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Characterization and partial purification of Candida albicans Secretory IL-12 Inhibitory Factor.

Wang M, Mukherjee PK, Chandra J, Lattif AA, McCormick TS, Ghannoum MA - BMC Microbiol. (2008)

Bottom Line: The minimal inhibitory dose of CA-SIIF was found to be 200 mug/ml.CA-SIIF-GP produced a higher inhibitory effect on IL-12 production compared to CA-SIIF-NGP and CA-SIIF crude (P < 0.01), proving that CA-SIIF is a glycoprotein in nature.These results suggest important role for CA-SIIF in interactions of C. albicans with the host immune system.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Medical Mycology, Department of Dermatology, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, Ohio, USA. mingyuewang@gmail.com

ABSTRACT

Background: We have previously shown that supernatant from Candida albicans (CA) culture contains a Secretory Interleukin (IL)-12 Inhibitory Factor (CA-SIIF), which inhibits IL-12 production by human monocytes. However, the effect of CA-SIIF on secretion of other cytokines by monocytes is unknown, and detailed characterization of this factor has not been performed.

Results: In this study, we demonstrate that the IL-12 inhibitory activity of CA-SIIF was serum-independent, based on the reduction of IL-12 levels in monocytes stimulated under serum-independent conditions. The minimal inhibitory dose of CA-SIIF was found to be 200 mug/ml. Investigation of CA-SIIF's effect on macrophages IL-12 production in vitro and in vivo also showed that CA-SIIF inhibited IL-12 production by murine macrophages both in vitro (from 571 +/- 24 pg/ml to 387 +/- 87 pg/ml; P = 0.05) and in vivo (from 262 +/- 6 pg/ml to 144 +/- 30 pg/ml; P < 0.05). In addition to IL-12, cytokine array analysis revealed that CA-SIIF induced differential production of other cytokines also. In this regard, reduction in levels were observed for IL-8, IL-10, IL-13, monocyte chemoattractant protein (MCP)-1, MCP-2, macrophage inflammatory protein (MIP)-1, RANTES, etc. In contrast, levels of other chemokines e.g. MCP-4, MIF and MIP-3alpha (P < 0.05) were increased. We also found that CA-SIIF suppressed the maturation of human monocytes to dendritic cells (CD1a expression = 13 +/- 3% vs 36 +/- 2% of the control; P < 0.01). Next, to identify the biochemical nature of CA-SIIF, we separated this factor into a Concanavalin A (ConA)-binding glycoprotein fraction (CA-SIIF-GP) and a non-ConA-binding protein fraction (CA-SIIF-NGP) using ConA affinity chromatography. Both fractions were then tested for this inhibitory effect on human monocyte IL-12 production. CA-SIIF-GP produced a higher inhibitory effect on IL-12 production compared to CA-SIIF-NGP and CA-SIIF crude (P < 0.01), proving that CA-SIIF is a glycoprotein in nature.

Conclusion: CA-SIIF is a glycoprotein which exhibits serum-independent inhibition of IL-12 production from monocytes in vitro and in vivo, and also modulates differentiation of monocytes into dendritic cells. These results suggest important role for CA-SIIF in interactions of C. albicans with the host immune system.

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CA-SIIF inhibited induced IL-12 production by human monocytes in a dose dependent manner. 1 × 106/ml human monocytes were primed with IFN-γ for 16 hours and activated by LPS for 24 h with supernatants (>30 kDa) from C. albicans or from S. cerevisiae or media control collected under same conditions. The supernatants were then measured for IL-12 p70 production. Monocytes (MN), monocytes activated by IFN-γ and LPS, 30 kDa MWCO media and supernatant from S. cerevisiae served as various controls. MN: monocytes without activation. Activated MN: monocytes activated by IFN-γ and LPS. CA-SIIF: activated MN cultured with supernatants from C. albicans. SC: activated MN cultured with supernatants from S. cerevisiae. n ≥ 3.
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Figure 2: CA-SIIF inhibited induced IL-12 production by human monocytes in a dose dependent manner. 1 × 106/ml human monocytes were primed with IFN-γ for 16 hours and activated by LPS for 24 h with supernatants (>30 kDa) from C. albicans or from S. cerevisiae or media control collected under same conditions. The supernatants were then measured for IL-12 p70 production. Monocytes (MN), monocytes activated by IFN-γ and LPS, 30 kDa MWCO media and supernatant from S. cerevisiae served as various controls. MN: monocytes without activation. Activated MN: monocytes activated by IFN-γ and LPS. CA-SIIF: activated MN cultured with supernatants from C. albicans. SC: activated MN cultured with supernatants from S. cerevisiae. n ≥ 3.

Mentions: Previously, we showed that CA-SIIF is secreted by C. albicans grown in the presence of fetal bovine serum (FBS), and that this factor can inhibit IL-12 production by monocytes activated by heat-killed C. albicans (HKCA) cells [8]. Since it is possible that factors present in FBS and/or heat-killed C. albicans cells may influence the inhibitory activity of CA-SIIF, we determined whether CA-SIIF obtained from C. albicans grown in serum-free medium also inhibited IL-12 production by monocytes. CA-SIIF was collected from C. albicans cultures grown for 20 h in serum-free media and added in different concentrations (50, 100, 200 and 300 μg/ml) to monocytes co-cultured with IFN-γ and LPS. We found that CA-SIIF obtained from C. albicans grown in serum-free medium also inhibited IL-12 production by monocytes. Furthermore, this inhibition was dose-dependent, with the highest inhibition observed for 300 μg/ml (IL-12 level = 10 ± 7 pg/ml) and the lowest for 200 μg/ml C. albicans supernatant (IL-12 level = 251 ± 28 pg/ml), compared to untreated monocytes (705 ± 31 pg/ml,P < 0.01 for all comparisons). At lower concentration (100 μg/ml), this supernatant exhibited a trend to decrease IL-12 levels, but the decrease was not statistically significant. As expected, supernatants obtained from S. cerevisiae (SC) (661 ± 93 pg/ml) or RPMI-1640 media controls (662 ± 63 pg/ml) did not induce significant inhibition of IL-12 levels (P < 0.01, Figure 2). These results demonstrated that CA-SIIF is produced by C. albicans cells in a serum-independent, but dose-dependent manner.


Characterization and partial purification of Candida albicans Secretory IL-12 Inhibitory Factor.

Wang M, Mukherjee PK, Chandra J, Lattif AA, McCormick TS, Ghannoum MA - BMC Microbiol. (2008)

CA-SIIF inhibited induced IL-12 production by human monocytes in a dose dependent manner. 1 × 106/ml human monocytes were primed with IFN-γ for 16 hours and activated by LPS for 24 h with supernatants (>30 kDa) from C. albicans or from S. cerevisiae or media control collected under same conditions. The supernatants were then measured for IL-12 p70 production. Monocytes (MN), monocytes activated by IFN-γ and LPS, 30 kDa MWCO media and supernatant from S. cerevisiae served as various controls. MN: monocytes without activation. Activated MN: monocytes activated by IFN-γ and LPS. CA-SIIF: activated MN cultured with supernatants from C. albicans. SC: activated MN cultured with supernatants from S. cerevisiae. n ≥ 3.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2289826&req=5

Figure 2: CA-SIIF inhibited induced IL-12 production by human monocytes in a dose dependent manner. 1 × 106/ml human monocytes were primed with IFN-γ for 16 hours and activated by LPS for 24 h with supernatants (>30 kDa) from C. albicans or from S. cerevisiae or media control collected under same conditions. The supernatants were then measured for IL-12 p70 production. Monocytes (MN), monocytes activated by IFN-γ and LPS, 30 kDa MWCO media and supernatant from S. cerevisiae served as various controls. MN: monocytes without activation. Activated MN: monocytes activated by IFN-γ and LPS. CA-SIIF: activated MN cultured with supernatants from C. albicans. SC: activated MN cultured with supernatants from S. cerevisiae. n ≥ 3.
Mentions: Previously, we showed that CA-SIIF is secreted by C. albicans grown in the presence of fetal bovine serum (FBS), and that this factor can inhibit IL-12 production by monocytes activated by heat-killed C. albicans (HKCA) cells [8]. Since it is possible that factors present in FBS and/or heat-killed C. albicans cells may influence the inhibitory activity of CA-SIIF, we determined whether CA-SIIF obtained from C. albicans grown in serum-free medium also inhibited IL-12 production by monocytes. CA-SIIF was collected from C. albicans cultures grown for 20 h in serum-free media and added in different concentrations (50, 100, 200 and 300 μg/ml) to monocytes co-cultured with IFN-γ and LPS. We found that CA-SIIF obtained from C. albicans grown in serum-free medium also inhibited IL-12 production by monocytes. Furthermore, this inhibition was dose-dependent, with the highest inhibition observed for 300 μg/ml (IL-12 level = 10 ± 7 pg/ml) and the lowest for 200 μg/ml C. albicans supernatant (IL-12 level = 251 ± 28 pg/ml), compared to untreated monocytes (705 ± 31 pg/ml,P < 0.01 for all comparisons). At lower concentration (100 μg/ml), this supernatant exhibited a trend to decrease IL-12 levels, but the decrease was not statistically significant. As expected, supernatants obtained from S. cerevisiae (SC) (661 ± 93 pg/ml) or RPMI-1640 media controls (662 ± 63 pg/ml) did not induce significant inhibition of IL-12 levels (P < 0.01, Figure 2). These results demonstrated that CA-SIIF is produced by C. albicans cells in a serum-independent, but dose-dependent manner.

Bottom Line: The minimal inhibitory dose of CA-SIIF was found to be 200 mug/ml.CA-SIIF-GP produced a higher inhibitory effect on IL-12 production compared to CA-SIIF-NGP and CA-SIIF crude (P < 0.01), proving that CA-SIIF is a glycoprotein in nature.These results suggest important role for CA-SIIF in interactions of C. albicans with the host immune system.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Medical Mycology, Department of Dermatology, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, Ohio, USA. mingyuewang@gmail.com

ABSTRACT

Background: We have previously shown that supernatant from Candida albicans (CA) culture contains a Secretory Interleukin (IL)-12 Inhibitory Factor (CA-SIIF), which inhibits IL-12 production by human monocytes. However, the effect of CA-SIIF on secretion of other cytokines by monocytes is unknown, and detailed characterization of this factor has not been performed.

Results: In this study, we demonstrate that the IL-12 inhibitory activity of CA-SIIF was serum-independent, based on the reduction of IL-12 levels in monocytes stimulated under serum-independent conditions. The minimal inhibitory dose of CA-SIIF was found to be 200 mug/ml. Investigation of CA-SIIF's effect on macrophages IL-12 production in vitro and in vivo also showed that CA-SIIF inhibited IL-12 production by murine macrophages both in vitro (from 571 +/- 24 pg/ml to 387 +/- 87 pg/ml; P = 0.05) and in vivo (from 262 +/- 6 pg/ml to 144 +/- 30 pg/ml; P < 0.05). In addition to IL-12, cytokine array analysis revealed that CA-SIIF induced differential production of other cytokines also. In this regard, reduction in levels were observed for IL-8, IL-10, IL-13, monocyte chemoattractant protein (MCP)-1, MCP-2, macrophage inflammatory protein (MIP)-1, RANTES, etc. In contrast, levels of other chemokines e.g. MCP-4, MIF and MIP-3alpha (P < 0.05) were increased. We also found that CA-SIIF suppressed the maturation of human monocytes to dendritic cells (CD1a expression = 13 +/- 3% vs 36 +/- 2% of the control; P < 0.01). Next, to identify the biochemical nature of CA-SIIF, we separated this factor into a Concanavalin A (ConA)-binding glycoprotein fraction (CA-SIIF-GP) and a non-ConA-binding protein fraction (CA-SIIF-NGP) using ConA affinity chromatography. Both fractions were then tested for this inhibitory effect on human monocyte IL-12 production. CA-SIIF-GP produced a higher inhibitory effect on IL-12 production compared to CA-SIIF-NGP and CA-SIIF crude (P < 0.01), proving that CA-SIIF is a glycoprotein in nature.

Conclusion: CA-SIIF is a glycoprotein which exhibits serum-independent inhibition of IL-12 production from monocytes in vitro and in vivo, and also modulates differentiation of monocytes into dendritic cells. These results suggest important role for CA-SIIF in interactions of C. albicans with the host immune system.

Show MeSH