Pseudotyping Improves the Yield of Functional SARS-CoV-2 Virus-like Particles (VLPs) as Tools for Vaccine and Therapeutic Development

Virus-like particles (VLPs) have been proposed as an attractive tool in SARS-CoV-2 vaccine development, both as (1) a vaccine candidate with high immunogenicity and low reactogenicity and (2) a substitute for live virus in functional and neutralization assays. Though multiple SARS-CoV-2 VLP designs have already been explored in Sf9 insect cells, a key parameter ensuring VLPs are a viable platform is the VLP spike yield (i.e., spike protein content in VLP), which has largely been unreported. In this study, we show that the common strategy of producing SARS-CoV-2 VLPs by expressing spike protein in combination with the native coronavirus membrane and/or envelope protein forms VLPs, but at a critically low spike yield (~0.04-0.08 mg/L). In contrast, fusing the spike ectodomain to the influenza HA transmembrane domain and cytoplasmic tail and co-expressing M1 increased VLP spike yield to ~0.4 mg/L. More importantly, this increased yield translated to a greater VLP spike antigen density (~96 spike monomers/VLP) that more closely resembles that of native SARS-CoV-2 virus (~72-144 Spike monomers/virion). Pseudotyping further allowed for production of functional alpha (B.1.1.7), beta (B.1.351), delta (B.1.617.2), and omicron (B.1.1.529) SARS-CoV-2 VLPs that bound to the target ACE2 receptor. Finally, we demonstrated the utility of pseudotyped VLPs to test neutralizing antibody activity using a simple, acellular ELISA-based assay performed at biosafety level 1 (BSL-1). Taken together, this study highlights the advantage of pseudotyping over native SARS-CoV-2 VLP designs in achieving higher VLP spike yield and demonstrates the usefulness of pseudotyped VLPs as a surrogate for live virus in vaccine and therapeutic development against SARS-CoV-2 variants.

Imaging Mass Cytometry Reveals Predominant Innate Immune Signature and Endothelial-Immune Cell Interaction in Juvenile Myositis Compared to Lupus Skin

OBJECTIVE

Cutaneous inflammation can signal disease in juvenile dermatomyositis (DM) and childhood-onset systemic lupus erythematosus (cSLE), but we do not fully understand cellular mechanisms of cutaneous inflammation. In this study, we used imaging mass cytometry to characterize cutaneous inflammatory cell populations and cell-cell interactions in juvenile DM as compared to cSLE.

METHODS

We performed imaging mass cytometry analysis on skin biopsy samples from juvenile DM patients (n = 6) and cSLE patients (n = 4). Tissue slides were processed and incubated with metal-tagged antibodies for CD14, CD15, CD16, CD56, CD68, CD11c, HLA-DR, blood dendritic cell antigen 2, CD20, CD27, CD138, CD4, CD8, E-cadherin, CD31, pan-keratin, and type I collagen. Stained tissue was ablated, and raw data were acquired using the Hyperion imaging system. We utilized the Phenograph unsupervised clustering algorithm to determine cell marker expression and permutation test by histoCAT to perform neighborhood analysis.

RESULTS

We identified 14 cell populations in juvenile DM and cSLE skin, including CD14+ and CD68+ macrophages, myeloid and plasmacytoid dendritic cells (pDCs), CD4+ and CD8+ T cells, and B cells. Overall, cSLE skin had a higher inflammatory cell infiltrate, with increased CD14+ macrophages, pDCs, and CD8+ T cells and immune cell-immune cell interactions. Juvenile DM skin displayed a stronger innate immune signature, with a higher overall percentage of CD14+ macrophages and prominent endothelial cell-immune cell interaction.

CONCLUSION

Our findings identify immune cell population differences, including CD14+ macrophages, pDCs, and CD8+ T cells, in juvenile DM skin compared to cSLE skin, and highlight a predominant innate immune signature and endothelial cell-immune cell interaction in juvenile DM, providing insight into candidate cell populations and interactions to better understand disease-specific pathophysiology.

Nonlesional lupus skin contributes to inflammatory education of myeloid cells and primes for cutaneous inflammation

Cutaneous lupus erythematosus (CLE) is a disfiguring and poorly understood condition frequently associated with systemic lupus. Previous studies suggest that nonlesional keratinocytes play a role in disease predisposition, but this has not been investigated in a comprehensive manner or in the context of other cell populations. To investigate CLE immunopathogenesis, normal-appearing skin, lesional skin, and circulating immune cells from lupus patients were analyzed via integrated single-cell RNA sequencing and spatial RNA sequencing. We demonstrate that normal-appearing skin of patients with lupus represents a type I interferon-rich, prelesional environment that skews gene transcription in all major skin cell types and markedly distorts predicted cell-cell communication networks. We also show that lupus-enriched CD16⁺ dendritic cells undergo robust interferon education in the skin, thereby gaining proinflammatory phenotypes. Together, our data provide a comprehensive characterization of lesional and nonlesional skin in lupus and suggest a role for skin education of CD16⁺ dendritic cells in CLE pathogenesis.

B Cell Signatures Distinguish Cutaneous Lupus Erythematosus Subtypes and the Presence of Systemic Disease Activity

Cutaneous lupus erythematosus (CLE) is a chronic inflammatory skin disease characterized by a diverse cadre of clinical presentations. CLE commonly occurs in patients with systemic lupus erythematosus (SLE), and CLE can also develop in the absence of systemic disease. Although CLE is a complex and heterogeneous disease, several studies have identified common signaling pathways, including those of type I interferons (IFNs), that play a key role in driving cutaneous inflammation across all CLE subsets. However, discriminating factors that drive different phenotypes of skin lesions remain to be determined. Thus, we sought to understand the skin-associated cellular and transcriptional differences in CLE subsets and how the different types of cutaneous inflammation relate to the presence of systemic lupus disease. In this study, we utilized two distinct cohorts comprising a total of 150 CLE lesional biopsies to compare discoid lupus erythematosus (DLE), subacute cutaneous lupus erythematosus (SCLE), and acute cutaneous lupus erythematosus (ACLE) in patients with and without associated SLE. Using an unbiased approach, we demonstrated a CLE subtype-dependent gradient of B cell enrichment in the skin, with DLE lesions harboring a more dominant skin B cell transcriptional signature and enrichment of B cells on immunostaining compared to ACLE and SCLE. Additionally, we observed a significant increase in B cell signatures in the lesional skin from patients with isolated CLE compared with similar lesions from patients with systemic lupus. This trend was driven primarily by differences in the DLE subgroup. Our work thus shows that skin-associated B cell responses distinguish CLE subtypes in patients with and without associated SLE, suggesting that B cell function in skin may be an important link between cutaneous lupus and systemic disease activity.

Contribution of plasma cells and B cells to hidradenitis suppurativa pathogenesis

Hidradenitis suppurativa (HS) is a debilitating chronic inflammatory skin disease characterized by chronic abscess formation and development of multiple draining sinus tracts in the groin, axillae, and perineum. Using proteomic and transcriptomic approaches, we characterized the inflammatory responses in HS in depth, revealing immune responses centered on IFN-γ, IL-36, and TNF, with lesser contribution from IL-17A. We further identified B cells and plasma cells, with associated increases in immunoglobulin production and complement activation, as pivotal players in HS pathogenesis, with Bruton’s tyrosine kinase (BTK) and spleen tyrosine kinase (SYK) pathway activation as a central signal transduction network in HS. These data provide preclinical evidence to accelerate the path toward clinical trials targeting BTK and SYK signaling in moderate-to-severe HS.

B-cells and plasma cells are critical pathogenic cell populations in chronic Hidradenitis Suppurativa and are potential therapeutic targets.

The Coming Age of Insect Cells for Manufacturing and Development of Protein Therapeutics

Protein therapeutics is a rapidly growing segment of the pharmaceutical market. Currently, the majority of protein therapeutics are manufactured in mammalian cells for their ability to generate safe and efficacious human-like glycoproteins. The high cost of using mammalian cells for manufacturing has motivated a constant search for alternative host platforms. Insect cells have begun to emerge as a promising candidate, largely due to the development of the baculovirus expression vector system. While there are continuing efforts to improve insect-baculovirus expression for producing protein therapeutics, key limitations including cell lysis and the lack of homogeneous humanized glycosylation still remain. The field has started to see a movement toward virus-less gene expression approaches, notably the use of clustered regularly interspaced short palindromic repeats to address these shortcomings. This review highlights recent technological advances that are realizing the transformative potential of insect cells for the manufacturing and development of protein therapeutics.

Self-assembled hybrid supraparticles that proteolytically degrade tumor necrosis factor-α

The strategies of pathogens to evade the human immune system are highly sophisticated and modulate a variety of inflammatory pathways. The similarities in the demands for modulation of inflammatory responses during disease treatment and during pathogenic infection provide opportunities to use pathogenic virulence factors to develop a new class of therapeutic materials that control inflammation. In this work, we harness a strategy from Porphyromonas gingivalis by transforming its major virulence factor, an arginine-specific cysteine protease, into self-assembled protease-inorganic hybrid supraparticles. The cysteine protease degrades the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α). It is an irreversible inhibition of TNF-α, which avoids some of the adverse effects of current TNF-α antagonists. We fabricated self-assembled porous supraparticles that specifically incorporate the pathogen-derived protease and showed improved inactivation of TNF-α over soluble enzyme, creating a potential therapeutic for various autoimmune diseases or other sources of inflammation.

Ethical dilemmas in the care of cancer patients near the end of life

By definition, an ethical dilemma involves the need to choose from among two or more morally acceptable options or between equally unacceptable courses of action, when one choice prevents selection of the other. Advances in medicine, increasing economic stress, rise of patient self-determination and differing values between healthcare workers and patients are among the many factors contributing to the frequency and complexity of ethical issues in healthcare. In the cancer patient near the end of life, common ethical dilemmas include those dealing with artificial nutrition and hydration, truth-telling and disagreements over management plans. It would stand the clinician in good stead to be aware of these issues and have an approach toward dealing with such problems. In addition, organisations have a responsibility to ensure that systems are in place to minimise its occurrence and ensure that staff are supported through the process of resolving dilemmas and conflicts that may arise.

Experimental modification of P50 suppression

White and Yee (1997) found that normal suppression of the P50 component of the event-related potential was disrupted during a paired-click paradigm when nonpsychiatric subjects performed mental arithmetic (MA) problems aloud, concurrently with the presentation of auditory stimuli. In fact, the degree of disruption reflected in the P50 suppression ratio fell within the range that is typically observed in schizophrenia patients. The present study was conducted to clarify the processes that might underlie the apparent disruption of P50 suppression during performance of an oral MA task. Participants completed a series of tasks designed to examine the impact of competing cognitive activity, competing auditory stimulation, muscle activity, and acute psychological stress on P50 amplitude and P50 suppression. Results suggested that psychological stress and heightened facial muscle activity may exert modulatory effects on P50 suppression.

P50 suppression in recent-onset schizophrenia: clinical correlates and risperidone effects

Chronic schizophrenic patients often do not suppress the auditory P50 component of the event-related potential to the second of 2 clicks, presented 500 ms apart, suggesting a loss of normal inhibition. This study attempted to replicate the P50 suppression deficit in patients with recent-onset schizophrenia and to examine whether P50 is related to clinical symptoms or is affected by an atypical antipsychotic medication. Data from 22 recent-onset schizophrenia patients and 11 normal controls revealed that disruption in P50 suppression is present during the early stages of illness. In addition, impaired P50 suppression covaried with clinical ratings of anxiety, depression, and anergia; results also suggested that the P50 inhibitory deficit may be related to the degree of patients' attentional impairment. Finally, risperidone, compared with a typical antipsychotic medication, improved inhibition of P50 to the second click. These results support P50 suppression as a measure of disordered neurocognition in schizophrenia.

P50 suppression in recent-onset schizophrenia: clinical correlates and risperidone effects

Chronic schizophrenic patients often do not suppress the auditory P50 component of the event-related potential to the second of 2 clicks, presented 500 ms apart, suggesting a loss of normal inhibition. This study attempted to replicate the P50 suppression deficit in patients with recent-onset schizophrenia and to examine whether P50 is related to clinical symptoms or is affected by an atypical antipsychotic medication. Data from 22 recent-onset schizophrenia patients and 11 normal controls revealed that disruption in P50 suppression is present during the early stages of illness. In addition, impaired P50 suppression covaried with clinical ratings of anxiety, depression, and anergia; results also suggested that the P50 inhibitory deficit may be related to the degree of patients' attentional impairment. Finally, risperidone, compared with a typical antipsychotic medication, improved inhibition of P50 to the second click. These results support P50 suppression as a measure of disordered neurocognition in schizophrenia.

A longitudinal analysis of eye tracking dysfunction and attention in recent-onset schizophrenia

The effect of an attentional manipulation on eye tracking dysfunction (ETD) in the early stages of schizophrenia was examined in 34 recent-onset schizophrenic patients and 24 demographically matched normal subjects over a 1-year period. An attentional enhancement manipulation improved eye tracking performance of recent-onset schizophrenic patients more than that of normal subjects. Eye tracking level also was moderately stable for both groups over the course of 1 year. The possible role of attentional allocation in ETD highlights the need for further examination of the interface between attentional and eye tracking measures of vulnerability to schizophrenia.

Effects of attentional and stressor manipulations on the P50 gating response

The decline in amplitude of the P50 component of the event-related potential to the second of paired clicks has been suggested as a measure of preattentional gating. Two experiments were conducted to assess the effects of attention and a psychological stressor on P50. Experiment 1 included two choice reaction time tasks designed to direct attention selectively to the first or second click in each pair. Results suggest that the N100 component was responsive to attentional manipulations, whereas P50 was not affected. Experiment 2 examined the impact of a brief psychological stressor on the P50 response. Parallel mental arithmetic tasks were administered silently and orally. Self-report and measures of autonomic activity were used to assess the level of stress occurring during the performance of the mental arithmetic tasks. Results indicate that P50 suppression was sensitive to the acute stressor, the oral mental arithmetic task. Implications of these findings for studies of P50 suppression in schizophrenia are discussed.

Event-related potential correlates of linguistic information processing in schizophrenics

Event-related potentials (ERPs) were recorded from adult schizophrenics and age- and education-matched normal controls during performance of an idiom recognition task involving judgments of the meaningfulness of idiomatic, literal, and nonsense phrases. Schizophrenics produced more errors and had prolonged reaction times while attempting to correctly differentiate meaningful from meaningless phrases. An ERP correlate of that deficit was a larger than normal N400 to idioms and literals, with no difference in N400 amplitude to nonsense phrases. This result was interpreted as evidence that the influence of the linguistic context provided by the first word of two-word idiomatic and literal phrases is reduced in schizophrenia. Schizophrenics also showed reduced amplitude P300.

Ethnicity and gender in scales of psychosis proneness and mood disorders

Data for Caucasian, African American, Asian American, and Latino college-student samples were compared for several popular self-report scales of psychopathology. Significant group differences were obtained for all scales, with the Caucasian sample consistently having the lowest means. Some gender effects and interactions with ethnic group were also observed. The authors discuss implications of these findings for use of these scales, including implications for use of Caucasian norms with other ethnic samples.

Ethnicity and gender in scales of psychosis proneness and mood disorders

Data for Caucasian, African American, Asian American, and Latino college-student samples were compared for several popular self-report scales of psychopathology. Significant group differences were obtained for all scales, with the Caucasian sample consistently having the lowest means. Some gender effects and interactions with ethnic group were also observed. The authors discuss implications of these findings for use of these scales, including implications for use of Caucasian norms with other ethnic samples.

A dual-task analysis of resource allocation in dysthymia and anhedonia

Research has shown dysthymic individuals to be hyporesponsive at various stages of information processing, yet it is not clear whether dysthymics are deficient in the amount of available attentional resources for information processing or, instead, in the allocation of those resources. To distinguish between these possibilities, the authors compared dysthymics to anhedonic and normal control Ss during the performance of memory tasks, under conditions of varying task priority and difficulty. Although there were no performance differences, dysthymics and anhedonics exhibited a consistently smaller P300 component of the event-related potential. Furthermore, P300 results indicated that dysthymics and anhedonics responded differently from controls to variations in task demands. Thus, although evidence was obtained for group differences in both resource capacity and resource allocation strategy, the overall pattern of results is interpreted as favoring the latter.

A dual-task analysis of resource allocation in dysthymia and anhedonia

Research has shown dysthymic individuals to be hyporesponsive at various stages of information processing, yet it is not clear whether dysthymics are deficient in the amount of available attentional resources for information processing or, instead, in the allocation of those resources. To distinguish between these possibilities, the authors compared dysthymics to anhedonic and normal control Ss during the performance of memory tasks, under conditions of varying task priority and difficulty. Although there were no performance differences, dysthymics and anhedonics exhibited a consistently smaller P300 component of the event-related potential. Furthermore, P300 results indicated that dysthymics and anhedonics responded differently from controls to variations in task demands. Thus, although evidence was obtained for group differences in both resource capacity and resource allocation strategy, the overall pattern of results is interpreted as favoring the latter.

Early stimulus processing in dysthymia and anhedonia

Previous event-related brain potential (ERP) research has found that dysthymic subjects differ from control subjects during later stages of information processing. An important issue that emerges from this literature is whether differences found in these ERP components, typically associated with cognitive processing, can be attributed to earlier differences in basic perceptual processing. This study was undertaken to determine whether early processing deficits are apparent in dysthymic persons. Responses of dysthymics (n = 23) were compared with those of anhedonic (n = 15) and normal control (n = 17) subjects. ERPs were recorded while subjects heard tones at 55, 65, 75, 85, and 95 dB. Overall, N1-P1 and N1-P2 components of the ERP increased in a strong linear fashion as stimulus intensity increased. Dysthymics did exhibit a smaller N1-P2 response than normal subjects, which suggests the presence of difficulties in initial perceptual processing.

Developmental Processes in Schizophrenic Disorders: longitudinal studies of vulnerability and stress

The Developmental Processes in Schizophrenic Disorders project is a longitudinal study of schizophrenic patients who have recently had a first episode of psychosis. The project focuses on discriminating characteristics of schizophrenic patients that are "stable vulnerability indicators," "mediating vulnerability factors," and "episode indicators" by comparing normal subjects to schizophrenic patients assessed in clinically remitted and psychotic states. A parallel project goal is to identify predictors of relapse, social and work impairment, and illness course among potential psychobiological vulnerability factors and environmental potentiating factors. Hypothesized vulnerability factors and potential environmental stressors are examined first under standardized maintenance antipsychotic medication conditions for at least 1 year. Patients showing stable remission of psychosis after 1 year of maintenance antipsychotic medication are invited to enter drug crossover and withdrawal protocols to determine the need for continuous antipsychotic medication. Vulnerability and stress factors are again assessed. A summary of results to date is presented. Deficits in early components of processing visual arrays and in sustained discrimination of successive ambiguous perceptual inputs are relatively stable across psychotic and clinically remitted states in the schizophrenic patients. Performance on a vigilance task demanding active, working memory also remains abnormal during clinical remission but covaries significantly with psychotic state and is a candidate for a mediating vulnerability factor. Autonomic activation level does not appear to be an enduring vulnerability factor, but it predicts the extent of short-term symptomatic recovery and may mediate the impact of stressors. Under conditions of standardized, injectable antipsychotic medication, independent stressful life events and highly critical attitudes toward the patient in the social environment predict relapse risk. Prospective data suggest that signs and symptoms prodromal to psychotic relapse may be present in about 60 percent of patients.

Early stimulus processing in dysthymia and anhedonia

Previous event-related brain potential (ERP) research has found that dysthymic subjects differ from control subjects during later stages of information processing. An important issue that emerges from this literature is whether differences found in these ERP components, typically associated with cognitive processing, can be attributed to earlier differences in basic perceptual processing. This study was undertaken to determine whether early processing deficits are apparent in dysthymic persons. Responses of dysthymics (n = 23) were compared with those of anhedonic (n = 15) and normal control (n = 17) subjects. ERPs were recorded while subjects heard tones at 55, 65, 75, 85, and 95 dB. Overall, N1-P1 and N1-P2 components of the ERP increased in a strong linear fashion as stimulus intensity increased. Dysthymics did exhibit a smaller N1-P2 response than normal subjects, which suggests the presence of difficulties in initial perceptual processing.