Publications by authors named "Richey S"

Current COVID-19 vaccines are largely limited in their ability to induce broad, durable immunity against emerging viral variants. Design and development of improved vaccines utilizing existing platforms requires an in-depth understanding of the antigenic and immunogenic properties of available vaccines. Here we examined the antigenicity of two of the original COVID-19 vaccines, mRNA-1273 and NVX-CoV2373, by electron microscopy-based polyclonal epitope mapping (EMPEM) of serum from immunized non-human primates (NHPs) and clinical trial donors.

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During infection, the fusion peptide (FP) of HIV envelope glycoprotein (Env) serves a central role in viral fusion with the host cell. As such, the FP is highly conserved and therefore an attractive epitope for vaccine design. Here, we describe a vaccination study in non-human primates (NHPs) where glycan deletions were made on soluble HIV Env to increase FP epitope exposure.

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Cellular and molecular characterization of immune responses elicited by influenza virus infection and seasonal vaccination have informed efforts to improve vaccine efficacy, breadth, and longevity. Here, we use negative stain electron microscopy polyclonal epitope mapping (nsEMPEM) to structurally characterize the humoral IgG antibody responses to hemagglutinin (HA) from human patients vaccinated with a seasonal quadrivalent flu vaccine or infected with influenza A viruses. Our data show that both vaccinated and infected patients had humoral IgGs targeting highly conserved regions on both H1 and H3 subtype HAs, including the stem and anchor, which are targets for universal influenza vaccine design.

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Germline-targeting (GT) HIV vaccine strategies are predicated on deriving broadly neutralizing antibodies (bnAbs) through multiple boost immunogens. However, as the recruitment of memory B cells (MBCs) to germinal centers (GCs) is inefficient and may be derailed by serum antibody-induced epitope masking, driving further B cell receptor (BCR) modification in GC-experienced B cells after boosting poses a challenge. Using humanized immunoglobulin knockin mice, we found that GT protein trimer immunogen N332-GT5 could prime inferred-germline precursors to the V3-glycan-targeted bnAb BG18 and that B cells primed by N332-GT5 were effectively boosted by either of two novel protein immunogens designed to have minimum cross-reactivity with the off-target V1-binding responses.

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Influenza A virus subtype H2N2, which caused the 1957 influenza pandemic, remains a global threat. A recent phase 1 clinical trial investigating a ferritin nanoparticle vaccine displaying H2 hemagglutinin (HA) in H2-naive and H2-exposed adults enabled us to perform comprehensive structural and biochemical characterization of immune memory on the breadth and diversity of the polyclonal serum antibody response elicited. We temporally map the epitopes targeted by serum antibodies after vaccine prime and boost, revealing that previous H2 exposure results in higher responses to the variable HA head domain.

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Influenza A virus subtype H2N2, which caused the 1957 influenza pandemic, remains a global threat. A recent phase I clinical trial investigating a ferritin nanoparticle displaying H2 hemagglutinin in H2-naïve and H2-exposed adults. Therefore, we could perform comprehensive structural and biochemical characterization of immune memory on the breadth and diversity of the polyclonal serum antibody response elicited after H2 vaccination.

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Electron microscopy-based polyclonal epitope mapping (EMPEM) can delineate epitope specificities of serum antibodies to a given antigen following vaccination or infection. Here, we present a protocol for the EMPEM method for rapid high-throughput assessment of antibody responses to glycoprotein antigens in vaccination and infection studies. We describe steps for antibody isolation and digestion, antigen complex and purification, and electron microscope imaging.

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Article Synopsis
  • The study investigates the persistence of germinal centre B cells for over 6 months following HIV Env protein immunization in rhesus monkeys, showing a significant increase in B cells at week 10 compared to conventional methods.
  • Continuous somatic hypermutation of the B cells during the 29-week period indicates ongoing selection pressure, leading to a substantial boost in HIV-neutralizing antibodies after a single booster.
  • Findings suggest that a longer priming strategy can enhance immune memory, allowing B cells to better recognize challenging antigens, potentially improving vaccine efficacy for difficult targets.
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The widespread CBASS (cyclic oligonucleotide-based anti-phage signaling system) immune systems in bacteria protect their hosts from bacteriophage infection by triggering programmed cell death. CBASS systems all encode a cyclic oligonucleotide synthase related to eukaryotic cGAS but use diverse regulators and effector proteins including nucleases, phospholipases, and membrane-disrupting proteins to effect cell death. Cap18 is a predicted 3'-5' exonuclease associated with hundreds of CBASS systems, whose structure, biochemical activities, and biological roles remain unknown.

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Broadly neutralizing antibodies that target epitopes of haemagglutinin on the influenza virus have the potential to provide near universal protection against influenza virus infection. However, viral mutants that escape broadly neutralizing antibodies have been reported. The identification of broadly neutralizing antibody classes that can neutralize viral escape mutants is critical for universal influenza virus vaccine design.

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Rationally designed protein subunit vaccines are being developed for a variety of viruses including influenza, RSV, SARS-CoV-2, and HIV. These vaccines are based on stabilized versions of the primary targets of neutralizing antibodies on the viral surface, namely, viral fusion glycoproteins. While these immunogens display the epitopes of potent neutralizing antibodies, they also present epitopes recognized by non-neutralizing or weakly neutralizing ("off-target") antibodies.

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Evaluating the structure-function relationship of viral envelope (Env) evolution and the development of broadly cross-neutralizing antibodies (bnAbs) in natural infection can inform rational immunogen design. In the present study, we examined the magnitude and specificity of autologous neutralizing antibodies induced in rabbits by a novel HIV-1 clade C Env protein (1PGE-THIVC) vis-à-vis those developed in an elite neutralizer from whom the env sequence was obtained that was used to prepare the soluble Env protein. The novel 1PGE-THIVC Env trimer displayed a native like pre-fusion closed conformation in solution as determined by small angle X-ray scattering (SAXS) and negative stain electron microscopy (EM).

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Objectives: Clinical assessment of persons with dementia should include potential causes of behavioral problems, including pain, depression, and caregiver-patient relationship quality. Many validated assessment tools are available; however, a brief screening tool is needed, as administering a battery of instruments is impractical in most clinical settings. We evaluated (a) the construct validity of brief screens for pain, depression, and relationship strain by examining their associations with validated measures and medication use and (b) the predictive validity of each screen and the screens as a set by examining their associations with frequency of disruptive behaviors.

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Rationally designed protein subunit vaccines are being developed for a variety of viruses including influenza, RSV, SARS-CoV-2 and HIV. These vaccines are based on stabilized versions of the primary targets of neutralizing antibodies on the viral surface, namely viral fusion glycoproteins. While these immunogens display the epitopes of potent neutralizing antibodies, they also present epitopes recognized by non or weakly neutralizing ("off-target") antibodies.

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The NCCN Guidelines for Prostate Cancer address staging and risk assessment after a prostate cancer diagnosis and include management options for localized, regional, and metastatic disease. Recommendations for disease monitoring and treatment of recurrent disease are also included. The NCCN Prostate Cancer Panel meets annually to reevaluate and update their recommendations based on new clinical data and input from within NCCN Member Institutions and from external entities.

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Novel influenza A virus (IAV) strains elicit recall immune responses to conserved epitopes, making them favorable antigenic choices for universal influenza virus vaccines. Evaluating these immunogens requires a thorough understanding of the antigenic sites targeted by the polyclonal antibody (pAb) response, which single-particle electron microscopy (EM) can sensitively detect. In this study, we employ EM polyclonal epitope mapping (EMPEM) to extensively characterize the pAb response to hemagglutinin (HA) after H5N1 immunization in humans.

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Objectives: We examined associations among three measures of caregiver experiences (i.e., positive aspects of caring [PAC], caregiver burden, and mutuality) in 228 dyads involving persons with dementia (PWD) and their informal caregivers.

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Influenza viruses remain a major public health threat. Seasonal influenza vaccination in humans primarily stimulates pre-existing memory B cells, which differentiate into a transient wave of circulating antibody-secreting plasmablasts. This recall response contributes to 'original antigenic sin'-the selective increase of antibody species elicited by previous exposures to influenza virus antigens.

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Objective: International appeals call for interventions to prevent aggression and other behavioral problems in individuals with dementia (IWD). Aggression Prevention Training (APT), based on intervening in three contributors to development of aggression (IWD pain, IWD depression, and caregiver-IWD relationship problems) aims to reduce incidence of aggression in IWD over 1 year.

Design: Randomized, controlled trial.

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Background: People with dementia experience a decline in language skills required to self-report pain; researchers thus recommend the use of nonverbal behaviors to assess pain. Although multiple instruments exist for assessing nonverbal pain behaviors, psychometric data are lacking for African American nursing home residents with dementia.

Aims And Design: The purpose of this methodological study was to describe the development and testing of the Pain Assessment Tool in Cognitively Impaired Elders (PATCIE) in African American and Caucasian nursing home residents with dementia.

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Purpose: This open-label, phase Ib, dose-escalation, and dose-expansion study (NCT01862081) evaluated taselisib with a taxane in locally advanced or metastatic breast cancer (BC) and/or non-small cell lung cancer (NSCLC).

Methods: Patients received taselisib (2-6 mg tablet or 3-6 mg capsule) plus docetaxel or paclitaxel. Primary endpoints were safety, dose-limiting toxicities, maximum tolerated dose, and identification of a recommended phase II dose.

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Anomalous origin of the right coronary artery from the pulmonary artery is an extremely rare condition with an uncertain natural history. Here, we present an otherwise healthy active duty service member who was found to have anomalous right coronary artery arising from the pulmonary artery as an incidental discovery during a workup for possible pulmonary embolus. We describe a preoperative workup which showed dilation of the coronaries and evidence of ischemia.

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The NCCN Guidelines for Prostate Cancer include recommendations regarding diagnosis, risk stratification and workup, treatment options for localized disease, and management of recurrent and advanced disease for clinicians who treat patients with prostate cancer. The portions of the guidelines included herein focus on the roles of germline and somatic genetic testing, risk stratification with nomograms and tumor multigene molecular testing, androgen deprivation therapy, secondary hormonal therapy, chemotherapy, and immunotherapy in patients with prostate cancer.

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We describe a case of type A aortic dissection in a 25-year-old woman who had undergone a Ross procedure for aortic valve endocarditis 13 years previously. She was pregnant and noted to have significant enlargement of the aortic root during the latter portion of the third trimester of her pregnancy. An echocardiogram after delivery demonstrated new aortic valve insufficiency in addition to an aortic root diameter of 6.

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