Generation of a Universal Human Complement Source by Large-Scale Depletion of IgG and IgM from Pooled Human Plasma.

Complement is a key component of functional immunological assays used to evaluate vaccine-mediated immunity to a range of bacterial and viral pathogens. However, standardization of these assays is complicated due to the availability of a human complement source that lacks existing antibodies acquired either through vaccination or natural circulation of the pathogen of interest. We have developed a method for depleting both IgG and IgM in 200 mL batches from pooled hirudin-derived human plasma by sequential affinity chromatography using a Protein G Sepharose column followed by POROS™ CaptureSelect™ IgM Affinity resin.

Structural insight into the role of the PAS domainfor signal transduction in sensor-kinase BvgS.

The two-component system BvgAS controls the virulence regulon in BvgS is the prototype of a family of sensor histidine-kinases harboring periplasmic Venus flytrap (VFT) domains. The VFT domains are connected to the cytoplasmic kinase moiety by helical linkers separated by a Per-ARNT-Sim (PAS) domain. Antagonism between the two linkers, as one forms a coiled coil when the other is dynamic and vice versa, regulates BvgS activity.

Acellular Pertussis Vaccines Induce Anti-pertactin Bactericidal Antibodies Which Drives the Emergence of Pertactin-Negative Strains.

Despite high vaccination coverage, the causative agent of whooping cough is still a health concern worldwide. A resurgence of pertussis cases has been reported, particularly in countries using acellular vaccines with waning immunity and pathogen adaptation thought to be responsible. A better understanding of protective immune responses is needed for the development of improved vaccines.

Distinct virulence ranges for infection of mice by Bordetella pertussis revealed by engineering of the sensor-kinase BvgS.

The whooping cough agent Bordetella pertussis coordinately regulates the expression of its virulence factors with the two-component system BvgAS. In laboratory conditions, specific chemical modulators are used to trigger phenotypic modulation of B. pertussis from its default virulent Bvg+ phase to avirulent Bvg- or intermediate Bvgi phases, in which no virulence factors or only a subset of them are produced, respectively.

Coiled-Coil Antagonism Regulates Activity of Venus Flytrap-Domain-Containing Sensor Kinases of the BvgS Family.

controls the expression of its virulence regulon through the two-component system BvgAS. BvgS is a prototype for a family of multidomain sensor kinases. In BvgS, helical linkers connect periplasmic Venus flytrap (VFT) perception domains to a cytoplasmic Per-Arnt-Sim (PAS) domain and the PAS domain to the dimerization/histidine phosphotransfer (DHp) domain of the kinase.

Conformational Changes of an Interdomain Linker Mediate Mechanical Signal Transmission in Sensor Kinase BvgS.

The whooping cough agent, , controls the expression of its large virulence regulon in a coordinated manner through the two-component system BvgAS. BvgS is a dimeric, multidomain sensor kinase. Each monomer comprises, in succession, tandem periplasmic Venus flytrap (VFT) domains, a transmembrane segment, a cytoplasmic Per-Arnt-Sim (PAS) domain, a kinase module, and additional phosphorelay domains.

Characterization of a Bvg-regulated fatty acid methyl-transferase in Bordetella pertussis.

The whooping cough agent Bordetella pertussis controls the expression of its large virulence regulon in a coordinated manner through the two-component signal transduction system BvgAS. In addition to the genes coding for bona fide virulence factors, the Bvg regulon comprises genes of unknown function. In this work, we characterized a new Bvg-activated gene called BP2936.

Translocation path of a substrate protein through its Omp85 transporter.

TpsB proteins are Omp85 superfamily members that mediate protein translocation across the outer membrane of Gram-negative bacteria. Omp85 transporters are composed of N-terminal POTRA domains and a C-terminal transmembrane β-barrel. In this work, we track the in vivo secretion path of the Bordetella pertussis filamentous haemagglutinin (FHA), the substrate of the model TpsB transporter FhaC, using site-specific crosslinking.