ABSTRACT
Vaccines that induce potent neutralizing antibody (NAb) responses against emerging variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are essential for combating the coronavirus disease 2019 (COVID-19) pandemic. We demonstrated that mouse plasma induced by self-assembling protein nanoparticles (SApNPs) that present 20 rationally designed S2G{Delta}HR2 spikes of the ancestral Wuhan-Hu-1 strain can neutralize the B.1.1.7, B.1.351, P.1, and B.1.617 variants with the same potency. The adjuvant effect on vaccine-induced immunity was investigated by testing 16 formulations for the multilayered I3-01v9 SApNP. Using single-cell sorting, monoclonal antibodies (mAbs) with diverse neutralization breadth and potency were isolated from mice immunized with the receptor binding domain (RBD), S2G{Delta}HR2 spike, and SApNP vaccines. The mechanism of vaccine-induced immunity was examined in mice. Compared with the soluble spike, the I3-01v9 SApNP showed 6-fold longer retention, 4-fold greater presentation on follicular dendritic cell dendrites, and 5-fold stronger germinal center reactions in lymph node follicles. ONE-SENTENCE SUMMARYWith a well-defined mechanism, spike nanoparticle vaccines can effectively counter SARS-CoV-2 variants.
ABSTRACT
Objective:To explore the effect of post-pyloric feeding by spiral nasoenteric tubes on the prognosis of critically ill patients with acute gastrointestinal injury (AGI) grade Ⅱ.Methods:A retrospective study was performed to analyze the clinical data of critically ill adult patients with AGI grade Ⅱ, who were enrolled in three randomized controlled trials conducted by Guangdong Provincial People's Hospital for post-pyloric tube placement between April 2012 and May 2019. Data including demographic characteristics, serological indicators of nutrition, the tube tip position confirmed by abdominal X-ray 24 h after tube insertion, and intensive care unit (ICU), 28-day and hospital mortality were collected. Patients were divided into the post-pyloric feeding group and gastric feeding group according to the tube tip position. Propensity score matching method was used to perform 1:1 matching, and the differences of each index between the two groups were compared after matching. Then the influencing factors of P<0.1 were included in multivariate logistic regression analysis to investigate the potential ICU mortality risk factors of critically ill patients with AGI gradeⅡ. Factors with 0.1 level of significance from the univariate analysis were considered in the multivariate analysis. Results:There were 90 patients in post-pyloric feeding group and 90 patients in the gastric feeding group. Demographics and clinical characteristics of study population were well balanced between the two groups after matching. ICU, 28-day and hospital mortality in the post-pyloric feeding group were significantly lower than those in the gastric feeding group (4.4% vs 15.6%, 14.4% vs 27.8%, 6.7% vs 17.8%, all P < 0.05). Multivariate logistic regression analysis indicated that post-pyloric feeding was an independent protective factor [odds ratio ( OR)=0.295, 95% confidence internal (95% CI): 0.091-0.959, P=0.042] and APACHEⅡ score was an independent risk factor ( OR=1.111, 95% CI: 1.025-1.203, P=0.010) for ICU mortality of critically ill patients with AGI gradeⅡ. Conclusions:Post-pyloric feeding for critically ill patients with AGI grade Ⅱ could decrease ICU mortality and is an independent protective factor against mortality.
ABSTRACT
Vaccination against SARS-CoV-2 provides an effective tool to combat the COIVD-19 pandemic. Here, we combined antigen optimization and nanoparticle display to develop vaccine candidates for SARS-CoV-2. We first displayed the receptor-binding domain (RBD) on three self-assembling protein nanoparticle (SApNP) platforms using the SpyTag/SpyCatcher system. We then identified heptad repeat 2 (HR2) in S2 as the cause of spike metastability, designed an HR2-deleted glycine-capped spike (S2G{Delta}HR2), and displayed S2G{Delta}HR2 on SApNPs. An antibody column specific for the RBD enabled tag-free vaccine purification. In mice, the 24-meric RBD-ferritin SApNP elicited a more potent neutralizing antibody (NAb) response than the RBD alone and the spike with two stabilizing proline mutations in S2 (S2P). S2G{Delta}HR2 elicited two-fold-higher NAb titers than S2P, while S2G{Delta}HR2 SApNPs derived from multilayered E2p and I3-01v9 60-mers elicited up to 10-fold higher NAb titers. The S2G{Delta}HR2-presenting I3-01v9 SApNP also induced critically needed T-cell immunity, thereby providing a promising vaccine candidate. ONE-SENTENCE SUMMARYThe SARS-CoV-2 receptor binding domain and S2G{Delta}HR2 spike elicited potent immune responses when displayed on protein nanoparticles as vaccine candidates.
