Wall-associated kinase 1 (WAK1) is a transmembrane protein containing a cytoplasmic Ser/Thr kinase domain and an extracellular domain in contact with the pectin fraction of the plant cell walls. In order to characterize further the interaction of WAK1 with pectin, a 564 bp DNA sequence corresponding to amino acids 67-254 of the extracellular domain of WAK1 from Arabidopsis thaliana was cloned and expressed as a soluble recombinant peptide in yeast. Using enzyme-linked immunosorbent assays (ELISA), we show that peptide WAK(67-254) binds to polygalacturonic acid (PGA), oligogalacturonides, pectins extracted from A. thaliana cell walls and to structurally related alginates. Our results suggest that both ionic and steric interactions are required to match the relatively linear pectin backbone. Binding of WAK(67-254) to PGA, oligogalacturonides and alginates occurred only in the presence of calcium and in ionic conditions promoting the formation of calcium bridges between oligo-and polymers (also known as 'egg-boxes'). The conditions inhibiting the formation of calcium bridges (EDTA treatment, calcium substitution, high NaCl concentrations, depolymerization and methylesterification of pectins) also inhibited the binding of WAK(67-254) to calcium-induced egg-boxes. The relevance of this non-covalent link between WAK(67-254) and cell wall pectins is discussed in terms of cell elongation, cell differentiation and host-pathogen interactions.

No abstract

Early auxin-regulated tobacco cDNAs, belonging to the Aux/IAA gene family have been isolated by screening of a cDNA library prepared from auxin-treated suspension-grown etiolated seedlings of Nicotiana tabacum. The probes used were either RT-PCR fragments or an insert resulting from mRNA differential display selection. All of them possessed the structural features which characterize the Aux/IAA gene products. The auxin response of three distinct Nt-iaa subclasses has been characterized in terms of kinetics, dose-response and specificity as several plant hormones and chemicals have been tested for their ability to alter Nt-iaa mRNA accumulation. Differences of auxin responses have been observed between the Nt-iaa analysed, revealing significant differences of regulation. The effect of the protein synthesis inhibitor cycloheximide suggested that Nt-iaa2.3, Nt-iaa4.3 and strictly related genes can be classified as primary auxin-responsive genes and Nt-iaa28 as a late one. The steady-state mRNA level of these Nt-iaa has also been determined in organs of tobacco plants.

This study assessed long-term immunogenicity and safety following 3 doses of AS04-adjuvanted human papillomavirus (HPV)-16/18 L1 virus-like particle (VLP) vaccine in females 10-14 years old. Girls included in the immunogenicity subset in the primary controlled, observer-blinded, randomized study (NCT00196924) who received 3 doses were invited for a 10-year follow-up (NCT00316706 and NCT00877877). Serum antibody responses against HPV-16/18 (vaccine types) and HPV-31/45 (nonvaccine types) were measured by enzyme-linked immunosorbent assay (ELISA) using type-specific VLP as coating antigens. Serious adverse events (SAEs) and pregnancy information were recorded. At Month (M) 120, all subjects (N = 418, according-to-protocol immunogenicity cohort) were seropositive for anti-HPV-16/18 antibodies. Geometric mean titers (GMTs) were 1589.9 ELISA Units [EU]/mL (95% confidence interval [CI]: 1459.8-1731.6) for anti-HPV-16 and 597.2 EU/mL (95% CI: 541.7-658.5) for anti-HPV-18 in subjects seronegative at baseline for the type analyzed. Post hoc mathematical modeling predicted a durability ≥50 years for anti-HPV-16 and anti-HPV-18. For the non-vaccine humoral type response, all initially seronegative subjects had seroconverted at M7, with anti-HPV-31 GMT of 2030.5 EU/mL (95% CI: 1766.2-2334.4) and anti-HPV-45 GMT of 2300.8 EU/mL (95% CI: 2036.8-2599.0). At M120, 87.7% and 85.1% remained seropositive for anti-HPV-31 with GMT of 242.9 EU/mL (95% CI: 201.4-293.0) and anti-HPV-45 with GMT of 204.7 EU/mL (95% CI: 170.0-246.6). During the 10-year follow-up, no SAEs or abnormal pregnancy outcomes were causally related to vaccination. Three doses of the AS04-HPV-16/18 vaccine induced high and sustained antibody response against HPV-16,18,31 and 45 in girls aged 10-14 years during the 10-year follow-up, with an acceptable long-term safety profile.

The pestivirus bovine viral diarrhea virus (BVDV) is known to bind to the CD46 molecule, which subsequently promotes entry of the virus. Mapping of the BVD-virion-binding site has shown that two peptides, 66EQIV69 and 82GQVLAL87, located on antiparallel beta sheets in the most distal complement control protein module (CCP1), provide the attachment platform. In the present study, we reveal the existence of ten distinct allelic versions of the CCP1 module, varying significantly in frequency among taurine and indicine races. A complex mRNA splicing pattern was also evidenced for bovine CD46, generating three different serine-threonine-proline segments and five different cytoplasmic domains. The four most frequent allelic variants and the six splice variants were then expressed in BVDV-nonpermissive porcine cells and the quantity of progeny virions generated by each cell preparation was measured 48 h post-infection. As expected, ectopic expression of the 10 bovine CD46 isoforms rendered the PK15 cells permissive to BVDV, as attested by the 100,000-fold greater recovery of virions from these cells than from non-transfected cells. This permissivity increase was significantly lower (-33%, P<0.001) when the canonical CCP1 was replaced with the variant most frequent in zebus, suggesting positive or negative selection of this allele in the latter and in the former, respectively. The predicted secondary structure of this variant suggests that the measured loss of function is due to the disappearance of one of the two beta sheets constituting the BVDV attachment platform. On the other hand we showed that for a given CCP1, the titer recovered at 48 hpi also depended on the nature of the CD46 cytoplasmic domain (P<0.001). This result implies that virus binding generates a cytoplasmic-tail-dependent outside-in signal that determines permissivity to BVDV.

This analysis focused on long-term cross-reactive immunogenicity against nonvaccine human papillomavirus (HPV) types 31 and 45 following 2 doses of AS04-adjuvanted HPV-16/18 vaccine in girls aged 9–14 years or following 3 doses in women aged 15–25 years, for up to 3 years (HPV-070 study) and up to 5 years (HPV-048 study) after the first vaccination. Both schedules elicited antibodies against HPV-31 and HPV-45 up to 5 years after first dose. The antibody concentration was similar in young girls as compared to women. Specific CD4+ T-cell and B-cell responses to HPV-31 and HPV-45 at month 36 were similar across groups. Clinical trials registration: NCT01381575 and NCT00541970.

No abstract

Mx proteins are interferon-induced members of the dynamin superfamily of large guanosine triphosphatases. These proteins have attracted much attention because some display antiviral activity against pathogenic RNA viruses, such as members of the orthomyxoviridae, bunyaviridae, and rhabdoviridae families. Among the diverse mammalian Mx proteins examined so far, we have recently demonstrated in vitro that the Bos taurus isoform 1 (boMx1) is endowed with exceptional anti-rabies-virus activity. This finding has prompted us to seek an appropriate in vivo model for confirming and evaluating gene therapy strategies. Using a BAC transgene, we have generated transgenic mouse lines expressing the antiviral boMx1 protein and boMx2 proteins under the control of their natural promoter and short- and long-range regulatory elements. Expressed boMx1 and boMx2 are correctly assembled, as deduced from mRNA sequencing and western blotting. Poly-I/C-subordinated expression of boMx1 was detected in various organs by immunohistochemistry, and transgenic lines were readily classified as high- or low-expression lines on the basis of tissue boMx1 concentrations measured by ELISA. Poly-I/C-induced Madin-Darby bovine kidney cells, bovine turbinate cells, and cultured cells from high-expression line of transgenic mice were found to contain about the same concentration of boMx1, suggesting that this protein is produced at near-physiological levels. Furthermore, insertion of the bovine Mx system rendered transgenic mice resistant to vesicular-stomatitis-virus-associated morbidity and mortality, and embryonic fibroblasts derived from high-expression transgenic mice were far less permissive to the virus. These results demonstrate that the Bos taurus Mx system is a powerful anti-VSV agent in vivo and suggest that the transgenic mouse lines generated here constitute a good model for studying in vivo the various antiviral functions-known and yet to be discovered-exerted by bovine Mx proteins, with priority emphasis on the antirabic function of boMx1.