Neutralization against SARS-CoV-2 Delta/Omicron variants and B cell response after inactivated vaccination among COVID-19 convalescents / 医学前沿

Emerging SARS-CoV-2 variants have made COVID-19 convalescents susceptible to re-infection and have raised concern about the efficacy of inactivated vaccination in neutralization against emerging variants and antigen-specific B cell response. To this end, a study on a long-term cohort of 208 participants who have recovered from COVID-19 was conducted, and the participants were followed up at 3.3 (Visit 1), 9.2 (Visit 2), and 18.5 (Visit 3) months after SARS-CoV-2 infection. They were classified into three groups (no-vaccination (n = 54), one-dose (n = 62), and two-dose (n = 92) groups) on the basis of the administration of inactivated vaccination. The neutralizing antibody (NAb) titers against the wild-type virus continued to decrease in the no-vaccination group, but they rose significantly in the one-dose and two-dose groups, with the highest NAb titers being observed in the two-dose group at Visit 3. The NAb titers against the Delta variant for the no-vaccination, one-dose, and two-dose groups decreased by 3.3, 1.9, and 2.3 folds relative to the wild-type virus, respectively, and those against the Omicron variant decreased by 7.0, 4.0, and 3.8 folds, respectively. Similarly, the responses of SARS-CoV-2 RBD-specific B cells and memory B cells were boosted by the second vaccine dose. Results showed that the convalescents benefited from the administration of the inactivated vaccine (one or two doses), which enhanced neutralization against highly mutated SARS-CoV-2 variants and memory B cell responses. Two doses of inactivated vaccine among COVID-19 convalescents are therefore recommended for the prevention of the COVID-19 pandemic, and vaccination guidelines and policies need to be updated.

Neutralization against SARS-CoV-2 Delta/Omicron variants and B cell response after inactivated vaccination among COVID-19 convalescents / 医学前沿

Emerging SARS-CoV-2 variants have made COVID-19 convalescents susceptible to re-infection and have raised concern about the efficacy of inactivated vaccination in neutralization against emerging variants and antigen-specific B cell response. To this end, a study on a long-term cohort of 208 participants who have recovered from COVID-19 was conducted, and the participants were followed up at 3.3 (Visit 1), 9.2 (Visit 2), and 18.5 (Visit 3) months after SARS-CoV-2 infection. They were classified into three groups (no-vaccination (n = 54), one-dose (n = 62), and two-dose (n = 92) groups) on the basis of the administration of inactivated vaccination. The neutralizing antibody (NAb) titers against the wild-type virus continued to decrease in the no-vaccination group, but they rose significantly in the one-dose and two-dose groups, with the highest NAb titers being observed in the two-dose group at Visit 3. The NAb titers against the Delta variant for the no-vaccination, one-dose, and two-dose groups decreased by 3.3, 1.9, and 2.3 folds relative to the wild-type virus, respectively, and those against the Omicron variant decreased by 7.0, 4.0, and 3.8 folds, respectively. Similarly, the responses of SARS-CoV-2 RBD-specific B cells and memory B cells were boosted by the second vaccine dose. Results showed that the convalescents benefited from the administration of the inactivated vaccine (one or two doses), which enhanced neutralization against highly mutated SARS-CoV-2 variants and memory B cell responses. Two doses of inactivated vaccine among COVID-19 convalescents are therefore recommended for the prevention of the COVID-19 pandemic, and vaccination guidelines and policies need to be updated.

Durability of neutralizing antibodies and T-cell response post SARS-CoV-2 infection / 医学前沿

The ongoing pandemic of Coronavirus disease 19 (COVID-19) is caused by a newly discovered β Coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). How long the adaptive immunity triggered by SARS-CoV-2 can last is of critical clinical relevance in assessing the probability of second infection and efficacy of vaccination. Here we examined, using ELISA, the IgG antibodies in serum specimens collected from 17 COVID-19 patients at 6-7 months after diagnosis and the results were compared to those from cases investigated 2 weeks to 2 months post-infection. All samples were positive for IgGs against the S- and N-proteins of SARS-CoV-2. Notably, 14 samples available at 6-7 months post-infection all showed significant neutralizing activities in a pseudovirus assay, with no difference in blocking the cell-entry of the 614D and 614G variants of SARS-CoV-2. Furthermore, in 10 blood samples from cases at 6-7 months post-infection used for memory T-cell tests, we found that interferon γ-producing CD4

Host Cell Responses to Dengue Virus / 中山大学学报(医学科学版)

@#Recent outbreak of dengue virus （DENV） in subtropics and tropics and the increasing incidence of DENV infection have seriously threatened the public health. Upon virus infection，the host cells rapidly elicit various responses through activating different signaling pathways，to fight against the invasion of DENV. On the other hand，dengue virus has evolved many strategies of escaping，antagonizing or even utilizing these host responses. This review summarizes the progress of molecular biology of DENV and the cellular responses against DENV infection，including innate immune response，adaptive immune response，cell death，autophagy，unfolded protein response，and stress granule formation.

Research progress on the T cell receptor CDR3 spectral sequence of periodontitis / 口腔疾病防治

@#Periodontitis is a chronic inflammatory and destructive disease of periodontal support tissue initiated by plaque microorganisms, and its pathogenesis and progression are closely related to the immune response of the host, in which T cells play an important role in the periodontitis immune response. This article will start with the T cell immune response and the characteristics of the T cell receptor complementarity-determining region 3 (TCR CDR3) spectrum and will review the relationship between the characteristics of the TCR CDR3 spectrum and the pathogenesis of periodontitis to provide some new ideas for the studies of pathogenesis and the clinical personalized treatment of periodontitis. The study on the TCR CDR3 spectrum of periodontitis by reviewing the literature suggests that there is an oligoclonal accumulation of T cells and biased access of Variable (V) and Joining (J) genes in local lesions of periodontitis; moreover, the repeated use of nucleotide sequences and a conservative amino acid motif were found in the CDR3 region, which suggests that the characteristics of the TCR CDR3 group library play an important role in the immune pathogenesis of periodontitis.

Interferon-α modulates HBV specific T-cell response to inhibit viral gene expression in chronic HBV infection mouse model / 中国感染与化疗杂志

Objective To explore the antiviral effect and mechanism of interferon-α (IFN-α) in chronic HBV infection mouse model by hydrodynamic tail vein injection. Methods Chronic HBV infection mouse model was constructed with C57BL/6j mice by hydrodynamic tail vein injection of pAAV-HBV1.2 plasmid. Serum IFN-α was determined by ELISA after injection of IFNα- expressing plasmid (i.e., plasmid pKCMvint.IFN-α-2a) or control plasmid pKCMvint. HBsAg and HBeAg levels were assayed on Abbot ARCHITECT i2000SR. Total lymphocytes in liver or spleen were counted and the frequency and function of CD8+T cells and HBV-specific CD8+T cells were analyzed by flow cytometry. Results Serum IFN-α expression level was significantly higher in the animals injected with pKCMvint.IFN-α-2a plasmid than in control group (P＜0.01). Serum HBsAg decreased quickly 12 days after injection and significantly lower than control group. Serum HBeAg was undetectable after IFN-α expression. Interestingly, the frequency of CD8+T cells in the liver of animals injected with pKCMvint.IFN-α-2a plasmid was significant higher than control group (P＜0.05), while total liver lymphocytes and HBV-specific CD8+T cells had a similar trend. Consistently, the HBV-specific CD8+T cells in IFN-α-expressing animals showed higher level of producing IFN-γ, TNF-α and IL-2 than control group. IFN-γ production was significantly different between IFN-α- expressing group and control group (P＜0.05). Conclusions IFN-α can increase the frequency and function of liver CD8+T cells to inhibit HBV gene expression in chronic HBV infection mouse model.

An in vitro activity study of titanium surface modified by cluster-like anatase/rutile nanowires / 实用医学杂志

Objective Exploration of the titanium surface nano structure on the cellular bioactivity is of great significance to modifying the pure titanium surface. The unique cluster-like anatase/rutile nanowires (AR@NWs)was prepared and we further examined whether this surface was beneficial for early biological reaction in osteoblast.Methods Unique cluster-like anatase/rutile NWs(AR@NWs)was generated by using a simple hy-drothermal reaction via a three-step synthesis process.The crystal structure of nanowires on titanium surface was de-tected by X-ray diffractometer. The biological activity of nanowires was studied using in vitro cellular experiments. Results The AR@NWs was with a diameter of 200 nm. Three different types of NWs were generated during the production process,displaying different crystal structure and biological characteristics but similar surface topogra-phy and wettability.Compared with sodium titanate NWs(STi@NWs)and H2Ti2O5nanowires(HTi@NWs),AR@NWs surface was conductive to cell attachment. The data indicated that the surface titanium chemical composi-tion and crystal structure played an important role in the cell early response.To some extent,the generation of ana-tase and rutile compensated the cell-repelling properties of NWs. Conclusion Not only the surface physical prop-erties such as surface topography but also the surface chemistry plays an important role in promoting the cell early bioactivity.

Human Leukocyte Antigen-A Allele Distribution in Nasopharyngeal Carcinoma Patients Showing Anti-Melanoma-Associated Antigen A or Synovial Sarcoma X-2 T Cell Response in Blood / 中华医学杂志(英文版)

<p><b>Background</b>Development of innovative immunotherapy is imperative to improve the poor survival of the nasopharyngeal carcinoma (NPC) patients. In this study, we evaluated the T cell response to melanoma-associated antigen (MAGE)-A1, MAGE-A3, or synovial sarcoma X-2 (SSX-2) in the peripheral blood of treatment-naive NPC patients. The relationship of responses among the three proteins and the human leukocyte antigen (HLA)-A types were analyzed to provide evidence of designing novel therapy.</p><p><b>Methods</b>Sixty-one NPC patients admitted into the Tumor Hospital affiliated to the Xinjiang Medical University between March 2015 and July 2016 were enrolled. Mononuclear cells were isolated from the peripheral blood before any treatment. HLA-A alleles were typed with Sanger sequence-based typing technique. The T cell response to the MAGE-A1, MAGE-A3, or SSX-2 was evaluated with the Enzyme-Linked ImmunoSpot assay. Mann-Whitney U-test was used to compare the T cell responses from different groups. Spearman's rank correlation was used to analyze the relationship of T cell responses.</p><p><b>Results</b>HLA-A*02:01, A*02:07, and A*24:02 were the three most frequent alleles (18.9%, 12.3%, and 11.5%, respectively) among the 22 detected alleles. 31.1%, 19.7%, and 16.4% of the patients displayed MAGE-A1, MAGE-A3, or SSX-2-specific T cell response, respectively. The magnitudes of response to the three proteins were 32.5, 38.0, and 28.7 SFC/10 peripheral blood mononuclear cells, respectively. The T cell response against the three proteins correlated with each other to different extent. The percentage of A*02:01 and A*24:02 carriers were significantly higher in patients responding to any of the three proteins compared to the nonresponders.</p><p><b>Conclusion</b>MAGE-A1, MAGE-A3, or SSX-2-specific T cell responses were detectable in a subgroup of NPC patients, the frequency and magnitude of which were correlated.</p>

Effects of polysaccharide-containing aqueous extracts of Cistanche deserticola Y. C. Ma on T lympho-cyte subsets and duration of antibody response / 中华微生物学和免疫学杂志

Objective To study the effects of aqueous extracts of cultivated Cistanche deserticola Y. C. Ma (AECCD) on T cell responses and the duration of antibody response and to investigate its immunoen-hancing activities in mice. Methods Two batches of female ICR mice were used in this study with 30 from each batch. Each batch of mice was randomly divided into six groups (n=5). Low, medium and high doses of AECCD in combination with ovalbumin ( OVA) were used to set up three experimental groups, while 0. 9% NaCl, OVA alone and aluminium adjuvant were respectively used as blank, negative and positive controls. All mice were intramuscularly injected twice at an interval of two weeks. Flow cytometry was used to detect the ex-pression of T lymphocyte subsets, cytokines and surface molecules of dendritic cells (DC). Indirect ELISA was used to detect IgG antibody levels. Results AECCD could significantly increase the percentage of CD4+and CD8+T lymphocytes in spleen (P<0. 05), up-regulate the expression of CD4+CD44+and CD8+CD44+effector T lymphocytes (P<0. 05), promote the secretion of IFN-γ in T lymphocytes and enhance the expression of CD40 and CD80 on the surface of DC (P<0. 05). ELISA results showed that high-dose AECCD could significantly prolong the duration of IgG antibody response induced by OVA (P<0. 05). Conclusion AECCD could en-hance the T lymphocyte immune response induced by OVA and keep it maintained at a high level, which might help to improve the body′s immune response.

Sequential immunization with domain Ⅲ of dengue envelope proteins induces immune responses against dengue virus / 中华微生物学和免疫学杂志

Objective To investigate whether a novel sequential immunization strategy was more superior to the traditional immunization strategy in eliciting immune responses by using domainⅢof dengue envelope proteins (EDⅢs) as immunogens. Methods EDⅢ subunit proteins of four serotypes of dengue viruses (DENVs) were expressed in a baculovirus expression system. SDS-PAGE and Western blot were performed to analyze the purity and specificity of purified recombinant proteins, respectively. In order to evaluate the immunogenicity of EDⅢ-based immunization strategies, female BALB/c mice were subcutane-ously immunized with PBS,tetravalent mixture of four EDⅢrecombinant proteins,or the four EDⅢproteins sequentially for four times with two weeks interval between each immunization. Two-week after the final im-munization,splenocytes were isolated and analyzed by ELISPOT assay to evaluate T cell responses and serum samples were collected for plaque reduction neutralization test(PRNT). Results Both immunization strate-gies of sequential EDⅢproteins and tetravalent EDⅢproteins could elicit stronger antigen-specific Th2(IL-4) cell responses in immunized mice than PBS did and the former was superior to the latter. Only the se-quential immunization strategy could induce Th2 cell responses in immunized mice against peptide segments of DENV2 EDⅢ. Tetravalent EDⅢ proteins performed better than the sequential immunization strategy in inducing higher levels of neutralizing antibodies against DENV-1,DENV-2 and DENV-3,while both immu-nization strategies failed to generate neutralizing antibodies against DENV-4. Conclusion Sequential immu-nization with DENV EDⅢ proteins induced stronger T cell responses, but weaker neutralizing antibody re-sponses against DENV than tetravalent EDⅢ proteins did.

Mechanism of IL-35 inhibition of inflammatory response and T cell response in alleviate of allergic rhinitis / 中国免疫学杂志

Objective:To investigate the effect of IL-35 on inflammatory response and T cell response in allergic rhinitis.Methods: 37 patients(observation group) with allergic rhinitis and 35 healthy volunteers(control group) after allergen detection of allergic rhinitisin in our hospital from Jan 2012 to Jan 2016 were selected as study subjects.The peripheral blood of observation group and control group were collected,and the serum levels of IL-35 were detected by ELISA.The animal model of allergic rhinitis in mice was established,the peripheral blood of mice was collected,and the serum level of IL-35 and IgE were detected by ELISA.The eosinophils that infiltrated in nasal mucosa were detected after tissue biopsy in mice.The mouse spleen cells were isolated and the ovalbumin antigen was added in the culture medium,IL-35 was or was not added into the culture medium,the ovalbumin specific T cell responses was detected.The cytokines IL-2,IL-4,IL-5,IL-10,IL-13,IL-17,IL-23,IL-27 and TNF-α in culture supernatant of ovalbumin specific T cells were detected by ELISA.The expression of IL-2,IL-4,IL-5,IL-10,IL-13,IL-17,IL-23,IL-27 and TNF-α in ovalbumin specific T cells were detected by Real-time PCR.The activation of JNK,Erk1/2 and p38 signal pathway in ovalbumin specific T cells were detected by Western blot.Results: The serum level of IL-35 in observation group was significantly lower than control group(P<0.05).The results showed that the number of eosinophils which infiltrated in AR mice nasal mucosa was significantly higher than normal mice(P<0.05),while the serum level of IL-35 in AR mice was significantly lower than normal mice(P<0.05).Ovalbumin specific T cell reactivity assay showed that IL-35 could significantly inhibit the T cell response.ELISA and Real-time PCR results showed that IL-35 could significantly down regulate the expression of IL-4,IL-5,IL-13,IL-17,IL-23 and TNF-α,and up regulate the expression of IL-2,IL-10 and IL-27.The Western blot results showed that IL-35 can inhibit the activation of JNK,Erk1/2 and p38 signal pathway of ovalbumin specific T in cells.Conclusion: IL-35 can regulate the expression of inflammatory cytokines in inflammatory response and inhibit T cell response,thus reducing allergic rhinitis,the mechanism may be through regulation of JNK,Erk1/2 and p38 signal pathway activation.

Research progress of mechanical overload on osteoblast injury and its repair by traditional Chinese medicine / 医用生物力学

The growth and metabolism of bone are controlled by osteogenesis of osteoblasts and absorption of osteoclasts, and osteoblasts play a main role in the process of osteogenesis. Overload will affect proliferation and differentiation of osteoblasts, while the loading mode, intensity, duration and other factors can change the biological properties of osteoblasts and further affect the functional activity of osteoblasts. However, the mechanism of osteoblast response to overload is still at the exploratory stage and needs in-depth study. Numerous studies have demonstrated that icariin, a kind of Chinese herbal medicine, can promote proliferation and differentiation of osteoblasts, and icariin with a certain concentration plays an important role in the repair of osteoblast injuries. In this paper, the response of osteoblasts to overload stimulation and repair of osteoblast injuries by icariin were summarized.

Cross protective immune responses in mice elicited by prime-boost strategy with a recombinant DNA vaccine and adenoviral 5-based vaccine expressing structural antigens of hepatitis C virus / 中华微生物学和免疫学杂志

Objective To investigate the development strategy of novel T cell based vaccine against HCV infection.Methods BALB/c mice were primed with pSCK-based DNA vaccine and boosted with type 5 adenoviral vector-based vaccine, which expressed the structural proteins ( Core, E1 and E2) de-rived from a Chinese HCV patient (genotype 1b, Hebei strain).Enzyme linked immunospot assay (ELIS-POT) and intracellular cytokine staining ( ICS) were used to analyze the elicited antigen-specific immune re-sponses and the efficacy of cross-protection.Results Immunization of mice with the prime-boost vaccination strategy elicited stronger T cell immune responses against multiple HCV antigens than using the DNA vac-cines alone, especially the IFN-γ-secreting T cell responses against E1 protein as indicated by ELISPOT as-say.ICS data indicated that the prime-boost regimen elicited more TNF-α-producing CD4+and IFN-γ-produ-cing CD8+T cells against E1 protein and high levels of IFN-γ-producing CD4+and CD8+T cells against E2 protein in comparison with immunization with DNA vaccines.Moreover, the prime-boost vaccination was ca-pable of eliciting effective cross-protection in a surrogate challenge model based on a recombinant heterolo-gous HCV (JFH1, 2a) vaccinia virus.Conclusion The prime-boost vaccination using DNA and rAd5-based vaccine expressing HCV structural antigens induced significant cellular immune response and cross-protection in mice, suggesting the possibility of using it as a promising T cell based vaccine against HCV in-fection.

The control effects of FLT3 signaling-dependent pulmonary conventional dendritic ceils on the initiation of acute lung inflammation response to lipopolysaccharide induced acute lung injury in mice / 中华急诊医学杂志

Objective To clarify the role of FLT3 signaling-dependent pulmonary conventional dendritic cells (cDCs) in the pathogenesis of lipopolysaccharide (LPS)-induced acute lung injury (ALI),and as well as the modulation effects of cDCs in vivo on the inflammatory responses to acute lung injury.Methods Thirty C57BL/6 male mice were divided into normal control group,LPS group,FLT3L pretreatment group,lestaurtinib,(a high efficient and specific blocker in FLT3 signal pathway) pretreatment group and vehicle (DMSD) control group.FLT3L and lestaurtinib were administrated subcutaneously for 5 days.Murine model of ALI was subsequently established by intra-tracheal application of LPS and lung specimens were harvested 6 h or 24 h later.The accumulation and maturation of pulmonary cDCs were assessed by flow cytometry.IL-6 and TNF-α were quantified to evaluate lung inflammation.Lung injury was estimated by lung wet weight/body weight ratio (LWW/BW) and histopathological assessment.Lung myeloperoxidase (MPO) activity was measured to evaluate neutrophil infiltration.Transcription factors Tbet/GATA-3 mRNA ratio was determined to estimate balance of Th1/Th2 response.IFN-γ and IL-4 were quantified to evaluate Th1-specific and Th2-specific cytokine production respectively.Results The accumulation and maturation of pulmonary cDCs peaked at 6h after LPS challenge.FLT3L pretreatment significantly stimulated the accumulation and maturation of pulmonary cDCs (P ＜ 0.05),leading to markedly deterioration of LWW/BW and lung histopathological changes.Meanwhile lung MPO activity and T-bet/GATA-3 mRNA ratio were elevated (P ＜ 0.05).Furthermore,the production of IL-6,TNF-α and IFN-γwas markedly increased by FLT3L pretreatment (P ＜ 0.05).In contrast,lestaurtinib pretreatment markedly inhibited the accumulation and maturation of pulmonary cDCs (P ＜ 0.05),leading to significant improvement of LWW/BW and lung histopathological changes.Meanwhile lung MPO activity and T-bet/ GATA-3 mRNA ratio were decreased (P ＜ 0.05).Furthermore lestaurtinib efficiently suppressed the production of IL-6,TNF-α and IFN-γ (P ＜ 0.05).Conclusion This study thus demonstrated that FLT3 signaling-dependent pulmonary cDCs could control the initiation of acute lung inflammation response to LPS-induced ALI through the regulation of neutrophil infiltration and balance of Thl/Th2 response.

Costimulate moleculars amplified the DRibble mediated T cells response / 中国药科大学学报

@#Autophagosomes derived from tumor cells have been proved to induce potent T cell response both in mouse and human. In human in vitro study, dendritic cells(DC)loaded with cytomegalovirus(CMV)pp65 antigen-containing DRibble were capable to efficiently re-stimulate pp65-specific T-cell recall responses from freshly isolated or frozen humanperipheral blood mononuclear cell(PBMC). This study developed more robust assays using in vitro expanded antigen-specific T cells that contained a much higher percentage of antigen-specific T cells. DC cross-presentation efficiency of OX40 and CD80 modified pp65-DRibble was detected by intracellular IFN-γ staining. Compared with Ctrl/pp65 DRibble, the percentage of IFN-γ+ in total CD8+ T cells andCD4+ T cells was improvedwith OX40/pp65 DRibbleand CD80/pp65 DRibble stimulation. In addition, vaccine induced IL-12indendritic cells, whichpolarizes Th cells toward the IFN-γ high Th1 phenotype, evaluated by ELISA inco-culture supernatantwas dramatically higher in OX40/pp65 DRibble and CD80/pp65 DRibblegroups than in Ctrl/pp65 DRibble group. These results have implications for the immuneactivity of OX40 and CD80 modified DRibble and choice for prospective clinical use ofDRibble-based cancer immunotherapy.

House Dust Mite-Derived Chitin Enhances Th2 Cell Response to Inhaled Allergens, Mainly via a TNF-α-Dependent Pathway

PURPOSE: Chitin is a potent adjuvant in the development of immune response to inhaled allergens in the airways. According to other studies, chitin is known as multi-faced adjuvants which can induce Th2 responses. Recently, we found that TNF-α is a key mediator in the development of Th2 cell response to inhaled allergens. Here, we evaluated the immunologic mechanisms in the development of airway hypersensitivity to inhaled allergens, enhanced by house dust mite (HDM)-derived chitin. METHODS: The role of TNF-α and TLRs was evaluated in an airway hypersensitivity mouse model induced by a sensitization with an allergen (ovalbumin, OVA) and HDM-derived chitin using mice with the null mutation of target genes. RESULTS: The present study showed that airway sensitization with HDM-derived chitin plus OVA enhanced OVA-induced airway inflammation v. OVA alone. This phenotype was associated with the increased expression of Th1, Th2, and Th17 cytokines and also with the enhanced production of OVA-specific IgE, IgG1, and IgG2a. As for T cell responses, OVA-specific Th2 cell response, enhanced by chitin, was abolished by the treatment of chitinase, whereas Th1 and Th17 cell responses enhanced by this treatment. Moreover, the null mutation of the TNF-α gene revealed similar effects as the chitinase treatment. In contrast, all the OVA-specific T cell responses, enhanced by chitin, were blocked by the absence of TLR2, but not of TLR1, TLR4, or TLR6. CONCLUSIONS: In conclusion, these data suggest that HDM-derived chitin may enhance airway hypersensitivity to inhaled allergens, via the TLR2-dependent pathway, and that chitin-induced TNF-α can be a key mediator in the development of Th2 cell response to inhaled allergens.

Evaluation of the immunogenicity of recombinant replicative DNA vaccines expressing multiple anti-gens of hepatitis C virus in a mice model / 中华微生物学和免疫学杂志

Objective To investigate the immunogenicity and cross protective effects of two novel HCV DNA vaccines in a mice model.Methods Two self-replicating alphavirus vector-based HCV DNA vaccines, pSCK CE1E2Y and pSCK H155, were constructed based on the genes encoding the structural pro-teins (Core, E1 and E2) and structural and NS3 fusion proteins (Core, E1 , E2 and NS3) of a HCV strain isolated from a Chinese patient (genotype 1b, Hebei strain), respectively.Western blot analysis was per-formed to detect the expression of fusion antigens.The BALB/c mice were intradermally immunized with the recombinant DNA vaccines by using electroporation.The immune responses induced in mice and the cross protective effects of the recombinant DNA vaccines were evaluated.Results The DNA vaccines effectively expressed the target antigens in vitro.The antigen-specific antibody responses and specific T cell immune re-sponses were induced in mice by the immunization of replicative DNA vaccines.However, no effective cross protection was provided by either of the DNA vaccines in the surrogate challenge model based on a recombi-nant heterologous HCV (JFH1, 2a) vaccinia virus strain.Conclusion Although no effective cross protec-tion was observed, both of the two replicative DNA vaccines could induce strong humoral and cellular im-mune responses against multi-target antigens of HCV strains.This study has paved the way for further inves-tigation on the development of novel HCV vaccines.

Epitope competition weakens specific T cell response to subdominant epitopes / 中华微生物学和免疫学杂志

Objective To elucidate the influences of epitope competition on the frequency and average intensity of specific T cell response.Methods C57BL/6 mice were immunized with either single epitope DNA vaccines (pSV-gag92 or pSV-env203) or fusion gene DNA vaccine (pSV-gag/env).Gag92and Env203 epitope-specific CD8 T cell responses were analyzed by intracellular cytokine staining assay.Results Gag92-specific IFN-γ+CD8 T cells that were induced by pSV-gag92 accounted for 0.415 00％ ±0.045 88％ of the total CD8 T cells,which was much more than that induced by pSV-gag/env of 0.058 67％ + 0.019 64％.Moreover,the mean fluorescence intensity of Gag92-specific TNF-α-IFN-γ+CD8 T cells (296.70+14.08) elicited by pSV-gag/env was significantly lower than that of Env203-specific TNF-α-IFN-γ+CD8 T cells (818.00+49.34).Conclusion Epitope competition could significantly decrease both the frequency and the average intensity of specific T cell response to subdominant epitopes.

Requirement of CD4 Help for Induction of CD8 T Cell Response Specific for Virally Derived H60

CD40-CD40L-mediated help from CD4 T cells is essential to induce primary CD8 T cell responses specific to the non-inflammatory cell-based antigen H60. In this study, using H60 as a model antigen, we generated recombinant vaccinia viruses (rVVs) expressing the H60 CD8 epitope and investigated whether CD4 help was required to activate the CD8 T cell response specific to the virally expressed H60. The immune response after infection with rVVs expressing H60 was similar to that after immunization with H60 congenic splenocytes, with a peak frequency of H60-specific CD8 T cells detected in the blood on day 10 post-infection. A CD8 T cell response specific for virally derived H60 was not induced in CD4-depleted mice, but was in CD40-deficient mice. These results provide insights into the characterization of the CD8 T cell response specifically for antigens originating from cellular sources compared to viral sources.

Analysis of influence of HLA-B broad specific Bw4 motif on HCV specific T cell response / 中华微生物学和免疫学杂志

Objective To study the influence of Bw4 broad specific motif on hepatitis C virus (HCV) specific T cell response.Methods The 86 patients with HCV infection were enrolled in this study,who had history of non-standard paid blood donation.The sequence specific primer SSP-PCR and specific primer Amplification Refractory Mutation system was used to analyze HLA type.The T cell response,using PBMCs stimulated by HCV nonstructural protein NS3,NS4 and NS5 was tested by ELISPOT assay.Results There were 29 (33.7％) cases with homozygosity Bw4/4,38 cases (44.2％) with heterozygosity Bw4/6 and 19(22.1％) cases with homozygosity Bw6/6 in 86 patients with HCV infection.HCV viral loads in Bw4/4group,Bw4/6 group and Bw6/6 group were (3.98±0.32) Log (copy/ml),(5.22± 0.29) Log (copy/ml),(5.04±0.38) Log(copy/ml),respectively and there was a significant difference in HCV load among three groups(P=0.0153).The 24 cases with HCV infection were test HCV specific T cell response divided homozygosity Bw4/4 group and non-homozygosity Bw4/4 group.The HCV specific T cell response frequency in homozygosity Bw4/4 group and non-homozygosity Bw4/4 group was 50％ (5/10) and 14.28％ (2/14,respectively.The HCV specific T cell response magnitude in homozygosity Bw4/4 group and non-homozygosity Bw4/4 group was 70 SFU/106 PBMC (0-2020 SFU/106 PBMC)and 0 SFU/106 PBMC (0-200 SFU/106 PBMC).The response magnitude and frequency in homozygosity Bw4/4 group was significantly higher than that of non-homozygosity Bw4/4 group,P value was 0.0450 and 0.069,respectively.In homozygosity Bw4/4 group NS5 induced T cell response was dominant.The NS5 specific T cell response frequency in Bw4/4 group and non-Bw4/4 group was 50％ and 7.14％,respectively,and the difference was nearly significant(P=0.050).Conclusion The HCV-infected blood donors with homozygosity for HLA-Bw4 alleles is associated with a significant lower HCV virus load and stronger HCV specific T cell response,compared with non-homozygosity Bw4/4 group.