Retreatment with HBV siRNA Results in Additional Reduction in HBV Antigenemia and Immune Stimulation in the AAV-HBV Mouse Model

BACKGROUND AND AIMS

Treatment with siRNAs that target HBV has demonstrated robust declines in HBV antigens. This effect is also observed in the AAV-HBV mouse model, which was used to investigate if two cycles of GalNAc-HBV-siRNA treatment could induce deeper declines in HBsAg levels or prevent rebound, and to provide insights into the liver immune microenvironment.

METHODS

C57Bl/6 mice were transduced with one of two different titers of AAV-HBV for 28 days, resulting in stable levels of HBsAg of about 103 or 105 IU/mL. Mice were treated for 12 weeks (four doses q3wk) per cycle with 3 mg/kg of siRNA-targeting HBV or an irrelevant sequence either once (single treatment) or twice (retreatment) with an 8-week treatment pause in between. Blood was collected to evaluate viral parameters. Nine weeks after the last treatment, liver samples were collected to perform phenotyping, bulk RNA-sequencing, and immunohistochemistry.

RESULTS

Independent of HBsAg baseline levels, treatment with HBV-siRNA induced a rapid decline in HBsAg levels, which then plateaued before gradually rebounding 12 weeks after treatment stopped. A second cycle of HBV-siRNA treatment induced a further decline in HBsAg levels in serum and the liver, reaching undetectable levels and preventing rebound when baseline levels were 103 IU/mL. This was accompanied with a significant increase in inflammatory macrophages in the liver and significant upregulation of regulatory T-cells and T-cells expressing immune checkpoint receptors.

CONCLUSIONS

Retreatment induced an additional decline in HBsAg levels, reaching undetectable levels when baseline HBsAg levels were 3log10 or less. This correlated with T-cell activation and upregulation of Trem2.

Sustained Liver HBsAg Loss and Clonal T- and B-Cell Expansion upon Therapeutic DNA Vaccination Require Low HBsAg Levels

BACKGROUND

Suppression of HBV DNA, inhibition of HBV surface (HBsAg) production and therapeutic vaccination to reverse HBV-specific T-cell exhaustion in chronic HBV patients are likely required to achieve a functional cure. In the AAV-HBV mouse model, therapeutic vaccination can be effective in clearing HBV when HBsAg levels are low. Using a single-cell approach, we investigated the liver immune environment with different levels of HBsAg and sustained HBsAg loss through treatment with a GalNAc-HBV-siRNA followed by therapeutic vaccination.

METHODS

AAV-HBV-transduced C57BL/6 mice were treated with GalNAc-HBV-siRNA to lower HBsAg levels and then vaccinated using a DNA vaccine. We used single-cell RNA and V(D)J sequencing to understand liver immune microenvironment changes.

RESULTS

GalNAc-HBV-siRNA, followed by therapeutic vaccination, achieved sustained HBsAg loss in all mice. This was accompanied by CD4 follicular helper T-cell induction, polyclonal activation of CD8 T cells and clonal expansion of plasma cells that were responsible for antibody production.

CONCLUSIONS

This study provides novel insights into liver immune changes at the single-cell level, highlighting the correlation between induced reduction of HBsAg levels and clonal expansion of CD4, CD8 T cells and plasma cells in the liver upon HBV siRNA and subsequent therapeutic vaccination.

A single, oral dose of the TLR7 agonist JNJ-64794964 induces transcriptomic and phenotypic changes in peripheral immune cells in healthy adults

BACKGROUND

Chronic hepatitis B (CHB) is responsible for major disease burden worldwide. However, the number of available therapies is limited; cure remains an elusive goal. JNJ-64794964 (JNJ-4964) is an oral toll-like receptor-7 (TLR7) agonist being evaluated for the treatment of CHB. Here, we investigated the capacity of JNJ-4964 to induce transcriptomic and immune cell changes in peripheral blood in healthy volunteers.

METHODS

Peripheral blood was collected in the JNJ-4964 first-in-human phase 1 trial at multiple time points to assess transcriptomics and changes in frequency and phenotype of peripheral-blood mononuclear cells. Correlation of changes to JNJ-4964 exposure (C_max) and changes in cytokine levels (C-X-C motif chemokine ligand 10 [CXCL10] and interferon alpha [IFN-α]) were evaluated.

RESULTS

Fifty-nine genes, mainly interferon-stimulated genes, were up-regulated between 6 hours and 5 days after JNJ-4964 administration. JNJ-4964 increased frequencies of CD69, CD134, CD137, and/or CD253-expressing natural killer (NK) cells, indicative of NK cell activation. These changes correlated with C_max, increase of CXCL10, and induction of IFN-α and were observed at IFN-α levels that are associated with no/acceptable flu-like adverse events. JNJ-4964 administration resulted in increased frequencies of CD86-expressing B cells, indicative of B-cell activation. These changes were predominantly observed at high IFN-α levels, which are associated with flu-like adverse events.

CONCLUSIONS

JNJ-4964 administration led to changes in transcriptional profiles and immune cell activation phenotype, particularly for NK cells and B cells. Together, these changes could represent a set of biomarkers for the characterization of the immune response in CHB patients receiving TLR7 agonists.

Follicular Regulatory T Cells Can Access the Germinal Center Independently of CXCR5

The germinal center (GC) response is critical for generating high-affinity humoral immunity and immunological memory, which forms the basis of successful immunization. Control of the GC response is thought to require follicular regulatory T (Tfr) cells, a subset of suppressive Foxp3⁺ regulatory T cells located within GCs. Relatively little is known about the exact role of Tfr cells within the GC and how they exert their suppressive function. A unique feature of Tfr cells is their reported CXCR5-dependent localization to the GC. Here, we show that the lack of CXCR5 on Foxp3⁺ regulatory T cells results in a reduced frequency, but not an absence, of GC-localized Tfr cells. This reduction in Tfr cells is not sufficient to alter the magnitude or output of the GC response. This demonstrates that additional, CXCR5-independent mechanisms facilitate Treg cell homing to the GC.

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CXCR5-deficient Tfr cells can migrate into the B cell follicle and the germinal center

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Absence of CXCR5 on Treg cells reduces the number of Tfr cells by half

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Halving Tfr cell numbers does not affect germinal center B cell or Tfh cell frequency

The adjuvant GLA-SE promotes human Tfh cell expansion and emergence of public TCRβ clonotypes

A rational strategy to achieve optimal vaccine responses is to potentiate Tfh cells and the germinal center response. This work shows the adjuvant GLA-SE enhances circulating Tfh cells and enduring antibody responses to a malaria vaccine in Tanzanian adults.

The generation of protective humoral immunity after vaccination relies on the productive interaction between antigen-specific B cells and T follicular helper (Tfh) cells. Despite the central role of Tfh cells in vaccine responses, there is currently no validated way to enhance their differentiation in humans. From paired human lymph node and blood samples, we identify a population of circulating Tfh cells that are transcriptionally and clonally similar to germinal center Tfh cells. In a clinical trial of vaccine formulations, circulating Tfh cells were expanded in Tanzanian volunteers when an experimental malaria vaccine was adjuvanted in GLA-SE but not when formulated in Alum. The GLA-SE–formulated peptide was associated with an increase in the extrafollicular antibody response, long-lived antibody production, and the emergence of public TCRβ clonotypes in circulating Tfh cells. We demonstrate that altering vaccine adjuvants is a rational approach for enhancing Tfh cells in humans, thereby supporting the long-lived humoral immunity that is required for effective vaccines.

Human blood Tfr cells are indicators of ongoing humoral activity not fully licensed with suppressive function

Germinal center (GC) responses are controlled by T follicular helper (Tfh) and T follicular regulatory (Tfr) cells and are crucial for the generation of high-affinity antibodies. Although the biology of human circulating and tissue Tfh cells has been established, the relationship between blood and tissue Tfr cells defined as CXCR5+Foxp3+ T cells remains elusive. We found that blood Tfr cells are increased in Sjögren syndrome, an autoimmune disease with ongoing GC reactions, especially in patients with high autoantibody titers, as well as in healthy individuals upon influenza vaccination. Although blood Tfr cells correlated with humoral responses, they lack full B cell-suppressive capacity, despite being able to suppress T cell proliferation. Blood Tfr cells have a naïve-like phenotype, although they are absent from human thymus or cord blood. We found that these cells were generated in peripheral lymphoid tissues before T-B interaction, as they are maintained in B cell-deficient patients. Therefore, blood CXCR5+Foxp3+ T cells in human pathology indicate ongoing humoral activity but are not fully competent circulating Tfr cells.

A novel Zap70 mutation with reduced protein stability demonstrates the rate-limiting threshold for Zap70 in T-cell receptor signalling

Loss of ζ-associated protein 70 (Zap70) results in severe immunodeficiency in humans and mice because of the critical role of Zap70 in T-cell receptor (TCR) signalling. Here we describe a novel mouse strain generated by N-ethyl-N-nitrosourea mutagenesis, with the reduced protein stability (rps) mutation in Zap70. The A243V rps mutation resulted in decreased Zap70 protein and a reduced duration of TCR-induced calcium responses, equivalent to that induced by a 50% decrease in catalytically active Zap70. The reduction of signalling through Zap70 was insufficient to substantially perturb thymic differentiation of conventional CD4 and CD8 T cells, although Foxp3(+) regulatory T cells demonstrated altered thymic production and peripheral homeostasis. Despite the mild phenotype, the Zap70(A243V) variant lies just above the functional threshold for TCR signalling competence, as T cells relying on only a single copy of the Zap70(rps) allele for TCR signalling demonstrated no intracellular calcium response to TCR stimulation. This addition to the Zap70 allelic series indicates that a rate-limiting threshold for Zap70 protein levels exists at which signalling capacity switches from nearly intact to effectively null.

Foxp3+ follicular regulatory T cells control the germinal center response

Follicular helper (T(FH)) cells provide crucial signals to germinal center B cells undergoing somatic hypermutation and selection that results in affinity maturation. Tight control of T(FH) numbers maintains self tolerance. We describe a population of Foxp3(+)Blimp-1(+)CD4(+) T cells constituting 10-25% of the CXCR5(high)PD-1(high)CD4(+) T cells found in the germinal center after immunization with protein antigens. These follicular regulatory T (T(FR)) cells share phenotypic characteristics with T(FH) and conventional Foxp3(+) regulatory T (T(reg)) cells yet are distinct from both. Similar to T(FH) cells, T(FR) cell development depends on Bcl-6, SLAM-associated protein (SAP), CD28 and B cells; however, T(FR) cells originate from thymic-derived Foxp3(+) precursors, not naive or T(FH) cells. T(FR) cells are suppressive in vitro and limit T(FH) cell and germinal center B cell numbers in vivo. In the absence of T(FR) cells, an outgrowth of non-antigen-specific B cells in germinal centers leads to fewer antigen-specific cells. Thus, the T(FH) differentiation pathway is co-opted by T(reg) cells to control the germinal center response.

Considering the nature of intersubjectivity within professional nursing

The notion of intersubjectivity raises fundamental epistemological and ontological questions concerning how individuals come to know one another and how that knowing affects action. Within the sphere of professional nursing, relationship, as an intersubjective process between individuals, constitutes an integral element of professional nursing practice. Understanding the notion of relationship in terms of an intersubjective process is frequently laden with difficulty due to the polarization of intersubjectivity within either a traditional scientific position or a human science perspective. Reconciliation of both ways of knowing, however, may allow nurses to bring forward a broader base and scope of information to appreciate the experience of others. This article examines some of the notions of intersubjectivity and proposes an alternative understanding.

Management of elder abuse in the emergency department

Emergency physicians are in an ideal position to diagnose and intervene in suspected cases of elder abuse. This article reviews domestic violence against the elderly, highlighting the risk factors for elder abuse, its prevalence, and related medicolegal issues. A special section on mistreatment of the elderly in long-term care facilities is included. In addition to the management of elderly abuse in the emergency department, possible future directions for improved detection of elder abuse or neglect are reviewed.

Reflection and nursing education

The notion of reflection has become a significant concept within nursing education. What is it? How is it learned/taught? How is it implemented in practice? This paper explores reflection as both a technique and a purposeful inter-subjective process. Some of the current theoretical underpinnings of reflection, with particular attention to a Heideggerian perspective, are examined. It is suggested that the Heideggerian notion of reflection as the integration of calculative and contemplative thinking is an effective way to consider the concept of reflection.

Financial implications of noninvasive positive pressure ventilation (NPPV)

Noninvasive positive pressure ventilation (NPPV) is effective in the treatment of acute and chronic respiratory failure. However, the costs and financial balance between costs and diagnosis-related group (DRG) reimbursement for patients with moderate to severe respiratory failure treated with NPPV are unknown. We examined the costs and DRG reimbursement for 27 patients receiving Medicare referred with moderately severe respiratory failure for NPPV to the ventilator rehabilitation unit (VRU) at Temple University Hospital. This unit is one of four Health Care Financing Administration chronic ventilator-dependent demonstration sites that evaluates patients for NPPV, instructs them in home NPPV use, emphasizes rehabilitation, and uses strict cost accounting methods. Nineteen patients were treated with NPPV in the ICU and then referred to the VRU, and 8 patients were directly admitted for NPPV to the VRU. Patients were (mean +/- SE) 69 +/- 9 years age, 14 had severe COPD, and 13 had various restrictive disorders. All were hypercapneic at the time of hospital admission (restrictive 60 +/- 15; obstructive 67 +/- 3 mm Hg, PaCO2) with impaired lung mechanics and limited functional status. Patients averaged 8 +/- 15 days in the ICU, or 8 +/- 4.7 days on the medical floor prior to VRU transfer. The VRU length of stay averaged 20 +/- 18 days, for a total length of stay of 29 +/- 21 days. After implementation of NPPV, all patients had an improvement in gas exchange while spontaneously breathing and functional status that was maintained in follow-up. At 1 and 2 years of follow-up, 74% and 63% of patients were alive, respectively. Eleven patients were admitted with DRG 475 (respiratory system diagnosis with ventilator support); however, 16 of 27 patients were admitted across five different non-475 DRG codes with reimbursement rates ranging from $2,673 to $4,215. After DRG and outlier reimbursement, a total deficit of $261,948 remained (average deficit $9,701 per patient). However, individual patient deficits ranged from $1,113 to $32,892. Eighty-two percent of patients treated with NPPV incurred substantial financial losses that were underreimbursed across all assigned DRGs, including DRG 475, the highest-weighted DRG. We conclude that patients with moderate to severe respiratory failure receiving NPPV demonstrate an improvement in functional status and gas exchange that is maintained in follow-up. In addition, patients treated with NPPV incur high costs that are currently underreimbursed by the present DRG system. Newer DRG payment scales that recognize NPPV as specific treatment should be implemented.

The effect of inhibition of 5-lipoxygenase by zileuton in mild-to-moderate asthma

OBJECTIVE

To evaluate the effectiveness of inhibiting the formation of the 5-lipoxygenase products of arachidonic acid by the 5-lipoxygenase inhibitor zileuton in the treatment of mild-to-moderate asthma.

DESIGN

Randomized, double-blind, placebo-controlled study.

SETTING

University hospitals and private allergy and pulmonary practices.

PATIENTS

A total of 139 persons with asthma who had a forced expiratory volume in 1 second (FEV1) of 40% to 75% of the predicted value and who were not being treated with inhaled or oral steroids.

INTERVENTION

Zileuton, 2.4 g/d or 1.6 g/d, or placebo for 4 weeks.

MEASUREMENTS

Airway function, beta-agonist use, and symptoms; inhibition of 5-lipoxygenase assessed by measurement of urinary leukotriene E4 (LTE4).

RESULTS

Zileuton produced a 0.35-L (95% CI, 0.25 to 0.45 L) increase in the FEV1 within 1 hour of administration (P < 0.001 compared with placebo), equivalent to a 14.6% increase from baseline. After 4 weeks of zileuton therapy, airway function and symptoms improved, with the greatest improvements occurring in the 2.4 g/d group: This group's FEV1 increased by 0.32 L (CI, 0.16 to 0.48 L), a 13.4% increase, compared with a 0.05-L (CI, -0.10 to 0.20 L) increase in patients taking placebo (P = 0.02). Symptoms and frequency of beta-agonist use also decreased with zileuton, 2.4 g/d. The mean urinary LTE4 level decreased by 39.2 pg/mg creatinine (CI, 18.1 to 60.4 pg/mg creatinine) and 26.5 pg/mg creatinine (CI, 6.6 to 46.5 pg/mg creatinine) in the 2.4 g/d and 1.6 g/d groups, respectively, compared with a slight increase in the placebo group (P = 0.007 and P = 0.05). No difference was noted in the number of adverse events among treatment groups.

CONCLUSIONS

Inhibition of 5-lipoxygenase can improve airway function and decrease symptoms and medication use in patients with asthma, suggesting that this inhibition can be useful therapy for asthma. Also, 5-lipoxygenase products may mediate part of the baseline airway obstruction in patients with mild-to-moderate asthma.

Serial biparietal diameter and femur length measurements in twin gestations

Biparietal diameter and femur length measurements from 60 twin pairs were used to construct fetal twin growth tables. From 18 through 38 weeks of gestation the biparietal diameter measurements were accurate within +/- 1.9 weeks, and the femur length within +/- 2.1 weeks in the prediction of gestational age. Since this data was obtained from a predominantly white middle class population it may prove more reliable in similar groups for predicting the adequacy of fetal growth and gestational age than prior data obtained using indigent populations.

Recertification in allergy and immunology: an historical review with special emphasis on the 1983 examination

Recertification offers a method of evaluating a diplomate's cognitive knowledge of allergy and immunology. In 1983 candidates for the American Board of Allergy and Immunology recertification examination were offered the entire certifying examination but were informed that they would, for recertification purposes, be held responsible only for a subset of questions judged to be particularly clinically relevant. All 40 candidates elected to take the entire certifying examination. Differences between the performance of certifying and recertifying candidates on the recertifying questions were small. Except for the five-choice questions, the differences in performance between the two groups on the remaining questions were also small in an absolute sense. Recertification performance was not related to the time of original certification. Ninety-eight percent of the candidates completed a questionnaire after the examination. Ninety percent stated that they would encourage their colleagues to participate in the recertification process.

Distribution and characterization of cyclo (His-Pro)-like immunoreactivity in anuran (frog) skins

The distribution of cyclo (His-Pro)-like immunoreactivity in frog skins from seven frog species was examined. The chromatographic elution profile of cyclo (His-Pro)-like immunoreactivity in amphibian skins measured by radioimmunoassay corresponded precisely to that of [3H-Pro]-cyclo (His-Pro) after DEAE-Cellulose, Sephadex G-25 and high-pressure liquid chromatography. The concentrations of cyclo (His-Pro) in frog skins were much higher than the concentrations of TRH previously observed in skin and the concentrations of cyclo (His-Pro) in both brain and gastrointestinal tract.

Ritodrine hydrochloride infusion in pregnant baboons. II. Sodium and water compartment alterations

To evaluate the effects of intravenously administered ritodrine hydrochloride on sodium and water metabolism, a pregnant baboon model was studied. Animals given ritodrine retained significantly more sodium (p less than 0.001) and administered fluids (p less than 0.002) compared with control animals. Although plasma volume did not change significantly within or between the two groups, extracellular volume increased by a mean of 1,480 ml in those given ritodrine compared with 790 ml in the control animals. There was no significant difference between animals given ritodrine and their controls regarding serial hematocrits, serum sodium, or colloid oncotic pressures. From this we conclude that the retained sodium and water was in the interstitial space. Since plasma volume was unaltered by ritodrine administration it seems unlikely that pure volume overload can explain the pulmonary edema induced by beta-mimetics. Combined with the prior observation that direct pulmonary capillary membrane toxicity does not occur, the likely pathophysiology of beta-agonist-induced pulmonary edema involves left ventricular failure.

Developmental changes in the distribution of rat brain pyroglutamate aminopeptidase, a possible determinant of endogenous cyclo(His-Pro) concentrations

The distribution of cyclo(His-Pro), thyrotropin-releasing hormone (TRH) and Pyroglutamate aminopeptidase activity in adult and developing rat brains were studied. A comparison of the subcellular distribution of Pyroglutamate aminopeptidase activity in hypothalamic and cerebral cortical extracts from adult rats exhibited remarkable differences. In hypothalamus, the enzyme activity was mainly associated with the soluble fraction whereas in cortex it was predominantly associated with the particulate fractions. During postnatal development, the brain concentrations of cyclo(His-Pro) and Pyroglutamate aminopeptidase activities declined with age. These data suggest that Pyroglutamate aminopeptidase activity, but not TRH, plays an active role in determining the levels of endogenous cyclo(His-Pro) concentrations in brain.

Distribution and metabolism of cyclo (His-Pro): a new member of the neuropeptide family

Cyclo (His-Pro) is a biologically active cyclic dipeptide derived from thyrotropin-releasing hormone by its limited proteolysis. We have developed a specific radioimmunoassay for this cyclic peptide and shown its presence throughout rat and monkey brains. The normal rat brain concentration of cyclo (His-Pro) ranged from 35-61 pmols/brain. The elution profiles of rat brain cyclo (His-Pro)-like immunoreactivity and synthetic radioactive cyclo (His-Pro) following gel filtration, ion-exchange chromatography, and high pressure liquid chromatography were similar. An analysis of the regional distribution of cyclo (His-Pro) and TRH in rat and monkey brains exhibited no apparent precursor-product relationship. The possible additional factors determining regional differences in the endogenous cyclo (His-Pro) concentrations are discussed. The endogenous levels of brain cyclo (His-Pro) were elevated when rats were made either hypothyroid by surgical thyroidectomy or forced to drink alcohol for six weeks. These studies demonstrate that cyclo (His-Pro) is present throughout the central nervous system in physiologically relevant concentrations which can be modulated by appropriate physiological and pharmacological manipulations. These data in conjunction with earlier reports of multiple biological activities of exogenous cyclo (His-Pro), suggest that endogenous cyclo (His-Pro) is a biologically active peptide and it may play a neurotransmitter or neuromodulator role in the central nervous system.