Research Article Rotavirus Recombinant VP6 Nanotubes Act as an Immunomodulator and Delivery Vehicle for Norovirus Virus-Like Particles Maria Malm, Kirsi Tamminen, Suvi Lappalainen, Timo Vesikari, and Vesna Blazevic Vaccine Research Center, University of Tampere, Biokatu 10, 33520 Tampere, Finland Correspondence should be addressed to Vesna Blazevic; vesna.blazevic@uta.f Received 23 February 2016; Revised 5 July 2016; Accepted 19 July 2016 Academic Editor: Aurelia Rughetti Copyright © 2016 Maria Malm et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We have recently shown that tubular form of rotavirus (RV) recombinant VP6 protein has an in vivo adjuvant efect on the immunogenicity of norovirus (NoV) virus-like particle (VLP) vaccine candidate. In here, we investigated in vitro efect of VP6 on antigen presenting cell (APC) activation and maturation and whether VP6 facilitates NoV VLP uptake by these APCs. Mouse macrophage cell line RAW 264.7 and dendritic cell line JAWSII were used as model APCs. Internalization of VP6, cell surface expression of CD40, CD80, CD86, and major histocompatibility class II molecules, and cytokine and chemokine production were analyzed. VP6 nanotubes were efciently internalized by APCs. VP6 upregulated the expression of cell surface activation and maturation molecules and induced secretion of several proinfammatory cytokines and chemokines. Te mechanism of VP6 action was shown to be partially dependent on lipid raf-mediated endocytic pathway as shown by methyl--cyclodextrin inhibition on tumor necrosis factor  secretion. Tese fndings add to the understanding of mechanism by which VP6 exerts its immunostimulatory and immunomodulatory actions and further support its use as a part of nonlive RV-NoV combination vaccine. 1. Introduction Noroviruses (NoVs) and rotaviruses (RVs) are the major causative agents of pediatric acute gastroenteritis (AGE) in children worldwide. Tere is no licensed vaccine for NoV available, and despite efcacious live RV vaccines currently in use [1], there is a need [2] for nonlive RV vaccines that could be safer [3], more afordable, and more efcacious in developing countries [4–6]. Our group has developed a subunit combination vaccine candidate against NoV and RV gastroenteritis, consisting of NoV virus-like particles (VLPs) and RV VP6, aiming to confer protection from both leading etiological agents of severe AGE [7–9]. Te double-stranded (ds) RNA genome of triple-layered RV particle is surrounded by core protein VP2 [10]. Te out- ermost layer, composed of VP7 capsid glycoprotein and the spike protein VP4, contains most epitopes for RV neutralizing antibody interaction [11]. Te intermediate layer is formed by the major internal structural protein VP6 that represents 51% of the virion mass [12]. VP6 trimers are organized into hexagons and packed into higher order structures, for example, nanotubes, nanospheres, or sheets when expressed in vitro in baculovirus (BV) or bacterial expression systems [12–16]. Te variable morphology of polymeric VP6 protein expressed in vitro depends on biochemical composition, mainly on pH and ionic strength [17]. Recombinant VP6 has been considered as a nonlive next generation vaccine candidate against RV by us and others, being the most abundant, highly conserved, and immu- nogenic RV protein [2, 7, 8, 18]. B-cell-mediated immune responses, especially IgA seroconversion following RV vac- cination and natural infection, are mostly directed against VP6 [19]. Even though the inner capsid protein VP6 cannot elicit classical neutralizing antibodies, it induced heterotypic protective immunity against live RV challenge in mice that correlated with postchallenge VP6-specifc serum IgA [20]. VP6-specifc polymeric IgA inhibits RV replication intra- cellularly during IgA transcytosis, a phenomenon termed intracellular neutralization [21–23]. Hindawi Publishing Corporation Journal of Immunology Research Volume 2016, Article ID 9171632, 13 pages http://dx.doi.org/10.1155/2016/9171632