Antibody-independent protection against heterologous SARS-CoV-2 challenge conferred by prior infection or vaccination

Vaccines have reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) morbidity and mortality, yet emerging variants challenge their effectiveness. The prevailing approach to updating vaccines targets the antibody response, operating under the presumption that it is the primary defense mechanism following vaccination or infection. This perspective, however, can overlook the role of T cells, particularly when antibody levels are low or absent. Here we show, through studies in mouse models lacking antibodies but maintaining functional B cells and lymphoid organs, that immunity conferred by prior infection or mRNA vaccination can protect against SARS-CoV-2 challenge independently of antibodies. Our findings, using three distinct models inclusive of a novel human/mouse ACE2 hybrid, highlight that CD8+ T cells are essential for combating severe infections, whereas CD4+ T cells contribute to managing milder cases, with interferon-γ having an important function in this antibody-independent defense. These findings highlight the importance of T cell responses in vaccine development, urging a broader perspective on protective immunity beyond just antibodies.

Immunogenicity and Pre-Clinical Efficacy of an OMV-Based SARS-CoV-2 Vaccine

The vaccination campaign against SARS-CoV-2 relies on the world-wide availability of effective vaccines, with a potential need of 20 billion vaccine doses to fully vaccinate the world population. To reach this goal, the manufacturing and logistic processes should be affordable to all countries, irrespective of economical and climatic conditions. Outer membrane vesicles (OMVs) are bacterial-derived vesicles that can be engineered to incorporate heterologous antigens. Given the inherent adjuvanticity, such modified OMVs can be used as vaccines to induce potent immune responses against the associated proteins. Here, we show that OMVs engineered to incorporate peptides derived from the receptor binding motif (RBM) of the spike protein from SARS-CoV-2 elicit an effective immune response in vaccinated mice, resulting in the production of neutralizing antibodies (nAbs) with a titre higher than 1:300. The immunity induced by the vaccine is sufficient to protect the animals from intranasal challenge with SARS-CoV-2, preventing both virus replication in the lungs and the pathology associated with virus infection. Furthermore, we show that OMVs can be effectively decorated with the RBM of the Omicron BA.1 variant and that such engineered OMVs induce nAbs against Omicron BA.1 and BA.5, as measured using the pseudovirus neutralization infectivity assay. Importantly, we show that the RBM438-509 ancestral-OMVs elicited antibodies which efficiently neutralize in vitro both the homologous ancestral strain, the Omicron BA.1 and BA.5 variants with a neutralization titre ranging from 1:100 to 1:1500, suggesting its potential use as a vaccine targeting diverse SARS-CoV-2 variants. Altogether, given the convenience associated with the ease of engineering, production and distribution, our results demonstrate that OMV-based SARS-CoV-2 vaccines can be a crucial addition to the vaccines currently available.

Immunogenicity and pre-clinical efficacy of an OMV-based SARS-CoV-2 vaccine

The vaccination campaign against SARS-CoV-2 relies on the world-wide availability of effective vaccines, with a potential need of 20 billion vaccine doses to fully vaccinate the world population. To reach this goal, the manufacturing and logistic processes should be affordable to all countries, irrespectively of economical and climatic conditions. Outer membrane vesicles (OMV) are bacterial-derived vesicles that can be engineered to incorporate heterologous antigens. Given the inherent adjuvanticity, such modified OMV can be used as vaccine to induce potent immune responses against the associated protein. Here we show that OMVs engineered to incorporate peptides derived from the receptor binding motif (RBM) of the spike protein from SARS-CoV-2 elicit an effective immune response in vaccinated mice, resulting in the production of neutralizing antibodies (nAbs). The immunity induced by the vaccine is sufficient to protect the animals from intranasal challenge with SARS-CoV-2, preventing both virus replication in the lungs and the pathology associated with virus infection. Furthermore, we show that OMVs can be effectively decorated with the RBM of the Omicron BA.1 variant and that such engineered OMVs induced nAbs against Omicron BA.1 and BA.5, as judged by pseudovirus infectivity assay. Importantly, we show that the RBM438-509 ancestral-OMVs elicited antibodies which efficiently neutralized in vitro both the homologous ancestral strain, the Omicron BA.1 and BA.5 variants, suggesting its potential use as a pan SARS-CoV-2 vaccine. Altogether, given the convenience associated with ease of engineering, production and distribution, our results demonstrate that OMV-based SARS-CoV-2 vaccines can be a crucial addition to the vaccines currently available.

Nirmatrelvir treatment of SARS-CoV-2-infected mice blunts antiviral adaptive immune responses

Alongside vaccines, antiviral drugs are becoming an integral part of our response to the SARS-CoV-2 pandemic. Nirmatrelvir-an orally available inhibitor of the 3-chymotrypsin-like cysteine protease-has been shown to reduce the risk of progression to severe COVID-19. However, the impact of nirmatrelvir treatment on the development of SARS-CoV-2-specific adaptive immune responses is unknown. Here, by using mouse models of SARS-CoV-2 infection, we show that nirmatrelvir administration blunts the development of SARS-CoV-2-specific antibody and T cell responses. Accordingly, upon secondary challenge, nirmatrelvir-treated mice recruited significantly fewer memory T and B cells to the infected lungs and mediastinal lymph nodes, respectively. Together, the data highlight a potential negative impact of nirmatrelvir treatment with important implications for clinical management and might help explain the virological and/or symptomatic relapse after treatment completion reported in some individuals.

Administration of aerosolized SARS-CoV-2 to K18-hACE2 mice uncouples respiratory infection from fatal neuroinvasion

The development of a tractable small animal model faithfully reproducing human coronavirus disease 2019 pathogenesis would arguably meet a pressing need in biomedical research. Thus far, most investigators have used transgenic mice expressing the human ACE2 in epithelial cells (K18-hACE2 transgenic mice) that are intranasally instilled with a liquid severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) suspension under deep anesthesia. Unfortunately, this experimental approach results in disproportionate high central nervous system infection leading to fatal encephalitis, which is rarely observed in humans and severely limits this model’s usefulness. Here, we describe the use of an inhalation tower system that allows exposure of unanesthetized mice to aerosolized virus under controlled conditions. Aerosol exposure of K18-hACE2 transgenic mice to SARS-CoV-2 resulted in robust viral replication in the respiratory tract, anosmia, and airway obstruction but did not lead to fatal viral neuroinvasion. When compared with intranasal inoculation, aerosol infection resulted in a more pronounced lung pathology including increased immune infiltration, fibrin deposition, and a transcriptional signature comparable to that observed in SARS-CoV-2–infected patients. This model may prove useful for studies of viral transmission, disease pathogenesis (including long-term consequences of SARS-CoV-2 infection), and therapeutic interventions.

COVID-eVax, an electroporated DNA vaccine candidate encoding the SARS-CoV-2 RBD, elicits protective responses in animal models

The COVID-19 pandemic caused by SARS-CoV-2 has made the development of safe and effective vaccines a critical priority. To date, four vaccines have been approved by European and American authorities for preventing COVID-19, but the development of additional vaccine platforms with improved supply and logistics profiles remains a pressing need. Here we report the preclinical evaluation of a novel COVID-19 vaccine candidate based on the electroporation of engineered, synthetic cDNA encoding a viral antigen in the skeletal muscle. We constructed a set of prototype DNA vaccines expressing various forms of the SARS-CoV-2 spike (S) protein and assessed their immunogenicity in animal models. Among them, COVID-eVax-a DNA plasmid encoding a secreted monomeric form of SARS-CoV-2 S protein receptor-binding domain (RBD)-induced the most potent anti-SARS-CoV-2 neutralizing antibody responses (including against the current most common variants of concern) and a robust T cell response. Upon challenge with SARS-CoV-2, immunized K18-hACE2 transgenic mice showed reduced weight loss, improved pulmonary function, and lower viral replication in the lungs and brain. COVID-eVax conferred significant protection to ferrets upon SARS-CoV-2 challenge. In summary, this study identifies COVID-eVax as an ideal COVID-19 vaccine candidate suitable for clinical development. Accordingly, a combined phase I-II trial has recently started.

Incidence rate of Healthcare Associated Infections in a COVID-19 Intensive Care Unit

Background

Intensive Care Units (ICU) faced a high pressure under the COVID-19 pandemic. It is recognized that patients admitted in these wards are more susceptible to Healthcare Associated Infections (HAIs). This study aims at comparing the incidence of HAIs in a COVID-19 ICU to a No-COVID ward.

Methods

A retrospective cohort study including patients admitted to the ICU of the Teaching Hospital Policlinico Umberto I in Rome from April 2020 to March 2021 was performed. Data on age, gender, hospitalization, different types of devices (ventilation, central venous and urinary catheter), number and type of device-related HAI were collected. Statistical analyses were performed with Episheet and STATA 13.

Results

Out of 347 patients admitted in the ICUs, 329 were included in the study (217 had COVID-19 and 112 had not). In the COVID-19 group, patients were mainly male (69.58%) with a mean age of 62.5±13.5 years, whereas the other group was slightly older (63.2±16.2 years) and more balanced between the two sexes (52.68% male). A total of 133 patients developed at least one HAI, 94 of which were SARS-CoV-2 positive. Globally, 246 HAIs were diagnosed: 163 occurred in the COVID group and 83 in the No-COVID one. The cumulative days of hospitalization were 3233 for the COVID group and 2134 for the No-COVID. The incidence of HAI considered for 1000 days of hospitalization among COVID patients was 50.42 (IC 95%: 42.97-58.78), compared to 38.89 (IC 95%: 30.98-48.22) for the No-COVID one, for an incidence rate ratio of 1.30 (IC 95%: 0.99-1.71).

Conclusions

Even though the confidence interval contains the value 1, the results point out that there is an increase in the incidence rate of HAI among COVID-19 patients. Further investigations are needed to better understand the reasons behind the present findings.

Key messages

Patients admitted to Intensive Care Units are more susceptible to Healthcare Associated Infections. Our study aims at describing the impact of COVID-19 on the risk of developing such conditions.

Being infected with COVID-19 leads to an increase in the incidence rate of Healthcare Associated Infections. Further studies are needed to understand the underlying reasons.

Undergraduates' perception of health risk of body arts: results of an Italian multicentre study

Background

In the last decades, body art practices such as tattooing and piercing have known an increasing popularity, mainly in young people. These procedures are associated with infectious and non-infectious health risks. The aim of this multicenter study was to evaluate the knowledge of health risks related to body art procedures among undergraduate students from ten Italian universities.

Methods

A cross-sectional study was performed on undergraduate students attending universities in northern, central and southern Italy. An anonymous questionnaire was administered to the participants for collecting their socio-demographic characteristics and for assessing their knowledge about health risks associated with tattoos and piercing.

Results

A total of 2985 students (mean age 23.15 ± 3.99, 73.9% females) completed the questionnaire. 775 (25.9%) of them were from northern Italy, 906 (30.3%) from the Centre and 1324 (44.4%) from the South. More than 90% of the sample were aware that tattoo/piercing procedures can cause health problems. However, the mean values of correct answers about the health risks associated to body art practices were low (5.38 ± 2.39 on a total of 11 correct answers for tattooing and 5.93 ± 3.12 on a total of 14 for piercing). Higher knowledge of the health risks related to tattooing was found among those attending university since more than four years (p < 0.001), life science courses (p < 0.001) and residing/living in the university area (p = 0.023). Those attending North/Centre universities (p < 0.001), since more than 4 years (p < 0.001), life science courses (p < 0.001), and those with graduated father (p = 0.013) had better knowledge of the health risks related to piercing.

Conclusions

These results show a lack of knowledge about health risks related to body art practices in the sample. Educational interventions on this issue targeted to youth are needed in Italy.

Key messages

Undergraduates do not show a good knowledge of health risks related to tattooing and piercing. Educational interventions are needed to raise youth awareness and knowledge of health risks of body art.

A survey on knowledge and awareness on the issue "microplastics": a pilot study on a sample of future public health professionals

BACKGROUND

Microplastics pollution represents a global public health concern. Since the greatest amount of microplastics are of anthropogenic origin, one of the most relevant strategies to reduce microplastics pollution is to raise awareness among the population and this is even more important for all those involved in public health prevention interventions. The aim of this study was to assess the level of knowledge and awareness on microplastics of a samples of future healthcare workers.

STUDY DESIGN

A cross-sectional study was performed on 151 university students in the field of Public Health, both pre- and post-graduate, attending the Sapienza University of Rome courses.

METHODS

A questionnaire consisting of three sections was administered to the participants. The first section assessed knowledge and awareness on microplastics, the second consisted of an informative brochure on microplastics, the third evaluated the awareness after reading the brochure, and interventions considered useful to manage microplastics pollution.

RESULTS

About 25% of participants had never heard of microplastics. The scores on knowledge about microplastics were low, and differences between the investigated courses were not statistically significant (p-Value=0.134). Internet was the main source of information on microplastics, while the scores describing concern about the investigated issue resulted always higher after reading the informative brochure respect to before reading.

CONCLUSIONS

The lack of knowledge about microplastics pollution highlights that future public health workers should be better informed and, therefore, able to transfer essential information to the population. Increasing general population's knowledge and awareness would increase risk perception and make all individuals more active actors for reducing microplastics pollution.

The impact of the COVID-19 pandemic on healthcare-associated infections in intensive care unit patients: a retrospective cohort study

Background

During the intensive care units’ (ICUs) reorganization that was forced by the COVID-19 emergency, attention to traditional infection control measures may have been reduced. Nevertheless, evidence on the effect of the COVID-19 pandemic on healthcare-associated infections (HAIs) is still limited and mixed. In this study, we estimated the pandemic impact on HAI incidence and investigated the HAI type occurring in COVID-19 patients.

Methods

Patients admitted to the main ICU of the Umberto I teaching hospital of Rome from March 1st and April 4th 2020 were compared with patients hospitalized in 2019. We assessed the association of risk factors and time-to-first event through multivariable Fine and Grey’s regression models, that consider the competitive risk of death on the development of HAI (Model 1) or device related-HAI (dr-HAI, Model 2) and provide estimates of the sub-distribution hazard ratio (SHR) and its associated confidence interval (CI). A subgroup analysis was performed on the 2020 cohort.

Results

Data from 104 patients were retrieved. Overall, 59 HAIs were recorded, 32 of which occurred in the COVID-19 group. Patients admitted in 2020 were found to be positively associated with both HAI and dr-HAI onset (SHR: 2.66, 95% CI 1.31–5.38, and SHR: 10.0, 95% CI 1.84–54.41, respectively). Despite being not confirmed at the multivariable analysis, a greater proportion of dr-HAIs seemed to occur in COVID-19 patients, especially ventilator-associated pneumonia, and catheter-related urinary tract infections.

Conclusions

We observed an increase in the incidence of patients with HAIs, especially dr-HAIs, mainly sustained by COVID-19 patients. A greater susceptibility of these patients to device-related infections was hypothesized, but further studies are needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-021-00959-y.

NCLs and ER: A stressful relationship

The Neuronal Ceroid Lipofuscinoses (NCLs, Batten disease) are a group of inherited neurodegenerative disorders with variable age of onset, characterized by the lysosomal accumulation of autofluorescent ceroid lipopigments. The endoplasmic reticulum (ER) is a critical organelle for normal cell function. Alteration of ER homeostasis leads to accumulation of misfolded protein in the ER and to activation of the unfolded protein response. ER stress and the UPR have recently been linked to the NCLs. In this review, we will discuss the evidence for UPR activation in the NCLs, and address its connection to disease pathogenesis. Further understanding of ER-stress response involvement in the NCLs may encourage development of novel therapeutical agents targeting these pathogenic pathways.

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ER-stress activation has been linked to various neurodegenerative diseases.

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ER-stress is a common patho-mechanism in four forms of NCL.

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Pharmacological modulation of UPR could provide new treatment for NCL.

In Vivo Characterization of Zirconia Toughened Alumina Material: A Comparative Animal Study

The development of a new chromia-doped Zirconia Toughened Alumina (ZTA) material was previously reported as displaying mechanical properties suitable for implants with load bearing applications, such as orthopaedic and dental implants. This type of biomaterial is expected to be in contact with living tissues for a long period of time and its long-term toxicity must be carefully evaluated. In this study the suitability of this ZTA material as a candidate biomaterial for orthopaedic implants and dental devices was further investigated in vivo in comparison to alumina and zirconia, which are currently used in orthopaedic and dental surgery. Cylinders of the materials were implanted in vivo in white rabbits, and local and systemic tissue reactions were analyzed at different time intervals after surgery. Radiologic examinations displayed the absence of radiolucence around cylinders and no signs of implant loosening up to twelve months. No tumours developed in the animals either locally (at the site of implantation), or systemically in the peripheral organs. The results obtained suggest that this new ZTA material does not display any long term pathogenic effect in vivo. These findings extend our previous observations on the biocompatibility and the absence of any long-term carcinogenic effect in vitro of this material which displays interesting properties for biomedical applications. In conclusion, we report the in vivo characterization of a new chromia-doped ZTA material and confirm its suitability as a candidate biomaterial for orthopaedic implants and dental devices since it does not give any local nor systemic toxicity even after a long period of time after implantation.

Development of a New Zirconia-Toughened Alumina: Promising Mechanical Properties and Absence of In Vitro Carcinogenicity

High purity alumina as well as zirconia ceramics have been widely used as orthopaedic implant biomaterials and dental devices displaying optimal, but sometimes exclusive, mechanical properties. In order to combine the advantages of alumina and zirconia ceramic materials different types of composites have been developed in which either zirconia is dispersed in an alumina matrix or vice versa. Orthopaedic and dental implant biomaterials are expected to be in contact with living tissues for a long period of time and their long term toxicity must be carefully evaluated. In this study we report the development of a high performance chromia-doped Zirconia Toughened Alumina (ZTA) material which displays promising mechanical properties in terms of hardness, strength and fracture toughness that make it suitable for prosthesis even for small joints. The long-term biocompatibility of this material was also evaluated, mainly in terms of DNA damage, mutagenicity and cancerogenetic potential in mammalian cells. The results obtained suggest that this new ZTA material does not display any long-term carcinogenic effect and it is suitable for biomedical applications from a cancerogenetic point of view. In conclusion, we report the development of a new chromia-doped ZTA material with interesting properties both from a mechanical and a biocompatibility point of view which warrant further studies on its suitability as a candidate biomaterial for orthopaedic implants and dental devices.

Identification of 14 new glucokinase mutations and description of the clinical profile of 42 MODY-2 families

Mutations in glucokinase are associated with defects in insulin secretion and hepatic glycogen synthesis resulting in mild chronic hyperglycaemia, impaired glucose tolerance or diabetes mellitus. We screened members of 35 families with features of maturity-onset diabetes of the young for mutations in the glucokinase gene and found 16 different mutations. They included 14 new mutations in the glucokinase gene: 9 missense mutations (A53S, G80A, H137R, T168P, M210T, C213R, V226M, S336L and V367M); 2 nonsense mutations (E248X and S360X); a deletion of one nucleotide resulting in a frameshift (V401del1); a substitution of a conserved nucleotide at a splice acceptor site (L122-1G-->T); and a 10 base pair deletion that removed the GT of the splice donor site and the following eight nucleotides (K161 + 2del10). In addition, we found two previously identified mutations: R186X and G261R. Study of 260 subjects with glucokinase-deficient hyperglycaemia from 42 families with 36 different GCK mutations made it possible to define the clinical profile of this subtype of non-insulin-dependent diabetes mellitus (NIDDM). Hyperglycaemia due to glucokinase deficiency is often mild (fewer than 50% of subjects have overt diabetes) and is evident during the early years of life. Despite the long duration of hyperglycaemia, glucokinase-deficient subjects have a low prevalence of micro- and macro-vascular complications of diabetes. Obesity, arterial hypertension and dyslipidaemia are also uncommon in this form of NIDDM.

Effect of mutations on the sensitivity of human beta-cell glucokinase to liver regulatory protein

Human beta-cell glucokinase and its liver counterpart displayed a half-saturating concentration of glucose (S0.5) of about 8 mmol/l and a Hill coefficient of 1.7, and were as sensitive to inhibition by the rat liver regulatory protein as the rat liver enzyme. These results indicate that the N-terminal region of glucokinase, which differs among these three enzymes, is not implicated in the recognition of the regulatory protein. They also suggest that the regulatory protein, or a related protein, could modulate the affinity of glucokinase for glucose in beta cells. We have also tested the effect of several mutations, many of which are implicated in maturity onset diabetes of the young. The mutations affected the affinity for glucose and for the regulatory protein to different degrees, indicating that the binding site for these molecules is different. An Asp158 Ala mutation, found in the expression plasmid previously thought to encode the wild-type enzyme, increased the affinity for glucose by about 2.5-fold without changing the affinity for the regulatory protein. The mutations that were found to decrease the affinity for the regulatory protein (Asn166 Arg. Val203 Ala, Asn204 Gln, Lys414 Ala) clustered in the hinge region of glucokinase and nearby in the large and small domains. These results are in agreement with the concept that part of the binding site for the regulatory protein is situated in the hinge region of this enzyme.

Electroencephalographic consequences of sodium dehydrocholate-induced blood-brain barrier disruption: Part 2. Generation and propagation of spike activity after the topical application of sodium dehydrocholate

Sodium dehydrocholate was applied topically to the right hemispheric cortex of eight rats and the electrocorticogram was monitored from both the treated cortex and the homotopic cortex of the contralateral hemisphere. All animals developed blood-brain barrier (BBB) disruption in the treated cortex as evidenced by cortical staining with systemically administered Evans blue dye. Spike activity developed in three of eight animals after the topical application of dehydrocholate. The subsequent intravenous injection of sodium dehydrocholate provoked spike activity in both hemispheres in all eight animals. Dependent and independent spike activity was recorded in the nondisrupted hemisphere. The intravenous administration of gamma-aminobutyric acid (GABA) resulted in alterations in spike activity in four of five animals because of penetration of the GABA through the altered BBB. These findings demonstrate that sodium dehydrocholate can result in increased BBB permeability when applied directly to the cortical surface. Spike activity subsequent to the topical application of dehydrocholate can be enhanced by systemic loading with dehydrocholate. Spike activity occurring over the nontreated cortex (secondary focus) represents interhemispheric propagation of spike activity from the disrupted hemisphere (primary focus). The lack of Evans blue staining in the actively discharging secondary focus suggests that spike activity does not account for the increases in BBB permeability observed with dehydrocholate treatment.

Effect of intracarotid etoposide on opening the blood-brain barrier

The effect of an intracarotid artery infusion of etoposide on blood-brain barrier (BBB) integrity was investigated in a rat model system. The external carotid arteries of Sprague-Dawley rats were catheterized in a retrograde manner. Etoposide in a dose range from 3.0 mg/kg to 22.5 mg/kg was infused into the internal carotid artery by this technique. BBB disruption was evaluated qualitatively by the appearance in the infused hemisphere of the systemically administered dye Evans blue and quantitatively by the ratio of counts of the technetium-labeled chelate of diethylenetriaminepentaacetic acid (99mTc-DTPA) in the infused to the noninfused hemisphere. Evidence of increased BBB permeability was seen at all doses of etoposide. Degree of BBB disruption increased with increasing doses of etoposide. The intracarotid infusion and subsequent BBB disruption were well tolerated. Further clinical trials employing the intracarotid administration of etoposide should be cognizant of the potential for BBB disruption.