Immunity to Lutzomyia intermedia saliva modulates the inflammatory environment induced by Leishmania braziliensis.
BACKGROUND
During blood feeding, sand flies inject Leishmania parasites in the presence of saliva. The types and functions of cells present at the first host-parasite contact are critical to the outcome on infection and sand fly saliva has been shown to play an important role in this setting. Herein, we investigated the in vivo chemotactic effects of Lutzomyia intermedia saliva, the vector of Leishmania braziliensis, combined or not with the parasite.


RESULTS
We tested the initial response induced by Lutzomyia intermedia salivary gland sonicate (SGS) in BALB/c mice employing the air pouch model of inflammation. L. intermedia SGS induced a rapid influx of macrophages and neutrophils. In mice that were pre-sensitized with L. intermedia saliva, injection of SGS was associated with increased neutrophil recruitment and a significant up-regulation of CXCL1, CCL2, CCL4 and TNF-alpha expression. Surprisingly, in mice that were pre-exposed to SGS, a combination of SGS and L. braziliensis induced a significant migration of neutrophils and an important modulation in cytokine and chemokine expression as shown by decreased CXCL10 expression and increased IL-10 expression.


CONCLUSIONS
These results confirm that sand fly saliva modulates the initial host response. More importantly, pre-exposure to L. intermedia saliva significantly modifies the host's response to L. braziliensis, in terms of cellular recruitment and expression of cytokines and chemokines. This particular immune modulation may, in turn, favor parasite multiplication.
de Moura
Tatiana R
TR
Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz (FIOCRUZ), Salvador, Brazil.
Oliveira
Fabiano
F
Rodrigues
Gabriele C
GC
Carneiro
Marcia W
MW
Fukutani
Kiyoshi F
KF
Novais
Fernanda O
FO
Miranda
José Carlos
JC
Barral-Netto
Manoel
M
Brodskyn
Claudia
C
Barral
Aldina
A
de Oliveira
Camila I
CI
D000818:Animals; D000941:Antigens / Q000276:immunology; D002634:Chemotaxis, Leukocyte / Q000276:immunology; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004431:Ear, External; D005260:Female; D006651:Histocytochemistry; D006790:Host-Parasite Interactions; D007106:Immune Sera; D007249:Inflammation / Q000276:immunology* / Q000469:parasitology; D007892:Leishmania braziliensis / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology* / Q000469:parasitology; D051379:Mice; D008807:Mice, Inbred BALB C; D020556:Neutrophil Infiltration / Q000276:immunology; D016133:Polymerase Chain Reaction; D011576:Psychodidae / Q000276:immunology* / Q000469:parasitology; D012463:Saliva / Q000276:immunology*; D012469:Salivary Glands; D012867:Skin / Q000166:cytology; D018709:Statistics, Nonparametric
D000941:Antigens; D016207:Cytokines; D007106:Immune Sera