ABSTRACT
There is an urgent need to limit and stop the worldwide coronavirus disease 2019 (COVID-19) pandemic via quick development of efficient and safe vaccination methods. Plasmid DNA vaccines are one of the most remarkable vaccines that can be developed in a short term. pVAX1-SARS-CoV2-co, which is a plasmid DNA vaccine, was designed to express severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike protein. The produced antibodies lead to Immunoreactions against S protein, anti-receptor-binding-domain, and neutralizing action of pVAX1-SARS-CoV2-co, as confirmed in a previous study. To promote the efficacy of the pVAX1-SARS-CoV2-co vaccine, a pyro-drive jet injector (PJI) was employed. PJI is an injection device that can adjust the injection pressure depending on various target tissues. Intradermally-adjusted PJI demonstrated that pVAX1-SARS-CoV2-co vaccine injection caused a strong production of anti-S protein antibodies, triggered immunoreactions and neutralizing actions against SARS-CoV-2. Moreover, a high dose of pVAX1-SARS-CoV2-co intradermal injection via PJI did not cause any serious disorders in the rat model. Finally, virus infection challenge in mice, confirmed that intradermally immunized (via PJI) mice were potently protected from COVID-19 infection. Thus, pVAX1-SARS-CoV2-co intradermal injection via PJI is a safe and promising vaccination method to overcome the COVID-19 pandemic.
ABSTRACT
To fight against the worldwide COVID-19 pandemic, the development of an effective and safe vaccine against SARS-CoV-2 is required. As potential pandemic vaccines, DNA/RNA vaccines, viral vector vaccines and protein-based vaccines have been rapidly developed to prevent pandemic spread worldwide. In this study, we designed plasmid DNA vaccine targeting the SARS-CoV-2 Spike glycoprotein (S protein) as pandemic vaccine, and the humoral, cellular, and functional immune responses were characterized to support proceeding to initial human clinical trials. After intramuscular injection of DNA vaccine encoding S protein with alum adjuvant (three times at 2-week intervals), the humoral immunoreaction, as assessed by anti-S protein or anti-receptor-binding domain (RBD) antibody titers, and the cellular immunoreaction, as assessed by antigen-induced IFN{gamma} expression, were up-regulated. In IgG subclass analysis, IgG2b was induced as the main subclass. Based on these analyses, DNA vaccine with alum adjuvant preferentially induced Th1-type T cell polarization. We confirmed the neutralizing action of DNA vaccine-induced antibodies via two different methods, a binding assay of RBD recombinant protein with angiotensin-converting enzyme 2 (ACE2), a receptor of SARS-CoV-2, and pseudovirus assay. Further B cell epitope mapping analysis using a peptide array showed that most vaccine-induced antibodies recognized the S2 and RBD subunits, but not the S1 subunit. In conclusion, DNA vaccine targeting the spike glycoprotein of SARS-CoV-2 might be an effective and safe approach to combat the COVID-19 pandemic.
ABSTRACT
The aim of this study is to understand adaptive immunity to SARS-CoV-2 through the analysis of B cell epitope and neutralizing activity in coronavirus disease 2019 (COVID-19) patients. We obtained serum from thirteen COVID-19 patients. Most individuals revealed neutralizing activity against SARS-CoV-2 assessed by a pseudotype virus-neutralizing assay. The antibody production against the spike glycoprotein (S protein) or receptor-binding domain (RBD) of SARS-CoV-2 was elevated, with large individual differences, as assessed by ELISA. In the analysis of the predicted the linear B cell epitopes, two regions (671-690 aa. and 1146-1164 aa.), which were located in S1 and S2 but not in the RBD, were highly reactive with the sera from patients. In the further analysis of the B cell epitope within the S protein by utilizing a B cell epitope array, a hot spot in the N-terminal domain of the S protein but not the RBD was observed in individuals with neutralizing activity. Overall, the analysis of antibody production and B cell epitopes of the S protein from patient serum may provide a novel target for the vaccine development against SARS-CoV-2.
ABSTRACT
The patient was a 57-year-old man who, in 1973, at 19 years of age, had undergone mitral valve replacement for mitral valve stenosis using a Björk-Shiley Delrin (BSD) valve. When the patient visited our hospital, he was living in an assisted-living facility due to paresis of the right side of the body, dysarthria, and other sequelae of cerebral infarction. The patient was referred to and visited our hospital with a chief complaint of chest pain in 2011, 38 years after the BSD valve was implanted. In 2012, mitral valve re-replacement, aortic valve replacement, and tricuspid annuloplasty were performed for congestive heart failure associated with prosthetic valve failure, combined aortic stenosis and insufficiency, and tricuspid insufficiency, which were identified by transesophageal echocardiography. The patient's postoperative course was generally favorable. The disc of the resected prosthetic valve showed a groove and bidirectional cracks caused by wear, and its condition suggested a risk of potential rupture. Transthoracic echocardiography on admission showed mild to moderate prosthetic transvalvular regurgitation, and the symptoms were therefore unlikely to have resulted from the prosthetic valve failure alone at this time. Consequently, it was considered that the heart failure was attributed to the prosthetic transvalvular regurgitation caused by the disc abnormalities in addition to the combined valvular disease by transesophageal echocardiography. In this case, detailed investigation of the heart failure by transesophageal echocardiography led to the discovery of prosthetic valve abnormalities, thus enabling the prevention of a serious cardiac accident due to disc rupture. Detailed examination by transesophageal echocardiography is essential, and early surgical intervention should also be considered if transthoracic echocardiography suggests even a minor prosthetic valve abnormality in a patient who has had this prosthetic valve implanted for such a long time.
ABSTRACT
Reconstruction of the right ventriclar outflow tract (RVOT) in congenital heart disease often requires implantation of a valved conduit. A hand-made expanded polytetrafluoroethylene (ePTFE) trileaflet Dacron graft conduit has been used at our center since 1997, and has been implanted in 31 patients. Midterm results of this conduit were investigated in 30 of the patients who have been followed at our outpatient clinic. There were 16 males and 14 females. The mean age and body weight were 16.4±7.2 (range, 3.4-33.4) years and 41.7±13.3 (range, 13.0-64.0)kg, respectively. Diagnoses were tetralogy of Fallot with pulmonary atresia in 14 patients, RVOT reconstruction associated with Ross procedure in 8, transposition with pulmonary stenosis in 3, pulmonary atresia with intact ventricular septum in 2, tetralogy with absent pulmonary valve syndrome in 1, pulmonary regurgitation developed after tetralogy repair in 1, and hemitruncus in 1. The median size of the graft was 22 (range, 20-26)mm. All patients were in NYHA functional class I at the time of the latest follow-up. The pressure gradient across the conduit was 11.0±5.8mmHg during the same hospitalization and 13.8±6.5mmHg on the latest echocardiogram (Interval, 2.4±1.5 years, <i>p</i>=0.85). The valve function was well maintained in all patients, with the regurgitation graded as non-trivial in 22 patients, mild in 7, and moderate in only 1. Midterm results of hand-made ePTFE trileaflet valved cunduit was satisfactory. A longer follow-up is mandatory to assess its actual durability.
