Treatment with the interleukin-17A-blocking antibody secukinumab does not interfere with the efficacy of influenza and meningococcal vaccinations in healthy subjects: results of an open-label, parallel-group, randomized single-center study.

Our objective was to evaluate the efficacy of influenza and meningococcal vaccinations in healthy subjects exposed to the anti-interleukin-17A (IL-17A) monoclonal antibody (MAb) secukinumab. We used an open-label, parallel-group, randomized single-center study of 50 healthy subjects. Subjects received a single 150-mg dose of secukinumab or no treatment, followed by vaccination with inactivated trivalent subunit influenza virus and conjugate group C meningococcal vaccine (Agrippal and Menjugate, respectively) 2 weeks later. Primary efficacy variables were responses of ≥4-fold increases in antibody titer (hemagglutination inhibition [HI; for influenza virus] and serum bactericidal assay [SBA; for Neisseria meningitides]) for meningococcus and influenza (at least two out of three serotypes), both at 4 weeks postvaccination. All subjects randomized to secukinumab (n = 25) or the control (n = 25) completed the study. Antibody responses to vaccinations measured at 4 weeks were comparable in both groups, with ≥4-fold increased responses following influenza virus vaccination of 20/25 (80%) for both groups and following meningococcal vaccination of 19/25 (76%) for the secukinumab group and 18/25 (72%) for the control group. Differences between groups were 0% (90% confidence intervals [CI], 19 and 19%) and 4% (90% CI, 16 and 24%) for influenza virus and meningococcal vaccines, respectively. Antibody responses were comparable between the 2 groups at different time points. Headache was the most frequently reported adverse effect. No deaths or serious adverse events were reported. Blockade of IL-17A by secukinumab does not appear to interfere with efficacy of influenza and meningococcal vaccinations, as assessed by the achievement of protective antibody levels. A protective (≥4-fold) immune response to both vaccinations at 4 weeks was achieved in 80 and 76% of subjects exposed to secukinumab and the control, respectively.

Impact of prior or concomitant seasonal influenza vaccination on MF59-adjuvanted H1N1v vaccine (Focetria) in adult and elderly subjects.

BACKGROUND: When H1N1v vaccines become widely available, most elderly subjects will have already received their seasonal influenza vaccination. Adults seeking H1N1v vaccination may be offered seasonal vaccine as well. We investigated prior seasonal vaccination in adult and elderly subjects, and concomitant vaccination with seasonal vaccine in adults, on the tolerability and immunogenicity of the Novartis MF59-adjuvanted H1N1v vaccine, Focetria. METHODS: A total of 264 adult (four groups) and 154 elderly (three groups) subjects were enrolled. The licensure study cohorts for plain (Agrippal) and MF59-adjuvanted (Fluad) 2009-2010 seasonal vaccines were invited to receive Focetria 3 months later, with seasonal vaccine-naïve controls, and adults who received Focteria and seasonal vaccine concomitantly. Immunogenicity of all vaccines was assessed by haemagglutination inhibition on Days 1 and 22, safety and reactogenicity were monitored using patient diaries. RESULTS: All adult and elderly groups met all the European CHMP licensing criteria for H1N1v, as did adults receiving concomitant seasonal vaccine for the three seasonal strains. Vaccines were generally well tolerated, causing no SAEs, and profiles typical of MF59-adjuvanted vaccines. Reactions were mainly mild or moderate and transient, and unaffected by prior or concomitant seasonal vaccination except for elderly subjects previously given MF59-adjuvanted seasonal vaccine, whose reaction rates to Focetria were about half those seen in groups receiving their first MF59 vaccine. CONCLUSION: One dose of MF59-adjuvanted H1N1v vaccine met the licensure criteria for adult and elderly subjects 3 months after seasonal vaccination, or concomitantly with seasonal vaccine in adults, without impacting the tolerability or immunogenicity of either vaccine, thus facilitating mass influenza immunisation campaigns.

In vitro reconstitution of the myxochelin biosynthetic machinery of Stigmatella aurantiaca Sg a15: Biochemical characterization of a reductive release mechanism from nonribosomal peptide synthetases.

Microorganisms produce iron-chelating compounds to sequester the iron essential for growth from the environment. Many of these compounds are biosynthesized by nonribosomal peptide synthetases, some in cooperation with polyketide synthases. Myxochelins are produced by the myxobacterium Stigmatella aurantiaca Sg a15, and the corresponding gene cluster was cloned recently. We have undertaken to express heterologously the myxochelin biosynthetic machinery in Escherichia coli. To activate the involved proteins posttranslationally, they were coexpressed with the phosphopantetheinyltransferase MtaA from the myxothiazol biosynthetic gene cluster. Phosphopantetheinylation of the carrier proteins could be verified by protein mass analysis. Six active domains in proteins MxcE, MxcF, and MxcG are capable of assembling myxochelin from ATP, NAD(P)H, lysine, and 2,3-dihydroxybenzoic acid in vitro. This fact demonstrates that the condensation domain of MxcG performs two condensation reactions, creating the aryl-capped alpha-amide and the aryl-capped gamma-amide of the molecule. A previously unknown type of reductive release is performed by the reduction domain of MxcG, which alternatively uses NADPH and NADH to set free the peptidyl-carrier protein-bound thioester as an aldehyde and further reduces it to the alcohol structure that can be found in myxochelin A. This type of reductive release seems to be a general mechanism in polyketide and nonribosomal peptide biosynthesis, because several systems with C-terminal similarity to the reductase domain of MxcG can be found in the databases. Alternatively, the aldehyde can be transaminated, giving rise to a terminal amine.

The mtaA gene of the myxothiazol biosynthetic gene cluster from Stigmatella aurantiaca DW4/3-1 encodes a phosphopantetheinyl transferase that activates polyketide synthases and polypeptide synthetases.

Myxothiazol is synthesized by the myxobacterium Stigmatella aurantiaca DW4/3-1 via a combined polyketide synthase/polypeptide synthetase. The biosynthesis of this secondary metabolite is also dependent on the gene product of mtaA. The deduced amino acid sequence of mtaA shows similarity to 4'-phosphopantetheinyl transferases (4'-PP transferase). This points to an enzyme activity that converts inactive forms of the acyl carrier protein domains of polyketide synthetases (PKSs) and/or the peptidyl carrier protein domains of nonribosomal polypeptide synthetases (NRPSs) of the myxothiazol synthetase complex to their corresponding holo-forms. Heterologous co-expression of MtaA with an acyl carrier protein domain of the myxothiazol synthetase was performed in Escherichia coli. The proposed function as a 4'-PP transferase was confirmed and emphasizes the significance of MtaA for the formation of a catalytically active myxothiazol synthetase complex. Additionally, it is shown that MtaA has a relaxed substrate specificity: it processes an aryl carrier protein domain derived from the enterobactin synthetase of E. coli (ArCP) as well as a peptidyl carrier protein domain from a polypeptide synthetase of yet unknown function from Sorangium cellulosum. Therefore, MtaA should be a useful tool for activating heterologously expressed PKS and NRPS systems.

Clustering of isochorismate synthase genes menF and entC and channeling of isochorismate in Escherichia coli.

There are two isochorismate synthase genes entC and menF in Escherichia coli. They encode enzymes (isochorismate synthase, EC 5.4.99.6) which reversibly synthesize isochorismic acid from chorismic acid. The genes share a 24.2% identity but are differently regulated. Activity of the MenF isochorismate synthase is significantly increased under anaerobic conditions whereas the activity of the EntC isochorismate synthase is greatly stimulated during growth in an iron deficient medium. Isochorismic acid synthesized by EntC is mainly channeled into enterobactin synthesis whereas isochorismic acid synthesized by MenF is mainly channeled into menaquinone synthesis. When menF or entC were separately placed onto overexpression plasmids and the plasmids introduced into a menF(-)/entC(-) double mutant in two separate experiments, the isochorismate formed was fed into both, the menaquinone and the enterobactin pathway. Moreover, in spite of a high isochorismate synthase activity menaquinone and enterobactin formation were not fully restored, indicating that isochorismate was lost by diffusion. Thus, under these conditions channeling was not observed. We conclude that in E. coli the chromosomal position of both menF and entC in their respective clusters is a prerequisite for channeling of isochorismate in both pathways.