Delivery of antigen to porcine dendritic cells by fusing antigen with porcine dendritic cells targeting peptide.

Dendritic cells (DCs) are professional antigen-presenting cells that can recognize, capture, and process antigens. Fusing molecules targeting DCs with antigens can effectively improve the efficiency with which antigens are recognized and captured by DCs. This targeting strategy can be used for vaccine development to effectively improve the efficiency of antigen recognition and capture by DCs. The targeting sequence of porcine cytotoxic T-lymphocyte associated protein 4 (CTLA4), which binds porcine DCs, was identified in this study. Recombinant Lactobacillus reuteri (L. reuteri) expressing CTLA4-6aa (LYPPPY) and CTLA4-87aa fused to the porcine epidemic diarrhea virus (PEDV) protective antigen core neutralizing epitope (COE) were used to evaluate the ability of the two targeting motifs to bind the B7 molecule on DCs. Our results demonstrate that CTLA4-6aa could bind porcine DCs, and recombinant Lactobacillus expressing the CTLA4-6aa captured by porcine DCs was more efficient than those expressing CTLA4-87aa. In addition, the expression of DC markers, toll-like receptors, and cytokines was significantly higher in the 6aa-COE/L. reuteri-stimulated porcine DCs compared to DCs treated with 87aa-COE/L. reuteri (p<0.01) and recombinant Lactobacillus expressing CTLA4-6aa enhanced the ability of porcine DCs to activate T-cell proliferation. Our analysis of the protein structure revealed that CTLA4-87aa contains intramolecular hydrogen bonds, which may have weakened the intermolecular force between the residues on porcine CTLA4 and that on B7. In conclusion, recombinant Lactobacillus expressing CTLA4-6aa were more efficiently captured by porcine DCs and had a stronger ability to promote DC maturation and enhance T-cell proliferation. The LYPPPY motif is the optimal sequence for binding to porcine DCs. Piglets immunized with recombinant Lactobacillus showed that recombinant Lactobacillus expressing CTLA4-6aa induced significant levels of anti-PEDV-specific IgG and IgA antibody responses. Our study may promote research on DC-targeting strategies to enhance the effectiveness of porcine vaccines.

Clinical features and imaging findings in six coronavirus disease 2019 patients

Objective To summarize the clinical features and imaging findings of six coronavirus disease 2019 (COVID-19) patients, so as to provide evidences for early diagnosis and clinical intervention. Methods Six COVID-19 patients with positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were enrolled from the Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine from Jan. 1 to Feb. 22, 2020. The epidemiological history, clinical manifestations, imaging data and laboratory indicators were retrospectively analyzed. Results All six patients had a clear travel or residence history in Wuhan. Four patients had fever, three had cough, two had upper respiratory tract symptoms such as runny nose and sore throat, and two had systemic symptoms such as headache and muscle ache. Chest computed tomography (CT) showed that all the six patients had abnormal manifestations in bilateral lungs, and the lower lung lesions were more common than the upper lung lesions. The main manifestations were multiple ground-glass opacities, consolidation shadows, crazy paving sign and different degrees of fibrosis in lateral field of bilateral lungs. Chest CT examination later after onset showed lung consolidation and severe fibrosis. Conclusion The imaging of COVID-19 has special characteristics. Combined with the epidemiological history, clinical manifestations and the detection of SARS-CoV-2 nucleic acid, COVID-19 can be effectively diagnosed in the early stage.

Lessons learned from early compassionate use of convalescent plasma on critically ill patients with Covid-19.

BACKGROUND: The management of critically ill patients with coronavirus disease 2019 (COVID-19), caused by a new human virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is challenging. Recently, there have been several reports with inconsistent results after treatment with convalescent plasma (CP) on critically ill patients with COVID-19, which was produced with a neutralizing antibody titer and tested in a P3 or P4 laboratory. However, due to the limitation of the conditions on mass production of plasma, most producers hardly had the capability to isolate the neutralizing antibody. Here, we report the clinical courses of three critically ill patients with COVID-19 receiving CP treatments by total immunoglobulin G (IgG) titer collection. METHODS: Three patients with COVID-19 in this study were laboratory confirmed to be positive for SARS-CoV-2, with radiographic and clinical features of pneumonia. CP was collected by total IgG titer of 160 (range, 200-225 mL), and patients were transfused between 20 and 30 days after disease onset at the critical illness stage as a trial in addition to standard care. The clinical courses of these patients, including laboratory results and pulmonary functional and image studies after receiving convalescent plasma infusions, were reviewed. RESULTS: No therapeutic effect of CP was observed in any of the patients; instead, all three patients deteriorated and required extracorporeal membrane oxygenation treatment. A potential cytokine storm 4 hours after infusion of CP in Patient 2 was observed. No more patients were put on the trial of CP transfusion. CONCLUSIONS: We recommend extreme caution in using CP in critically ill patients more than 2 weeks after the onset of COVID-19 pneumonia.