The alternate layer‐by‐layer (LBL) deposition of polycations and polyanions for the build up of multilayered polyelectrolyte films is an original approach that allows the preparation of tunable, biologically active surfaces. The resulting supramolecular nanoarchitectures can be functionalized with drugs, peptides, and proteins, or DNA molecules that are able to transfect cells in vitro. We monitor, for the first time, the embedding of a bioactive adenoviral (Ad) vector in multilayered polyelectrolyte films. Ad efficiently adsorbs on poly(L‐lysine)–poly(L‐glutamic acid) (PLL–PGA), PLL–HA (HA: hyaluronan), poly(allylamin hydrochloride)–poly(sodium‐4‐styrenesulfonate) (PAH–PSS), and CHI–HA (CHI: chitosan) films; it preserves its transduction capacity (which can reach 95 %) for a large number of cell types, and also allows vector uptake into receptor‐deficient cells, thus abrogating the restricted tropism of Ad.

Rotavirus (RV) predominantly replicates in intestinal epithelial cells (IEC), and ''danger signals'' released by these cells may modulate viral immunity. We have recently shown that human model IEC (Caco-2 cells) infected with rhesus-RV release a non-inflammatory group of immunomodulators that includes heat shock proteins (HSPs) and TGF-b1. Here we show that both proteins are released in part in association with membrane vesicles (MV) obtained from filtrated Caco-2 supernatants concentrated by ultracentrifugation. These MV express markers of exosomes (CD63 and others), but not of the endoplasmic reticulum (ER) or nuclei. Larger quantities of proteins associated with MV were released by RV-infected cells than by non-infected cells. VP6 co-immunoprecipitated with CD63 present in these MV, and VP6 co-localized with CD63 in RV-infected cells, suggesting that this viral protein is associated with the MV, and that this association occurs intracellularly. CD63 present in MV preparations from stool samples from 36 children with gastroenteritis due or not due to RV were analyzed. VP6 coimmunoprecipitated with CD63 in 3/8 stool samples from RV-infected children, suggesting that these MV are released by RV-infected cells in vivo. Moreover, fractions that contained MV from RV-infected cells induced death and inhibited proliferation of CD4 þ T cells to a greater extent than fractions from non-infected cells. These effects were in part due to TGF-b, because they were reversed by treatment of the T cells with the TGF-b-receptor inhibitor ALK5i. MV from RV-infected and non-infected cells were heterogeneous, with morphologies and typical flotation densities described for exosomes (between 1.10 and 1.18 g/mL), and denser vesicles (>1.24 g/mL). Both types of MV from RV-infected cells were more efficient at inhibiting T-cell function than were those from non-infected cells. We propose that RV infection of IEC releases MV that modulate viral immunity.

Rotavirus replication and virulence are strongly influenced by virus strain and host species. The rotavirus proteins VP3, VP4, VP7, NSP1, and NSP4 have all been implicated in strain and species restriction of replication; however, the mechanisms have not been fully determined. Simian (RRV) and bovine (UK) rotaviruses have distinctive replication capacities in mouse extraintestinal organs such as the biliary tract. Using reassortants between UK and RRV, we previously demonstrated that the differential replication of these viruses in mouse embryonic fibroblasts is determined by the respective NSP1 proteins, which differ substantially in their abilities to degrade interferon (IFN) regulatory factor 3 (IRF3) and suppress the type I IFN response. In this study, we used an in vivo model of rotavirus infection of mouse gallbladder with UK ؋ RRV reassortants to study the genetic and mechanistic basis of systemic rotavirus replication. We found that the low-replication phenotype of UK in biliary tissues was conferred by UK VP4 and that the high-replication phenotype of RRV was conferred by RRV VP4 and NSP1. Viruses with RRV VP4 entered cultured mouse cholangiocytes more efficiently than did those with UK VP4. Reassortants with RRV VP4 and UK NSP1 genes induced high levels of expression of IRF3-dependent p54 in biliary tissues, and their replication was increased 3-fold in IFN-␣/␤ and -␥ receptor or STAT1 knockout (KO) mice compared to wild-type mice. Our data indicate that systemic rotavirus strain-specific replication in the murine biliary tract is determined by both viral entry mediated by VP4 and viral antagonism of the host innate immune response mediated by NSP1.Group A rotaviruses (RVs) are segmented double-stranded RNA viruses that replicate primarily in mature epithelial cells on the tips of small intestinal villi (7). Rotavirus is the most common cause of severe dehydrating diarrhea in infants and young children worldwide; these infections result in more than 600,000 deaths annually, mostly in developing countries, and over 2 million hospitalizations each year (20). Rotavirus infection is ubiquitous among mammals; however, virulent viral strains isolated from one animal species generally have a diminished replication capacity and diminished virulence in heterologous hosts. This phenomenon of rotavirus host range restriction was employed for the development of two rotavirus vaccines in which animal rotaviruses that are naturally attenuated in humans were used to produce the genetic backbone of human vaccines. The pentavalent rotavirus vaccine Rotateq (Merck), for example, is derived from a bovine rotavirus strain, WC, with incorporated human rotavirus genes that encode VP7 of serotypes 1, 2, 3, and 4 and VP4 of serotype P1A to induce neutralizing antibody (Ab) responses to the most common human RV serotypes.The viral factors underlying rotavirus host range restriction are not fully understood but are likely to be multigenic. Early studies using reassortants between simian and bovine strains demonstrated that the ...