Epitope-based vaccines designed to induce antibody responses specific for severe acute respiratory syndrome-associated coronavirus (SARS-CoV) are being developed as a means for increasing vaccine potency. In this study, we identified four B cell epitopes from the spike (S) and membrane (M) protein through bioinformatics analysis and constructed a multi-epitope DNA vaccine. Intramuscular immunization of mice with this vaccine was sufficient to induce specific prime as well as a long-term memory humoral immune response to at least two candidate epitopes, S(437-459) and M(1-20). A DNA prime-protein boost strategy greatly enhanced the antibody generation and the immune sera not only reacted with the lysates of SARS-CoV-infected Vero cells but also neutralized the cytopathic effect of SARS by 75% at 1:160 dilution. The novel immunogenic S protein peptide revealed in this study provides new target for SARS vaccine design; and our work indicated multi-epitope DNA vaccine as an effective means for eliciting polyvalent humoral immune response against SARS-CoV.

Epitope-based DNA vaccines designed to induce T cell responses specific for Mycobacterium tuberculosis (M. tb) are being developed as a means of addressing vaccine potency. In this study, we predicted 4 T cell epitopes from ESAT-6, Ag85A/B and CFP-10 antigens and constructed an ECANS (epitopes casted in a natural structure) DNA vaccine by inserting the epitope DNA segments separately into the gene backbone of M. tb-derived HSP65 (heat shock protein 65) carrier. The immunogenicity and protective efficacy of pECANS DNA vaccine were assessed in BALB/c mice after intramuscular immunization with 4 doses of 50 microg ECANS DNA and followed by mycobaterial challenge 4 weeks after the last immunization. Compared to plasmid encoding HSP65, pECANS DNA immunization elicited remarkably higher levels of IFN-gamma production by both CD4(+) and CD8(+) T cells, which were coupled with higher frequencies of antigen-specific T cells and higher CTL activity. Significantly enhanced levels of Th1 cytokines (IFN-gamma and IL-12) and increased serum IgG2a/IgG1 ratio were also noted, indicating a predominant Th1 immune response achieved by pECANS DNA immunization. In the consequence, a better protection against Mycobacterium bovis BCG challenge was achieved which was evidenced by reduced bacterial loads in lungs and spleens and profound attenuation of lung inflammation and injury. Our results suggested that multi-T cell-epitope based ECANS gene vaccine induced T cell response to multiple T cell epitopes and led to enhanced protection against mycobacterial challenge. This strategy might be a useful platform to design multi-T cell epitope-based vaccine against M. tb infection.

Background The shortage of healthcare workers is becoming a serious global problem. The underlying reasons may be specific to the healthcare system in each country. Over the past decade, medicine has become an increasingly unpopular profession in China due to the heavy workload, long-term training, and inherent risks. The ongoing COVID-19 pandemic has placed the life-saving roles of healthcare professionals under the spotlight. This public health crisis may have a profound impact on career choices in Chinese population. Methods We conducted a questionnaire-based online survey among 21,085 senior high school students and 21,009 parents from 24 provinces (or municipalities) of China. We investigated the change of interest in medical study due to the outbreak of COVID-19 and the potential motivational factors based on the expectancy-value theory framework. Pearson correlation analysis was used to assess the correlation of static or dynamic interest in medical career pursuit with the reported number of COVID-19 cases. Logistic regression model was adopted to analyze the main factors associated with students’ choices. Results We observed an increased preference for medical study post the outbreak of COVID-19 in both students (17.5 to 29.6%) and parents (37.1 to 47.3%). Attainment value was found to be the main reason for the choice among students, with the contribution to society rated as the top motivation. On the other hand, the predominant demotivation in high school students was lack of interest, followed by concerns regarding violence against doctors, heavy workload, long-term training and heavy responsibility as a doctor. Additionally, students who were female, in the resit of final year, had highly educated parents and outside of Hubei province were significantly associated with a keen interest in pursuing medical study. Conclusions This is the first multi-center cross-sectional study exploring the positive change and motivations of students’ preferences in medical study due to the outbreak of COVID-19. Our results may help medical educators, researchers and policymakers to restructure medical education to make it more appealing to high school students, particularly, to develop a more supportive social and working environment for medical professionals to maintain the observed enhanced enthusiasm.

TB is a chronic infectious disease caused by MTB. Because of HIV & MTB co-infection and the appearance of multidrug-resistant tuberculosis, there are 8.5 million new cases of tuberculosis in the world annually, causing at least 2 million deaths (1). TB is also one of the most prevalent diseases in developing countries (2). Currently, the only List of Abbreviations:Aa, amino acid(s), BCG, bacillus Calmette-Guérin; CFSE, carboxyfluorescein succinimidyl ester; CFU, colony forming unit; cpm, counts per minute; CTL, cytotoxic T lymphocytes; DC, dendritic cells; DNA-HSP65, DNA vaccine encoding the Mycobacterium leprae 65 kDa heat shock protein; ECANS, epitopes cast in a natural structure; ELISA, enzyme linked immunosorbent assay; FITC, fluorescein isothiocyanate; GAPDH, glyceraldehyde phosphate dehydrogenase; HRP, horseradish peroxidase; HSP65, heat shock protein 65; IFN-γ, interferon γ; MHC, major histocompatibility complex; MTB, Mycobacterium tuberculosis; PBS/Tween, PBS containing 0.05% Tween 20; PerCP, peridinin-chlorophyll-protein complex; PI, propidium iodide; PPD, purified protein derivative of tuberculin; RT, room temperature; TB, tuberculosis; TMB, 3,3,5,5-tetramethyl benzidin; TNF-α, tumor necrosis factor-α. available vaccine against TB is BCG. However, several trials conducted in different parts of the world have shown that this vaccine does not always provide consistent protection against the disease (3). A novel, effective vaccination strategy against TB has therefore become an international research priority. Research and development in this

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