A receptor-binding domain-based nanoparticle vaccine elicits durable neutralizing antibody responses against SARS-CoV-2 and variants of concern

Numerous vaccines have been developed to address the current COVID-19 pandemic, but safety, cross-neutralizing efficacy, and long-term protectivity of currently approved vaccines are still important issues. In this study, we developed a subunit vaccine, ASD254, by using a nanoparticle vaccine platform to encapsulate the SARS-CoV-2 spike receptor-binding domain (RBD) protein. As compared with the aluminum-adjuvant RBD vaccine, ASD254 induced higher titers of RBD-specific antibodies and generated 10- to 30-fold more neutralizing antibodies. Mice vaccinated with ASD254 showed protective immune responses against SARS-CoV-2 challenge, with undetectable infectious viral loads and reduced typical lesions in lung. Besides, neutralizing antibodies in vaccinated mice lasted for at least one year and were effective against various SARS-CoV-2 variants of concern, including B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), B.1.617.2 (Delta), and B.1.1.529 (Omicron). Furthermore, particle size, polydispersity index, and zeta-potential of ASD254 remained stable after 8-month storage at 4°C. Thus, ASD254 is a promising nanoparticle vaccine with good immunogenicity and stability to be developed as an effective vaccine option in controlling upcoming waves of COVID-19.

Development of AAV-delivered broadly neutralizing anti-human ACE2 antibodies against SARS-CoV-2 variants

The ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), resulting in the emergence of new variants that are resistant to existing vaccines and therapeutic antibodies, has raised the need for novel strategies to combat the persistent global COVID-19 epidemic. In this study, a monoclonal anti-human angiotensin-converting enzyme 2 (hACE2) antibody, ch2H2, was isolated and humanized to block the viral receptor-binding domain (RBD) binding to hACE2, the major entry receptor of SARS-CoV-2. This antibody targets the RBD-binding site on the N terminus of hACE2 and has a high binding affinity to outcompete the RBD. In vitro, ch2H2 antibody showed potent inhibitory activity against multiple SARS-CoV-2 variants, including the most antigenically drifted and immune-evading variant Omicron. In vivo, adeno-associated virus (AAV)-mediated delivery enabled a sustained expression of monoclonal antibody (mAb) ch2H2, generating a high concentration of antibodies in mice. A single administration of AAV-delivered mAb ch2H2 significantly reduced viral RNA load and infectious virions and mitigated pulmonary pathological changes in mice challenged with SARS-CoV-2 Omicron BA.5 subvariant. Collectively, the results suggest that AAV-delivered hACE2-blocking antibody provides a promising approach for developing broad-spectrum antivirals against SARS-CoV-2 and potentially other hACE2-dependent pathogens that may emerge in the future.

A booster dose of Delta × Omicron hybrid mRNA vaccine produced broadly neutralizing antibody against Omicron and other SARS-CoV-2 variants

BACKGROUND

With the continuous emergence of new SARS-CoV-2 variants that feature increased transmission and immune escape, there is an urgent demand for a better vaccine design that will provide broader neutralizing efficacy.

METHODS

We report an mRNA-based vaccine using an engineered "hybrid" receptor binding domain (RBD) that contains all 16 point-mutations shown in the currently prevailing Omicron and Delta variants.

RESULTS

A booster dose of hybrid vaccine in mice previously immunized with wild-type RBD vaccine induced high titers of broadly neutralizing antibodies against all tested SARS-CoV-2 variants of concern (VOCs). In naïve mice, hybrid vaccine generated strong Omicron-specific neutralizing antibodies as well as low but significant titers against other VOCs. Hybrid vaccine also elicited CD8+/IFN-γ+ T cell responses against a conserved T cell epitope present in wild type and all VOCs.

CONCLUSIONS

These results demonstrate that inclusion of different antigenic mutations from various SARS-CoV-2 variants is a feasible approach to develop cross-protective vaccines.

[Course of disease and related epidemiological parameters of COVID-19: a prospective study based on contact tracing cohort]

Objective: To analyze the course of disease and epidemiological parameters of COVID-19 and provide evidence for making prevention and control strategies. Methods: To display the distribution of course of disease of the infectors who had close contacts with COVID-19 cases from January 1 to March 15, 2020 in Guangdong Provincial, the models of Lognormal, Weibull and gamma distribution were applied. A descriptive analysis was conducted on the basic characteristics and epidemiological parameters of course of disease. Results: In total, 515 of 11 580 close contacts were infected, with an attack rate about 4.4%, including 449 confirmed cases and 66 asymptomatic cases. Lognormal distribution was fitting best for latent period, incubation period, pre-symptomatic infection period of confirmed cases and infection period of asymptomatic cases; Gamma distribution was fitting best for infectious period and clinical symptom period of confirmed cases; Weibull distribution was fitting best for latent period of asymptomatic cases. The latent period, incubation period, pre-symptomatic infection period, infectious period and clinical symptoms period of confirmed cases were 4.50 (95%CI:3.86-5.13) days, 5.12 (95%CI:4.63-5.62) days, 0.87 (95%CI:0.67-1.07) days, 11.89 (95%CI:9.81-13.98) days and 22.00 (95%CI:21.24-22.77) days, respectively. The latent period and infectious period of asymptomatic cases were 8.88 (95%CI:6.89-10.86) days and 6.18 (95%CI:1.89-10.47) days, respectively. Conclusion: The estimated course of COVID-19 and related epidemiological parameters are similar to the existing data.

[Clinical effects of retrograde anterolateral thigh perforator flaps assisted with computed tomography angiography in repairing skin and soft tissue defects around the knee or in proximal lower leg]

Objective: To investigate the clinical effects of retrograde anterolateral thigh perforator flaps assisted with computed tomography angiography (CTA) in repairing skin and soft tissue defects around the knee or in proximal lower leg. Methods: A retrospective cohort study was conducted. From May 2015 to October 2019, 17 patients with skin and soft tissue defects around the knee or in proximal lower leg were admitted to the Department of Orthopedics of Jizhong Energy Xingtai Mig General Hospital, including 12 males and 5 females, aged 16-65 years, with an average age of 35 years. The areas of skin and soft tissue defects after debridement ranged from 6.0 cm×3.0 cm to 15.0 cm×9.0 cm. The retrograde anterolateral thigh perforator flaps were designed according to the origin and distribution of the perforating branches in flaps and the length of the vascular pedicle examined with CTA and the condition of the wound to repair the wounds. The areas of resected flaps ranged from 6.5 cm×3.5 cm to 15.5 cm×9.5 cm. The wounds in donor sites of flaps were sutured directly or covered with medium-thickness skin grafts from healthy upper leg. The sources of the perforating branches in flaps were recorded. The lateral circumflex femoral artery, its branches, and the relative length of the vascular pedicle were compared between preoperative CTA detection and intraoperative observation. The survivals of the flaps were observed. At the last follow-up, the effects of flaps in repairing wounds were evaluated according to evaluation standard of efficacy satisfaction; the motion ranges of flexion and extension of the knee joint were measured, and the knee joint function was evaluated according to the Hohl knee joint function evaluation standard; the sensory function in the flap area was evaluated according to the sensory function evaluation standard formulated by the British Medical Research Council; the wound healing and the occurrence of complication affecting motor function of limb of flap donor sites was observed. Data were statistically analyzed with paired sample t test. Results: The perforating branches in flaps originated from descending branches, oblique branches, and rectus femoris branches of lateral circumflex femoral artery in 7, 6, and 4 patients, respectively. The flaps with blood supply from descending branches, oblique branches, and rectus femoris branches of lateral circumflex femoral artery were type 1, 2, and 3 retrograde anterolateral thigh perforator flaps, respectively. The preoperative CTA examination of lateral circumflex femoral artery and its branches were consistent with those observed during operation. The relative lengths of vascular pedicles of type 1, 2, and 3 retrograde anterolateral thigh perforator flaps calculated after CTA examination were 0.32±0.13, 0.56±0.07, and 0.56±0.15, which were close to 0.35±0.12, 0.52±0.10, and 0.53±0.12 measured and calculated during operation, respectively (t=0.45, 0.80, 0.31, P>0.05). All flaps survived in 17 cases without vascular crisis. At the last follow-up, 16 patients were satisfied with effects of flaps in wound repair, with 1 patient feeling average about the effect; the flexion range of knee joint was 100-120°, and the extension range of knee joint was -2-0°; knee joint function was evaluated as excellent in 9 cases, good in 7 cases, and poor in 1 case; the sensory function of the flap area reached S₄ level in 2 cases, S₃ level in 8 cases, and S₂ level in 7 cases; the wounds in flap donor sites healed well; there was no adverse effect in motor function of limbs. Conclusions: Retrograde anterolateral thigh perforator flap is an effective method for repairing skin and soft tissue defects around the knee or in proximal lower leg. Preoperative CTA examination can fully show the anatomical characteristics of the branches of the lateral circumflex femoral artery and the perforating vessels of each branch, which can guide preoperative flap design and operation, thus shortening operation time and improving flap survival rate, with good clinical effects.

Efficiency-based recruitment plan for chained quick-service enterprise

This paper describes a research method called two-stage design consisting of the determination of the efficiency for each quick-service restaurant of chained enterprise at the first stage by using Data Envelopment Analysis (DEA), and then proposes an approach of Recruitment and Allocation (RA) plan for supporting the everlasting running of the enterprise in the second stage. The technical efficiency, the scale efficiency, the production efficiency, and the return to scale are conducted in the first stage of this two-stage research design. In addition, this study also proposes the potentially improved value to promote the relative efficiency of each chained restaurant through the improvement of inputs or outputs items. Besides, the RA plan is proposed in the second stage of the two-stage design. The RA plan is an efficiency-based quantitative approach to recruit employees as well as to determine the allocation of those recruited employees. This study indeed provides a constructive and quantitative approach of solving the dilemma issue “how to reasonably recruit and allocate employees” for decision makers with profound insight in the quick-service enterprise.

Growth and body composition of Meishan and Yorkshire barrows and gilts

Five barrows and five gilts of each of two breeds (Meishan [Ms] and Yorkshire [Y]) were slaughtered at birth and at 41, 71, 123, and 171 d of age and five gilts of each breed were slaughtered at 260 d of age. Major organ and visceral weights were obtained immediately postmortem (PM), whereas carcass characteristics, carcass composition, femur measurements, and two individual muscle weights were obtained 24 h PM. Linear and quadratic regression coefficients on age differed between the two breeds, in favor of Y barrows and gilts, for live weight, carcass weight, longissimus muscle area (LMA), liver, heart, spleen, and kidney weights, and femur cross-sectional, medullary, and cortical areas (P < .001), leaf fat weight, and percentage of body fat and protein. In contrast to somatic tissue, Ms gilts had uteri and ovaries that grew faster than those of Y gilts from birth to 260 d of age (P < .05), although the uterus and ovary weights were similar for both breeds by 260 d of age (P < .05). Regression coefficients differed (P < .05) between the two sexes for live, carcass, liver, lung and trachea, stomach and esophagus and leaf fat weights, dressing percentage, percentage of body protein, 10th rib backfat (TRBF) thickness (P < .001), and small intestine, kidney (P < .01), heart, and spleen weights (P < .05). Breed differences in regression coefficients differed between the two sexes for percentage of body protein and leaf fat weights (P < .05). Yorkshire pigs were larger, later-maturing pigs that grew faster from birth to 171 d of age. Yorkshire pigs slaughtered at 171 d of age had heavier total wholesale cut (WC), trimmed cut (TC), and boneless cut (BC) weights than did Ms pigs of the same age (P < .001).

Effects of porcine somatotropin on growth and carcass composition of Meishan and Yorkshire barrows

Effects of porcine somatotropin (pST) on growth and carcass characteristics of Meishan (Ms) and Yorkshire (Y) barrows given 3 mg of pST or saline daily were determined for two end points. First, 26 Ms and 26 Y barrows were treated from 119 d of age until the Y barrows reached 108 kg. Second, another 18 Ms barrows were treated to 108 kg BW. Age- and weight-matched treatments were analyzed. Results for both groups indicated pST effects (P < .05) for feed conversion (+) and intake (-), dressing percentage (-), percentage of carcass fat (-) and protein and water (+), leaf fat (-), backfat (BF) thickness (-), longissimus muscle area (LMA; +), skin thickness (+), muscle firmness and marbling scores (-), organ weights (+), belly (-), clear plate (-), ham (+), and total boneless cuts (BC; +). Somatotropin effects were also present for loin (-) and boneless Boston butt (BBB; +) in the age-matched group and for ADG (+), carcass weight (-), loin (-), jowl (-), and tenderloin (+) in the weight-matched group. Breed effects (P < .05), in favor of Y barrows, in both treatments existed for ADG (+) and feed intake (+), carcass weight (+), dressing percentage (+), LMA (+), skin thickness (-), muscle color and firmness scores (-), muscling score (+), all wholesale cuts (WC; +) except clear plate (age-matched), all trimmed cuts (TC; +) except picnic shoulder (weight-matched), and all BC (+). Breed effects, in favor of Y barrows, were also determined for carcass length (+), percentage of carcass ash (-), leaf fat (+), average BF thickness (+), and heart (-) and liver (-) weights in age-matched animals and percentage of carcass fat (-), protein (+), water (+), leaf fat (-), 10th rib, average, and P2 BF thicknesses (-), marbling score (-), femur length (-), and liver weights (+) in weight-matched animals. A higher response to pST (P < .05) was determined in Ms barrows than in Y barrows for percentage of carcass protein (+), liver (+), and heart (+) in the age-matched treatment and 10th rib BF thickness (-) and heart weight (+) in the weight-matched treatment. Yorkshire barrows treated with pST had more improved values for color score (+; age-matched) and BBB (+; weight-matched).

Carcass and muscle characteristics of Yorkshire, Meishan, Yorkshire x Meishan, Meishan x Yorkshire, Fengjing x Yorkshire, and Minzhu x Yorkshire pigs

Five barrows and five gilts from each of the following breed types, Yorkshire (Y), Meishan (Ms), Fengjing x Y, Minzhu x Y, Ms x Y, and Y x Ms were slaughtered at an average live weight of 103 kg. Carcass composition and muscle characteristics were evaluated at 24 h postmortem. Chemical characteristics and palatability attributes were evaluated on the longissimus and semimembranosus muscles. No significant interactions between breed x muscle, breed x sex, or muscle x sex were observed so data were pooled across muscle and sex. Yorkshire had higher (P < .05) carcass weight, longissimus muscle area, trimmed and boneless ham and loin weights, and boneless picnic weight than Ms and the crossbreds were intermediate between Y and Ms. Yorkshire had higher (P < .05) muscling score, untrimmed ham weight, trimmed picnic weight, and juiciness score. Yorkshire had a lower cholesterol content than Ms or crossbreds, and Y had the highest water-holding capacity. The longissimus muscle from Ms and the crossbreds was firmer than that from Y (P < .05), and muscle from Ms had a higher pigment concentration (P < .05). Yorkshire and Fengjing x Y had higher tenderness scores (P < .05).

Effect of hyperalimentation on body composition in swine

Fifty growing pigs were used in two experiments to evaluate the effects of cannulation and hyperalimentation on performance and body composition responses. Surgical implantation of a cannula into the greater curvature of the stomach and subsequent management associated with maintenance of the cannula did not result in a reduction (P > .05) of voluntary feed intake. Cannulation did not negatively affect gain (P > .05). Over the entire trial, feed efficiency was not changed by cannulation (P > .05). Cannulation itself did not affect protein or fat deposition (P > .05) in the carcass. Hyperalimentation to approximately 120% of control intake resulted in increased daily gain (P < .05) and similar feed efficiency (P > .05) compared with that of control animals. Hyperalimentation decreased protein deposition (P < .05) and tended to increase fat deposition.

DMSO potentiates aminonucleoside of puromycin nephrosis in rats

Dimethyl sulphoxide (DMSO), 3 g/kg body weight, administered daily by the intraperitoneal route, potentiated the proteinuria and formation of tubular casts in aminonucleoside of puromycin (PA) induced nephrosis in Sprague-Dawley rats. The effect was evident at 4 as well as 8-9 days following PA administration. In the absence of PA, DMSO did not induce proteinuria or cast formation. The mechanism by which DMSO enhanced proteinuria and cast formation is not known.