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https://www.arca.fiocruz.br/handle/icict/18145
IMMUNITY TO LUTZOMYIA WHITMANI SALIVA PROTECTS AGAINST EXPERIMENTAL LEISHMANIA BRAZILIENSIS INFECTION
Author
Affilliation
Fundação Oswaldo Cruz (FIOCRUZ). Escritório Técnico Regional. Teresina, PI, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil
Fundação Oswaldo Cruz (FIOCRUZ). Escritório Técnico Regional. Teresina, PI, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil
Federal University of Bahia. School of Medicine. Salvador, BA, Brazil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / INCT. Instituto de Investigação em Imunologia. São Paulo, SP, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / INCT. Instituto de Investigação em Imunologia. São Paulo, SP, Brasil / Universidade Federal da Bahia. Salvador, BA, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil
Fundação Oswaldo Cruz (FIOCRUZ). Escritório Técnico Regional. Teresina, PI, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil
Federal University of Bahia. School of Medicine. Salvador, BA, Brazil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / INCT. Instituto de Investigação em Imunologia. São Paulo, SP, Brasil
Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / INCT. Instituto de Investigação em Imunologia. São Paulo, SP, Brasil / Universidade Federal da Bahia. Salvador, BA, Brasil
Abstract
Previous works showed that immunization with saliva from Lutzomyia intermedia, a vector of Leishmania braziliensis, does not protect against experimental infection. However, L. braziliensis is also transmitted by Lutzomyia whitmani, a sand fly species closely related to Lu. intermedia. Herein we describe the immune response following immunization with Lu. whitmani saliva and the outcome of this response after L. braziliensis infection. Methods and findings
BALB/c mice immunized with Lu. whitmani saliva developed robust humoral and cellular
immune responses, the latter characterized by an intense cellular infiltrate and production
of IFN-γ and IL-10, by both CD4+ and CD8+ cells. Mice immunized as above and challenged
with L. braziliensis plus Lu. whitmani saliva displayed significantly smaller lesions
and parasite load at the challenge site. This protection was associated with a higher
(p<0.05) IFN-γ production in response to SLA stimulation. Long-term persisting immunity
was also detected in mice immunized with Lu. whitmani saliva. Furthermore, individuals
residing in an endemic area for cutaneous leishmaniasis (CL) presented antibody
responses to Lu. whitmani saliva. However CL patients, with active lesions, displayed a
lower humoral response to Lu. whitmani saliva compared to individuals with subclinical
Leishmania infection.
Conclusion
Pre-exposure to Lu. whitmani saliva induces protection against L. braziliensis in a murine
model. We also show that Lu. whitmani salivary proteins are immunogenic in naturally exposed individuals. Our results reinforce the importance of investigating the immunomodulatory
effect of saliva from different species of closely related sand flies.
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