Interleukin-6 treatment enhances human monocyte permissiveness for Paracoccidioides brasiliensis growth by modulating cytokine production

Author(s)

Siqueira, Keila Zaniboni ^[1] ; Victoriano De Campos Soares, Angela Maria ^[1] ; Dias-Melicio, Luciane Alarcao ^[1] ; Calvi, Sueli Aparecida ^[2] ; Serrao Peracoli, Maria Terezinha ^[1]

Affiliation

^[1] Sao Paulo State Univ, Inst Biosci, Dept Microbiol & Immunol, Botucatu, SP - Brazil

^[2] Sao Paulo State Univ, Sch Med, Dept Trop Dis & Diag Image, Botucatu, SP - Brazil

• Document type: Journal article
• Source: Medical Mycology; v. 47, n. 3, p. 259-267, 2009.
• Web of Science Citations: 8

Abstract

The effect of interleukin (IL)-6 on cytokine production was evaluated in human monocyte cultures infected with the virulent strain of Paracoccidioides brasiliensis (Pb18). Peripheral blood monocytes from healthy individuals were preincubated for 24 h with or without human recombinant IL-6, and then challenged with Pb18 for 4 h and 18 h. P. brasiliensis growth was assessed by viable fungi recovery from co-cultures after plating on BHI-agar. Moreover, tumor necrosis factor-alpha (TNF-), IL-6 and IL-10 production in supernatant cultures was determined by enzyme immunoassay (ELISA). Monocyte preincubation with IL-6, and challenged with Pb18 for 4 h, led to significantly higher fungi recovery compared to non-treated co-cultures. The pretreatment of monocytes with IL-6 induced an inhibitory effect on TNF- and IL-10 production during 18 h fungal infection. Otherwise, an autocrine stimulatory effect on IL-6 production was detected at 4 h and 18 h as represented by an elevation in IL-6 levels. The reduction in TNF- levels and stimulation of IL-6 production induced by previous IL-6 treatment might be responsible for a significant increase in fungal growth in human monocytes. The results suggest that IL-6, by exerting a modulatory effect on cytokines production, makes monocyte more permissive for fungal growth. (AU)