A broad antibody class engages the influenza virus hemagglutinin head at its stem interface

Influenza infection and vaccination impart strain-specific immunity that fails to protect against both seasonal antigenic variants and the next pandemic. However, antibodies directed to conserved sites can confer broad protection. We identify and characterize a class of human antibodies that engage a previously undescribed, conserved, epitope on the influenza hemagglutinin protein (HA). Prototype antibody S8V1-157 binds at the normally occluded interface between the HA head and stem. Antibodies to this HA head-stem interface epitope are non-neutralizing in vitro but protect against lethal infection in mice. Their breadth of binding extends across most influenza A serotypes and seasonal human variants. Antibodies to the head-stem interface epitope are present at low frequency in the memory B cell populations of multiple donors. The immunogenicity of the epitope warrants its consideration for inclusion in improved or "universal" influenza vaccines.

A new class of antibodies that overcomes a steric barrier to cross-group neutralization of influenza viruses

Antibody titers that inhibit the influenza virus hemagglutinin (HA) from engaging its receptor are the accepted correlate of protection from infection. Many potent antibodies with broad, intra-subtype specificity bind HA at the receptor binding site (RBS). One barrier to broad H1-H3 cross-subtype neutralization is an insertion (133a) between positions 133 and 134 on the rim of the H1 HA RBS. We describe here a class of antibodies that overcomes this barrier. These genetically unrestricted antibodies are abundant in the human B cell memory compartment. Analysis of the affinities of selected members of this class for historical H1 and H3 isolates suggest that they were elicited by H3 exposure and broadened or diverted by later exposure(s) to H1 HA. RBS mutations in egg-adapted vaccine strains cause the new H1 specificity of these antibodies to depend on the egg adaptation. The results suggest that suitable immunogens might elicit 133a-independent, H1-H3 cross neutralization by RBS-directed antibodies.

Structural basis of paralog-specific KDM2A/B nucleosome recognition

The nucleosome acidic patch is a major interaction hub for chromatin, providing a platform for enzymes to dock and orient for nucleosome-targeted activities. To define the molecular basis of acidic patch recognition proteome wide, we performed an amino acid resolution acidic patch interactome screen. We discovered that the histone H3 lysine 36 (H3K36) demethylase KDM2A, but not its closely related paralog, KDM2B, requires the acidic patch for nucleosome binding. Despite fundamental roles in transcriptional repression in health and disease, the molecular mechanisms governing nucleosome substrate specificity of KDM2A/B, or any related JumonjiC (JmjC) domain lysine demethylase, remain unclear. We used a covalent conjugate between H3K36 and a demethylase inhibitor to solve cryogenic electron microscopy structures of KDM2A and KDM2B trapped in action on a nucleosome substrate. Our structures show that KDM2-nucleosome binding is paralog specific and facilitated by dynamic nucleosomal DNA unwrapping and histone charge shielding that mobilize the H3K36 sequence for demethylation.

Time Resolved-Fluorescence Resonance Energy Transfer platform for quantitative nucleosome binding and footprinting

Quantitative analysis of chromatin protein-nucleosome interactions is essential to understand regulation of genome-templated processes. However, current methods to measure nucleosome interactions are limited by low throughput, low signal-to-noise, and/or the requirement for specialized instrumentation. Here, we report a Lanthanide Chelate Excite Time-Resolved Fluorescence Resonance Energy Transfer (LANCE TR-FRET) assay to efficiently quantify chromatin protein-nucleosome interactions. The system makes use of commercially available reagents, offers robust signal-to-noise with minimal sample requirements, uses a conventional fluorescence microplate reader, and can be adapted for high-throughput workflows. We determined the nucleosome-binding affinities of several chromatin proteins and complexes, which are consistent with measurements obtained through orthogonal biophysical methods. We also developed a TR-FRET competition assay for high-resolution footprinting of chromatin protein-nucleosome interactions. Finally, we set up a TR-FRET competition assay using the LANA peptide to quantitate nucleosome acidic patch binding. We applied this assay to establish a proof-of-principle for regulation of nucleosome acidic patch binding by methylation of chromatin protein arginine anchors. Overall, our TR-FRET assays allow facile, high-throughput quantification of chromatin interactions and are poised to complement mechanistic chromatin biochemistry, structural biology, and drug discovery programs.

"Teach us to pray": pastoral care of the new nursing home resident

Discusses the many traumatic factors associated with leaving and entering a nursing home. Points to the significance of personal prayer in making such transitions, and offers specific guidelines for pastoral caregivers as they seek to meet the special needs of nursing home residents.

A protocol for magnetic resonance imaging of the temporomandibular joints

The complex concepts and procedures of magnetic resonance imaging (MRI) are unfamiliar to many dentists. Similarly, many radiologists lack understanding of the clinical requirements of the dentist for accurate assessment of TMJ abnormalities. Thus, TMJ imaging procedures may be inadequate or incomplete, may vary from facility to facility, and sometimes from patient to patient in a given facility. A protocol for TMJ imaging is presented which meets dental requirements and is rapidly performed in the MRI facility. The protocol may be copied and attached to the prescription to the imaging center. It may be modified or expanded to accommodate specific patient requirements or equipment performance.

Initial TMJ disk recapture with anterior repositioning appliances and relation to dental history

Fifty-eight consecutive patients in a referral based practice seeking treatment for complex chronic painful temporomandibular joint (TMJ) disease were enrolled in a prospective study to assess the recapture of displaced disks by anterior repositioning appliances (ARA) and the improvement in disk position in those disks that did not fully recapture. After standard clinical workup, including assessment of pain, maxillary and mandibular ARAs were constructed which repositioned condyles to the Gelb 4/7 position as determined by cephalometrically-corrected linear tomograms. Multi-planar magnetic resonance imaging (MRI) was performed immediately before and after insertion of the mandibular ARA, showing three-dimensional recapture of disks in 85% and improved disk position in 6% of reducing displacements. Disk position was improved in 28% of nonreducing joints, but none were totally recaptured. Recapture or improvement was achieved in 91% of reducing, 28% of nonreducing, and 63% of all joints with internal derangements. Initial disk position, reduction on opening and recapture by ARA were statistically independent of patient age, number of teeth missing, number of third molars missing, malocclusion (Angle's class), overjet, overbite, prosthetic appliances, and previous orthodontic treatment. It was concluded that ARA therapy provided effective recapture of displaced TMJ disks that reduce upon mouth opening. In this population of patients with chronic TMJ pain, previous dental treatment had no statistically significant effect on the incidence of internal derangement or on disk recapture by ARA therapy. There was no evidence of adverse effect from orthodontics, prosthetics, or any other dental care.

Recapture of temporomandibular joint disks using anterior repositioning appliances: an MRI study

Thirty consecutive patients seeking treatment for painful temporomandibular joint (TMJ) disease were enrolled in a prospective study to assess the relationship between the recapture of displaced disks by anterior repositioning appliances (ARA) and the relief of symptoms. After standard clinical workup including assessment of pain, maxillary and mandibular ARAs were constructed that repositioned condyles to the Gelb 4/7 position. Magnetic resonance imaging (MRI) was performed before and immediately after the insertion of ARAs. Initial MRI findings showed 26 joints with reducing disk displacements in 17 patients, seven partially-reducing joints in four patients, 14 nonreducing joints in 11 patients, and 13 normal joints in eight patients. Postinsertion MRI showed recapture of disks in 25 of 26 reducing displacements (96%), but no recapture in partially-reducing or nonreducing joints. All but one of the normal joints remained unchanged. Pain assessment showed significant relief of symptoms in all three categories. The degree of pain relief was significantly greater in recaptured reducing disks than the other categories (p < 0.05). ARA therapy provides effective pain relief regardless of disk status, although a greater degree of relief may be achieved in recaptured reducing internal derangements.