Immunomodulation of human monocytes following exposure to Lutzomyia intermedia saliva

Maria José Menezes¹ , Dirceu J Costa¹ , Jorge Clarêncio¹ , José Carlos Miranda¹ , Aldina Barral¹^,2^,3 , Manoel Barral-Netto¹^,2^,3 , Cláudia Brodskyn¹^,2^,3 and Camila I de Oliveira¹

¹Centro de Pesquisas Gonçalo Moniz-FIOCRUZ, Salvador, Brazil

²Universidade Federal da Bahia, Salvador, Brazil

³Instituto de Investigação em Imunologia, Salvador, Brazil

author email corresponding author email

BMC Immunology 2008, 9:12doi:10.1186/1471-2172-9-12


Published:	10 April 2008

Abstract

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-α, 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.

Conclusion

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.