Immunomodulation of human monocytes following exposure to Lutzomyia intermedia saliva.
BACKGROUND
Sand fly saliva contains potent and complex pharmacologic molecules that are able to modulate the host's hemostatic, inflammatory, and immune systems. In this study, we evaluated the effects of salivary gland sonicate (SGS) of Lutzomyia intermedia, the natural vector of Leishmania braziliensis, on monocytes obtained from the peripheral blood mononuclear cells (PBMC) of healthy volunteers. We investigated the effects of sand fly saliva on cytokine production and surface molecule expression of LPS-stimulated human monocytes uninfected or infected with L. braziliensis.


RESULTS
Pre-treatment of non-infected human monocytes with L. intermedia SGS followed by LPS-stimulation led to a significant decrease in IL-10 production accompanied by a significant increase in CD86, CD80, and HLA-DR expression. Pre-treatment with SGS followed by LPS stimulation and L. braziliensis infection led to a significant increase in TNF-alpha, IL-6, and IL-8 production without significant alterations in co-stimulatory molecule expression. However, pre-treatment with L. intermedia SGS did not result in significant changes in the infection rate of human monocytes.


CONCLUSIONS
Our data indicate that L. intermedia saliva is able to modulate monocyte response, and, although this modulation is dissociated from enhanced infection with L. braziliensis, it may be associated with successful parasitism.
Menezes
Maria José
MJ
Centro de Pesquisas Gonçalo Moniz-FIOCRUZ, Salvador, Brazil. mjmenezes@usp.br
Costa
Dirceu J
DJ
Clarêncio
Jorge
J
Miranda
José Carlos
JC
Barral
Aldina
A
Barral-Netto
Manoel
M
Brodskyn
Cláudia
C
de Oliveira
Camila I
CI
D000328:Adult; D000818:Animals; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007892:Leishmania braziliensis; D007896:Leishmaniasis / Q000276:immunology; D008297:Male; D009000:Monocytes / Q000276:immunology* / Q000469:parasitology; D011576:Psychodidae; D012463:Saliva / Q000737:chemistry* / Q000276:immunology*
D016207:Cytokines