[Predictive value of postoperative serum procalcitonin concentration for moderate to severe acute respiratory distress syndrome in patients undergoing cardiopulmonary bypass surgery].

OBJECTIVE: To explore the changes of serum procalcitonin (PCT) level in patients with moderate and severe acute respiratory distress syndrome (ARDS) after cardiac surgery under cardiopulmonary bypass (CPB), and try to find out the best cut-off of PCT to predict the progression to moderate and severe ARDS. METHODS: Medical records of patients undergoing cardiac surgery with CPB in Fujian Provincial Hospital from January 2017 to December 2019 were retrospectively analyzed. Adult patients who were admitted in intensive care unit (ICU) for more than 1 day and had PCT values on the first postoperative day were enrolled. Clinical data such as patient demographics, past history, diagnosis, and New York Heart Association (HYHA) classification, and the operation mode, procedure duration, CPB duration, aortic clamp duration, intraoperative fluid balance, calculation of 24 hours postoperative fluid balance and vasoactive-inotropic score (VIS); 24 hours postoperative C-reactive protein (CRP), N-terminal B-type natriuretic peptide precursor (NT-proBNP) and PCT levels were collected. Two clinicians independently made the diagnosis of ARDS according to the Berlin definition, and the diagnosis was established only in patients with a consistent diagnosis. The differences in each parameter were compared between patients with moderate to severe ARDS and those without or with mild ARDS. Analysis of the ability of PCT to predict moderate to severe ARDS was evaluated by receiver operator characteristic curve (ROC curve). Multivariate Logistic regression was conducted to determine the risk factors of the development of moderate to severe ARDS. RESULTS: 108 patients were finally enrolled, including 37 patients with mild ARDS (34.3%), 35 patients with moderate ARDS (32.4%), 2 patients with severe ARDS (1.9%), and 34 patients without ARDS. Compared with patients with no or mild ARDS, patients with moderate to severe ARDS were older (years old: 58.5±11.1 vs. 52.8±14.8, P < 0.05), with a higher proportion of combined hypertension [45.9% (17/37) vs. 25.4% (18/71), P < 0.05], longer operative time (minutes: 363.2±120.6 vs. 313.5±97.6, P < 0.05), and higher mortality (8.1% vs. 0, P < 0.05), but there were no differences in the VIS score, incidence of acute renal failure (ARF), CPB duration, aortic clamp duration, and intraoperative bleeding, transfusion volume, and fluid balance between the two groups. Serum PCT and NT-proBNP levels in patients with moderate to severe ARDS at postoperative day 1 were significantly higher than those in patients with no or mild ARDS [PCT (µg/L): 16.33 (6.96, 32.56) vs. 2.21 (0.80, 5.76), NT-proBNP (ng/L): 2 405.0 (1 543.0, 6 456.5) vs. 1 680.0 (1 388.0, 4 667.0), both P < 0.05]. ROC curve analysis showed that the area under the curve (AUC) for PCT to predict the occurrence of moderate to severe ARDS was 0.827 [95% confidence interval (95%CI) was 0.739-0.915, P < 0.05]. When PCT cut-off value was 7.165 µg/L, the sensitivity was 75.7% and the specificity was 84.5%, for differentiating patients who developed moderate to severe ARDS from who did not. Multivariate Logistic regression showed that age and the elevated PCT concentration were independent risk factors for the development of moderate to severe ARDS [age: odds ratio (OR) = 1.105, 95%CI was 1.037-1.177, P = 0.002; PCT: OR = 48.286, 95%CI was 10.282-226.753, P < 0.001]. CONCLUSIONS: Patients with moderate to severe ARDS undergoing CPB cardiac surgery have a higher serum concentration of PCT than patients with no or mild ARDS. Serum PCT level may be a promising biomarker to predict the development of moderate to severe ARDS, the cut-off value is 7.165 µg/L.

Patient hematology during hospitalization for viral pneumonia caused by SARS-CoV-2 and non-SARS-CoV-2 agents: a retrospective study.

BACKGROUND: Hematological comparison of coronavirus disease (COVID-19) and other viral pneumonias can provide insights into COVID-19 treatment. METHODS: In this retrospective case-control single-center study, we compared the data of 126 patients with viral pneumonia during different outbreaks [severe acute respiratory syndrome (SARS) in 2003, influenza A (H1N1) in 2009, human adenovirus type 7 in 2018, and COVID-19 in 2020]. RESULTS: One of the COVID-19 characteristics was a continuous decline in the hemoglobin level. The neutrophil count was related to the aggravation of COVID-19 and SARS. Thrombocytopenia occurred in patients with SARS and severe COVID-19 even at the recovery stage. Lymphocytes were related to the entire course of adenovirus infection, recovery of COVID-19, and disease development of SARS. CONCLUSIONS: Dynamic changes in hematological counts could provide a reference for the pathogenesis and prognosis of pneumonia caused by respiratory viruses in clinics.

Recent Findings on Cell-Based Therapies for COVID19-Related Pulmonary Fibrosis.

COVID-19 has spread worldwide, including the United States, United Kingdom, and Italy, along with its site of origin in China, since 2020. The virus was first found in the Wuhan seafood market at the end of 2019, with a controversial source. The clinical symptoms of COVID-19 include fever, cough, and respiratory tract inflammation, with some severe patients developing an acute and chronic lung injury, such as acute respiratory distress syndrome (ARDS) and pulmonary fibrosis (PF). It has already claimed approximately 300 thousand human lives and the number is still on the rise; the only way to prevent the infection is to be safe till vaccines and reliable treatments develop. In previous studies, the use of mesenchymal stem cells (MSCs) in clinical trials had been proven to be effective in immune modulation and tissue repair promotion; however, their efficacy in treating COVID-19 remains underestimated. Here, we report the findings from past experiences of SARS and MSCs, and how SARS could also induce PF. Such studies may help to understand the rationale for the recent cell-based therapies for COVID-19.

COVID-19, microthromboses, inflammation, and platelet activating factor.

Recent articles report elevated markers of coagulation, endothelial injury, and microthromboses in lungs from deceased COVID-19 patients. However, there has been no discussion of what may induce intravascular coagulation. Platelets are critical in the formation of thrombi and their most potent trigger is platelet activating factor (PAF), first characterized by Demopoulos and colleagues in 1979. PAF is produced by cells involved in host defense and its biological actions bear similarities with COVID-19 disease manifestations. PAF can also stimulate perivascular mast cell activation, leading to inflammation implicated in severe acute respiratory syndrome (SARS). Mast cells are plentiful in the lungs and are a rich source of PAF and of inflammatory cytokines, such as IL-1ß and IL-6, which may contribute to COVID-19 and especially SARS. The histamine-1 receptor antagonist rupatadine was developed to have anti-PAF activity, and also inhibits activation of human mast cells in response to PAF. Rupatadine could be repurposed for COVID-19 prophylaxis alone or together with other PAF-inhibitors of natural origin such as the flavonoids quercetin and luteolin, which have antiviral, anti-inflammatory, and anti-PAF actions.

Genetic variation of the human α-2-Heremans-Schmid glycoprotein (AHSG) gene associated with the risk of SARS-CoV infection.

Genetic background may play an important role in the process of SARS-CoV infection and SARS development. We found several proteins that could interact with the nucleocapsid protein of the SARS coronavirus (SARS-CoV). α-2-Heremans-Schmid Glycoprotein (AHSG), which is required for macrophage deactivation by endogenous cations, is associated with inflammatory regulation. Cytochrome P450 Family 3A (CYP4F3A) is an ω-oxidase that inactivates Leukotriene B4 (LTB4) in human neutrophils and the liver. We investigated the association between the polymorphisms of these two inflammation-associated genes and SARS development. The linkage disequilibrium (LD) maps of these two genes were built with Haploview using data on CHB+JPT (version 2) from the HapMap. A total of ten tag SNPs were selected and genotyped. In the Guangzhou cohort study, after adjusting for age and sex, two AHSG SNPs and one CYP4F3 SNP were found to be associated with SARS susceptibility: rs2248690 (adjusted odds ratio [AOR] 2.42; 95% confidence interval [CI] 1.30-4.51); rs4917 (AOR 1.84; 95% CI 1.02-3.34); and rs3794987 (AOR 2.01; 95% CI 1.10-3.68). To further validate the association, the ten tag SNPs were genotyped in the Beijing cohort. After adjusting for age and sex, only rs2248690 (AOR, 1.63; 95% CI, 1.30-2.04) was found to be associated with SARS susceptibility. The combined analysis of the two studies confirmed tag SNP rs2248690 in AHSG as a susceptibility variant (AOR 1.70; 95% CI 1.37-2.09). The statistical analysis of the rs2248690 genotype data among the patients and healthy controls in the HCW cohort, who were all similarly exposed to the SARS virus, also supported the findings. Further, the SNP rs2248690 affected the transcriptional activity of the AHSG promoter and thus regulated the AHSG serum level. Therefore, our study has demonstrated that the AA genotype of rs2268690, which leads to a higher AHSG serum concentration, was significantly associated with protection against SARS development.

[Study on the changing regularity of special antibody and expression of stomach and enteric involvement on SARS-coronavirus infection in the recovery period of severe acute respiratory syndrome].

OBJECTIVE: To study the change of special antibodies titer IgG, IgM and nucleocapsid to SARS coronavirus (CoV) and observing the expression of stomach and enteric involvement on SARS-CoV infection by monoclonal antibody against N protein of SARS-CoV in the 7-year recovery period among family clustering cases of severe acute respiratory syndrome. METHODS: Special antibody titer to SARS-CoV of 14 patients from 5 different families and their 10 kinfolks continuously tested by IFA and antigen-capturing ELISA methods. Samples were taken in the 1(st) - 7(th) year periods after SARS patients infected by SARS-CoV, being diluted and measured on it titers of three kinds of antibodies. Immunochemical staining with monoclonal antibody (mAb) against N protein of SARS-CoV was used to determine the stomach and enteric tissues among 5 SARS patients with their nucleocapsid antibody titer ascended obviously after 1(st)-7(th) year. RESULTS: When testing the IgG antibody titer of the 14 SARS patients by IFA method, the average titer was 1/71 (95%CI: 1/58 - 1/85) in the 1(st) year, but began to descend in the following years, and the IgG antibody of the most SARS patients disappeared in the 7(th) year. Regarding the IgM titer, it disappeared in most of the SARS patients 1 year later. The average value of nucleocapsid antibody titer was 1/146 (95%CI: 1/122 - 1/171) in the 1(st) year, and it descended as the IgG antibody titer did. In 5 cases, differences appeared. The nucleocapsid antibody titer was between 1/156 and 1/210 in 3 cases, and 2 cases were normal. Immunochemical staining with mAb against N protein of SARS-CoV was identified in the stomach and enteric tissues of 5 SARS patients with the nucleocapsid antibody titer increased significantly, 1(st)-7(th) year later. The five patients were detected by gastroscopy detection and cell immunohistochemistry test. 3 cases showed N protein antibody positive in the serum, and positive immunohistochemical expression in most of the cytoplasm in the gastric tissue mucous gland epithelial cells. 1 case also expressed in the intestinal tissue slurry columnar epithelium and interstitial cells. The other two cases showed negative on both serum N protein antibody and immunohistochemical expression. The biopsy results of the 5 patients were as follows: 1 case diagnosed as "signet-ring cell carcinoma of the stomach and rectum multiple transfer", 1 case of gastric polyp, 1 case of superficial antral gastritis and 2 cases were normal. CONCLUSION: By testing the special IgG, IgM, nucleocapsid antibody to SARS-CoV of the 14 family clustering cases, we found that they all decreased in the 7(th) year, and most of them disappeared. The nucleocapsid antibody titer was related to pathogenetic condition. SARS-CoV was proved to be still present in stomach and enteric tissues of SARS patients with the nucleocapsid antibody titer increased significantly after the 7(th) year.

Toll-like receptors, chemokine receptors and death receptor ligands responses in SARS coronavirus infected human monocyte derived dendritic cells.

BACKGROUND: The SARS outbreak in 2003 provides a unique opportunity for the study of human responses to a novel virus. We have previously reported that dendritic cells (DCs) might be involved in the immune escape mechanisms for SARS-CoV. In this study, we focussed on the gene expression of toll-like receptors (TLRs), chemokine receptors (CCRs) and death receptor ligands in SARS-CoV infected DCs. We also compared adult and cord blood (CB) DCs to find a possible explanation for the age-dependent severity of SARS. RESULTS: Our results demonstrates that SARS-CoV did not modulate TLR-1 to TLR-10 gene expression but significantly induced the expression of CCR-1, CCR-3, and CCR-5. There was also strong induction of TNF-related apoptosis-inducing ligand (TRAIL), but not Fas ligand gene expression in SARS-CoV infected DCs. Interestingly, the expressions of most genes studied were higher in CB DCs than adult DCs. CONCLUSION: The upregulation of chemokines and CCRs may facilitate DC migration from the infection site to the lymph nodes, whereas the increase of TRAIL may induce lymphocyte apoptosis. These findings may explain the increased lung infiltrations and lymphoid depletion in SARS patients. Further explorations of the biological significance of these findings are warranted.

A chimeric multi-epitope DNA vaccine elicited specific antibody response against severe acute respiratory syndrome-associated coronavirus which attenuated the virulence of SARS-CoV in vitro.

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.

Peptide mimicrying between SARS coronavirus spike protein and human proteins reacts with SARS patient serum.

Molecular mimicry, defined as similar structures shared by molecules from dissimilar genes or proteins, is a general strategy used by pathogens to infect host cells. Severe acute respiratory syndrome (SARS) is a new human respiratory infectious disease caused by SARS coronavirus (SARS-CoV). The spike (S) protein of SARS-CoV plays an important role in the virus entry into a cell. In this study, eleven synthetic peptides from the S protein were selected based on its sequence homology with human proteins. Two of the peptides D07 (residues 927-937) and D08 (residues 942-951) were recognized by the sera of SARS patients. Murine hyperimmune sera against these peptides bound to proteins of human lung epithelial cells A549. Another peptide D10 (residues 490-502) stimulated A549 to proliferate and secrete IL-8. The present results suggest that the selected S protein regions, which share sequence homology with human proteins, may play important roles in SARS-CoV infection.

Thrombopoietin levels increased in patients with severe acute respiratory syndrome.

Hematological changes in patients with Severe Acute Respiratory Syndrome (SARS) are common and frequently include thrombocytopenia. Using a ELISA method, we found an increase in thrombopoietin (TPO) levels in the plasma of convalesced SARS patients (290+/-53 pg/ml) and active SARS patients (251+/-23 pg/ml) comparing to that from normal control patients (228+/-17 pg/ml). In addition, the plasma from active SARS patients had an inhibitory effect on CFU-MK formation, which could be neutralized by anti-TGF-beta antibodies. In the experiment to determine whether SARS-CoV can directly infect hematopoietic stem cells and megakaryocytic cells, incubation of the cells with SARS-CoV did not show active infection. Our findings of increased TPO levels in the plasma of SARS patients provide a possible explanation for the genesis of thrombocytosis, which frequently develops from thrombocytopenia in SARS patients.

Chimeric coronavirus-like particles carrying severe acute respiratory syndrome coronavirus (SCoV) S protein protect mice against challenge with SCoV.

We tested the efficacy of coronavirus-like particles (VLPs) for protecting mice against severe acute respiratory syndrome coronavirus (SCoV) infection. Coexpression of SCoV S protein and E, M and N proteins of mouse hepatitis virus in 293T or CHO cells resulted in the efficient production of chimeric VLPs carrying SCoV S protein. Balb/c mice inoculated with a mixture of chimeric VLPs and alum twice at an interval of four weeks were protected from SCoV challenge, as indicated by the absence of infectious virus in the lungs. The same groups of mice had high levels of SCoV-specific neutralizing antibodies, while mice in the negative control groups, which were not immunized with chimeric VLPs, failed to manifest neutralizing antibodies, suggesting that SCoV-specific neutralizing antibodies are important for the suppression of viral replication within the lungs. Despite some differences in the cellular composition of inflammatory infiltrates, we did not observe any overt lung pathology in the chimeric-VLP-treated mice, when compared to the negative control mice. Our results show that chimeric VLP can be an effective vaccine strategy against SCoV infection.

Heterologous viral RNA export elements improve expression of severe acute respiratory syndrome (SARS) coronavirus spike protein and protective efficacy of DNA vaccines against SARS.

The SARS-CoV spike glycoprotein (S) is the main target of the protective immune response in humans and animal models of SARS. Here, we demonstrated that efficient expression of S from the wild-type spike gene in cultured cells required the use of improved plasmid vectors containing donor and acceptor splice sites, as well as heterologous viral RNA export elements, such as the CTE of Mazon-Pfizer monkey virus or the PRE of Woodchuck hepatitis virus (WPRE). The presence of both splice sites and WPRE markedly improved the immunogenicity of S-based DNA vaccines against SARS. Upon immunization of mice with low doses (2 microg) of naked DNA, only intron and WPRE-containing vectors could induce neutralizing anti-S antibodies and provide protection against challenge with SARS-CoV. Our observations are likely to be useful for the construction of plasmid and viral vectors designed for optimal expression of intronless genes derived from cytoplasmic RNA viruses.

Temporal changes in cytokine/chemokine profiles and pulmonary involvement in severe acute respiratory syndrome.

OBJECTIVE AND BACKGROUND: Pathological changes in severe acute respiratory syndrome (SARS) suggest that SARS sequelae are associated with dysregulation of cytokine and chemokine production. To improve understanding of the immuno-pathological processes involved in lung injury associated with SARS, the temporal changes in cytokine/chemokine profiles in the sera of SARS patients were compared with those of patients with community-acquired pneumonia (CAP), according to the degree of lung involvement. METHODS: Serum levels of 11 cytokines and chemokines, in 14 patients with SARS and 24 patients with CAP, were serially checked using a bead-based multiassay system. Sera from 12 healthy subjects were used as normal controls. RESULTS: The serum levels of interferon-gamma-inducible protein-10 (IP-10), IL-2 and IL-6 were significantly elevated during SARS infection. In patients with CAP, but not in those with SARS, the levels of interferon-gamma, IL-10, IL-8 and monokine induced by interferon-gamma (MIG) were significantly elevated compared with the levels in healthy controls. Among the chemokines/cytokines, IL-6 levels correlated most strongly with radiographic scores (r=0.62). The elevation of IP-10 and IL-2 antedated the development of chest involvement and reached peak levels earlier than the radiographic scores. In contrast, the dynamic changes in IL-6, C-reactive protein and neutrophils occurred synchronously with the changes in radiographic scores. The mean ratio of IL-6 to IL-10 in SARS patients (4.84; range 0.41-21) was significantly higher than that in CAP patients (2.95; range 0.02-10.57) (P=0.04). CONCLUSIONS: The early induction of IP-10 and IL-2, as well as the subsequent over-production of IL-6 and lack of IL-10 production, probably contribute to the main immuno-pathological processes involved in lung injury in SARS. These changes in cytokine/chemokine profile are remarkably different from those observed in CAP patients.

Enhanced induction of SARS-CoV nucleocapsid protein-specific immune response using DNA vaccination followed by adenovirus boosting in BALB/c mice.

OBJECTIVE: To investigate immunogenicity in the induction of humoral and cellular immune responses to genetic vaccines of the recombinant severe acute respiratory syndrome-associated coronavirus (SARS-CoV)-N gene expressing the same protein plasmid, pcDNA3.1-N, and replication-defective adenoviral vector, rAd-N, in a pcDNA3.1-N prime-rAd-N boost regimen and the reverse sequence in a rAd-N prime-pcDNA3.1-N boost regimen. METHOD: After the mice had been immunized intramuscularly and/or intraperitoneally with pcDNA3.1-N and rAd-N in prime-triple boost immunization, humoral and cellular immune responses were detected. RESULTS: After detection, different levels of anti-N humoral and cellular responses are shown compared to controls. The humoral immune response was induced more effectively by the DNA priming and recombinant adenovirus boosting regimen and the reverse sequence of heterogeneous combinations. There is a significant difference between heterogeneous and homologous vaccinations. However, the cytotoxic T lymphocyte (CTL) response was not significantly altered by the different prime-boost immunizations or the recombinant adenovirus of pcDNA3.1-N prime-rAd-N boost regimen alone, but lymphoproliferation and interferon-gamma (IFN-gamma) secretion were all enhanced by heterologous combination immunizations compared to homologous combinations. For the reverse sequence immunization regimen, lymphoproliferation, IFN-gamma and CTL responses were all significantly weaker compared with pcDNA3.1-N prime-rAd-N boost regimen. CONCLUSION: Taken together, of all the combinations, the prime-triple boost immunization of pcDNA3.1-N/pcDNA3.1-N/pcDNA3.1-N/rAd-N can effectively induce SARS-CoV-N-specific and strong humoral and cellular immune responses in mice. The present results suggest that DNA immunization followed by recombinant adenovirus boosting could be used as a potential SARS-CoV vaccine in the induction of an enhanced humoral and cellular immune response.

[A follow up study of total IgM, IgG, nucleoprotein and spike protein antibodies against severe acute respiratory syndrome (SARS) coronavirus in patients with SARS].

OBJECTIVE: To survey the dynamic changing and persistence of the special antibodies, including total IgM, IgG, nucleocapsid protein and spike protein antibodies, against severe acute respiratory syndrome coronavirus (SARS-CoV) in patients with SARS. METHODS: 146 cases, all clinically diagnosed as SARS with positive SARS-CoV IgG, were followed up. 362 serum samples were collected from the onset of the disease to 660 days afterward. Total IgM and IgG against SARS-CoV were tested with commercial ELISA kits. For recombinant nucleoprotein and spike protein, we developed an ELISA to test these two antibodies. RESULTS: Within 20 days of the onset, the positive rate of anti-SARS-CoV IgM was 46.5% (20/43); it reached a peak after 21 - 40 days (80.6%, 25/31). Then, the positive rate of IgM went down gradually to 8.2% (6/73) until 550 days after the onset. The patient's IgG positive rate was lower (34.9%, 15/43) than that of IgM within 20 days of the onset. Then it went up rapidly to 100%. It remained positive (98.6%, 70/71) until 600 - 660 days after the onset. When N-IgG and S-IgG were tested 40 days after the onset of the disease at three different times, the positive rate of N-IgG (92.5%, 37/40) was higher than that of S-IgG (67.5%, 27/40), but the two structure protein antibodies were always lower than the total IgG. CONCLUSIONS: In SARS patients with definite clinical and etiological diagnosis, the highest positive rate of the antibodies against SARS-CoV was found at 21 - 40 days after the onset. IgM disappeared almost 500 days (91.8%) after the onset. Total IgG positive rate could reach 100% and 98.6% and the positivity might persist nearly two years. So it is speculated that the total IgG antibody may be positive 3 to 5 years after infection, but it seems that N-IgG and S-IgG keep positive shorter in time than total IgG antibody.

[A field trial of recombinant human interferon alpha-2b for nasal spray to prevent SARS and other respiratory viral infections].

OBJECTIVE: To study the preventive effect of recombinant human interferon alpha-2b for nasal spray against SARS and other common respiratory viral infections by serum-epidemiological method. METHODS: A randomized, placebo-controlled, double-blind field trial study in populations with 14,391 persons from SARS prevalent cities or provinces in China during May-Jun, 2003 and Dec-Apr, 2004. Interferon alpha-2b was given twice per day, once 9 x 10(5) IU by nasal spray for 5 days. Serum samples were taken at 15 days after last administration. Serological tests included SARS IgG antibody and IgM antibodies against influenza B, parainfluenza virus types 1-3, adenovirus type 3, 7 and respiratory syncytial virus by using commercial ELISA kits. RESULTS: No statistically significant difference in serum SARS IgG antibody positive rate was found between the interferon and control groups among 2,757 serum samples. On the other hand, after using interferon, all four respiratory viruses (parainfluenza virus types 1-3 influenza B, adenovirus types 3, 7 and respiratory syncytial virus) in interferon group had lower IgM antibody positive rates than those in control group. Among them there were statistically significant differences between the interferon and control groups for parainfluenza virus, influenza B and adenovirus. The preventive efficacy of interferon against four respiratory viruses was different, from high to low, the rank was Flu B (66.76%), parainfluenza types 1-3 (66.75%), RSV (39.61%) and adenovirus (32.86%). The average preventive efficacy was 50.27%. CONCLUSION: The recombinant human interferon alpha-2b for nasal spray could decrease the rates of common respiratory viruses infection in the selected population.

[Cloning, purification, and antigenic characterization of three recombinant fragments derived from SARS-CoV S1 domain].

OBJECTIVE: The present study aimed to clone and express three fragments of genomic RNA derived from SARS associated coronavirus (SARS-CoV) S1 domain and to study its immunogenicity. METHODS: The S1 domain gene was amplified by PCR with specific primers and was inserted into the prokaryotic expression vector pQE-30. Three fragments (40-751, 746-1344 and 746-2001 bp) derived from S1 domain produced after the recombinant plasmid (pQE-30/S1) was digested by restriction endonucleases. The three fragments were cloned into pQE-30 and expressed in M15 strains of Escherichia coli. The expression products, designated S1a, S1b and S1c respectively, were purified by Ni affinity chromatography. The immunogenicity was analyzed by Western Blot and ELISA using serologically confirmed sera from SARS patients and the sera from healthy donors was used as control at the same assay. RESULTS: Three recombinant plasmids (pQE-30/S1a, pQE-30/S1b, pQE-30/S1c) were constructed.Fusion proteins with relative molecular mass of 26,700, 22,500 and 46,000 dalton were successfully expressed with amounts of 35%, 35% and 30% of total cell protein and purified by Ni affinity chromatography, respectively. Western Blot and ELISA analysis showed that the S1c protein could be specifically recognized by the sera from SARS patients. CONCLUSION: The recombinant S1c protein was a good immunogen and has the potential to be used as a vaccine against SARS-CoV infection.

An animal model of SARS produced by infection of Macaca mulatta with SARS coronavirus.

A new SARS animal model was established by inoculating SARS coronavirus (SARS-CoV) into rhesus macaques (Macaca mulatta) through the nasal cavity. Pathological pulmonary changes were successively detected on days 5-60 after virus inoculation. All eight animals showed a transient fever 2-3 days after inoculation. Immunological, molecular biological, and pathological studies support the establishment of this SARS animal model. Firstly, SARS-CoV-specific IgGs were detected in the sera of macaques from 11 to 60 days after inoculation. Secondly, SARS-CoV RNA could be detected in pharyngeal swab samples using nested RT-PCR in all infected animals from 5 days after virus inoculation. Finally, histopathological changes of interstitial pneumonia were found in the lungs during the 60 days after viral inoculation: these changes were less marked at later time points, indicating that an active healing process together with resolution of an acute inflammatory response was taking place in these animals. This animal model should provide insight into the mechanisms of SARS-CoV-related pulmonary disease and greatly facilitate the development of vaccines and therapeutics against SARS.

Retrospective serological investigation of severe acute respiratory syndrome coronavirus antibodies in recruits from mainland China.

Different assays were used to analyze 1,621 serum specimens collected from military recruits from the People's Republic of China in 2002 for severe acute respiratory syndrome (SARS) coronavirus antibodies. The results demonstrated that the subjects either had rarely been exposed to the virus before the 2003 SARS outbreak or had not been exposed but the nucleocapsid protein cross-reacted with other antibodies in humans.