NIR-triggered on-site NO/ROS/RNS nanoreactor:Cascade-amplified photodynamic/photothermal therapy with local and systemic immune responses activation

Photothermal and photodynamic therapies(PTT/PDT)hold promise for localized tumor treatment,yet their full potential is hampered by limitations such as the hypoxic tumor microenvironment and inadequate systemic immune activation.Addressing these challenges,we present a novel near-infrared(NIR)-triggered RNS nanoreactor(PBNO-Ce6)to amplify the photodynamic and photothermal therapy efficacy against triple-negative breast cancer(TNBC).The designed PBNOCe6 combines sodium nitroprusside-doped Prussian Blue nanoparticles with Chlorin e6 to enable on-site RNS production through NIR-induced concurrent NO release and ROS generation.This not only enhances tumor cell eradication but also potentiates local and systemic antitumor immune responses,protecting mice from tumor rechallenge.Our in vivo evaluations revealed that treatment with PBNO-Ce6 leads to a remarkable 2.7-fold increase in cytotoxic T lymphocytes and a 62%decrease in regulatory T cells in comparison to the control PB-Ce6(Prussian Blue nanoparticles loaded with Chlorin e6),marking a substantial improvement over traditional PTT/PDT.As such,the PBNO-Ce6 nanoreactor represents a transformative approach for improving outcomes in TNBC and potentially other malignancies affected by similar barriers.

Regulating Effects of Novel CpG Chitosan-nanoparticles on Immune Responses of Mice to Porcine Paratyphoid Vaccines

Objective To study the regulating effects of a novel CpG oligodeoxynuleotide and the synergistic effect of chitosan-nanoparticles （CNP） with CpG on immune responses of mice, which were used to develop a novel immunoadjuvant to boost immune response to conventional vaccines. Methods A novel CpG ODN containing 11 CpG motifs was synthesized and its bioactivities to stimulate the proliferation of lymphocytes of pig in vitro were detected. Then it was entrapped with CNP prepared in our laboratory by the method of ionic cross linkage, and immunized Kunming mice were co-inoculated with paratyphoid vaccine. The peripheral blood was collected weekly from the tail vein of inoculated mice to detect the contents of IgG, IgA, IgM, and specific antibody against salmonella as well as the levels of interleukin-2 （IL2）, IL-4, and IL-6 by SABC-ELISA assay. The numbers of leucocytes, monocytes, granuloytes, and lymphocytes were calculated separately using the routine method. The experimental mice were orally challenged with virulent salmonella 35 days after inoculation. Results This CpG ODN could remarkably provoke the proliferation of lymphocytes of pig in vitro in contrast with the control （P〈0.05）. Compared with those of the control, immunoglobulins, including IgG, IgA, IgM, and specific antibodies to paratyphoid vaccine, increased significantly in sera from the CpG or CpG-CNP-vaccinated mice （P〈0.05）. IL-2, IL-4, and IL-6 increased remarkably in sera from immunized mice （P〈0.05）. The leucocytes, monocytes, granuloytes, and lymphocytes of the mice immunized with CpG or CpG-CNP were also increased in number （P〈0.05）. After the challenge, these immunity values were elevated in the mice vaccinated with CpG or CpG-CNP. The immunized mice all survived, while the control mice fell ill with evident lesions with diffuse hemorrhage in stomach, small intestine, and peritoneum. Conclusions CpG ODN entrapped with CNP is a promising effective immunoadjuvant for vaccination, which promotes humoral and cellular immune responses, enhances immunity and resistance against salmonella by co-administration with paratyphoid vaccine. Key words：

Vaccination with dendritic cells pulsed with hepatitis C pseudo particles induces specific immune responses in mice

AIM: To explore dendritic cells (DCs) multiple functions in immune modulation. METHODS: We used bone-marrow derived dendritic cells from BALB/c mice pulsed with pseudo particles from the hepatitis C virus to vaccinate naive BALB/c mice. Hepatitis C virus (HCV) pseudo particles consist of the genotype 1b derived envelope proteins E1 and E2, covering a non-HCV core structure. Thus, not a single epitope, but the whole "viral surface" induces immunogenicity. For vaccination, mature and activated DC were injected subcutaneously twice. RESULTS: Humoral and cellular immune responses measured by enzyme-linked immunosorbent assay and interferon-gamma enzyme-linked immunosorbent spot test showed antibody production as well as T-cellsdirected against HCV. Furthermore, T-cell responses confi rmed two highly immunogenic regions in E1 and E2 outside the hypervariable region 1. CONCLUSION: Our results indicate dendritic cells as a promising vaccination model for HCV infection that should be evaluated further.

Pulmonary Immune Responses to Aspergillus Fumigatus in Rats

Objective To evaluate immunologic mechanisms underlying Aspergillus fumigatus pulmonary infections in immunocompetent Dark Agouti （DA） and Albino Oxford （AO） rats recognized as being susceptible to some inflammatory diseases in different manners. Methods Lung fungal burden （quantitative colony forming units, CFU, assay）, leukocyte infiltration （histology, cell composition） and their function （phagocytosis, oxidative activity, CDllb adhesion molecule expression） and cytokine interferon-y （IFN-y） and interleukin-17 and -4 （IL-17 and IL-4） lung content were evaluated following infection （intratracheally, lxl07 conidia）. Results Slower reduction of fungal burden was observed in AO rats in comparison with that in DA rats, which was coincided with less intense histologically evident lung cell infiltration and leukocyte recovery as well as lower level of most of the their activities including intracellular myeloperoxidase activity, the capacity of nitroblue tetrazolium salt reduction and CDllb adhesion molecule expression （except for phagocytosis of conidia） in these rats. Differential patterns of changes in proinflammatory cytokine levels （unchanged levels of IFN-v and transient increase of IL-17 in AO rats vs continuous increase of both cytokines in DA rats） and unchanged levels of IL-4 were observed. Conclusion Genetically-based differences in the pattern of antifungal lung leukocyte activities and cytokine milieu, associated with differential efficiency of fungal elimination might be useful in the future use of rat models in studies of pulmonary aspergillosis.

Co-administration of Interleukin-2 Enhances Cellular and Humoral Immune Responses to HIV Vaccine DNA Prime/MVA Boost Regime

Interleukine-2(IL-2) is a growth factor for antigen-stimulated T lymphocytes and is responsible for ~T-cell clonal expansion after antigen recognition. It has been demonstrated that DNA vaccine-elicited immune responses in mice could be augmented substantially by using either an IL-2 protein or a plasmid expressing ~IL-2. Twenty mice, divided into four experimental groups, were immunized with: (1) sham plasmid; ^(2) HIV-1 DNA vaccine alone; (3) HIV-1 DNA vaccine and IL-2 protein; or (4) HIV-1 DNA vaccine and IL-2 plasmid, separately. All the groups were immunized 3 times at a 2-week interval. Fourteen days after the last DNA vaccine injection, recombinant MVA was injected into all the mice except those in group 1. ELISA and ELISPOT were employed to investigate the effect of IL-2 on DNA vaccine immune responses. The obtained results strongly indicate that the efficacy of HIV vaccine can be enhanced by co-administration of a plasmid encoding IL-2.

Hepatitis B virus S gene enhances immune responses of a multiple-epitope DNA construct of hepatitis C virus in mice

The purpose of this study was to construct an eukaryotic DNA vector encoding a multiple-epitope antigen (MFC) of hepatitis C virus (HCV) and a hepatitis B surface antigen (HBsAg) , and explore the effect of HBsAg gene on the immunity of HCV multiple-epitope DNA construct in vitro and in vivo in mice. An HCV DNA vector (pVAX1-HBs-MFC) was constructed by fusing HBsAg gene to the N-terminal of an HCV multiple-epitope antigen gene. The pVAX1-HBs-MFC was transfected into HEK 293T cells and its expression was measured by ELISA and Western blotting. BALB/c mice were intramuscularly immunized with the pVAX1-HBs-MFC, and an ELISA approach was applied to determine the specific antibody titers and subtypes in the mouse serum. The cross-reactivity of the antibodies was also checked with two synthesized HCV hypervariable region 1 (HVR1) peptides. The IFN-γ production and cell proliferation of the mouse spleen cells were evaluated by ELISA and MTS (3-[4, 5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl] -2H-tetrazolium, inner salt) assays, respectively. The expression of pVAX1-HBs-MFC was detectable in the transfected HEK 293T cells. The serum antibody response was effectively elicited in BALB/c mice injected with pVAX1-HBs-MFC. The highest titer of antibody against HCV (MFC) was 1∶1280, and the ratio of IgG2a/IgG1 was 1.50±0.12 at the fifth week after first immunization. Moreover, the collected mouse serum antibody had the ability to cross-react with the two synthesized HCV HVR1 peptides. The stimulation index of the mouse splenocytes to MFC was 1.79 ±0.07, and the IFN-γ level was 287±6?pg/ml at week 21 after first immunization. The highest titer of the antibody in control BALB/c mice immunized with pVAX1-MFC was 1∶320, and the ratio of IgG2a/IgG1 was 1.33±0.11 at week 5 post-immunization. Furthermore, the stimulation index of the mouse splenocytes cells to MFC was 1.52±0.06, and the IFN-γ level was 225±9.3?pg/ml at week 21 post-immunization. The HBsAg gene can enhance the effects of an HCV multiple-epitope DNA construct on its humoral and cellular immune responses. This HBsAg enhanced HCV multiple-epitope DNA vector may be of potential use in the development of HCV vaccines.

Effects of thymol and carvacrol supplementation on intestinal integrity and immune responses of broiler chickens challenged with Clostridium perfringens

Background： Necrotic enteritis caused by Clostfidium perffingens infection leads to serious economic losses in the global poultry production. In the present study, we investigated the protective effects of essential oils （EO, which contained 25 % thymol and 25 % carvacrol as active components） supplementation on growth performance, gut lesions, intestinal morphology, and immune responses of the broiler chickens infected with C. perfringens. A total of 448 1-day-old male broiler chicks were allocated into eight treatment groups following a 4 x 2 factorial arrangement with four dietary EO dosages （0, 60, 120, or 240 mg/kg） and two infection status （with or without C. perfringens challenge from d 14 to 20）. Results： The challenge did not impair the growth performance of birds, but induced gut lesions and increased crypt depth in the ileum （P ≤ 0.05）. It also down-regulated the claudin-1 and occludin mRNA expression （P ≤0.05）, up-regulated the mRNA expression of interleukin-113 （P≤ 0.05）, tended to increase the toll-like receptor （TLR） 2 mRNA expression （P 〈 0.10） in the ileum, and enhanced the mucosal secretory IgA production （P 〈 0.05）. In the challenged birds, dietary EO supplementation linearly alleviated the gut lesions and improved the ratio of villus height to crypt depth （P ≤0.05）, and the supplementation of 120 and 240 mg/kg EO increased the serum antibody titers against Newcastle disease virus （P≤ 0.05）. Regardless of challenge, the EO supplementation showed a tendency to linearly elevate the feed conversion efficiency between 14 and 28 d of age as well as the occludin mRNA expression （P〈 0.10）, and linearly inhibited the mRNA expression of TLR2 and tumor necrotic factor-o in the ileum （P≤ 0.05）. Conclusions： The dietary supplementation of EO could alleviate the intestinal injury by improving intestinal integrity and modulating immune responses in the C. perffingens-challenged broiler chickens.

CagA+ H pylori infection is associated with polarization of T helper cell immune responses in gastric carcinogenesis

AIM:To characterize the immune responses including local and systemic immunity induced by infection with H pylori,especially with CagA+ H pylori strains and the underlying immunopathogenesis. METHODS:A total of 711 patients with different gastric lesions were recruited to determine the presence of H pylori infection and cytotoxin associated protein A (CagA),the presence of T helper (Th) cells and regulatory T (Treg) cells in peripheral blood mononuclear cells (PBMCs),expression of plasma cytokines,and RNA and protein expression of IFN-γ and IL-4 in gastric biopsies and PBMCs were determined by rapid urease test,urea 14C breath test,immunoblotting test,flow cytometry ,real time RT-PCR and immunohistochemistry. RESULTS:Of the patients,629 (88.47%) were infected with H pylori ; 506 (71.16%) with CagA+ and 123 (17.30%) with CagA- strains. Among patients infected with CagA+ H pylori strains,Th1-mediated cellular immunity was associated with earlier stages of gastric carcinogenesis,while Th2-mediated humoral immunity dominated the advanced stages and was negatively associated with an abundance of Treg cells. However,there was no such tendency in Th1/Th2 polarization in patients infected with CagA- H pylori strains and those without H pylori infection. CONCLUSION:Polarization of Th cell immune responses occurs in patients with CagA+ H pyloriinfection,which is associated with the stage and severity of gastric pathology during the progression of gastric carcinogenesis. This finding provides further evidence for a causal role of CagA+ H pylori infection in the immunopathogenesis of gastric cancer.

Immune responses to Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection is one of the most common infections in human beings worldwide. H. pylori express lipopolysaccharides and flagellin that do not activate efficiently Toll-like receptors and express dedicated effectors, such as γ-glutamyl transpeptidase, vacuolating cytotoxin (vacA), arginase, that actively induce tolerogenic signals. In this perspective, H. pylori can be considered as a commensal bacteria belonging to the stomach microbiota. However, when present in the stomach, H. pylori reduce the overall diversity of the gastric microbiota and promote gastric inflammation by inducing Nod1-dependent pro-inflammatory program and by activating neutrophils through the production of a neutrophil activating protein. The maintenance of a chronic inflammation in the gastric mucosa and the direct action of virulence factors (vacA and cytotoxin-associated gene A) confer pro-carcinogenic activities to H. pylori. Hence, H. pylori cannot be considered as symbiotic bacteria but rather as part of the pathobiont. The development of a H. pylori vaccine will bring health benefits for individuals infected with antibiotic resistant H. pylori strains and population of underdeveloped countries.

Science Letters:A synthetic Toll-like receptor 2 ligand decreases allergic immune responses in a mouse rhinitis model sensitized to mite allergen

It has been proposed that activation of Toll-like receptors （TLRs） plays crucial roles in the polarization of adaptive immune responses. A synthetic Toll-like receptor 2 （TLR2） ligand, Pam3CSK4, has been reported to modulate the balance of Th1/Th2 responses. We evaluated the modulation effect of Pam3CSK4 on allergic immune response in a mouse rhinitis model sensitized to house dust mite allergen （HDM）. Mice were sensitized and challenged with Dermatophagoidesfarinae allergen （Der f）, and then the allergic mice were treated by Pam3CSK4. Nasal allergic symptoms and eosinophils were scored. Der f-specific cytokine responses were examined in the splenocytes and bronchoalveolar lavage fluid （BALF）. Serum level of total IgE was also detected. After establishing a mouse allergic rhinitis model with HDM, we have showed that Pam3CSK4 treatment not only ameliorated the nasal allergic symptoms remarkably but also decreased the eosinophils and total inflammation cells in BALF significantly. Analysis of cytokine profile found that IFN-7 released from either BALF or stimulated splenocytes increased markedly in Pam3CSK4-treated mice, while IL-13 decreased significantly. Moreover, serum level of total IgE was significantly lower in Pam3CSK4-treated mice than in the untreated. Thus, in an allergic rhinitis mouse model developed with HDM, Pam3CSK4 was shown to exhibit an antiallergic effect, indicating its potential application in allergic diseases.

Dynamic changes in the systemic immune responses of spinal cord injury model mice

Intraspinal inflammatory and immune responses are considered to play central roles in the pathological development of spinal cord injury.This study aimed to decipher the dynamics of systemic immune responses,initiated by spinal cord injury.The spinal cord in mice was completely transected at T8.Changes in the in vivo inflammatory response,between the acute and subacute stages,were observed.A rapid decrease in C-reactive protein levels,circulating leukocytes and lymphocytes,spleen-derived CD4~+interferon-γ+T-helper cells,and inflammatory cytokines,and a marked increase in neutrophils,monocytes,and CD4~+CD25~+FOXP3~+regulatory T-cells were observed during the acute phase.These systemic immune alterations were gradually restored to basal levels during the sub-acute phase.During the acute phase of spinal cord injury,systemic immune cells and factors showed significant inhibition;however,this inhibition was transient,and the indicators of these serious disorders gradually returned to baseline levels during the subacute phase.All experiments were performed in accordance with the institutional animal care guidelines,approved by the Institutional Animal Care and Use Committee of Experimental Animal Center of Drum Tower Hospital,China(approval No.2019 AE01040)on June 25,2019.

Comparison of Immune Responses against FMD by a DNA Vaccine Encoding the FMDV/O/IRN/2007 VP1 Gene and the Conventional Inactivated Vaccine in an Animal Model

Foot-and-mouth disease virus （FMDV） is highly contagious and responsible for huge outbreaks among cloven hoofed animals. The aim of the present study is to evaluate a plasmid DNA immunization system that expresses the FMDV/OflRN/2007 VP1 gene and compare it with the conventional inactivated vaccine in an animal model. The VP1 gene was sub-cloned into the unique Kpn I and BamH I cloning sites of the peDNA3.1＋ and pEGFP-N1 vectors to construct the VPI gene cassettes. The transfected BHKT7 cells with sub-cloned pEGFP-N1-VP1 vector expressed GFP-VP1 fusion protein and displayed more green fluorescence spots than the transfected BHKT7 cells with pEGFP-N1 vector, which solely expressed the GFP protein. Six mice groups were respectively immunized by the sub-cloned pcDNA3.1＋-VP1 gene cassette as the DNA vaccine, DNA vaccine and PCMV-SPORT-GMCSF vector （as molecular adjuvant） together, conventional vaccine, PBS （as negative control）, pcDNA3.1＋ vector （as control group） and PCMV-SPORT vector that contained the GMCSF gene （as control group）. Significant neutralizing antibody responses were induced in the mice which were immunized using plasmid vectors expressing the VP1 and GMCSF genes together, the DNA vaccine alone and the conventional inactivated vaccine （P〈0.05）. Co-administration of DNA vaccine and GMCSF gene improved neutralizing antibody response in comparison with administration of the DNA vaccine alone, but this response was the most for the conventional vaccine group. However, induction of humeral immunity response in the conventional vaccine group was more protective than for the DNA vaccine, but T-cell proliferation and IFN-？ concentration were the most in DNA vaccine with the GMCSF gene. Therefore the group that was vaccinated by DNA vaccine with the GMCSF gene, showed protective neutralizing antibody response and the most Thl cellular immunity.

Immune Responses of Chicken Immunizedwith Marek's Disease Vaccines

The experiment was conducted to study the dynamic changes of immune responses of chicks immunized with March's disease(MD)trivalent vaccine and turkey herpesvirus(HVT)at one day age.Results were found that after immunization of chicks with MD vaccines,the intcrlcukinc-2(IL-2)inductive activity and IL-2 receptor expression of T cells from thymus and spleen significantly increased,suggesting that the immunoregulativc function was markedly enhanced in the immune organs;the number of antibody-producing cells,the number and proliferative function of T cells rose markedly in Bursa Fabricius,spleen and thymus,indicating that the cellular and humoral immune responses were elevated remarkablly in the central and peripheral immune organs;the number of T and antibody-producing cells as well as the content of IgG,IgA and IgM obviously mounted in cecal tonsil, Harder tan gland mucosal lymphoid tissues of bronchus along with tears,trachea washings, bile and intestinal fluids,demonstrating that the local and mucosal immunity was raised in the respiratory and digestive tract;the levels of immune responses mentioned above in the trivalent vaccine-immuniaed chicks were apparently higher than those of HVT-immunized birds.

Effects of dietary phosphorous supplementation on laying performance,egg quality,bone health and immune responses of laying hens challenged with Escherichia coli lipopolysaccharide

Background: Phosphorus is an essential nutrient to maintain poultry health and performance. The objective of this study was to evaluate the effect of dietary phosphorus levels on egg production, egg quality, bone health, immune responses of laying hens challenged with Escherichia coli lipopolysaccharide.Methods: Three hundred laying hens at 28 wk were randomly divided into 2 dietary treatments with 10 replicates of 15 birds. The wheat-soybean based diets contained either 0.12% or 0.4% non-phytate phosphorus(NPP). At 32 wk of age, all the birds of each dietary treatment were injected into the abdomen with 1.5 mg/kg body weight(BW) of either LPS or saline once a day at 24-h intervals for continuous 9 d. The performance of laying hens was evaluated for 9 d. The eggs after the fifth injection were collected to value the egg quality. Three hours after the first injection, blood was collected to measure serum metabolite and immune response associated parameters.Three hours after the fifth injection, the hens were euthanized to obtain tibia, cecal tonsils and jejunum.Results: Compared with saline-injected hens, LPS-injected hens had lower feed intake and egg production(P < 0.05).Eggshell thickness, strength, albumin height and Haugh unit were significantly increased in LPS-injected hens compared with saline-injected hens(P < 0.05). Furthermore, laying hens challenged with LPS had lower villious height/crypt depth ration than those received saline. Serum calcium, phosphorus and SOD activities significantly decreased in the LPS-injected hens compared with the control(P < 0.05). LPS up-regulated expression of IL-1β, IL-6 and IL-10 in cecum, and serum concentration of MDA, IL-1β and IL-6(P < 0.05), whereas 0.40% dietary non-phytate phosphorus supplementation significantly increased(P < 0.05) villi height/crypt depth ratio, decreased(P < 0.05) serum MDA and IFN-γ concentration compared with the 0.12% non-phytate phosphorus group.Conclusion: In summary, this study demonstrates that 0.40% dietary non-phytate phosphorus supplementation significantly increased calcium and phosphorus levels of eggshell, increased villi height/crypt depth ratio, decreased serum MDA and IFN-γ concentration compared with the 0.12% non-phytate phosphorus groups. The results indicate that high level of dietary non-phytate phosphorus exerts a potential effect in alleviating systemic inflammation of LPSchallenged laying hens.

Dynamics of host immune responses to SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),the most recent global health threat,is spreading throughout the world with worrisome speed,and the current wave of coronavirus disease 2019(COVID-19)seems to have no mercy.While this mysterious virus challenges our ability to control viral infections,our opportunities to control the COVID-19 pandemic are gradually fading.Currently,pandemic management relies on preventive interventions.Although prevention is a good strategy to mitigate SARS-CoV-2 transmission,it still cannot be considered an absolute solution to eliminate this pandemic.Currently,developing a potent immunity against this viral infection seems to be the most promising strategy to drive down this ongoing global tragedy.However,with the emergence of new challenges in the context of immune responses to COVID-19,the road to control this devastating pandemic seems bumpier;thus,it is pivotal to characterize the dynamics of host immune responses to COVID-19,in order to develop efficient prophylactic and therapeutic tools.This begs the question of whether the effector mechanisms of the immune system are indeed potent or a possible contributing factor to developing more severe and lethal forms of COVID-19.In this review,the possible role of the immunopathologic phenomena including antibody-dependent enhancement,cytokine storm,and original antigenic sin in severity and mortality of COVID-19 will be discussed.

Construction of the Eukaryotic Expression Vector for Outer Membrane Protein Tp92 from Treponema pallidum and Its Preliminary Study on the Immune Responses in New Zealand Rabbits

To construct the recombinant plasmid of eukaryotic expression containing Tp92 gene from Treponema pallidum and study its immunogenicity in New Zealand white rabbits. Tp92 gene was amplified from the genomic DNA of T. pallidum by polymerase chain reaction (PCR) and subcloned into appropriate site of pcDNA3.1(+) vector. After identification by sequencing and restrictive enzyme digestion, the recombinant plasmid was transfected into HeLa cells using liposome, and the expressed protein was identified by immunocytochemistry and Western blotting. After verifying that the Tp92 antigen gene fragment could be expressed in HeLa cells, 100?μg of recombinant plasmids [pcDNA3.1(+)-Tp92], 100 μg of control plasmids [pcDNA3.1(+)] or 0.5 ml PBS buffer were administered in 3 groups of New Zealand white rabbits (6 rabbits/group), and the booster immunizations were employed at 2-week interval for 3 times. ELISA assay was used for the quantitative detection of the specific antibody in the sera of rabbits, and the proliferation response of spleen cells was detected by MTT assay. It was found that the target gene Tp92 segment about 2103 bp was obtained, and the DNA sequence of Tp92 gene constructed in pcDNA3.1 (+) vector was consistent with the published nucleotide sequence. The homologies of the nucleotide and putative amino acid sequences of Tp92 gene between T.pallidum subsp. pallidum Nichols and various pathogenic treponeme strains were 95.5%-100%. The analysis of immunocytochemistry and Western blotting showed that Tp92 gene segment constructed in pcDNA3.1(+) vector could express a fusion protein with a calculated molecular mass of 77 kDa in HeLa cells and the expressed protein could react with positive blood serum from syphilis patient. The specific antibody IgG titers were observed and the highest titer was 1∶1024 in rabbits after 3 times with pcDNA3.1(+)-Tp92. The proliferation response of spleen cells were significantly higher than that of rabbits injected with pcDNA3.1(+) ( P <0.05). The successful expression of the eukaryotic expression plasmid of Tp92 gene from T. pallidum was obtained in eukaryotic system and strong responses of humoral and cellular immunity was evoked by DNA vaccine of pcDNA3.1(+)-Tp92 in rabbits thus establishing a solid basis for the future studies in the biological activities and for the development of the syphilis DNA vaccine.

Mechanical Stress Induces Neuroendocrine and Immune Responses of Sea Cucumber(Apostichopus japonicus)

Grading procedure in routine sea cucumber hatchery production is thought to affect juvenile sea cucumber immunologi- cal response. The present study investigated the impact of a 3-min mechanical perturbation mimicking the grading procedure on neuroendocrine and immune parameters of the sea cucumber Apostichopusjaponicus. During the application of stress, concentrations of noradrenaline and dopamine in coelomic fluid increased significantly, indicating that the mechanical perturbation resulted in a transient state of stress in sea cucumbers. Coelomocytes concentration in coelomic fluid increased transiently after the beginning of stressing, and reached the maximum in 1 h. Whereas, coelomocytes phagocytosis at 3 min, superoxide anion production from 3 min to 0.5 h, acid phosphatase activity at 0.5 h, and phenoloxidase activity from 3 min to 0.5 h were all significantly down-regulated. All of the immune parameters recovered to baseline levels after the experiment was conducted for 8 h, and an immunostimulation occurred after the stress considering the phagocytosis and acid phosphatase activity. The results suggested that, as in other marine invertebrates, neuroendocrine/immnne connections exist in sea cucumber A. japonicus. Mechanical stress can elicit a profound influence on sea cucumber neuroendocrine system. Neuroendocrine messengers act in turn to modulate the immunity fimctions. Therefore, these ef- fects should be considered for developing better husbandry procedures.

Differences in Immune Responses between Children and Adults with COVID-19

Over 85590000 individuals have been infected with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Although there have been an increasing number of reports on coronavirus disease 2019(COVID-19),it is unclear why infected children show milder symptoms than adults.A retrospective case study was performed at two designated hospitals for COVID-19.Patients(56 children and 63 adults)with confirmed SARS-CoV-2 infection and mild pneumonia were randomly enrolled in this study.The median age of the children was 7.0 years,and 51.79%of them were boys.The median age of the adults was 57 years,and 47.62%were men.The most common symptoms were fever,cough,sputum and diarrhoea.There were no significant differences in symptoms between children and adult patients.In terms of immunological indices on admission,adult patients displayed typical leukopenia and markedly higher levels of IL-2,IL-4,and IL-6 than child patients.The elevation of IL-2,IL-4 and IL-6 in adults induced more extensive lung injury.The effective and non-aggressive immune response successfully resisted SARS-CoV-2 invasion and maintained mild symptoms in child patients.The correlation of higher IL-2,IL-4,and IL-6 with the lung injury might be evidence that preventing excessive cytokine production can avoid further lung damage in these patients.

Cigarette smoking and innate immune responses to influenza infection

Cigarette smoking(CS) suppresses the immune system, and smoking is a well-known major risk factor for respiratory tract infections, including influenza infection. Both smoking cigarettes and passive smoking alter a wide range of immunological functions, including innate and adaptive immune responses. Past reviews on CS and innate immunity have been focused on the effects of CS on structural changes of the lung, as well as the effects on the function of alveolar macrophages, leukocytes, natural killer cells and dendritic cells. The study of innate immunity has developed rapidly in the last decade with the discovery of new receptors for virus recognition and interferon responses. This review aims to give a brief summary of recent findings on the suppressive effects of CS on the innate response to influenza virus, especially as it pertains to suppression of the function of pattern recognition receptors for influ-enza virus.

Characterization of humoral immune responses against SARS-CoV-2 accessory proteins in infected patients and mouse model

Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),the causative agent of COVID-19,encodes several accessory proteins that have been shown to play crucial roles in regulating the innate immune response.However,their expressions in infected cells and immunogenicity in infected humans and mice are still not fully understood.This study utilized various techniques such as luciferase immunoprecipitation system(LIPS),immunofluorescence assay(IFA),and western blot(WB)to detect accessory protein-specific antibodies in sera of COVID-19 patients.Specific antibodies to proteins 3a,3b,7b,8 and 9c can be detected by LIPS,but only protein 3a antibody was detected by IFA or WB.Antibodies against proteins 3a and 7b were only detected in ICU patients,which may serve as a marker for predicting disease progression.Further,we investigated the expression of accessory proteins in SARS-CoV-2-infected cells and identified the expressions of proteins 3a,6,7a,8,and 9b.We also analyzed their ability to induce antibodies in immunized mice and found that only proteins 3a,6,7a,8,9b and 9c were able to induce measurable antibody productions,but these antibodies lacked neutralizing activities and did not protect mice from SARS-CoV-2 infection.Our findings validate the expression of SARS-CoV-2 accessory proteins and elucidate their humoral immune response,providing a basis for protein detection assays and their role in pathogenesis.