflammatory cytokine (IFN-γ).


Lutzomyia longipalpis saliva or salivary protein LJM19 protects against Leishmania braziliensis and the saliva of its vector, Lutzomyia intermedia.

Tavares NM, Silva RA, Costa DJ, Pitombo MA, Fukutani KF, Miranda JC, Valenzuela JG, Barral A, de Oliveira CI, Barral-Netto M, Brodskyn C - PLoS Negl Trop Dis (2011)

Cytokines production by lymph node cells from hamsters immunized with LJM19 DNA plasmid in L. braziliensis infection.Hamsters were inoculated three times in the right ear with DNA plasmid LJM19 salivary protein (closed triangle; 9 hamsters per group total) or empty DNA plasmid (CTR – open triangle; 10 hamsters per group total) and were challenged in the left ear with 105 L. braziliensis in the presence of Lu. intermedia SGS. The IFN-γ (A), IL-10 (B) and TGF-β (C) relative mRNA expression was evaluated by Real-Time PCR 5 weeks after the infection. The ratio IFN-γ/TGF-β obtained in A and C for each group was compared (D). Points represent each animal, experiments were repeated three times and were evaluated by Mann-Whitney non-parametric t test. *p<0.05.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3104964&req=5

pntd-0001169-g005: Cytokines production by lymph node cells from hamsters immunized with LJM19 DNA plasmid in L. braziliensis infection.Hamsters were inoculated three times in the right ear with DNA plasmid LJM19 salivary protein (closed triangle; 9 hamsters per group total) or empty DNA plasmid (CTR – open triangle; 10 hamsters per group total) and were challenged in the left ear with 105 L. braziliensis in the presence of Lu. intermedia SGS. The IFN-γ (A), IL-10 (B) and TGF-β (C) relative mRNA expression was evaluated by Real-Time PCR 5 weeks after the infection. The ratio IFN-γ/TGF-β obtained in A and C for each group was compared (D). Points represent each animal, experiments were repeated three times and were evaluated by Mann-Whitney non-parametric t test. *p<0.05.
Mentions: In order to investigate the mechanism involved in the protection conferred by LJM19 DNA plasmid immunization, the cytokine expression in draining lymph node cells was evaluated 5 weeks after challenge with L. braziliensis + Lu. intermedia SGS by Real-Time PCR (Fig. 5). There was a significant increase in the IFN-γ expression in LJM19 DNA plasmid immunized group, p = 0.011 (Fig. 5A). However, no differences were found in IL-10 (Fig. 5B) or TGF-β (Fig. 5C) expression in hamsters immunized with LJM19 DNA plasmid compared to control group. Moreover, the ratio of IFN-γ/TGF-β expression was significantly higher (p = 0.011) in LJM19 DNA plasmid immunized hamsters compared with the control group (Fig. 5D). Together, these results suggest that immunization with a defined protein induces a protective immune response, with higher expression of pro-inflammatory cytokine (IFN-γ).

Bottom Line: Animals immunized with Lu. longipalpis saliva exhibited smaller lesion sizes as well as reduced disease burdens both at lesion site and in the draining lymph nodes.These alterations were associated with a significant decrease in the expression levels of IL-10 and TGF-β.These findings point out an important role of immune response against saliva components, suggesting the possibility to develop a vaccine using a single component of Lu. longipalpis saliva to generate protection against different species of Leishmania, even those transmitted by a different vector.

View Article: PubMed Central - PubMed

Affiliation: Centro de Pesquisa Gonçalo Moniz, FIOCRUZ, Salvador, Bahia, Brazil.

ABSTRACT

Background: Leishmania transmission occurs in the presence of insect saliva. Immunity to Phlebotomus papatasi or Lutzomyia longipalpis saliva or salivary components confers protection against an infection by Leishmania in the presence of the homologous saliva. However, immunization with Lutzomyia intermedia saliva did not protect mice against Leishmania braziliensis plus Lu. intermedia saliva. In the present study, we have studied whether the immunization with Lu. longipalpis saliva or a DNA plasmid coding for LJM19 salivary protein would be protective against L. braziliensis infection in the presence of Lu. intermedia saliva, the natural vector for L. braziliensis.

Methodology/principal findings: Immunization with Lu. longipalpis saliva or with LJM19 DNA plasmid induced a Delayed-Type Hypersensitivity (DTH) response against Lu. longipalpis as well as against a Lu. intermedia saliva challenge. Immunized and unimmunized control hamsters were then intradermally infected in the ears with L. braziliensis in the presence of Lu. longipalpis or Lu. intermedia saliva. Animals immunized with Lu. longipalpis saliva exhibited smaller lesion sizes as well as reduced disease burdens both at lesion site and in the draining lymph nodes. These alterations were associated with a significant decrease in the expression levels of IL-10 and TGF-β. Animals immunized with LJM19 DNA plasmid presented similar findings in protection and immune response and additionally increased IFN-γ expression.

Conclusions/significance: Immunization with Lu. longipalpis saliva or with a DNA plasmid coding LJM19 salivary protein induced protection in hamsters challenged with L. braziliensis plus Lu. intermedia saliva. These findings point out an important role of immune response against saliva components, suggesting the possibility to develop a vaccine using a single component of Lu. longipalpis saliva to generate protection against different species of Leishmania, even those transmitted by a different vector.

Show MeSH
Related in: MedlinePlus