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.

CD4+ T cell responses in hepatitis C virus infection

Hepatitis C virus (HCV) infection is a major cause of liver damage, with virus-induced end-stage disease such as liver cirrhosis and hepatocellular carcinoma resulting in a high rate of morbidity and mortality worldwide. Evidence that CD4+ T cell responses to HCV play an important role in the outcome of acute infection has been shown in several studies. However, the mechanisms behind viral persistence and the failure of CD4+ T cell responses to contain virus are poorly understood. During chronic HCV infection, HCV-specific CD4+ T cell responses are rela- tively weak or absent whereas in resolved infection these responses are vigorous and multispecific. Persons with a T-helper type I profile, which promotes cellular effec- tor mechanisms are thought to be more likely to experi- ence viral clearance, but the overall role of these cells in the immunopathogenesis of chronic liver disease is not known. To define this, much more data is required on the function and specificity of virus-specific CD4+ T cells, especially in the early phases of acute disease and in the liver during chronic infection. The role and possible mechanisms of action of CD4+ T cell responses in deter- mining the outcome of acute and chronic HCV infection will be discussed in this review.

Potent T cell Responses Induced by Single DNA Vaccine Boosted with Recombinant Vaccinia Vaccine

Plasmid DNA, an effective vaccine vector, can induce both cellular and humoral immune responses. However, plasmid DNA raises issues concerning potential genomic integration after injection. This issue should be considered in preclinical studies. Tiantan vaccinia virus (TV) has been most widely utilized in eradicating smallpox in China. This virus has also been considered as a successful vaccine vector against a few infectious diseases. Potent T cell responses through T-cell receptor (TCR) could be induced by three injections of the DNA prime vaccine followed by a single injection of recombinant vaccinia vaccine. To develop a safer immunization strategy, a single DNA prime followed by a single recombinant Tiantan vaccinia (rTV) AIDS vaccine was used to immunize mice. Our data demonstrated that one DNA prime/rTV boost regimen induced mature TCR activation with high functional avidity, preferential T cell Vβ receptor usage and high sensitivity to anti-CD3 antibody stimulation. No differences in T cell responses were observed among one, two or three DNA prime/rTV boost regimens. This study shows that one DNA prime/rTV boost regimen is sufficient to induce potent T cell responses against HIV.

T cell immune response is correlated with fibrosis and inflammatory activity in hepatitis B cirrhotics

AIM： TO explore the relationship among interferon-γ （IFN-γ） activity, fibrogenesis, T cell immune responses and hepatic inflammatory activity. METHODS： Peripheral blood samples from a total of 43 hepatitis B cirrhotic patients （LC） and 19 healthy controls （NC） were collected to measure their serum levels of IFN-γ, interleukin-2 （IL-2）, soluble interleukin-2 receptor （sIL-2R）, interleukin-10 （IL-10） and three serological markers of fibrosis including hyaluronic acid （HA）, procollagen type III peptide （PIIIP）, and type iV collagen were measured using a double antibody sandwich ELISA. Also, serum total bilirubin （TB） and alanine aminotransferase （ALT） were measured by routine measures. RESULTS： The concentrations of serological markers of fibrosis in patients with active cirrhosis （ALC） were significantly higher than those in stationary liver cirrhosis （SLC） or NC groups. The levels of serological markers in HBeAg-positive patients were significantly higher than those in HBeAg-negative patients. In SLC and ALC patients, a negative linear correlation was found between IFN-γ levels and the serological markers of fibrosis. IFN-γ and IL-2 levels in the ALC group were significantly higher than those in the SLC and NC groups, but the statistical difference was not significant between the latter two. In contrast, IL-10 levels in the SLC group were significantly higher than that in the NC group, but no significant difference was found between SLC and ALC groups. The sIL-2R level was elevated gradually in all these groups, and the differences were significant. Positive linear correlations were seen between IFN-γ activity and ALT levels （r = 0.339, P 〈 0.05）, and IL-2 activity and TB levels （r = 0.517, P 〈 0.05）. sIL-2R expression was positively correlated with both ALT and TB levels （r = 0.324, 0.455, P 〈 0.05）, whereas there was no statistically significant correlation between IL-10 expression and serum ALT and TB levels （r = -0.102, -0.093, P 〉 0.05）. Finally, there was a positive correlation between IFN-γ and IL-2 levels. CONCLUSION： T cell immune responses are correlated with fibrosis and hepatic inflammatory activity and may play an important role in liver cirrhosis.

Dendritic cells engineered to secrete anti-Dc R3 antibody augment cytotoxic T lymphocyte response against pancreatic cancer in vitro

AIM To investigate the enhanced cytotoxic T lymphocyte responses against pancreatic cancer (PC) in vitro induced by dendritic cells (DCs) engineered to secrete anti-DcR3 monoclonal antibody (mAb). METHODS DCs, T lymphocytes and primary PC cells were obtained from PC patients. DCs were transfected with a designed humanized anti-DcR3 monoclonal antibody heavy and light chain mRNA and/or total tumor RNA (DC-tumor-anti-DcR3 RNA or DC-total tumor RNA) by using electroporation technology. The identification, concentration and function of anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA were determined by western blotting and enzyme-linked immunosorbent assay. After co-culturing of autologous isolated PC cells with target DCs, the effects of secreting anti-DcR3 mAb on RNA-DCs' viability and apoptosis were assessed by MTT assay and flow cytometry. Analysis of enhanced antigen-specific immune response against PC induced by anti-DcR3 mAb secreting DCs was performed using a Cr-51 releasing test. T cell responses induced by RNAloaded DCs were analyzed by measuring cytokine levels, including IFN-gamma, IL-10, IL4, TNF-alpha and IL-12. RESULTS The anti-DcR3 mAb secreted by DCs reacted with recombinant human DcR3 protein and generated a band with 35 kDa molecular weight. The secreting mAb was transient, peaking at 24 h and becoming undetectable after 72 h. After co-incubation with DCtumor- anti-DcR3 RNA for designated times, the DcR3 level in the supernatant of autologous PC cells was significantly down-regulated (P < 0.05). DCs secreting anti-DcR3 mAb could improve cell viability and slow down the apoptosis of RNA-loaded DCs, compared with DC-total tumor RNA (P < 0.01). The anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA could enhance the induction of cytotoxic T lymphocytes (CTLs) activity toward RNA-transfected DCs, primary tumor cells, and PC cell lines, compared with CTLs stimulated by DC-total tumor RNA or control group (P < 0.05). Meanwhile, the antigen-specific CTL responses were MHC class I-restricted. The CD4+ T cells and CD8+ T cells incubated with anti-DcR3 mAb secreting DCs could produce extremely higher level IFN-gamma and lower level IL4 than those incubated with DC-total tumor RNA or controls (P < 0.01). CONCLUSION DCs engineered to secrete anti-DcR3 antibody can augment CTL responses against PC in vitro, and the immune-enhancing effects may be partly due to their capability of down-regulating DC apoptosis and adjusting the Th1/Th2 cytokine network.

Immune Responses in Wild-type Mice Against Prion Proteins Induced Using a DNA Prime-Protein Boost Strategy

Objective To break immune tolerance to prion （PrP） proteins using DNA vaccines.Methods Four different human prion DNA vaccine candidates were constructed based on the pcDNA3.1 vector：PrP‐WT expressing wild‐type PrP,Ubiq‐PrP expressing PrP fused to ubiquitin,PrP‐LII expressing PrP fused to the lysosomal integral membrane protein type II lysosome‐targeting signal,and PrP‐ER expressing PrP locating the ER.Using a prime‐boost strategy,three‐doses of DNA vaccine were injected intramuscularly into Balb/c mice,followed by two doses of PrP protein.Two weeks after the last immunization,sera and spleens were collected and PrP‐specific humoral and cellular immune responses evaluated by ELISA and ELISPOT tests.Results Higher levels of serum PrP antibodies were detected in mice vaccinated using the strategy of DNA priming followed by protein boosting.Of these,WT‐PrP,Ubiq‐PrP,and PrP‐LII induced significantly higher humoral responses.ELISPOT tests showed markedly increased numbers of IFN‐γ‐secreting T cells in mice vaccinated using the strategy of DNA priming followed by protein boosting after stimulation with recombinant PrP23‐90 and PrP23‐231.PrP‐ER inducedthe strongest T‐cell response.Conclusion Prion vaccines can break tolerance to PrP proteins and induce PrP‐specific humoral and cellular immune responses.

Correlation of peripheral blood T cell changes with nerve damage, inflammatory response and stress response in patients with acute cerebral infarction

Objective: To investigate the correlation of peripheral blood T cell changes with nerve damage, inflammatory response and stress response in patients with acute cerebral infarction. Methods: 108 patients with acute cerebral infarction who received emergency treatment in Xuefu Hospital of Shaanxi Normal University between September 2015 and August 2017 were selected as the cerebral infarction group, and 100 healthy elderly volunteers who underwent physical examination during the same period were selected as the normal control group. The differences in the expressions of CD4+CD25+ regulatory T lymphocytes in peripheral blood as well as the levels of nerve damage indicators, inflammatory factors and oxidative stress indicators in serum were compared between the two groups. Pearson test was used to evaluate the intrinsic relationship between peripheral blood CD4+CD25+ regulatory T lymphocyte expression and infarction condition in patients with acute cerebral infarction. Results:Peripheral blood CD4+CD25+ regulatory T lymphocyte expression of the cerebral infarction group was higher than that of the normal control group;serum nerve damage indicators UCH-L1, GFAP, and Ang-1 levels were higher than those of the normal control group while IGF-1 and BDNF levels were lower than those of the normal control group;serum inflammatory factors IL-1β, VCAM-1, IL-13, and IL-18 levels were higher than those of the normal control group;serum oxidative stress indicators CAT and T-SOD levels were lower than those of the normal control group whereas MDA level was higher than that of the normal control group. Correlation analysis confirmed that peripheral blood CD4+CD25+ regulatory T lymphocyte expression in patients with acute cerebral infarction was directly correlated with the levels of nerve damage indicators, inflammatory factor, and oxidative stress indicators. Conclusion:The abnormal increase of peripheral blood CD4+CD25+ regulatory T lymphocyte expression in patients with acute cerebral infarction is related to the aggravation of nerve damage and systemic inflammatory stress response.

Correlation of peripheral blood regulatory T cell content with inflammatory stress response and immune response in children with both pneumonia and sepsis

Objective: To investigate the correlation of peripheral blood regulatory T cell content with inflammatory stress response and immune response in children with both pneumonia and sepsis. Methods: A total of 90 child patient with both pneumonia and sepsis who were treated in our hospital between September 2014 and April 2017 were selected as sepsis group and 100 healthy children who received vaccination in our hospital during the same period were selected as normal control group. The differences in peripheral blood regulatory T cell (Treg) expression as well as serum inflammatory mediator, oxidative stress index and immunoglobulin contents were compared between the two groups of children. Pearson test was used to evaluate the correlation between Treg expression and disease in patients with both pneumonia and sepsis. Results: Peripheral blood Treg expression of sepsis group was significantly higher than that of control group;serum inflammatory mediators PCT, hs-CRP, TNF-α and IL-6 contents were higher than those of control group;serum oxidative stress indexes―nitric oxide and malondialdehyde contents were higher than those of control group whereas superoxide dismutase content was lower than that of control group;immunoglobulin IgA, IgM and IgG contents were lower than those of normal control group. Pearson test showed that peripheral blood Treg expression of children with both pneumonia and sepsis was directly correlated with the inflammatory stress response and immune response. Conclusion: Peripheral blood Treg expression significantly increases in children with both pneumonia and sepsis, which could directly affect the inflammatory stress response extent and humoral immune function.

Evaluation of virus-specific cellular immune response in transplant patients

Virus-specific immune responses have a major impact on the outcome of the infection. Viral agents that are characterized by latency, such as herpesviruses and polyomaviruses, require a continuous immune control to reduce the extent of viral reactivation, as viral clearance cannot be accomplished, independently from the anti-viral treatment. In transplant patients, morbidity and mortality related to viral infections are significantly increased. In fact, the key steps of activation of T-cells are major target for anti-rejection immunosuppressive therapy and anti-viral immune response may be altered when infected cells and cellular effectors of immune response coexist in a transplanted organ. The role of cellular immune response in controlling viral replication and the main methods employed for its evaluation will be discussed. In particular, the main features, including both advantages and limitations, of available assays, including intracellular cytokine staining, major histocompatibility complex- multimer-based assays, Elispot assay, and Quanti FERON test, will be described. The potential applications of these assays in the transplant context will be discussed, particularly in relation to cytomegalovirus and polyomavirus BK infection. The relevance of introducing viro-immunological monitoring, beside virological monitoring, in order to identify the risk profile for viral infections in the transplant patients will allows for define a patient-tailored clinical management, particular in terms of modulation of immunosuppressive therapy and anti-viral administration.

成人接种2剂新冠灭活疫苗12个月后T细胞免疫应答特点

目的评估成年人接种新型冠状病毒(SARS-CoV-2)灭活疫苗12个月后不同抗原特异性T细胞免疫应答的特点。方法解放军总医院第五医学中心2022年4-6月招募15名健康成年人,于接种2剂新冠灭活疫苗12个月后采集其静脉血标本,以基于多色流式细胞术的活化诱导标记法(AIM)检测SARS-CoV-2抗原特异性T淋巴细胞水平,并分析其记忆表型与亚群分化特点。结果成年人接种2剂灭活疫苗12个月后,90%以上个体可检测到Spike及Non-spike特异性CD4^(+)T细胞反应(S:14/15,P=0.0001;NS:15/15,P<0.0001);80%个体检测到Spike及Non-spike特异性CD8^(+)T细胞反应(S:12/15,P=0.0463;NS:12/15,P=0.0806)。抗原特异性CD4^(+)T细胞主要表现为中央记忆细胞(CM)、1型效应记忆细胞(EM1)记忆表型,以及1/17型辅助性T细胞(Th1/17)、2型辅助性T细胞(Th2)辅助表型。结论灭活疫苗接种后能诱导广泛且持久的抗原特异性CD4^(+)T细胞反应,可能是当前国内新型冠状病毒感染重症化比例较低的关键因素。

反复呼吸道感染患儿外周血单个核细胞中TLR2、TLR4表达情况与Th1/Th2免疫应答的关系

目的探讨反复呼吸道感染(RRTI)患儿外周血单个核细胞(PBMC)Toll样受体2(TLR2)、Toll样受体4(TLR4)表达情况与辅助性T细胞1(Th1)/辅助性T细胞2(Th2)免疫应答的关系。方法将2020年12月至2022年12月该院收治的65例确诊为RRTI的患儿纳入研究作为RRTI组。另选取同期于该院体检的健康儿童45例作为对照组。采用实时荧光定量PCR(qPCR)检测PBMC中TLR2和TLR4的信使核糖核酸(mRNA)相对表达水平。采用流式细胞仪检测PBMC中TLR2和TLR4蛋白表达率。采用酶联免疫吸附法(ELISA)检测血浆中Th1细胞因子干扰素-γ(IFN-γ)、Th2细胞因子白细胞介素-4(IL-4)水平及二者比值(IFN-γ/IL-4)。采用Pearson相关分析TLR2、TLR4蛋白表达率与血浆IFN-γ、IL-4水平的相关性。结果RRTI组血浆Th2细胞因子IL-4水平高于对照组,血浆Th1细胞因子IFN-γ水平低于对照组,IFN-γ/IL-4低于对照组,差异均有统计学意义(P<0.05)。RRTI组PBMC中TLR2和TLR4 mRNA相对表达水平及蛋白表达率均高于对照组,差异均有统计学意义(P<0.05)。Pearson相关分析显示,RRTI患儿PBMC中TLR2和TLR4蛋白表达率与血浆IFN-γ水平及IFN-γ/IL-4均呈负相关(P<0.05),与血浆IL-4水平均呈正相关(P<0.05)。结论RRTI患儿PBMC中TLR2、TLR4的表达及血浆Th1/Th2细胞因子均可能参与疾病的发生、发展的过程。过度活化的TLR2和TLR4可能会使Th1功能减弱、Th2功能增强。

Natural course of chronic hepatitis B is characterized by changing patterns of programmed death type-1 of CD8-positive T cells

AIM:To investigate if and how programmed death type-1(PD-1)expression affects the natural course of hepatitis B virus(HBV)infection. METHODS:Sixty-four patients in different natural stages of chronic HBV infection were enrolled in this study.PD-1 expression in total T cells was detected by flow cytometry.Levels of total CD8+T cell responses and proliferation in relation to PD-1 expression levels were analyzed with intracellular staining and PD-1/ PD-L1 blockage. RESULTS:The PD-1 expression in T cells was dynamically changed during the natural course of chronic HBV infection,did not significantly increase in the immune tolerance phase,and returned to normal in the inactive virus carrier stage.Blockage of the PD-1/PD-L1 pathway could not affect the T-cell response in the immune tolerance and inactive virus carrier stages of chronic HBV infection.However,it could significantly restore the T-cell response in the immune clearance stage of chronic HBV infection.Furthermore,the PD-1 expression level in T cells was associated with the alanine aminotransferase level during the immune clearance stage of chronic HBV infection. CONCLUSION:The PD-l/PD-L1 pathway plays a different role in T-cell response during the natural course of chronic HBV infection.

Relationship between T-lymphocyte cytokine levels and sero-response to hepatitis B vaccines

AIM: To investigate the cellular defects by analyzing the (Th1/Th2) cytokine levels in vaccine responders and non-responders. METHODS: Peripheral blood mononuclear cell (PBMC) from responders and non-responders were stimulated with or with out recombinant HBsAg or PHA. Broad spectrum of cytokines viz (Th1) IFN-γ, IL-2, TNF-α, IL-12 and (Th2) IL-10, IL-4 were measured after in vitro stimulation with recombinant HBsAg and were compared with respective antibody titers. RESULTS: A significant decrease (P = 0.001) in Th1 and Th2 cytokines namely, IL-2, INF-γ, TNF-α and IL-10in non-responders was observed. The level of IL-4 was not significant between the three groups. Furthermore, despite a strong Th1 and Th2 cytokine response, the level of IL-12 was elevated in high-responders compared to other groups (P = 0.001) and demonstrated a positive correlation with anti-HBs titers and Th1 cytokine response. CONCLUSION: Our findings suggest that unrespon-siveness to recombinant hepatitis B vaccines (rHB) is multifactorial, including specific failure of antigen presentation or the lack of both T helper Th1 and Th2 response.

Analysis of circulating regulatory T cells （CD4 ＋CD25 ＋CD 127-）after cryosurgery in prostate cancer

This study was performed to assess the response of regulatory T cells （Tregs） following cryosurgery in prostate cancer （PCa） patients by measuring their frequency and immune function. Blood was collected prior to and at 4 and 8 weeks after treatment in 30 patients with high-risk PCa who underwent cryosurgery and from 15 healthy volunteers. Circulating CD4＋CD25＋CD127- Tregs were isolated. Their frequency was detected by flow cytometry, and immune suppressive function was evaluated by measuring the proliferation of CD4＋CD25- T cells cocultured with Tregs. The results showed that the percentage of circulating CD4＋CD25＋CD127- Tregs was increased in PCa patients compared to healthy volunteers （7.6%±0.73% vs. 5.8%±0.54%, P〈0.001）. The frequency of circulating CD4＋CD25＋CD127- Tregs was reduced 4 weeks after cryosurgery compared to before surgery （6.3%__.0.58% vs. 7.6%±0.73%, P〈0.001）, and the decrease persisted for 8 weeks. However, the suppressive function of Tregs was increased in eight of 12 patients, which might contribute to cancer recurrence. Then the response of circulating Tregs is complicated after cryosurgery for PCa, and further studies are warranted.

Activation and dramatically increased cytolytic activity of tumor specific T lymphocytes after radio-frequency ablation in patients with hepatocellular carcinoma and colorectal liver metastases

AIM： To assess if a specific cytotoxic T cell response can be induced in patients with malignant liver tumors treated with radio-frequency ablation （RFA）. METHODS： Six Patients with liver metastases of colorectal cancer and 6 with hepatocellular carcinoma （HCC） underwent RFA. Blood was sampled before, 4 and 8 wk after RFA. Test antigens were autologous liver and tumor lysate obtained from each patient by biopsy. Peripheral T cell activation was assessed by an interferon gamma （IFNγ） secretion assay and flow cytometry. T cells were double-stained for CD4/CD8 and IFNγ to detect cytotoxic T cells. The ratio of IFNγ positive and IFNγ negative T cells was determined as the stimulation index （SI）. To assess cytolytic activity, T cells were co-incubated with human CaCo colorectal cancer and HepG2 HCC cells and release of cytosolic adenylate kinase was measured by a luciferase assay. RESULTS： Before RFA SI was 0.021 （±0.006） for CD4^＋ and 0.022 （± 0.004） for CD8^＋T cells against nonmalignant liver tissue and 0.018 （± 0.005） for CD4^＋ and 0.021 （± 0.004） for CD8^＋ cells against autologous tumor tissue. Four weeks after RFA SI against tumor tissue increased to 0.109 （± 0.005） for CD4＋ and 0.11 （± 0.012） for CD8＋ T cells against HCC, and to 0.115 （± 0.031） for CD4^＋ and 0.15 （± 0.02） for CD8^＋ cells for colorectal metastases （P 〈 0.0001）. No increased SI was observed with nonmalignant tumor tissue at all time points. Before RFA cytolytic activity against the respect（ve cancer cells was low with 2.62 （± 0.37） relative luminescence units （RLU）, but rose more than 100 fold 4 and 8 wk after RFA. Spontaneous release was 〈 2% of maximum release in all experiments. CONCLUSION： Patients with primary and secondary tumors of the liver show a significant tumor-specific cytotoxic T-cell stimulation with a dramatically increased tumor specific cytolytic activity of CD8^＋ T cells after RFA.

Induced Th2 dominant immune response in APPswe, PSEN1dE9 transgenic mice after nasal immunization with an adenoviral vector encoding 10 tandem repeats of beta-amyloid 3-10

Immunotherapy for Alzheimer＇s disease （AD） is effective in improving cognitive function in transgenic mouse models of AD. Because the AN1792 [beta-amyloid （Aβ） 1-42] vaccine was halted because of T cell mediated meningoencephalitis, many scientists are searching for a nove） vaccine to avoid the T cell mediated immune response caused by the Aβ1-42. Importantly, the time when the immunization is begun can influence the immune effect. In this study, an adenovirus vaccine was constructed containing 10 x Aβ3-10 repeats and gene adjuvant CpG DNA. Transgenic AD mice were immunized intranasally for 3 months. After 10 × Aβ3-10 vaccine immunization, high titers of anti-Aβ42 IgG1 predominant antibodies were induced. In spatial learning ability and probe tests, the 10 × Aβ3-10 immunized mice showed significantly improved memories compared to control mice. The 10 × Aβ3-10 vaccine resulted in a robust Th2 dominant humoral immune response and reduced learning deficits in AD mice. In addition, the 10 × Aβ3-10 vaccine might be more efficient if administered before Aβ aggregation at an early stage in the AD mouse brain. Thus, the adenovirus vector encoding 10 × Aβ-10 is a promising vaccine for AD.

Deficiency of Tfh Cells and Germinal Center in Deceased COVID-19 Patients

Summary:The COVID-19 pandemic caused by SARS-CoV2 is characterized by a remarkable variation in clinical severity ranging from a mild illness to a fatal multi-organ disease.Understanding the dysregulated human immune responses in the fatal subjects is critical for management of COVID-19 patients and the pandemic.In this study,we examined the immune cell compositions in the lung tissues and hilar lymph nodes using immunohistochemistry on 6 deceased COVID-19 patients and 4 focal organizing pneumonia(FOP)patients who underwent lung surgery and served as controls.We found a dominant presence of macrophages and a general deficiency of T cells and B cells in the lung tissues from deceased COVID-19 patients.In contrast to the FOP patients,Tfh cells and germinal center formation were largely absent in the draining hilar lymph nodes in the deceased COVID-19 patients.This was correlated with reduced IgM and IgG levels compared to convalescent COVID-19 patients.In summary,our data highlight a defect of germinal center structure in deceased COVID-19 patients leading to an impaired humoral immunity.Understanding the mechanisms of this deficiency will be one of the key points for the management of this epidemic.

Interactions of Human T Cell Immunoglobin Mucins with Apoptotic Cells

T cell immunoglobulin mucin (TIM) family plays a key role in regulating immune re-sponses.In this study,the interactions of human TIM family with apoptotic cells were evaluated in order to provide a foundation for further study on the roles of human TIM genes in apoptosis.Nine kinds of pEGFP-N1 eukaryotic expression vectors containing different lengths of the three members of human TIM genes for the expression of TIM-EGFP and the vectors for the expression of TIM-Fc fusion pro-teins were constructed.It was found that human TIM proteins could recognize and bind to apoptotic cells directly,but not to viable cells.The interactions of sTIM-1-EGFP,sTIM-3-EGFP and sTIM-4-EGFP with apoptotic cells were blocked by TIM-1-Ig,TIM-3-Ig and TIM-4-Ig fusion proteins respectively.In addition,human TIM proteins mediated the recognition of apoptotic cells and bound to apoptotic cells directly via the IgV domains.In conclusion,the TIM family may play a key role in the regulation of apoptosis.Our data also suggest that human TIM proteins probably serve as novel proteins for the detection of the early cellular apoptosis.

Immune response to H pylori

The gastric mucosa separates the underlying tissue from the vast array of antigens that traffic through the stomach lumen. While the extreme pH of this environment is essential in aiding the activation of enzymes and food digestion, it also renders the gastric epithelium free from bacterial colonization, with the exception of one important human pathogen, Hpylori. This bacterium has developed mechanisms to survive the harsh environment of the stomach, actively move through the mucosal layer, attach to the epithelium, evade immune responses, and achieve persistent colonization. While a hallmark of this infection is a marked inflammatory response with the infiltration of various immune cells into the infected gastric mucosa, the host immune response is unable to clear the infection and may actually contribute to the associated pathogenesis. Here, we review the host responses involved during infection with Hpylori and how they are influenced by this bacterium.

Vasoactive intestinal polypeptide (VIP) corrects chronic inflammatory response syndrome (CIRS) acquired following exposure to water-damaged buildings

Exposure in water-damaged buildings (WDB) to airborne bioaerosols including metabolic products of toxigenic fungi, bacteria and actinomycetes;and inflammagens, can lead to a persistent innate immune inflammatory illness. This illness, termed a chronic inflammatory response syndrome (CIRS-WDB), is systemic with symptoms acquired from multiple organ systems. Treatment of CIRS-WDB has progressed rapidly as a better understanding of the inflammatory pathophysiology has led to targeted, sequential therapies. The fundamental basis of uncontrolled innate immune responses, the humoral deficiency of regulatory neuropeptides melanocyte stimulating hormone (MSH) or vasoactive intestinal polypeptide (VIP), seen in over 98% of pa tients, has not consistently responded to any treatment modality. Use of replacement VIP has been attempted anecdotally;VIP replacement therapies show promise in short term studies but longer therapies have not been attempted. Here we report an open label trial of 20 patients with refractory CIRS-WDB illness who took replacement VIP in a nasal spray for at least 18 months with confirmation of durable efficacy and absence of significant side effects. These 20 patients were similar in symptoms and lab find- ings to three previously published cohorts in- volving 1829 patients and 169 controls. Dosage of VIP was titrated downwards from four to zero doses a day to determine minimum effective dose, and retitrated upwards for maximum improvement over time. The trial showed that VIP therapy safely 1) reduced refractory symptoms to equal controls;2) corrected inflammatory parameters C4a, TGF beta-1, VEGF, MMP9;3) corrected estradiol, testosterone and 25-OH Vitamin D;4) returned pulmonary artery systolic pressure (PASP) during exercise to normal;and 5) enhanced quality of life in 100% of trial patients. Subsequent identification of correction of T-regulatory cell levels supports the potential role of VIP in both innate and adaptive immune function.