Objective:To evaluate the in vitro and in vivo immunostimulatory activity and the safety of ethanol extract of wild Artemisia rupestris L. (EEWAR). Methods:Bone marrow dendritic cells (BMDCs) from C57BL/6 mice were treated with different concentrations of EEWAR in vitro and the expression of CD40 and CD80 on BMDCs was detected by flow cytometry. ICR mice were subcutaneously immunized with different concentrations of EEWAR in combination with ovalbumin (OVA) or OVA alone. Aluminum adjuvant was used as the positive control. OVA-specific IgG antibodies in mouse serum samples were measured by ELISA following immunization. T cell proliferation in spleen tissues was detected by MTT method. Acute toxicity test was conducted in ICR mice to analyze the safety of EEWAR. Results:In vitro experiment showed that EEWAR at the concentrations of 10-20 μg/ml increased the expression of CD40 and CD80 on BMDCs ( P<0.05), and had no significant effect on the morphology of BMDCs; EEWAR at the concentrations of 100-200 μg/ml significantly promoted the expression of CD40 and CD80 on BMDCs ( P<0.01), but had a certain influence on the morphology of BMDCs. In vivo experiment showed that EEWAR enhanced the production of IgG, IgG 1 and IgG 2a antibodies against OVA and the proliferation of splenocytes ( P<0.05). In the acute toxicity test, EEWAR at the concentrations of 50-5 000 μg/ml had no side effects on mouse body weight and was relatively safe. Conclusions:EEWAR could promote the maturation of DCs and enhance the humoral and cellular immune responses when used as an adjuvant to OVA. It was safe in a certain dose range. This study provided reference for further research on EEWAR as a new-generation adjuvant.

Objective:To screen the neutralizing epitope of enterovirus 71 (EV71) and determine the specific minimum amino acid sequence that triggers immunity for providing a theoretical basis for the development of synthetic peptide vaccines.Methods:EV71 neutralizing antibody-specific binding clones were panned and sequenced using a phage display random 12-peptide library to obtain the key sequences of neutralizing epitopes. A series of peptides containing the key sequences with N-terminal acetylation (AC) and C-terminal linking to Keyhole limpet hemocyanin (KLH) were synthesized. Serum samples were collected after immunizing mice with the modified peptides. Then the immunogenicity of the peptides and the neutralizing activity of serum samples were analyzed by Western blot, ELISA and neutralization test.Results:After three rounds of panning, cloning and sequencing, KQEKDL was identified as the key motif. The serum samples collected from the mice immunized with the modified series of peptides containing key motifs had different degrees of binding ability to EV71 and VP1 protein. The serum samples of mice immunized the synthetic peptide containing only the minimum key motif (AC-KQEKDL-KLH) had the strongest response to the other three peptides and EV71 and the highest neutralizing titer.Conclusions:The EV71 neutralizing epitope was successfully screened using the phage display random peptide library. The key motif of KQEKDL might be the specific minimum amino acid sequence that triggered the immune system. This study provides a theoretical basis for better understanding the immune response mechanism, evaluating the immunogenicity of the antigens and further research and development of polypeptide vaccines.

Objective:To analyze the characteristics of immune cross-reaction between herpes simplex virus type 1 (HSV-1) and HSV-2 in terms of serology and clinical protection aiming to provide data for the control and prevention of diseases caused by the two viruses.Methods:An attenuated HSV-1 strain M3 was used to immunize BALB/c mice. Specific immune responses indicated by the production of neutralizing antibodies were detected. Wild-type HSV-1 and HSV-2 strains were respectively used to infect the mice through different ways 28 d after the immunization to observe the protective immunity in the M3-immunized mice against HSV-1/2 infection.Results:M3 strain could not induce specific neutralizing antibodies against HSV-2. Therefore, viral loads in tissues of the immunized mice increased significantly following different modes of HSV-2 exposure. However, no obvious abnormal clinical manifestations were found and the histopathological damage was only slight inflammatory reaction. In contrast, HSV-1-specific neutralizing antibodies were elicited in the M3-immunizaed mice with significant protective effects against HSV-1 infection.Conclusions:The immune response induced by attenuated HSV-1 strain M3 in mice exhibited immune-protective effects characterized by production of neutralizing antibodies and inhibition of virus proliferation in vivo against wild-type HSV-1 infection. For HSV-2, instead of neutralizing virus in form of antibodies, it featured by more of clinical cross-immunoprotective abilities to control virus growth.

Objective:To observe the changes in percentages and subsets of invariant nature kiler T (iNKT) cells in adipose and related tissues at different stages of obesity, and analyze the role of iNKT cells during chronic inflammation in adipose tissues in a mouse model of obesity established with high-fat diet.Methods:Changes in mouse body weight, mental state, glucose tolerance and insulin tolerance were recorded. Hematoxylin and eosin (HE) staining was used to observe pathological changes in adipose tissues. Flow cytometry was performed to detect the percentages and subsets of iNKT cells as well as the percentages and subtypes of macrophages. The levels of cytokines in serum samples and the culture supernatants of lymphocytes in adipose tissues were detected with CBA. The expression of related proteins in adipose tissues was detected by Western blot.Results:(1) The volume of adipose cells increased significantly after four weeks of high-fat feeding, but the infiltration of inflammatory cells was not obvious. Significantly increased infiltration of inflammatory cells was observed after 12 weeks of high-fat feeding. (2) High-fat feeding could reduce the percentage of iNKT cells, increase the proportion of iNKT1 subgroup and decrease the proportion of iNKT10 subgroup in adipose tissues. The proportion of iNKT1 subgroup in thymus increased, but that of iNKT2 subgroup decreased. The percentage of macrophages and the proportion of M1 subgroup in adipose tissues increased, while the proportion of M2 subgroup decreased, which were more obvious after 12 weeks of high-fat feeding. (3) High-fat feeding resulted in decreased expression of E4BP4 and arginase-1 (Arg-1) in adipose tissues and increased expression of inducible nitric oxide synthase (iNOS). (4) High-fat feeding significantly increased the pro-inflammatory cytokines and decreased the anti-inflammatory cytokines in mouse serum and culture supernatants of lymphocytes in adipose tissues with more significant changes observed after 12 weeks of high-fat feeding.Conclusions:Increased iNKT1 and decreased iNKT10 in obese adipose tissues might be closely related to the increased M1 polarization and the imbalance of iNKT subsets might be involved in the progression of chronic inflammation in obese adipose tissues.

Objective:To retrospectively analyze the clinical characteristics and drug resistance among COVID-19 patients with bacterial and fungal infections.Methods:Clinical data of COVID-19 patients whose blood, urine, sputum and alveolar lavage fluid samples were positive for bacteria and fungi were collected in Tongji Hospital from February 10 to March 31, 2020. WHONET5.6 software was used to analyze drug susceptibility test results.Results:A total of 95 COVID-19 patients positive for pathogenic bacteria were enrolled and among them, 23 were non-critical patients and 72 were critical patients. The main symptoms in these patients included fever, cough with sputum, fatigue and dyspnea. Male and female critical patients accounted for 63.89% and 36.11%, respectively. Most of the patients with bacterial and fungal infections were critical type, accounting for 23.61%. The mortality rates of non-critical and critical patients were 13.04% and 61.11%, respectively. A total of 179 strains of pathogenic bacteria were isolated. The positive rate of Escherichia coli in non-critical patients was 37.50%, which was higher than that in critical patients. However, the positive rates of Acinetobacter baumannii and Klebsiella pneumoniae in critical patients were both 29.87%, higher than those in non-critical patients. There was no significant difference in the positive rate of gram-positive bacteria or fungi between non-critical and critical patients. It was noteworthy that the positive rate of Candida parapsilosis in blood samples of critical patients was relatively high, reaching 36.40%. Drug susceptibility test results showed that no carbapenem-resistant Escherichia coli stains were detected and 60.87% of Klebsiella pneumoniae strains were resistant to carbapenems. Acinetobacter baumannii strains were 100% resistant to three antimicrobial drugs. Methicillin-resistant Staphylococcus aureus strains accounted for 71.43%, but no vancomycin-resistant gram-positive cocci were found. Conclusions:Critical COVID-19 patients were mostly male and prone to multiple bacterial and fungal infections. The mortality of critical patients was higher than that of non-critical patients. Critical COVID-19 was often complicated by hospital acquired infections caused by bacteria including Acinetobacter baumannii and Klebsiella pneumoniae with high drug resistance.

Objective:To investigate the effects of pre-existing antibody on seroconversion rate after influenza vaccination.Methods:This study recruited 1 900 healthy volunteers to receive influenza split vaccines in Xinjiang Uygur Autonomous region and Yunnan Province from September 2009 to October 2018. Hemagglutinin agglutination inhibition assay was used to detect the titers of specific antibodies in blood samples collected before vaccination and 28 d after vaccination and the effects of pre-existing antibody on the seroconversion to different influenza vaccine components were analyzed.Results:Trend analysis showed that with the increasing titer of pre-existing antibody, the seroconversion rates to A/H1N1, A/H3N2, B/Victoria and B/Yamagata vaccine components were gradually decreased (χ 2=121.76, P<0.001; χ 2=67.58, P<0.001; χ 2=45.25, P<0.001; χ 2=54.55, P<0.001). After adjusting for factors such as region, gender and age, multivariate logistic regression showed that pre-existing antibody titer equal to or higher than 40 was an independent factor that affected the seroconversion to A/H1N1, A/H3N2 and B/Victoria vaccine components, and the adjusted OR (95%CI) values were 2.50(2.00-3.13)、1.64(1.35-2.00) and 2.50(1.79-3.45), respectively. Conclusions:The seroconversion rate to each vaccine component was negatively correlated with the pre-existing antibody titer. The factor that pre-existing antibody titer equal to or higher than 40 was detrimental to the seroconversion to A/H1N1, A/H3N2 and B/Victoria vaccine components, but had no significant influence on B/Yamagata seroconversion.

Novel coronavirus (2019-nCoV) is the pathogen of COVID-19. Some severe cases may suffer from respiratory failure or even death, which poses a great challenge to global public health. 2019-nCoV proteins not only participate in virus proliferation, but also play an important role in antagonizing host innate immune response, especially interferon response. In this paper, 2019-nCoV proteins involved in regulating host interferon response and the complex interaction between 2019-nCoV and interferons were summarized, aiming to provide a theoretical reference for the prevention and control of COVID-19.

Dendritic cells (DC) represent a heterogeneous cell population including many subsets. DC subpopulations with different characteristics and functions have been identified. The liver, as an immunological organ, is important in induction of immune tolerance. The unique anatomical architecture and immune properties of the liver have given DC the ability to maintain liver homeostasis and respond quickly to liver tissue damage. This article reviewed the role of hepatic DC subsets in the maintenance of tissue homeostasis and repair of damaged tissue in the liver.

Objective:To investigate the whole genome characteristics of coxsackievirus A4 (CVA4) circulating in Qingdao city.Methods:Four CVA4 isolates circulating in Qingdao city during 2013 to 2015 were selected. Whole genome sequences of these strains were amplified by one-step reverse transcription-polymerase chain reaction (RT-PCR). Sequence alignment and phylogenetic analysis were performed using MEGA7.0 software package. Genetic recombination analysis was performed using similarity plots 3.5.1 software package.Results:Phylogenetic analysis showed that based on the sequences of the whole genome and P1, P2 and P3 regions, HS312/QD/CHN/2013 and HS605/QD/CHN/2014 strains together with the early domestic isolates belonged to the same clade, while FY218/QD/CHN/2015 strain and CV-A4/P1033/2013/China strain collected in Wenzhou in 2013 formed another clade in each phylogenetic tree. HS144/QD/CHN/2014 strain belonged to the same clade as HS312/QD/CHN/2014, HS605/QD/CHN/2014 and the early domestic CVA4 isolates in the phylogenetic tree based on the P1 region, but formed a separate clade in the phylogenetic trees based on the whole genome, P2 region and P3 region. Genetic recombination analysis revealed that there was genetic recombination between HS144/QD/CHN/2014 strain and the CVA2 strain of CV-A2/P373/2013/China isolated in mainland China in 2013 in the region of 2C-3D (5 081-7 301); FY218/QD/CHN/2015 and CV-A4/P1033/2013/China strains were highly homologous and recombination signal sequences were detected in the region of 2A-2B (3 821-4 161) between the two strains and the CVA2 strain of CV-A2/P373/2013/China.Conclusions:The CVA4 isolates circulating in Qingdao city presented obvious genetic diversity at the genome-wide level.

Neutrophil extracellular traps (NETs) are fibrous structures released by neutrophils and the formation process is called NETosis. NETs participate in the host innate immunity. Recent research has found that NETs is a double-edged sword. Under normal conditions, the formation of NETs can play a role in clearing pathogens and maintain the host homeostasis. However, when NETs are overproduced or not cleared in time, they can take part in the pathogenesis of many diseases. This article reviewed the formation of NETs, the mechanisms involved in NETosis and the role of NETs in the secretion of multiple cytokines in different diseases.