RESUMEN
Monoclonal neutralizing antibodies (mAbs) are considered an important prophylactic against SARS-CoV-2 infection in at-risk populations and a strategy to counteract future sarbecovirus-induced disease. However, most mAbs isolated so far neutralize only a few sarbecovirus strains. Therefore, there is a growing interest in bispecific antibodies (bsAbs) which can simultaneously target different spike epitopes and thereby increase neutralizing breadth and prevent viral escape. Here, we generate and characterize a panel of 30 novel broadly reactive bsAbs using an efficient controlled Fab-arm exchange protocol. We specifically combine some of the broadest mAbs described so far, which target conserved epitopes on the receptor binding domain (RBD). Several bsAbs show superior cross-binding and neutralization compared to the parental mAbs and cocktails against sarbecoviruses from diverse clades, including recent SARS-CoV-2 variants. BsAbs which include mAb COVA2-02 are among the most potent and broad combinations. As a result, we study the unknown epitope of COVA2-02 and show that this mAb targets a distinct conserved region at the base of the RBD, which could be of interest when designing next-generation bsAb constructs to contribute to a better pandemic preparedness.
Asunto(s)
Anticuerpos Biespecíficos , Anticuerpos Neutralizantes , Anticuerpos Antivirales , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , Anticuerpos Biespecíficos/inmunología , Humanos , SARS-CoV-2/inmunología , Anticuerpos Antivirales/inmunología , Anticuerpos Neutralizantes/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , COVID-19/inmunología , COVID-19/prevención & control , Epítopos/inmunología , Pruebas de Neutralización , Animales , Anticuerpos Monoclonales/inmunologíaRESUMEN
Neutralization of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by human sera is a strong correlate of protection against symptomatic and severe Coronavirus Disease 2019 (COVID-19). The emergence of antigenically distinct SARS-CoV-2 variants of concern (VOCs) and the relatively rapid waning of serum antibody titers, however, raises questions about the sustainability of serum protection. In addition to serum neutralization, other antibody functionalities and the memory B cell (MBC) response are suggested to help maintaining this protection. In this study, we investigate the breadth of spike (S) protein-specific serum antibodies that mediate effector functions by interacting with Fc-gamma receptor IIa (FcγRIIa) and FcγRIIIa, and of the receptor binding domain (RBD)-specific MBCs, following a primary SARS-CoV-2 infection with the D614G, Alpha, Beta, Gamma, Delta, Omicron BA.1 or BA.2 variant. Irrespectively of the variant causing the infection, the breadth of S protein-specific serum antibodies that interact with FcγRIIa and FcγRIIIa and the RBD-specific MBC responses exceeded the breadth of serum neutralization, although the Alpha-induced B cell response seemed more strain-specific. Between VOC groups, both quantitative and qualitative differences in the immune responses were observed, suggesting differences in immunogenicity. Overall, this study contributes to the understanding of protective humoral and B cell responses in the light of emerging antigenically distinct VOCs, and highlights the need to study the immune system beyond serum neutralization to gain a better understanding of the protection against emerging variants.
Asunto(s)
Anticuerpos Antivirales , COVID-19 , Células B de Memoria , Receptores de IgG , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , Humanos , SARS-CoV-2/inmunología , COVID-19/inmunología , COVID-19/virología , Glicoproteína de la Espiga del Coronavirus/inmunología , Anticuerpos Antivirales/inmunología , Receptores de IgG/inmunología , Células B de Memoria/inmunología , Anticuerpos Neutralizantes/inmunología , Linfocitos B/inmunología , Memoria Inmunológica/inmunologíaRESUMEN
Zoonotic events by sarbecoviruses have sparked an epidemic (severe acute respiratory syndrome coronavirus [SARS-CoV]) and a pandemic (SARS-CoV-2) in the past two decades. The continued risk of spillovers from animals to humans is an ongoing threat to global health and a pan-sarbecovirus vaccine would be an important contribution to pandemic preparedness. Here, we describe multivalent virosome-based vaccines that present stabilized spike proteins from four sarbecovirus strains, one from each clade. A cocktail of four monovalent virosomes or a mosaic virosome preparation induced broad sarbecovirus binding and neutralizing antibody responses in mice. Pre-existing immunity against SARS-CoV-2 and extending the intervals between immunizations enhanced antibody responses. These results should inform the development of a pan-sarbecovirus vaccine, as part of our efforts to prepare for and/or avoid a next pandemic.
RESUMEN
The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has remained a medical threat due to the evolution of multiple variants that acquire resistance to vaccines and prior infection. Therefore, it is imperative to discover monoclonal antibodies (mAbs) that neutralize a broad range of SARS-CoV-2 variants. A stabilized spike glycoprotein was used to enrich antigen-specific B cells from an individual with a primary Gamma variant infection. Five mAbs selected from those B cells showed considerable neutralizing potency against multiple variants, with COVA309-35 being the most potent against the autologous virus, as well as Omicron BA.1 and BA.2, and COVA309-22 having binding and neutralization activity against Omicron BA.4/5, BQ.1.1, and XBB.1. When combining the COVA309 mAbs as cocktails or bispecific antibodies, the breadth and potency were improved. In addition, the mechanism of cross-neutralization of the COVA309 mAbs was elucidated by structural analysis. Altogether these data indicate that a Gamma-infected individual can develop broadly neutralizing antibodies.
RESUMEN
Previously, we and others have shown that SARS-CoV-2 spike-specific IgG antibodies play a major role in disease severity in COVID-19 by triggering macrophage hyperactivation, disrupting endothelial barrier integrity, and inducing thrombus formation. This hyperinflammation is dependent on high levels of anti-spike IgG with aberrant Fc tail glycosylation, leading to Fcγ receptor hyperactivation. For development of immune-regulatory therapeutics, drug specificity is crucial to counteract excessive inflammation whereas simultaneously minimizing the inhibition of antiviral immunity. We here developed an in vitro activation assay to screen for small molecule drugs that specifically counteract antibody-induced pathology. We identified that anti-spike-induced inflammation is specifically blocked by small molecule inhibitors against SYK and PI3K. We identified SYK inhibitor entospletinib as the most promising candidate drug, which also counteracted anti-spike-induced endothelial dysfunction and thrombus formation. Moreover, entospletinib blocked inflammation by different SARS-CoV-2 variants of concern. Combined, these data identify entospletinib as a promising treatment for severe COVID-19.
Asunto(s)
COVID-19 , Humanos , SARS-CoV-2 , Anticuerpos Antivirales , Inflamación/tratamiento farmacológico , Inmunoglobulina G/farmacologíaRESUMEN
The worldwide pandemic caused by SARS-CoV-2 has remained a human medical threat due to the continued evolution of multiple variants that acquire resistance to vaccines and prior infection. Therefore, it is imperative to discover monoclonal antibodies (mAbs) that neutralize a broad range of SARS-CoV-2 variants for therapeutic and prophylactic use. A stabilized autologous SARS-CoV-2 spike glycoprotein was used to enrich antigen-specific B cells from an individual with a primary Gamma variant infection. Five mAbs selected from those B cells showed considerable neutralizing potency against multiple variants of concern, with COVA309-35 being the most potent against the autologous virus, as well as against Omicron BA.1 and BA.2. When combining the COVA309 mAbs as cocktails or bispecific antibody formats, the breadth and potency was significantly improved against all tested variants. In addition, the mechanism of cross-neutralization of the COVA309 mAbs was elucidated by structural analysis. Altogether these data indicate that a Gamma-infected individual can develop broadly neutralizing antibodies.
RESUMEN
Delineating the origins and properties of antibodies elicited by SARS-CoV-2 infection and vaccination is critical for understanding their benefits and potential shortcomings. Therefore, we investigate the SARS-CoV-2 spike (S)-reactive B cell repertoire in unexposed individuals by flow cytometry and single-cell sequencing. We show that â¼82% of SARS-CoV-2 S-reactive B cells harbor a naive phenotype, which represents an unusually high fraction of total human naive B cells (â¼0.1%). Approximately 10% of these naive S-reactive B cells share an IGHV1-69/IGKV3-11 B cell receptor pairing, an enrichment of 18-fold compared to the complete naive repertoire. Following SARS-CoV-2 infection, we report an average 37-fold enrichment of IGHV1-69/IGKV3-11 B cell receptor pairing in the S-reactive memory B cells compared to the unselected memory repertoire. This class of B cells targets a previously undefined non-neutralizing epitope on the S2 subunit that becomes exposed on S proteins used in approved vaccines when they transition away from the native pre-fusion state because of instability. These findings can help guide the improvement of SARS-CoV-2 vaccines.
Asunto(s)
COVID-19 , SARS-CoV-2 , Anticuerpos Neutralizantes , Anticuerpos Antivirales , Vacunas contra la COVID-19 , Epítopos , Humanos , Isotipos de Inmunoglobulinas , Receptores de Antígenos de Linfocitos B , Glicoproteína de la Espiga del CoronavirusRESUMEN
Large-scale vaccination campaigns have prevented countless hospitalizations and deaths due to COVID-19. However, the emergence of SARS-CoV-2 variants that escape from immunity challenges the effectiveness of current vaccines. Given this continuing evolution, an important question is when and how to update SARS-CoV-2 vaccines to antigenically match circulating variants, similarly to seasonal influenza viruses where antigenic drift necessitates periodic vaccine updates. Here, we studied SARS-CoV-2 antigenic drift by assessing neutralizing activity against variants of concern (VOCs) in a set of sera from patients infected with viral sequence-confirmed VOCs. Infections with D614G or Alpha strains induced the broadest immunity, whereas individuals infected with other VOCs had more strain-specific responses. Omicron BA.1 and BA.2 were substantially resistant to neutralization by sera elicited by all other variants. Antigenic cartography revealed that Omicron BA.1 and BA.2 were antigenically most distinct from D614G, associated with immune escape, and possibly will require vaccine updates to ensure vaccine effectiveness.
Asunto(s)
COVID-19 , SARS-CoV-2 , Anticuerpos Neutralizantes , Anticuerpos Antivirales , Antígenos Virales/genética , Vacunas contra la COVID-19 , Humanos , SARS-CoV-2/genéticaRESUMEN
Current SARS-CoV-2 vaccines are effective, but long-term protection is threatened by the emergence of virus variants. We generated a virosome vaccine containing the Beta spike protein and compared its immunogenicity in mice to a virosome vaccine containing the original Wuhan spike. Two administrations of the virosomes induced potent SARS-CoV-2 neutralizing antibodies in both vaccine groups. The level of autologous neutralization in Beta-vaccinated mice was similar to the level of autologous neutralization in Wuhan-vaccinated mice. However, heterologous neutralization to the Wuhan strain in Beta-vaccinated mice was 4.7-fold lower than autologous neutralization, whereas heterologous neutralization to the Beta strain in Wuhan-vaccinated mice was reduced by only 1.9-fold compared to autologous neutralization levels. In addition, neutralizing activity against the D614G, Alpha and Delta variants was also significantly lower after Beta spike vaccination than after Wuhan spike vaccination. Our results show that Beta spike vaccination induces inferior neutralization breadth. These results are informative for programs aimed to develop broadly active SARS-CoV-2 vaccines.
Asunto(s)
Vacunas contra la COVID-19/uso terapéutico , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Animales , Anticuerpos Neutralizantes/inmunología , Pruebas Respiratorias , Vacunas contra la COVID-19/inmunología , Femenino , Ratones , Ratones Endogámicos BALB C , Pruebas de Neutralización , Vacunas de Virosoma/inmunología , Vacunas de Virosoma/uso terapéuticoRESUMEN
Emerging SARS-CoV-2 variants of concern (VOCs) pose a threat to human immunity induced by natural infection and vaccination. We assessed the recognition of three VOCs (B.1.1.7, B.1.351, and P.1) in cohorts of COVID-19 convalescent patients (n = 69) and Pfizer-BioNTech vaccine recipients (n = 50). Spike binding and neutralization against all three VOCs were substantially reduced in most individuals, with the largest four- to sevenfold reduction in neutralization being observed against B.1.351. While hospitalized patients with COVID-19 and vaccinees maintained sufficient neutralizing titers against all three VOCs, 39% of nonhospitalized patients exhibited no detectable neutralization against B.1.351. Moreover, monoclonal neutralizing antibodies show sharp reductions in their binding kinetics and neutralizing potential to B.1.351 and P.1 but not to B.1.1.7. These data have implications for the degree to which pre-existing immunity can protect against subsequent infection with VOCs and informs policy makers of susceptibility to globally circulating SARS-CoV-2 VOCs.
RESUMEN
Emerging SARS-CoV-2 variants pose a threat to human immunity induced by natural infection and vaccination. We assessed the recognition of three variants of concern (B.1.1.7, B.1.351 and P.1) in cohorts of COVID-19 patients ranging in disease severity (n = 69) and recipients of the Pfizer/BioNTech vaccine (n = 50). Spike binding and neutralization against all three VOC was substantially reduced in the majority of samples, with the largest 4-7-fold reduction in neutralization being observed against B.1.351. While hospitalized COVID-19 patients and vaccinees maintained sufficient neutralizing titers against all three VOC, 39% of non-hospitalized patients did not neutralize B.1.351. Moreover, monoclonal neutralizing antibodies (NAbs) show sharp reductions in their binding kinetics and neutralizing potential to B.1.351 and P.1, but not to B.1.1.7. These data have implications for the degree to which pre-existing immunity can protect against subsequent infection with VOC and informs policy makers of susceptibility to globally circulating SARS-CoV-2 VOC.
RESUMEN
The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had a large impact on global health, travel, and economy. Therefore, preventative and therapeutic measures are urgently needed. Here, we isolated monoclonal antibodies from three convalescent coronavirus disease 2019 (COVID-19) patients using a SARS-CoV-2 stabilized prefusion spike protein. These antibodies had low levels of somatic hypermutation and showed a strong enrichment in VH1-69, VH3-30-3, and VH1-24 gene usage. A subset of the antibodies was able to potently inhibit authentic SARS-CoV-2 infection at a concentration as low as 0.007 micrograms per milliliter. Competition and electron microscopy studies illustrate that the SARS-CoV-2 spike protein contains multiple distinct antigenic sites, including several receptor-binding domain (RBD) epitopes as well as non-RBD epitopes. In addition to providing guidance for vaccine design, the antibodies described here are promising candidates for COVID-19 treatment and prevention.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Betacoronavirus/inmunología , Infecciones por Coronavirus/inmunología , Neumonía Viral/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Adulto , Anciano , Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Afinidad de Anticuerpos , Antígenos Virales/inmunología , Subgrupos de Linfocitos B/inmunología , Anticuerpos ampliamente neutralizantes/inmunología , COVID-19 , Línea Celular Tumoral , Infecciones por Coronavirus/prevención & control , Infecciones por Coronavirus/terapia , Epítopos/inmunología , Femenino , Humanos , Memoria Inmunológica , Inmunofenotipificación , Masculino , Persona de Mediana Edad , Pandemias/prevención & control , Neumonía Viral/prevención & control , Neumonía Viral/terapia , Dominios Proteicos , Dominios y Motivos de Interacción de Proteínas/inmunología , Receptores de Coronavirus , Receptores Virales/metabolismo , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus/químicaRESUMEN
AIM: In international nursing literature compassion and compassionate care has acquired a considerable importance and it's considered to be a growing phenomenon. The approach to the application of compassionate care to patients is clearly not well-defined in Italian nursing. The aim of this study is to define what compassionate care is through the analysis of Italian nurses' experiences. METHOD: The research is based on a qualitative method. Content analysis was used to analyze the transcript data. The research has been carried out by creating three focus groups, for a total of 15 nurses. RESULTS: All the participants expressed their opinions freely. The outcomes of the analysis can be grouped in four areas: definition of compassion and compassionate care; categorisation of patients; provision of care; and formation and training in compassionate care. The survey has shown contrasting opinions, negative opinions such as feelings of rejections and positive opinions such as love, charity, empathy and support. The last one (support) in particular has highlighted the importance of involving the patient's relatives in providing compassionate care. CONCLUSIONS: It is difficult to define exactly the meaning of compassion and compassionate care.This study has contributed to extend and deep the current knowledge in regard of the concept of compas-sionate care applied to assistance entities. Further research is needed in the field of compassionate care to strength the effectiveness of assistance provided by nurses.
Asunto(s)
Empatía , Grupos Focales , Atención de Enfermería , Humanos , Italia , Amor , Apoyo SocialRESUMEN
BACKGROUND: Contributing factors to medication errors include distractions, lack of focus, and failure to follow standard operating procedures. The nursing unit is vulnerable to a multitude of interruptions and distractions that affect the working memory and the ability to focus during critical times. Methods that prevent these environmental effects on nurses can help avert medication errors. METHODS: A process improvement study examined the effects of standard protocols and visible signage within a hospital setting. The project was patterned after another study using similar techniques. Rapid Cycle Testing was used as one of the strategies for this process improvement project. Rapid Cycle Tests have become a part of the newly adopted Define, Measure, Analyze, Improve, and Control steps at this particular hospital. RESULTS: As a result, a medication administration check-list improved focus and standardized practice. Visible signage also reduced nurses' distractions and improved focus. CONCLUSION: The results provide evidence that protocol checklists and signage can be used as reminders to reduce distractions, and are simple, inexpensive tools for medication safety.