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Pathogens (Basel, Switzerland) Feb 2022The handling of highly pathogenic viruses, whether for diagnostic or research purposes, often requires an inactivation step. This article reviews available inactivation... (Review)
Review
The handling of highly pathogenic viruses, whether for diagnostic or research purposes, often requires an inactivation step. This article reviews available inactivation techniques published in peer-reviewed journals and their benefits and limitations in relation to the intended application. The bulk of highly pathogenic viruses are represented by enveloped RNA viruses belonging to the , , , , , , , and families. Here, we summarize inactivation methods for these virus families that allow for subsequent molecular and serological analysis or vaccine development. The techniques identified here include: treatment with guanidium-based chaotropic salts, heat inactivation, photoactive compounds such as psoralens or 1.5-iodonaphtyl azide, detergents, fixing with aldehydes, UV-radiation, gamma irradiation, aromatic disulfides, beta-propiolacton and hydrogen peroxide. The combination of simple techniques such as heat or UV-radiation and detergents such as Tween-20, Triton X-100 or Sodium dodecyl sulfate are often sufficient for virus inactivation, but the efficiency may be affected by influencing factors including quantity of infectious particles, matrix constitution, pH, salt- and protein content. Residual infectivity of the inactivated virus could have disastrous consequences for both laboratory/healthcare personnel and patients. Therefore, the development of inactivation protocols requires careful considerations which we review here.
PubMed: 35215213
DOI: 10.3390/pathogens11020271 -
ACS Applied Bio Materials Dec 2021Filamentous nanomaterials are flexible with a high aspect ratio, conferring unique mechanical, electromagnetic, and optical properties; promoting tissue penetration; and...
Filamentous nanomaterials are flexible with a high aspect ratio, conferring unique mechanical, electromagnetic, and optical properties; promoting tissue penetration; and allowing the formation of hierarchical superstructures. The fabrication of synthetic nanofilaments with uniform properties is challenging, but this can be addressed by the use of filamentous plant viruses such as potato virus X (PVX), which are produced as monodisperse structures from a genetic template. To take advantage of PVX without risks to agriculture and the environment, it is necessary to inactivate the virus efficiently without disrupting its chemical and material properties. Herein, we report experiments showing that PVX can be completely inactivated by exposure to UV irradiation (0.5 J cm) or chemical treatment (1 mM β-propiolactone or 10 mM formalin) without interfering with the chemical addressability of lysine or cysteine residues, which are typically used as conjugation handles for virus nanoparticle functionalization.
Topics: Clinical Protocols; Cysteine; Nanoparticles; Plant Viruses; Potexvirus
PubMed: 35005940
DOI: 10.1021/acsabm.1c00838 -
The Lancet. Rheumatology Feb 2022We aimed to examine the immunogenicity pattern induced by the inactivated SARS-CoV-2 vaccine CoronaVac (Sinovac Life Sciences, Beijing, China) in SARS-CoV-2 seropositive...
Immunogenicity and safety of two doses of the CoronaVac SARS-CoV-2 vaccine in SARS-CoV-2 seropositive and seronegative patients with autoimmune rheumatic diseases in Brazil: a subgroup analysis of a phase 4 prospective study.
BACKGROUND
We aimed to examine the immunogenicity pattern induced by the inactivated SARS-CoV-2 vaccine CoronaVac (Sinovac Life Sciences, Beijing, China) in SARS-CoV-2 seropositive patients with autoimmune rheumatic diseases compared with seropositive controls, seronegative patients with autoimmune rheumatic diseases, and seronegative controls.
METHODS
CoronavRheum is an ongoing, prospective, controlled, phase 4 study, in which patients aged 18 years or older with autoimmune rheumatic diseases, and healthy controls were recruited from a single site (Rheumatology Division of Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo) in São Paulo, Brazil Participants were vaccinated with two doses of CoronaVac (intramuscular injection, 3 μg in 0·5 mL of β-propiolactone inactivated SARS-CoV-2) on day 0 and on day 28. Blood samples were taken pre-vaccination on day 0, day 28, and also on day 69. For this subgroup analysis, participants were defined as being SARS-CoV-2 seropositive or seronegative prevaccination via anti-SARS-CoV-2 spike (S)1 or S2 IgG (cutoff of 15·0 arbitrary units [AU] per mL) or neutralising antibody titres (cutoff of ≥30%) and were matched for age and sex, via convenience sampling, in a 1:3:1:1 ratio (seropositive patients to seronegative patients to seropositive controls to seronegative controls). The primary outcomes were rates of anti-SARS-CoV-2 S1 and S2 IgG seropositivity and SARS-CoV-2 neutralising antibody positivity at day 28 and day 69 and immunogenicity dynamics assessed by geometric mean titres (GMTs) of IgG and median neutralising activity in seropositive patients with autoimmune rheumatic diseases compared with seronegative patients and seropositive and seronegative controls. We assessed safety in all participants randomly selected for this subgroup analysis. This study is registered with ClinicalTrials.gov, NCT04754698, and is ongoing for long-term immunogenicity evaluation.
FINDINGS
Between Feb 4 and Feb 8, 2021, 1418 patients and 542 controls were recruited, of whom 1685 received two vaccinations (1193 patients and 492 controls). After random sampling, our immunogenicity analysis population comprised 942 participants, of whom 157 were SARS-CoV-2 seropositive patients with autoimmune rheumatic diseases, 157 were seropositive controls, 471 were seronegative patients, and 157 were seronegative controls; the median age was 48 years (IQR 38-56) and 594 (63%) were female and 348 (37%) were male. For seropositive patients and controls, an increase in anti-SARS-CoV-2 S1 and S2 IgG titres (seropositive patients GMT 52·3 [95% CI 42·9-63·9] at day 0 128·9 [105·6-157·4] at day 28; seropositive controls 53·3 [45·4-62·5] at day 0 202·0 [174·8-233·4] at day 28) and neutralising antibody activity (seropositive patients 59% [IQR 39-83] at day 0 82% [54-96] at day 28; seropositive controls 58% [41-79] at day 0 92% [79-96] at day 28), was observed from day 0 to day 28, without further increases from day 28 to day 69 (at day 69 seropositive patients' GMT was 137·1 [116·2-161·9] and neutralising antibody activity was 79% [57-94]); and seropositive controls' GMT was 188·6 [167·4-212·6] and neutralising antibody activity was 92% [75-96]). By contrast, for seronegative patients and controls, the second dose was required for maximum response at day 69, which was lower in seronegative patients than in seronegative controls. GMTs in seronegative patients were 2·3 (95% CI 2·2-2·3) at day 0, 5·7 (5·1-6·4) at day 28, and 29·6 (26·4-33·3) at day 69, and in seronegative controls were 2·3 (2·1-2·5) at day 0, 10·6 (8·7-13·1) at day 28, and 71·7 (63·5-81·0) at day 69; neutralising antibody activity in seronegative patients was 15% (IQR 15-15) on day 0, 15% (15-15) at day 28, and 39% (15-65) at day 69, and in seronegative controls was 15% (15-15) at day 0, 24% (15-37) at day 28, and 61% (37-79) at day 69. Neither seronegative patients nor seronegative controls reached the GMT or antibody activity levels of seropositive patients at day 69.
INTERPRETATION
By contrast with seronegative patients with autoimmune rheumatic diseases, seropositive patients have a robust response after a single dose of CoronaVac. Our findings raise the possibility that the reduced immunogenicity observed in seronegative patients might not be the optimum response potential to SARS-CoV-2 vaccination, and therefore emphasise the importance of at least a single booster vaccination in these patients.
FUNDING
Fundação de Amparo à Pesquisa do Estado de São Paulo, Conselho Nacional de Desenvolvimento Científico e Tecnológico, and B3-Bolsa de Valores do Brasil.
TRANSLATION
For the Portuguese translation of the abstract see Supplementary Materials section.
PubMed: 34901885
DOI: 10.1016/S2665-9913(21)00327-1 -
Proceedings of the National Academy of... Nov 2021The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mediates membrane fusion to allow entry of the viral genome into host cells. To...
The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mediates membrane fusion to allow entry of the viral genome into host cells. To understand its detailed entry mechanism and develop a specific entry inhibitor, in situ structural information on the SARS-CoV-2 spike protein in different states is urgent. Here, by using cryo-electron tomography, we observed both prefusion and postfusion spikes in β-propiolactone-inactivated SARS-CoV-2 virions and solved the in situ structure of the postfusion spike at nanometer resolution. Compared to previous reports, the six-helix bundle fusion core, the glycosylation sites, and the location of the transmembrane domain were clearly resolved. We observed oligomerization patterns of the spikes on the viral membrane, likely suggesting a mechanism of fusion pore formation.
Topics: Amino Acid Motifs; Animals; Chlorocebus aethiops; Cryoelectron Microscopy; Electron Microscope Tomography; Glycosylation; Protein Domains; Protein Multimerization; SARS-CoV-2; Spike Glycoprotein, Coronavirus; Vero Cells
PubMed: 34782481
DOI: 10.1073/pnas.2112703118 -
Langmuir : the ACS Journal of Surfaces... Nov 2021Using CO as a resource in the production of materials is a viable alternative to conventional, petroleum-based raw materials and therefore offers great potential for...
Using CO as a resource in the production of materials is a viable alternative to conventional, petroleum-based raw materials and therefore offers great potential for more sustainable chemistry. This study presents a detailed structural characterization of aggregates of nonionic dodecyl surfactants with different amounts of CO substituting ethylene oxide (EO) in the head group. The micellar structure was characterized as a function of concentration and temperature by dynamic and static light scattering and, in further detail, by small-angle neutron scattering (SANS). The influence of the CO unit in the hydrophilic EO group is systematically compared to the incorporation of propylene oxide (PO) and propiolactone (PL). The surfactants with carbonate groups in their head groups form ellipsoidal micelles in an aqueous solution similar to conventional nonionic surfactants, becoming bigger with increasing CO content. In contrast, the incorporation of PO units hardly alters the behavior, while the incorporation of a PL unit has an effect comparable to the CO unit. The analysis of the SANS data shows decreasing hydration with increasing CO and PL content. By increasing the temperature, a typical sphere-rod transition is observed, where CO surfactants show a much higher elongation with increasing temperature, which is correlated with the reduced cloud point and a lower extent of head group hydration. Our findings demonstrate that CO-containing surface-active compounds are an interesting, potentially "greener" alternative to conventional nonionic surfactants.
PubMed: 34735164
DOI: 10.1021/acs.langmuir.1c01737 -
Clinical and Experimental Vaccine... Sep 2021One of the essential goals regarding the successful control of rabies infection is the development of a safe, effective, and inexpensive vaccine. the current study aimed...
PURPOSE
One of the essential goals regarding the successful control of rabies infection is the development of a safe, effective, and inexpensive vaccine. the current study aimed to evaluate the inactivation potential of β-propiolactone (βPL), binary ethyleneimine (BEI), and hydrogen peroxide (HO).
MATERIALS AND METHODS
Estimating the inactivation kinetics of βPL, BEI, and HO revealed that the tested inactivants could completely and irreversibly inactivate rabies virus within 2, 12, and 4 hours, respectively while maintaining its viral immunogenicity. The potency of βPL, BEI, and HO inactivated vaccines was higher than the World Health Organization acceptance limit and were in the order of 3.75, 4.21, and 3.64 IU/mL, respectively. Monitoring the humoral and cellular immunity elicited post-immunization using derived hyaluronic acid (HA) and bacillus Calmette-Guérin purified protein derivative (PPD) adjuvanted rabies vaccine candidates were carried out using enzyme-linked immunosorbent assay.
RESULTS
Results demonstrated that both adjuvants could progressively enhance the release of anti-rabies total immunoglobulin G as well as the pro-inflammatory mediators (interferon-gamma and interleukin-5) relative to time. However, a higher immune response was developed in the case of HA adjuvanted rabies vaccine compared to PPD adjuvanted one. The harmful consequences of the tested adjuvants were considered via investigating the histopathological changes in the tissues of the immunized rats using hematoxylin and eosin stain. Lower adverse effects were observed post-vaccination with HA and PPD adjuvanted vaccines compared to that detected following administration of the currently used alum as standard adjuvant.
CONCLUSION
Our findings suggested that HA and PPD could serve as a promising platform for the development of newly adjuvanted rabies vaccines with elevated immune enhancing potentials and lower risk of health hazards.
PubMed: 34703805
DOI: 10.7774/cevr.2021.10.3.229 -
Bioorganic & Medicinal Chemistry Letters Dec 2021S-Palmitoylation is a reversible post-translational lipid modification that regulates protein trafficking and signaling. The enzymatic depalmitoylation of proteins is...
S-Palmitoylation is a reversible post-translational lipid modification that regulates protein trafficking and signaling. The enzymatic depalmitoylation of proteins is inhibited by the beta-lactones Palmostatin M and B, which have been found to target several serine hydrolases. In efforts to better understand the mechanism of action of Palmostatin M, we describe herein the synthesis, chemical proteomic analysis, and functional characterization of analogs of this compound. We identify Palmostatin M analogs that maintain inhibitory activity in N-Ras depalmitoylation assays while displaying complementary reactivity across the serine hydrolase class as measured by activity-based protein profiling. Active Palmostatin M analogs inhibit the recently characterized ABHD17 subfamily of depalmitoylating enzymes, while sparing other candidate depalmitoylases such as LYPLA1 and LYPLA2. These findings improve our understanding of the structure-activity relationship of Palmostatin M and refine the set of serine hydrolase targets relevant to the compound's effects on N-Ras palmitoylation dynamics.
Topics: Humans; Lactones; Molecular Structure; Propiolactone; Proteomics; Sulfones; ras Proteins
PubMed: 34666187
DOI: 10.1016/j.bmcl.2021.128414 -
Biosafety and Health Oct 2021Many factors have been identified as having the ability to affect the sensitivity of rapid antigen detection (RAD) tests for severe acute respiratory syndrome...
Many factors have been identified as having the ability to affect the sensitivity of rapid antigen detection (RAD) tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study aimed to identify the impact of sample processing on the sensitivity of the RAD tests. We explored the effect of different inactivation methods, viral transport media (VTM) solutions, and sample preservation on the sensitivity of four RAD kits based on two SARS-CoV-2 strains. Compared with non-inactivation, heat inactivation significantly impacted the sensitivity of most RAD kits; however, β-propiolactone inactivation only had a minor effect. Some of the VTM solutions (VTM2, MANTACC) had a significant influence on the sensitivity of the RAD kits, especially for low viral-loads samples. The detection value of RAD kits was slightly decreased, while most of them were still in the detection range with the extension of preservation time and the increase of freeze-thaw cycles. Our results showed that selecting the appropriate inactivation methods and VTM solutions is necessary during reagent development, performance evaluation, and clinical application.
PubMed: 34518817
DOI: 10.1016/j.bsheal.2021.09.001 -
Microscopy Research and Technique Feb 2022The severe COVID-19 pandemic drives the research toward the SARS-CoV-2 virion structure and the possible therapies against it. Here, we characterized the...
The severe COVID-19 pandemic drives the research toward the SARS-CoV-2 virion structure and the possible therapies against it. Here, we characterized the β-propiolactone inactivated SARS-CoV-2 virions using transmission electron microscopy (TEM) and atomic force microscopy (AFM). We compared the SARS-CoV-2 samples purified by two consecutive chromatographic procedures (size exclusion chromatography [SEC], followed by ion-exchange chromatography [IEC]) with samples purified by ultracentrifugation. The samples prepared using SEC and IEC retained more spikes on the surface than the ones prepared using ultracentrifugation, as confirmed by TEM and AFM. TEM showed that the spike (S) proteins were in the pre-fusion conformation. Notably, the S proteins could be recognized by specific monoclonal antibodies. Analytical TEM showed that the inactivated virions retained nucleic acid. Altogether, we demonstrated that the inactivated SARS-CoV-2 virions retain the structural features of native viruses and provide a prospective vaccine candidate.
Topics: Animals; COVID-19; Chlorocebus aethiops; Humans; Pandemics; Propiolactone; SARS-CoV-2; Vaccines, Inactivated; Vero Cells
PubMed: 34498784
DOI: 10.1002/jemt.23931 -
Virus Research Nov 2021Inactivated viral preparations are important resources in vaccine and antisera industry. Of the many vaccines that are being developed against COVID-19, inactivated...
Inactivated viral preparations are important resources in vaccine and antisera industry. Of the many vaccines that are being developed against COVID-19, inactivated whole-virus vaccines are also considered effective. β-propiolactone (BPL) is a widely used chemical inactivator of several viruses. Here, we analyze various concentrations of BPL to effectively inactivate SARS-CoV-2 and their effects on the biochemical properties of the virion particles. BPL at 1:2000 (v/v) concentrations effectively inactivated SARS-CoV-2. However, higher BPL concentrations resulted in the loss of both protein content as well as the antigenic integrity of the structural proteins. Higher concentrations also caused substantial aggregation of the virion particles possibly resulting in insufficient inactivation, and a loss in antigenic potential. We also identify that the viral RNA content in the culture supernatants can be a direct indicator of their antigenic content. Our findings may have important implications in the vaccine and antisera industry during COVID-19 pandemic.
Topics: Animals; Antigens, Viral; Antiviral Agents; COVID-19; COVID-19 Vaccines; Chlorocebus aethiops; Flocculation; Humans; Immune Sera; Propiolactone; RNA, Viral; SARS-CoV-2; Vaccines, Inactivated; Vero Cells; Virion; Virus Inactivation
PubMed: 34487766
DOI: 10.1016/j.virusres.2021.198555