APPLIED MICROBIAL AND CELL PHYSIOLOGY Short chain regioselectively hydrolyzed scleroglucans induce maturation of porcine dendritic cells Diane Bimczok & Julika Wrenger & Thomas Schirrmann & Hermann-Josef Rothkötter & Victor Wray & Udo Rau Received: 11 September 2008 / Revised: 21 November 2008 / Accepted: 5 December 2008 / Published online: 24 December 2008 # Springer-Verlag 2008 Abstract Branched β-1,3/1,6-glucans (scleroglucan) were produced by cultivation of Sclerotium rolfsii ATCC 15205. Regioselective hydrolysis at the β-1,3-linkage of the cell- free and purified polysaccharide was performed in borosil- icate glass bottles at pH 5, 121°C, and 1 bar for 72 h. The mixture was divided into four molar mass fractions by stepwise cross-flow filtration using different cutoffs. In vitro studies revealed that scleroglucan hydrolysates with a low molar mass of less than 5 kDa significantly stimulated the activation and maturation of porcine monocyte derived dendritic cells (MoDC) by upregulation of CD40 and CD80/86 as well as by reduction of antigen uptake. MoDC treated with low molar mass scleroglucan showed a considerable increase in the amounts of secreted proin- flammatory cytokine tumor necrosis factor alpha and stimulated the proliferation of lymphocytes. Therefore, scleroglucan molecules of low molecular weight are able to induce activation and maturation of porcine DC, which are key initiators of inflammatory and adaptive immune responses, and could provide improved protection against infectious diseases. Keywords Porcine dendritic cells . Cytokines . β-Glucan . Scleroglucan . Regioselective hydrolysis Introduction Many studies have been conducted on the production and downstream processing of scleroglucan (Schilling 2000; Maier et al. 2003; Survase et al. 2007), an extracellular polysaccharide produced by the fungus imperfectus Sclero- tium rolfsii ATCC 15205. Scleroglucan (Giavasis et al. 2005) is a water soluble neutral homoglucan consisting of a backbone chain of 1,3-β-D-glucopyranose units linked with single 1,6-β-D-glucopyranose residues at about every third glucose molecule in the basic chain. The primary molecular structure is almost identical with Schizophyllan secreted by Schizophyllum commune (Rau 2005). The viscosity of aqueous scleroglucan solutions is not affected over a broad range of pH 1–12, increased temperature up to 135°C, and high salinity (Rau 2004) and allows applications as viscosifier in creams and lotions (Huber et al. 2002) or for polymer flooding in enhanced oil recovery (Pirri et al. 1993). In dermatological applications, the anti-inflammatory characteristics of scleroglucan render it valuable for use as an active ingredient against sun burn (Huber et al. 2002). In the role as biological response modifier, the polysaccharide has been shown to have a stimulatory effect on the immune Appl Microbiol Biotechnol (2009) 82:321–331 DOI 10.1007/s00253-008-1813-7 J. Wrenger : T. Schirrmann : U. Rau (*) Institute of Biochemistry and Biotechnology, Technical University Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany e-mail: U.Rau@tu-bs.de D. Bimczok : H.-J. Rothkötter Institute for Anatomy, Faculty of Medicine, Otto-von-Guericke-University, Leipziger Strasse 44, 39120 Magdeburg, Germany V. Wray Department of Structure Biology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany Present address: D. Bimczok Division of Gastroenterology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA