乙型肝炎疫苗联合B7-H1蛋白疫苗对HBV转基因小鼠抗HBsAg免疫应答的影响

目的:研究B7-H1蛋白疫苗对HBV转基因小鼠免疫应答的影响,探索治疗慢性乙型肝炎的新方法。方法:用不同剂量的乙型肝炎疫苗和B7-H1蛋白疫苗联合免疫HBV转基因小鼠,应用ELISA法检测转基因小鼠在不同时间点血清抗B7-H1抗体滴度,同时在免疫后第14周末处死小鼠取脾细胞,检测不同的免疫方法对小鼠脾细胞产生HBsAg特异性Th1类细胞因子(IFN-γ及IL-2)、对HBsAg特异性分泌IFN-γT细胞数量及对小鼠淋巴细胞增殖的影响。结果:成功完成小鼠的免疫计划,5周起血清中即能测到B7-H1抗体,同一时间点各组之间的抗体滴度值并无明显差异。加B7-H1蛋白免疫各组与相同剂量单用HBsAg蛋白免疫各组相比:IL-2均明显减低(P<0.05),分泌IFN-γT的T细胞数量下降,但脾淋巴细胞分泌IFN-γ的水平各组间无明显差异;MTT法测定的淋巴细胞增殖能力各组间也无明显变化。结论:B7-H1蛋白疫苗可诱导HBV转基因小鼠产生明显的抗B7-H1抗体应答,但不能增强抗HBsAg的免疫应答。较小剂量的HBsAg即可引起HBV转基因小鼠Th1类细胞因子(IFN-γ及IL-2)的分泌以及淋巴细胞增殖。     

共刺激分子4-1BBL基因免疫对HBsAg核酸疫苗诱导小鼠特异性免疫应答的影响

目的 研究共刺激分子4-1BBL基因免疫对HBsAg核酸疫苗诱导小鼠特异性体液和细胞免疫应答的影响.方法 将HBV表面抗原核酸疫苗pcDS2单独或联合共刺激分子4-1BBL质粒肌肉注射免疫C57BL/6小鼠;ELISA法检测小鼠血清抗-HBs IgG及亚型IgG1和IgG2a;迟发型超敏反应(DTH)反应检测体内细胞反应;流式细胞仪检测CD4+ T淋巴细胞分泌IL-4和IFN-γ及CD8+T淋巴细胞分泌IFN-γ水平;流式细胞仪检测小鼠脾细胞HBsAg特异性体外细胞毒性T淋巴细胞杀伤作用(CTL).结果 与单纯免疫核酸疫苗pcDS2组比较,pcDS2和4-1BBL联合免疫组小鼠的抗-HBs水平显著提高,抗-HBs IgG亚类以IgG2a占优;免疫小鼠经HBsAg脚掌皮下刺激后,联合免疫组小鼠脚掌的厚度显著高于pcDS2组;联合免疫组CD4+T淋巴细胞的IL-4和IFN-γ表达水平及CD8+T淋巴细胞的IFN-γ表达水平显著升高;DNA疫苗免疫的各组小鼠,HBsAg特异性体外CIL杀伤作用高于对照组,其中联合免疫组小鼠的体外CTL杀伤作用最强.结论共刺激分子4-1BBL不仅能增强HBV DNA疫苗诱导特异性体液免疫应答,还能增强特异性型细胞免疫反应,尤其增强体内CIL的杀伤活性.     

A群脑膜炎球菌多糖结合物的免疫原性研究

目的：制备A群脑膜炎球菌多糖（PS）结合物，观察其免疫原性。方法：A群脑膜炎球菌多糖经溴化氰活化后共价接上己二酰肼手臂，在碳二亚胺催化下与精制破伤风类毒素（TT）偶联剂备结合物。单独多糖、多糖结合物和TT按相同程序免疫NIH小鼠，用ELISA法检测小鼠血清抗多糖抗体滴度和特异性及抗TT抗体滴度。结果：用上述实验方法制备的结合物具有多糖和蛋白质的抗原性，免疫小鼠可诱导高滴度的血清抗多糖IgG抗体，免疫2针后高滴度抗体至少持续存在3周。血清抗体可中和多糖。加强免疫提示有免疫记忆性。结合物还可诱导产生一定水平的TT抗体。结论：A群脑膜炎球菌多糖结合到TT上可明显增强多糖在小鼠中的免疫原性，为制备结合疫苗并研究其对婴幼儿的免疫原性提供了实验基础。     

重组IL-12对乙肝疫苗在小鼠诱导免疫应答的作用

目的:观察重组IL-12对乙肝疫苗在小鼠诱导应答的强度与性质的作用,探讨将重组IL-12用作乙肝治疗性疫苗分子佐剂的可能性.方法:将乙肝疫苗联合重组IL-12肌注免疫小鼠,检测小鼠产生的抗乙肝表面抗原特异性体液和细胞免疫应答.结果:乙肝疫苗联合重组IL-12能明显增强小鼠T淋巴细胞的增殖活性、促进分泌细胞因子IFN-γ和IL-2并提高IgG2a抗体水平.结论:重组IL-12可显著增强乙肝疫苗诱导的细胞免疫应答,并使免疫应答转向Th1型.     

宫内感染HBV婴儿免疫失败与IL-2、IFN-γ表达的相关性研究

目的:探讨宫内感染HBV婴儿免疫失败与外周血单核细胞在不同刺激下细胞因子IL-2、IFN-γ水平的相关性。方法:50例乙肝标志物示HBsAg阳性的母亲分娩的新生儿出生后均按照目前国际通用的0、1、6月方案接种10μg酵母重组疫苗并在出生24小时内联合应用200 U乙肝免疫球蛋白。7个月后进行随访抽静脉血进行乙肝标志物定量和HBV-DNA含量检测。婴儿的抗-HBs始终阴性或达不到保护滴度(抗-HBs<10 U/I)或同时出现HBsAg、抗-HBs阳性或HBV-DNA阳性为免疫失败组。HBsAg、HBV-DNA阴性且HBsAb阳性为免疫有效组。两组病例均采集股静脉血,提取外周血单核细胞,分别使用PHA和重组酵母HBsAg作为刺激源作细胞培养48小时后,再提取培养细胞悬液的上清液,采用ELISA检测细胞因子IFN-γ及IL-2的含量,同时选择20例正常孕妇分娩的婴儿作为对照组。结果:1)在丝裂原刺激诱导免疫反应时三组IL-2、IFN-γ分泌均有增加,但三组比较均无统计学意义(P<0.05)。2)在酵母重组HBsAg 2.5μg/ml刺激下,3组IL-2、IFN-γ分泌均有增加,三组比较均有显著性差异(P<0.01;P<0.01)。免疫失败组增加最明显,免疫失败组和对照组差异有非常显著性差异(P<0.01;P<0.01)。在HBsAg刺激时IL-2和IFN-γ分泌呈高度正相关(r=0.335,P=0.005)。结论:IL-2和IFN-γ分泌低下可能是宫内感染HBV婴儿免疫失败的原因之一,外源性加入IL-2可能是降低免疫失败的有效措施。     

口服免疫Ag85A脂质体DNA诱导T细胞亚群应答效应研究

目的:拟采用构建的可在真核细胞内表达Ag85A基因的质粒,以阳离子脂质体为运载体,制成DNA疫苗,经口途径投予小鼠,以观察Ag85A脂质体DNA疫苗诱导免疫应答效应,为口服DNA疫苗的临床应用提供理论和实验依据.方法:ELISA方法检测Ag85A特异性抗体产生水平及血清Th1型细胞因子IFN-γ及Th2型细胞因子IL-4的分泌水平,ELISPOT技术检测口服DNA疫苗后小鼠可分泌IFN-γ和IL-4脾淋巴细胞数量.流式细胞术观察口服DNA疫苗后小鼠脾淋巴细胞CD4+T细胞及CD8+T细胞亚群的变化,从而判断口服DNA疫苗的免疫效果及脂质体是否有免疫增强作用.结果:口服自制Ag85ADNA疫苗可见血清中抗Ag85A特异性抗体的产生;下调了脾CD4+T细胞和CD8+T细胞亚群的数量;分泌IFN-γ的Th1型细胞比率和血清中的IFN-γ水平下降,而分泌IL-4的Th2型细胞比率和血清中的IL-4水平升高.口服DNA疫苗组诱导Ag85A特异性抗体产生,脂质体具有免疫佐剂作用.结论:应用阳离子脂质体为运载体,重组Ag85A DNA疫苗口服免疫C57BL/6小鼠,诱导了CD4+及CD8+T细胞亚群的下调及IFN-γ的表达减少,而玎IL-4的分泌呈增高趋势;疫苗可诱导Ag85A特异性抗体的分泌,产生了明显的体液应答.     

HSV-2gD模拟抗原表位、HBsAg与IL-18融合蛋白DNA疫苗的免疫效果观察

目的:研究串联重组核酸疫苗pc(pcDNA3.1)-S(HBsAg)-P6-IL18和pc(pcDNA3.1)-S(HBsAg)-NP6-IL18对机体的免疫效果,P6是我们前期采用噬菌体展示技术筛选出的HSV-2gD的模拟抗原表位,NP6为与HSV-2gD模拟抗原表位P6最相似的天然抗原表位序列。方法:分别将空质粒pcDNA3.1(阴性对照组)和构建的真核表达质粒pc-S-P6-IL18和pc-S-NP6-IL18肌内注射免疫接种BALB/c小鼠3次,每次间隔2周。末次免疫后2周眼眶静脉采血,ELISA法检测小鼠血清特异性抗体滴度、IFN-γ及IL-18含量;末次免疫后一月,处死小鼠,无菌分离脾脏,用刀豆蛋白A刺激淋巴细胞,采用MTT法测定脾淋巴细胞增殖率。结果:重组核酸疫苗pc-S-P6-IL18和pc-S-NP6-IL18免疫小鼠后可刺激血清特异性抗体(抗HBsAg抗体和抗HSV-2gD模拟表位抗体)的产生,与阴性对照组相比可诱导分泌较高水平的IFN-γ和IL-18,可促进小鼠脾淋巴细胞的增殖。结论:重组核酸疫苗pc-S-P6-IL18和pc-S-NP6-IL18能诱导较强的细胞免疫和体液免疫,可用于今后预防HBV和HSV-2感染的研究。     

LPSp辅佐HBsAg诱导机体产生特异性抗体的机制

目的:研究革兰阴性非致病性成团泛菌脂多糖(LPSp)作为佐剂促进乙型肝炎表面抗原蛋白(HBsAg)诱导小鼠产生抗-HBs抗体的作用机制。方法:在体外用LPSp HBsAg、HBsAg、LPSp、生理盐水分别致敏小鼠腹腔巨噬细胞,观察致敏细胞回输体内后诱导HBs抗体产生水平,检测巨噬细胞培养上清中TNF-α活性和NO浓度;观察4组巨噬细胞吞噬功能变化,并检测致敏巨噬细胞诱导局部淋巴结细胞分泌IL-4和IFN-γ的能力。结果:HBsAg LPSp致敏巨噬细胞促进小鼠HBs抗体产生,LPSp致敏的巨噬细胞的吞噬能力显著增强(P<0.05),释放TNF-α和NO水平增加(P<0.05)。LPSp HBsAg致敏巨噬细胞诱导局部淋巴结细胞释放IL-4水平升高(P<0.05),诱导IFN-γ水平与单纯HBsAg致敏组差异无统计学意义(P>0.05)。结论:LPSp的佐剂机制为参与活化巨噬细胞,增强巨噬细胞对抗原的吞噬、消化和处理能力;同时促进HBsAg致敏的巨噬细胞诱导淋巴结内淋巴细胞释放IL-4,增强HBsAg致敏的巨噬细胞诱导Th2淋巴细胞活化,促进B细胞产生抗体。     

HBsAg重组腺病毒转染的树突状细胞诱导BALB/c小鼠抗HBV免疫的研究

目的 研究HBsAg重组腺病毒转染的小鼠树突状细胞（DC）体内外免疫刺激活性和诱导小鼠抗HBV免疫的特点。方法 BALB／c小鼠的骨髓细胞体外扩增为DC，转染HBsAg重组腺病毒Ad-S或被HBsAg蛋白冲击后，流式细胞术分析DC的表型，混合淋巴细胞反应（MLR）检测DC的刺激活性；或与pcDNA3．1（＋）-S质粒分别免疫小鼠后，LDH法测定脾细胞CTL活性，放免法检测血清抗．HBs；流式细胞术分析体外自体MLR中及免疫后小鼠脾脏T细胞内细胞因子。结果 DC／Ad-S、DC／HBsAg和各对照组DC之间的表型和MLR差异无统计学意义，并均刺激TH和Tc分泌IFN-γ。DC／Ad-S免疫后2周能诱导比DNA疫苗更强产生IFN-γ的TH（P〈0．05），以及比DC／HBsAg和DNA疫苗更强分泌IFN-γ的Tc（均P〈0．01）和特异性CTL（P〈0．05，P〈0．01）。但DC／Ad-S和DC／HBsAg诱导的CTL反应及Tc分泌IFN-γ在免疫后4周均明显减弱，且诱导抗．HBs作用弱于DNA疫苗。结论 HBsAg重组腺病毒转染的DC比HBsAg冲击的DC及DNA疫苗能诱导更强的TH1/Tcl（Ⅰ型）细胞免疫和特异性CTL反应，是诱导抗HBV细胞免疫的有效刺激细胞。     

小鼠抗—HBs的单克隆抗独特型抗体杂交瘤细胞系的建立及鉴定

用纯化的小鼠单克隆抗-HBs(Ab1)免疫同系BALB/c小鼠,取免疫小鼠脾细胞与Sp2/0骨髓细胞融合,获得两株(MA1、MA3)持续分泌抗-HBs的单克隆抗独特型抗体(抗-1d,Ab2)杂交瘤细胞系。对MA3做了较全面的鉴定。MA3的Ig类型为IgM,核型分析结果染色体数为106条。通过ELISA竞争抑制和中和抑制试验表明,MA3所分泌的Ab2既能被不同来源的抗-HBs所中和,又能被HBsAg所竞争,且都呈现剂量依赖关系。将纯化的MA3 IgM免疫同系小鼠,诱导出具有抗-HBs活性的抗-抗-独特型抗体(Ab3)。因此认为MA3所分泌单克隆抗体(McAb),可模似HBsAg,具有类似HBsAg的免疫原性,是一种带有HBsAg表位内影像的抗-HBs的单克隆抗-1d。     

Non-productive infection of human newborn blood mononuclear cells with herpes simplex virus: effect on T cell activation, IL-2 production and proliferation.

IgG subclasses of antibodies to the hepatitis B surface antigen (HBsAg) in sera from 40 healthy infants immunized with the vaccine against hepatitis B virus (HBV) were detected using an enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies. The infants were born to asymptomatic HBsAg-positive mothers. Total serum IgG subclasses were also tested to exclude a deficiency of certain subclasses in these infants but their distribution was the one expected according to age. In contrast, IgG subclass antibodies to HBsAg were predominantly IgG1 and IgG4. The collected data indicate that infants produce significantly higher levels of IgG1 and IgG4 than IgG2 and IgG3 in response to the vaccine for HBV. The IgG4 response to anti-viral vaccinations is uncommon. The role of that IgG4 subclass is not yet clear: even if an anaphylactic role was suggested, no adverse reactions were observed in vaccinated children.     

Synergistic and Additive Effects of Cimetidine and Levamisole on Cellular Immune Responses to Hepatitis B virus DNA Vaccine in Mice

We and others have previously shown that both cimetidine (CIM) and levamisole (LMS) enhance humoral and cellular responses to DNA vaccines via different mechanisms. In this study, we investigated the synergistic and additive effects of CIM and LMS on the potency of antigen‐specific immunities generated by a DNA vaccine encoding the hepatitis B surface antigen (HBsAg, pVax‐S2). Compared with CIM or LMS alone, the combination of CIM and LMS elicited a robust HBsAg‐specific cellular response that was characterized by higher IgG2a, but did not further increase HBsAg‐specific antibody IgG and IgG1 production. Consistent with these results, the combination of CIM and LMS produced the highest level of IL‐2 and IFN‐γ in antigen‐specific CD4⁺ T cells, whereas the combination of CIM and LMS did not further increase IL‐4 production. Significantly, a robust HBsAg‐specific cytotoxic response was also observed in the animals immunized with pVax‐S2 in the presence of the combination of CIM and LMS. Further mechanistic studies demonstrated that the combination of CIM and LMS promoted dendritic cell (DC) activation and blocked anti‐inflammatory cytokine IL‐10 and TGF‐β production in CD4⁺CD25⁺ T cells. These findings suggest that CIM and LMS have the synergistic and additive ability to enhance cellular response to hepatitis B virus DNA vaccine, which may be mediated by DC activation and inhibition of anti‐inflammatory cytokine expression. Thus, the combination of cimetidine and levamisole may be useful as an effective adjuvant in DNA vaccinations for chronic hepatitis B virus infection.     

In vitro anti-HBs antibody synthesis from anti-hepatitis B vaccine recipients.

Peripheral blood mononuclear cells (PBMC) from 'responders' recently boosted with hepatitis B vaccine, were studied for synthesis in vitro of antibody to hepatitis B surface antigen (anti-HBs Ab) when stimulated with pokeweed mitogen (PWM) or HBsAg. HBsAg alone can induce an antigen-specific anti-HBs Ab response in vitro; this antibody synthesis is T cell-dependent. In some responders both allogeneic T4+ cells (in absence of PWM or HBsAg) and mixed leucocyte culture supernatants (MLC/SN) (without T cells and antigen) can help responder B cells to produce anti-HBs Ab. Thus, in some immunized subjects, B lymphocytes involved in anti-HBs Ab synthesis are in an advanced phase of differentiation and require only non-antigen specific T cell signals (B cell growth factor or B cell differentiation factor or interleukin 2, etc) to differentiate into antibody-secreting cells. Moreover, the concentration of the antigen necessary to suppress anti-HBs Ab production induced by HBsAg was five times lower than that necessary to suppress antibody production induced by PWM. T cell help for antigen induced anti-HBs Ab could be different from T cell help for the PWM-induced anti-HBs Ab response. Moreover, the finding that the low HBsAg doses inhibiting specific response did not affect the PWM-driven anti-HBs response suggests that antigen-specific T suppressor cells could play a role in this context.     

Immunoregulation of the in vitro anti-HBs antibody synthesis in chronic HBsAg carriers and in recently boosted anti-hepatitis B vaccine recipients.

We report a study on immunoregulation of in vitro antibody to hepatitis B surface antigen (anti-HBs) synthesis induced by pokeweed mitogen (PWM) from peripheral blood mononuclear cells (PBMC) in chronic hepatitis B surface antigen (HBsAg) carriers and in 'high responders', (anti-HBs RIA ratio greater than or equal to 20 in serum), recently boosted with anti-hepatitis B vaccine. Anti-HBs was detected in 11 days PBMC supernatants (SN) from 24 out of 36 'high responders', but in none from 31 chronic HBsAg carriers, despite detectable amounts of polyclonal IgG and antibody to hepatitis B core antigen (anti-HBc) were produced. The lack of anti-HBs production by chronic HBsAg carriers did not seem to be determined by suppressor influences because T lymphocytes from the majority of chronic HBsAg carriers, co-cultured with 'high responders' PBMC did not suppress anti-HBs production. Co-cultures between HBsAg carriers T4 positive (helper/inducer) cells and allogenic 'high responder' non-T cells produced anti-HBs antibody, indicating that HBsAg carrier T cells are not deficient in this allogenic helper function under PWM stimulation. Allogenic cocultures between HBsAg carrier non-T cells and 'high responder' T4 positive cells failed in anti-HBs production: a specific B lymphocyte defect might be involved in the lacking anti-HBs synthesis in chronic HBV patients. Antigen-induced specific anti-HBs synthesis experiments indicate that B cells themselves seem to be the target for HBsAg-induced suppression of anti-HBs antibody response.     

Antigen-Antibody Complex as Therapeutic Vaccine for Viral Hepatitis B

In a previous study, hepatitis B surface antigen (HBsAg) complexed to human anti-HBs immunoglobulins (HBIG) in excess of HBsAg was used as therapeutic vaccine to treat chronic hepatitis B patients and promising results were obtained. To study the mechanisms of this approach, mice were immunized with HBsAg or IC (immunogenic complex, i.e. HBsAg complexed with mouse polyclonal anti-HBs). Studies indicate that IC induced enhanced immune responses by increasing uptake of HBsAg through Fc receptors on antigen presenting cells and modulated HBsAg processing and presentation. This modulation led to stimulation of T cell responses, and increased production of IL-2 and IFN-γ. Assay for antibody subclasses showed that higher ratio of IgG 2a was observed in the IC immunized group, which correlated with the production of lymphokine pattern. When alum was used as the adjuvant, though antibody response was enhanced, production of cytokines decreased. When DNA from a recombinant plasmid was added to IC as an adjuvant, the liter of anti-HBs was significantly higher than those in mice immunized only with the DNA or the IC. Since DNA immunization can induce both cellular and humoral immune responses, combined immunization using IC and DNA might serve as another type of therapeutic vaccine for viral hepatitis B.     

Antigen-antibody complex as therapeutic vaccine for viral hepatitis B

In a previous study, hepatitis B surface antigen (HBsAg) complexed to human anti-HBs immunoglobulins (HBIG) in excess of HBsAg was used as therapeutic vaccine to treat chronic hepatitis B patients and promising results were obtained. To study the mechanisms of this approach, mice were immunized with HBsAg or IC (immunogenic complex, i.e. HBsAg complexed with mouse polyclonal anti-HBs). Studies indicate that IC induced enhanced immune responses by increasing uptake of HBsAg through Fc receptors on antigen presenting cells and modulated HBsAg processing and presentation. This modulation led to stimulation of T cell responses, and increased production of IL-2 and IFN-gamma. Assay for antibody subclasses showed that higher ratio of IgG 2a was observed in the IC immunized group, which correlated with the production of lymphokine pattern. When alum was used as the adjuvant, though antibody response was enhanced, production of cytokines decreased. When DNA from a recombinant plasmid was added to IC as an adjuvant, the titer of anti-HBs was significantly higher than those in mice immunized only with the DNA or the IC. Since DNA immunization can induce both cellular and humoral immune responses, combined immunization using IC and DNA might serve as another type of therapeutic vaccine for viral hepatitis B.     

脂质体佐剂对增强HBsAg免疫原性的作用

利用DC Chol制备粒径为 5 0～ 30 0nm的正电荷脂质体 ,作为乙肝疫苗 (HBsAg)的佐剂 ,免疫BALB/c小鼠后进行血清中特异性抗体IgG1及IgG2a、脾细胞产生细胞因子的检测。结果该脂质体佐剂所诱导的抗体亚类以IgG2a为主 ,脾细胞产生的IL 2、IL 5、IFN γ分别比铝佐剂组高 16 5倍、 10倍、 2倍。表明该脂质体佐剂可以诱导很强的细胞免疫反应 ,是一种能促进Th1和Th2均衡应答的佐剂 ,值得作进一步的研究     

Synthesis and immunological properties of conjugates composed of group B streptococcus type III capsular polysaccharide covalently bound to tetanus toxoid

A synthetic scheme for covalently binding group B streptococcus type III to tetanus toxoid (TT), using adipic acid dihydrazide as a spacer, is described. Type III alone or as a conjugate with TT was injected subcutaneously into laboratory mice, and the type-specific and TT antibody responses elicited by these immunogens were assayed. Type III-TT elicited significantly higher levels of type-specific antibodies after each immunization than did the type III alone. These levels were related to the dosage of the conjugate, enhanced by Freund adjuvant, and exhibited booster responses. Type III alone elicited only immunoglobulin M (IgM) antibodies in Swiss albino mice and mostly IgM and low levels of IgG antibodies of the IgG3 subclass in BALB/c mice. Type III-TT conjugates, in contrast, elicited mostly IgG antibodies in both strains of mice. IgA type III antibodies were not detected. The first two immunizations with the conjugates elicited type III antibodies in the IgG1 and in the IgG3 subclasses. Low levels of IgG2a type III antibodies were detected after a third injection of type III-TT. Conjugate-induced antibodies facilitated opsonization of group B streptococcus type III organisms and did not react with the structurally related pneumococcus type 14. TT alone or as a component of type III-TT induced mostly antibodies of the IgG class: IgG1 levels were the highest of the four subclasses. No IgA TT antibodies were detected. The conjugation procedure, therefore, enhanced the immunogenicity of and conferred T-cell dependent properties to the type III while preserving the immunogenicity of the TT component. The T-cell dependent properties of the conjugates were responsible for stimulating IgG type III antibodies which could be boosted. Evaluation of type III-TT conjugates in antibody-negative women of child-bearing age is planned.     

IL-12对结构优化的HBV核心抗原DNA疫苗诱导免疫应答的影响

目的 探讨IL-12对一种结构优化的HBV核心抗原(HBcAg)DNA疫苗免疫效果的影响。方法 将小鼠IL-12基因插入结构优化的DKA疫苗pST-HBc，构成pST-HBc/IL12，将pST-HBc／IL12转染COS7细胞，ELISA检测培养上清中的HBcAg和小鼠IL-12。分别将pST-HBc／IL12和pST-HBc肌肉注射接种BALB／c小鼠，检测小鼠的体液和细胞免疫应答。结果 ELISA检测到培养上清液中的HBcAg和小鼠IL-12，pST-HBc／IL12诱导的抗-HBc总IgG阳转率和抗体水平不及pST-HBc，但其诱导的脾细胞增殖反应和细胞毒性T淋巴细胞反应均强于pST-HBc。结论 IL-12可进一步增强这种HBcAgDNA疫苗诱导的细胞免疫应答。     

大剂量HBsAg疫苗对小鼠细胞免疫应答的调节作用

目的:探讨大剂量HBsAg疫苗对机体细胞免疫应答的影响。方法:不同剂量HBsAg疫苗两次免疫小鼠后, 用氚-胸腺嘧啶核苷(-[H³]TdR)掺入法, ELISA方法分别测定免疫鼠T淋巴细胞增殖能力, 细胞培养上清中白细胞介素-2(IL-2), γ干扰素(IFN-γ)含量及血清中抗HBsIgG2a阳转率。结果:大剂量HBsAg疫苗单次免疫后, 小鼠T淋巴细胞增殖能力显著强于对照组(P＜0.05);Th1型细胞因子IL-2、IFN-γ显著多于对照组(P<0.05);抗HBsIgG2a阳转率显著高于小剂量组(P＜0.01)。加强免疫后, 各项指标增高更显著, 小剂量组才呈现显著性增高。结论:大剂量HBsAg疫苗可诱生特异性细胞免疫应答, 并使细胞免疫趋向Th1型。