受体相互作用蛋白激酶-3参与甲型H1N1流感病毒感染小鼠记忆性CD8＋ T细胞的应答

受体相互作用蛋白激酶-3(receptor-interacting protein kinase 3, RIPK3)是坏死复合体的关键成分之一,介导细胞程序性死亡(programmed cell death,PCD)的发生。前期研究发现流感抗原特异性CD8^＋T细胞的初次应答部分依赖于RIPK3分子,为探讨其在记忆性CD8^＋T细胞应答中的作用,对初次感染后的C57BL/6小鼠在免疫记忆阶段进行了再次感染,并用流式细胞仪检测了流感病毒特异性的记忆性CD8^＋T细胞的表型和功能。结果发现小鼠初次感染甲型 H1N1流感病毒株A/Puerto Rico/8/34后37 d, RIPK3敲除小鼠的CD8^＋T细胞比例及分泌细胞因子γ-干扰素(IFN-γ)和肿瘤坏死因子-α(TNF-α)的能力均显著低于野生型小鼠;在再次感染相同病毒时,RIPK3敲除小鼠流感病毒特异性CD8^＋T细胞比例及分泌细胞因子IFN-γ的能力依旧显著低于野生型小鼠;而CD8^＋中枢型记忆性T细胞(TCM)比例显著高于野生型小鼠,效应型记忆性T细胞(TEM)或效应性T细胞(TEff)比例却显著低于野生型小鼠。提示RIPK3分子参与调节流感病毒特异的记忆性CD8^＋T细胞诱生数量和分泌细胞因子功能,并影响其TCM与TEM/TEff的比例,为深入探索病毒特异的记忆性CD8^＋T细胞应答的分子机制提供了新线索。     

中东呼吸综合征冠状病毒S1蛋白在昆虫细胞中的重组表达及免疫效果评价

目的:利用昆虫杆状病毒表达系统重组表达中东呼吸综合征冠状病毒(MERS-Co V)S1蛋白,并对其免疫效果进行评价。方法:构建含有MERS-Co V S1基因的重组杆状病毒质粒,转染Sf9细胞包装杆状病毒;重组病毒传代3次获得种子病毒,感染Sf9细胞,收获感染上清,通过镍离子亲和层析纯化获得S1重组蛋白;用纯化的S1蛋白免疫BALB/c小鼠,采用ELISA检测免疫小鼠血清抗原特异性的抗体水平;采用假病毒中和试验检测血清中抗体的中和活性。结果:获得了表达MERS-Co V S1蛋白的重组病毒株,在昆虫细胞中表达并纯化了S1重组蛋白;利用重组表达的S1蛋白免疫小鼠3次,血清S1特异性Ig G抗体滴度可达1∶102 400,免疫小鼠血清稀释至1/5120后中和百分比仍达50%以上。结论:利用昆虫细胞重组表达的MERS-Co V S1蛋白具有良好的免疫原性,并能有效诱导产生高滴度中和抗体,为发展MERS-Co V重组蛋白疫苗奠定了基础。     

壳聚糖盐酸盐稳定乳液的制备及免疫效果分析

为了解决油乳佐剂在诱导细胞免疫方面的不足,引入正电荷的壳聚糖盐以稳定乳液,从而提升细胞免疫应答。本研究选取卵清蛋白为模式抗原,分别制备了单抗原疫苗、商品佐剂疫苗和乳液疫苗,表征了乳液的粒径、电势及抗原吸附率等参数。通过肌肉注射免疫BALB/c小鼠,检测免疫后抗体和细胞因子的分泌水平、淋巴细胞的活化水平以评价乳液的免疫效果。结果显示壳聚糖盐酸盐可有效稳定乳液,其粒径在600 nm左右,荷正电并对抗原吸附率达90%以上。免疫动物后,该乳液可有效提升血清特异性抗体水平并增强IL-4的分泌,显著提高抗原特异性CD8⁺T细胞的比例,提升细胞毒性T淋巴细胞(cytotoxic T lymphocyte, CTL)表面活化分子的表达水平,诱导高效的细胞免疫应答。此外,乳液能够有效提高记忆T细胞(CD44⁺CD62L⁺)的水平。综上所述,以壳聚糖盐酸盐稳定的乳液为佐剂能有效提升体液及细胞免疫效果,并有望起长期保护作用。     

布鲁氏菌粗糙型RA343株与光滑型A19株免疫小鼠后特异性T细胞和抗体动态变化分析

【背景】布鲁氏菌病（简称布病）严重威胁着人类健康和畜牧业的发展,使用毒力弱、免疫原性好、不干扰血清学诊断的疫苗是防控布病的有效措施。【目的】比较布鲁氏菌粗糙型RA343株与光滑型A19株免疫小鼠后机体特异性T细胞和抗体的动态变化,评价粗糙型RA343株的免疫效果。【方法】采用6周龄雌性BALB/c小鼠,共分为3组,RA343株免疫组和A19株免疫组各15只小鼠,空白对照组5只小鼠。免疫组的每只小鼠经腹股沟皮下注射0.1 mL （含菌量为1×10⁸ CFU）菌液。免疫后1、2和3周各免疫组及空白对照组分别剖杀5只小鼠,无菌取脾脏,一部分脾脏研磨分离淋巴细胞,用流式细胞术检测小鼠布鲁氏菌特异性CD4⁺T细胞与CD8⁺T细胞所占比例的变化趋势;另一部分脾脏称重后分离布鲁氏菌RA343株和A19株,评估RA343株和A19株在小鼠脾脏中的定殖情况。在剖杀小鼠的同时取外周血分离血清,用ELISA方法检测免疫后小鼠血清中IgM和IgG抗体的消长规律。采用GraphPad Prism 8.0软件作图并进行统计学分析。【结果】与A19免...     

表达乙型脑炎病毒抗原的非复制型重组痘苗病毒能在小鼠中诱发免疫保护

使用2×107PFU乙脑病毒野毒株GSS抗原preM-E-NS1-NS2a的非复制型重组痘苗病毒NTV-JEV免疫3周龄BALB/c小鼠,小鼠体内乙脑病毒特异性抗体滴度1∶71,IgG2a/IgG1为1.5,中和抗体滴度为1∶8,免疫组小鼠产生特异性补体介导的细胞杀伤作用。以10 LD50乙脑P3株病毒对小鼠进行了脑内攻击,NTV-JEV免疫组小鼠存活率为100%,与乙脑减毒活疫苗SA14-14-2免疫组存活率相同。100 LD50P3株病毒攻击后NTV-JEV免疫组存活率28.6%,与SA14-14-2组免疫效果无明显差别。存活小鼠体内乙脑病毒特异性抗体升高为1∶179,IgG2a/IgG1比值为1.9,中和抗体大于1∶16。以30 LD50GSS株病毒进行攻击后,NTV-JEV免疫组和SA14-14-2组保护率均为8.3%。上述结果表明,NTV-JEV与乙脑减毒活疫苗SA14-14-2株具有相近的保护力,NTV-JEV不仅可以保护小鼠抵抗同株病毒GSS的攻击,而且可以抵抗异株病毒P3的攻击。     

热处理肿瘤细胞抗原负载树突细胞抗小鼠结肠癌效应

研究了热处理肿瘤细胞抗原负载骨髓来源的树突细胞（dendritic cell,DC）对结肠癌小鼠的治疗作用.将小鼠结肠癌细胞CT26热处理后超声破膜,以其细胞裂解液负载BALB/c小鼠骨髓来源的DC,观察DC诱导肿瘤特异性细胞毒性T淋巴细胞（cytotoxic T lymphocyte,CTL）杀伤活性;并将DC接种于荷瘤小鼠皮下,观察其对肿瘤生长的抑制作用及对荷瘤小鼠生存期的影响.发现致敏DC诱导的CTL对CT26肿瘤细胞具有显著的杀伤作用.用致敏DC免疫小鼠后,对小鼠肿瘤的生长具有显著的抑制作用,并能显著延长荷瘤小鼠的生存时间.热处理肿瘤细胞抗原负载的树突细胞对结肠癌小鼠具有显著的治疗效果.     

重组CHO细胞乙肝表面抗原诱导小鼠细胞免疫应答的研究

为了研究重组CHO细胞乙肝表面抗原(CHO-rHBsAg)在小鼠中诱导T细胞免疫应答的能力,全面评价疫苗的免疫原性,以CHO-rHBsAg免疫BALB/c小鼠,常规制备小鼠脾脏淋巴细胞并在体外以抗原或特异多肽刺激;采用ELISA法测定抗原特异性T淋巴细胞分泌的细胞因子,乳酸脱氢酶法(LDH)测定抗原特异性细胞毒T淋巴细胞(CTL)活性,酶联斑点法(ELISPOT)测定CTL频数(CTLp),应用流式细胞仪分析T淋巴细胞亚群。结果显示,rHBsAg可在小鼠中诱导Th1及Th2类细胞因子;加铝佐剂的rHBsAg较未加佐剂的抗原可诱导较高水平的IFN-γ、CTL克隆及较高百分比的CD8+T淋巴细胞亚群。重组CHO细胞来源的HBsAg可在BALB/c小鼠中诱导一定程度的细胞免疫应答。     

狂犬病毒单克隆抗体的杂交瘤细胞系的建立

Wikter于1978年首先建立了狂犬病毒单克隆抗体(McAb),并用它发现了狂犬病毒株的抗原差异,而国内尚未见到有关狂犬病毒单克隆抗体的研究报道。为此,在建立快速检测狂犬病毒抗原和抗体的基础上又进行了狂犬病毒单克隆抗体的研究。 将感染狂犬病毒aG株(我国狂犬疫苗生产毒种)后发病的BALB/c乳鼠脑病毒免疫BALB/c小鼠,取其脾细胞与小鼠骨髓瘤细胞Sp2/0融合。融合率为95.7％(401/419),阳性克隆占26.8％。经克隆化     

茯苓多糖PCP-Ⅰ增强抗原特异性体液免疫反应的机制研究

目的:以炭疽芽孢杆菌保护性抗原(PA)为模式抗原,对茯苓多糖PCP-Ⅰ作为疫苗佐剂增强抗原特异性体液免疫反应的机制进行研究。方法:PCP-Ⅰ混合PA免疫BALB/c小鼠,分别采用ELISA和毒素中和实验,检测免疫后小鼠血清中PA特异性(anti-PA)抗体和炭疽毒素中和抗体;采用流式细胞术检测树突状细胞(DC)经PCP-Ⅰ体外刺激后的成熟情况,及二免后7 d小鼠脾脏中生发中心(GC)B细胞和滤泡状辅助T细胞(Tfh)的频率。结果:相对于单独PA免疫组,200μg PCP-Ⅰ能够显著提高二免后2周小鼠血清中anti-PA抗体和毒素中和抗体的水平(5.38×10~3vs 6.48×10~1,8.7×10~1vs 1.54×10~1)。PCP-Ⅰ与PA混合刺激培养DC,CD80和MHC-Ⅱ分子阳性细胞频率(82.2%,74.9%)显著高于PA刺激组(51.7%,46.8%)。二免后7 d,PA+PCP-Ⅰ组小鼠脾脏中Tfh细胞频率略高于PA组(4.97%vs 4.20%),GC B细胞频率显著高于PA组(7.73%vs 6.30%)。结论:PCP-Ⅰ可通过促进DC成熟和增强生发中心反应来增强抗原特异性体液免疫反应。     

重组HIV-1 gp120 AAV2/1在小鼠和恒河猴体内的免疫原性

本文旨在研究表达HIV-1中国流行株gp120基因的重组腺相关病毒疫苗在小鼠和恒河猴体内的免疫原性。用rAAV2/1-gp120免疫BALB/c小鼠和恒河猴,分别用ELISA和HIV-1假病毒中和试验检测免疫动物血清中HIV-1特异性IgG抗体水平和中和抗体水平,用ELISPOT方法和体内杀伤实验检测HIV-1特异性细胞免疫应答水平。结果显示在小鼠体内用rAAV2/1-gp120仅免疫一次就能诱导较高水平的IgG抗体,IgG抗体至少能持续21周,但没有检测到中和抗体。rAAV2/1-gp120在小鼠体内诱导微弱水平的HIV-1特异性细胞免疫应答。rAAV2/1-gp120在恒河猴体内诱导的HIV-1特异性细胞和抗体反应均很弱,且检测不到中和抗体。提示rAAV2/1载体在诱导抗体反应方面具有特殊优势,但若希望诱导HIV-1特异性中和抗体,则需要改造env基因以提高其免疫原性。     

Vaccination with recombinant vaccinia viruses expressing ICP27 induces protective immunity against herpes simplex virus through CD4+ Th1+ T cells.

This study was designed to evaluate the efficacy and mechanisms of protection mediated by recombinant vaccinia viruses encoding immediate-early (IE) proteins of herpes simplex virus type 2 (HSV-2). Three mouse strains were immunized against the IE proteins ICP27, ICP0, and ICP4, and mice were challenged intracutaneously in the zosteriform model with HSV-2 strain MS. Protection was observed only following immunization with the ICP27 construct and then only in the BALB/c mouse strain. Protection in BALB/c mice was ablated by CD4+ T-cell suppression but remained intact in animals depleted of CD8+ T cells. Moreover, protection could be afforded to SCID nude recipients with CD4+ but not CD8+ T cells from ICP27-immunized mice. Only BALB/c mice developed a delayed-type hypersensitivity reaction to HSV-2, and in vitro measurements of humoral and cell-mediated immunity revealed response patterns to ICP27 and HSV that differed between protected BALB/c and unprotected mouse strains. Accordingly, BALB/c responses showed antigen-induced cytokine profiles dominated by type 1 cytokines, whereas C57BL/6 and C3H/HeN mice generated cytokine responses mainly of the type 2 variety. Our results may indicate that protection against zosterification is mainly mediated by CD4+ T cells that express a type 1 cytokine profile and that protective vaccines against HSV which effectively induce such T-cell responses should be chosen.     

Leishmania major: analysis of lymphocyte and macrophage cellular phenotypes during infection of susceptible and resistant mice

Genetically susceptible BALB/c and resistant C57BL/6 mice were infected with Leishmania major and the phenotypes of the responding cells in the draining lymph nodes and cutaneous lesions were analyzed. As early as 1 week, significantly increased numbers of L3T4+ cells as compared to Lyt-2+ cells were present in BALB/c mice lymph nodes (P less than 0.005). Increases in L3T4+ and Lyt-2+ cells were comparable in C57BL/6 mice, resulting in threefold lower L3T4/Lyt-2 ratio than in BALB/c mice. T cell subsets were activated in both strains to express interleukin-2 receptor (IL2R) above resting values, although greater numbers of activated L3T4+ cells were present in the draining lymph nodes from BALB/c at 1 and 3 weeks of infection than in C57BL/6 (P = 0.02). Despite the presence of activated L3T4+ cells in both strains, macrophages differed in the expression of immunologically important surface molecules during infection. Tissue macrophages from BALB/c mice were IgG1/G2b Fc receptor (FcR)+ and Ia- late in disease, whereas macrophages in C57BL/6 became FcR and Ia during healing. BALB/c mice, treated with monoclonal antibody GK1.5 to transiently deplete L3T4+ cells, became resistant to subsequent infection and developed a macrophage phenotype that was FcR- and Ia+. These differences in macrophage phenotype were closely linked to susceptibility during infection with L. major and may play a role in the pathophysiology of murine leishmaniasis.     

Local expression of tumor necrosis factor alpha and interleukin-2 correlates with protection against corneal scarring after ocular challenge of vaccinated mice with herpes simplex virus type 1.

To correlate specific local immune responses with protection from corneal scarring, we examined immune cell infiltrates in the cornea after ocular challenge of vaccinated mice with herpes simplex virus type 1 (HSV-1). This is the first report to examine corneal infiltrates following ocular challenge of a vaccinated mouse rather than following infection of a naive mouse. Mice were vaccinated systemically with vaccines that following ocular challenge with HSV-1 resulted in (i) complete protection against corneal disease (KOS, an avirulent strain of HSV-1); (ii) partial protection, resulting in moderate corneal disease (baculovirus-expressed HSV-1 glycoprotein E [gE]); and (iii) no protection, resulting in severe corneal disease (mock vaccine). Infiltration into the cornea of CD4+ T cells, CD8+ T cells, macrophages, and cells containing various lymphokines was monitored on days 0, 1, 3, 7, and 10 postchallenge by immunocytochemistry of corneal sections. Prior to ocular challenge, no eye disease or corneal infiltrates were detected in any mice. KOS-vaccinated mice developed high HSV-1 neutralizing antibody titers (> 1:640) in serum. After ocular challenge, they were completely protected against death, developed no corneal disease, and had no detectable virus in their tear films at any time examined. In response to the ocular challenge, these mice developed high local levels of infiltrating CD4+ T cells and cells containing interleukin-2 (IL-2), IL-4, IL-6, or tumor necrosis factor alpha (TNF-alpha). In contrast, only low levels of infiltrating CD8+ T cells were found, and gamma interferon (IFN-gamma)-containing cells were not present until day 10. gE-vaccinated mice developed neutralizing antibody titers in serum almost as high as those of the KOS-vaccinated mice (> 1:320). After ocular challenge, they were also completely protected against death. However, the gE-vaccinated mice developed low levels of corneal disease and virus was detected in one-third of their eyes. Compared with KOS-vaccinated mice, the gE-vaccinated mice had a similar pattern of IFN-gamma, but a delay in the appearance of CD4+ T cells, CD8+ T cells, and IL-4-, IL-6-, and TNF-alpha-containing cells. In sharp contrast to those of the KOS-vaccinated mice, no cells containing IL-2 were detected in the eyes of gE-vaccinated mice at any time. Mock-vaccinated mice developed no detectable neutralizing antibody titer and were not protected from lethal HSV-1 challenge.(ABSTRACT TRUNCATED AT 400 WORDS)     

Spontaneous Autoimmunity in the Absence of IL-2 Is Driven by Uncontrolled Dendritic Cells

BALB/c IL-2-deficient (IL-2-KO) mice develop systemic autoimmunity, dying within 3 to 5 wk from complications of autoimmune hemolytic anemia. Disease in these mice is Th1 mediated, and IFN-γ production is required for early autoimmunity. In this study, we show that dendritic cells (DCs) are required for optimal IFN-γ production by T cells in the IL-2-KO mouse. Disease is marked by DC accumulation, activation, and elevated production of Th1-inducing cytokines. IL-2-KO DCs induce heightened proliferation and cytokine production by naive T cells compared with wild-type DCs. The depletion of either conventional or plasmacytoid DCs significantly prolongs the survival of IL-2-KO mice, demonstrating that DCs contribute to the progression of autoimmunity. Elimination of Th1-inducing cytokine signals (type 1 IFN and IL-12) reduces RBC-specific Ab production and augments survival, indicating that cytokines derived from both plasmacytoid DCs and conventional DCs contribute to disease severity. DC activation likely precedes T cell activation because DCs are functionally activated even in an environment lacking overt T cell activation. These data indicate that both conventional and plasmacytoid DCs are critical regulators in the development of this systemic Ab-mediated autoimmune disease, in large part through the production of IL-12 and type 1 IFNs.     

In vivo ablation of CD11c-positive dendritic cells increases susceptibility to herpes simplex virus type 1 infection and diminishes NK and T-cell responses

The precise role of each of the seven individual CD11c+ dendritic cell subsets (DCs) identified to date in the response to viral infections is not known. DCs serve as critical links between the innate and adaptive immune responses against many pathogens, including herpes simplex virus type 1 (HSV-1). The role of DCs as mediators of resistance to HSV-1 infection was investigated using CD11c-diphtheria toxin (DT) receptor-green fluorescent protein transgenic mice, in which DCs can be transiently depleted in vivo by treatment with low doses of DT. We show that ablation of DCs led to enhanced susceptibility to HSV-1 infection in the highly resistant C57BL/6 mouse strain. Specifically, we showed that the depletion of DCs led to increased viral spread into the nervous system, resulting in an increased rate of morbidity and mortality. Furthermore, we showed that ablation of DCs impaired the optimal activation of NK cells and CD4+ and CD8+ T cells in response to HSV-1. These data demonstrated that DCs were essential not only in the optimal activation of the acquired T-cell response to HSV-1 but also that DCs were crucial for innate resistance to HSV-1 infection.     

紫外灭活CVB3 病毒诱导BALB/c小鼠产生免疫保护作用的研究

目的:探讨紫外灭活型CVB3病毒诱导BALB/c小鼠产生特异性免疫应答及保护作用的评估。方法:采用紫外灭活的方法处理野生型CVB3m株,按照0.1 LD50(10~4 PFU)的剂量免疫小鼠,设置PBS免疫组作为对照,免疫后第3,5,7天收集小鼠血清,检测细胞因子含量;在第3,5,7,14天分离小鼠脾脏,流式分析T细胞亚群的分布比例;在免疫后一个月分离小鼠血清,检测中和抗体的滴度;同时间给予小鼠100LD 50野生型CVB3感染,观察小鼠的死亡率。结果:与对照组相比,在检测日期内紫外灭活型CVB3组小鼠血清中细胞因子IL-1α,TNF-α,IL-6的表达量明显增高(P0.05),IL-4的表达量没有明显差异;免疫后第14天CD3~+CD4~+T细胞的分布较对照组明显升高(P0.05);在免疫后一个月,紫外灭活型CVB3免疫组可以诱导机体产生高滴度中和抗体,同时,小鼠应对高致死量CVB3感染时有较高的存活率。结论:紫外灭活型CVB3感染能诱导机体产生特异性免疫应答,同时,产生的中和抗体可以提高小鼠应对致死剂量CVB3感染时的生存率,对机体有明显的保护作用。     

Host genetic background affects regulatory T-cell activity that influences the magnitude of cellular immune response against Mycobacterium tuberculosis

Using two mouse strains with different abilities to generate interferon (IFN)-γ production after Mycobacterium tuberculosis infection, we tested the hypothesis that the frequency and activity of regulatory T (Treg) cells are influenced by genetic background. Our results demonstrated that the suppressive activity of spleen Treg cells from infected or uninfected BALB/c mice was enhanced, inhibiting IFN-γ and interleukin (IL)-2 production. Infected C57BL/6 mice exhibited a decrease in the frequency of lung Treg cells and an increased ratio CD4(+):CD4(+)Foxp3(+) cells compared with infected BALB/c mice and uninfected C57BL/6 mice. Moreover, infected C57BL/6 mice also had a decrease in the immunosuppressive capacity of spleen Treg cells, higher lung IFN-γ and IL-17 production, and restricted the infection better than BALB/c mice. Adoptive transfer of BALB/c Treg cells into BALB/c mice induced an increase in bacterial colony-forming unit (CFU) counts. Furthermore, BALB/c mice treated with anti-CD25 antibody exhibited lung CFU counts significantly lower than mice treated with irrelevant antibody. Our results show that in BALB/c mice, the Treg cells have a stronger influence than that in C57BL/6 mice. These data suggest that BALB/c and C57BL/6 mice may use some different mechanisms to control M. tuberculosis infection. Therefore, the role of Treg cells should be explored during the development of immune modulators, both from the perspective of the pathogen and the host.     

H5N1重组禽流感病毒样颗粒免疫原性研究

目的对构建的H5N1重组禽流感病毒样颗粒(VLPs)进行初步免疫原性探讨,并与H5N1全病毒灭活疫苗(WIV)进行体液免疫和细胞免疫的比较。方法在0周和3周分别以纯化H5N1重组禽流感病毒样颗粒、H5N1全病毒灭活疫苗及pH7.2 PBS腿部肌肉注射BALB/c小鼠,于不同时间收集血清,以血凝抑制试验(HI)和血清IgG抗体酶联免疫吸附试验(ELISA)评估体液免疫,CD4+、CD8+T细胞亚群及酶联免疫斑点试验(ELISPOT)评估细胞免疫,并以同型毒株滴鼻攻击,观察小鼠存活率。结果病毒样颗粒各组和全病毒灭活疫苗免疫后小鼠血清ELISA IgG效价均有升高;中和抗体效价除病毒样颗粒120 ng/只免疫剂量外其他免疫小鼠HI效价均达1︰40;小鼠脾CD4+T淋巴细胞亚群分类:全病毒灭活疫苗组(600μg/只)为36.56%;病毒样颗粒组(120 ng/只,600 ng/只,2 500 ng/只)分别为26.58%,32.20%,29.25%;PBS组为26.65%;CD8+T淋巴细胞亚群分类:全病毒灭活疫苗组(600 ng/只)为10.78%;病毒样颗粒组(120 ng/只,600 ng/只,2 500 ng/只)分别为1 3.53%,14.24%,1 3.35%;PBS组为10.69%。ELISPOT试验统计学数据显示,病毒样颗粒和全病毒灭活疫苗的小鼠脾单个核细胞分泌IFN-γ细胞与PBS组有显著性差异;小鼠保护性试验结果显示,除病毒样颗粒120 ng/只免疫剂量小鼠的存活率为87.5%外,其他病毒样颗粒实验组小鼠均为100%,PBS对照组为12.5%。结论 H5N1重组禽流感病毒样颗粒能诱导体液免疫和细胞免疫,并能抵御同型病毒株的攻击,可作为H5N1人用禽流感的候选疫苗。     

T cell-intrinsic factors contribute to the differential ability of CD8+ T cells to rapidly secrete IFN-γ in the absence of antigen

A subset of CD44(hi)CD8(+) T cells isolated from C57BL/6/J (B6) mice, but not BALB/c/By/J (BALB/c) mice, rapidly secrete IFN-γ within 16 h of infection with Listeria monocytogenes. This Ag-independent response requires the presence of both IL-12 and IL-18. Previous studies showed that dendritic cells from B6 mice produced more Th1-type cytokines such as IL-12 than did those from BALB/c mice in response to L. monocytogenes infection. In this report, we demonstrate that the microenvironment in L. monocytogenes-infected BALB/c mice is sufficient to induce responsive B6 CD8(+) T cells to rapidly secrete IFN-γ. Furthermore, BALB/c CD8(+) T cells did not rapidly secrete IFN-γ even when they were exposed to high concentrations of IL-12 plus IL-18 in vitro. In the presence of IL-12 and IL-18, B6 CD44(hi)CD8(+) T cells upregulated expression of the receptor subunits for these cytokines more rapidly than did BALB/c T cells. In comparing particular subsets of memory phenotype CD8(+) T cells, we found that virtual memory cells, rather than true Ag-experienced cells, had the greatest level of impairment in BALB/c mice. These data suggest that the degree of cytokine-driven bystander activation of CD8(+) T cells that occurs during infection depends on both APCs and T cell-intrinsic properties that can vary among mouse strains.     

Polyclonal activation of the murine immune system by an antibody to IgD. X. Evidence that the precursors of IgG1-secreting cells are newly generated membrane IgD+B cells rather than the B cells that are initially activated by anti-IgD antibody

Injection of BALB/c mice with an affinity-purified goat antibody to mouse IgD (GaM delta) stimulates T cell-independent B cell activation as well as later T cell activation. Activated T cells then induce polyclonal differentiation of B cells into IgG1-secreting cells, which results in an approximately 100-fold increase in serum IgG1 level. It is not known whether the same B cells that are initially activated by GaM delta are the progenitors of the IgG1-secreting cells. To investigate this issue a system was developed in which CB20 mice, which are congenic to BALB/c mice but express Ig of the beta allotype rather than the BALB/c alpha allotype, were injected with GaM delta and simultaneously or subsequently also received BALB/c B cells. The IgG1 response generated by the donor BALB/c B cells was quantitated by an assay specific for IgG1 of the alpha allotype. Our experiments with this system indicate that: 1) BALB/c B cells transferred 2 days after CB20 mice were injected with GaM delta generate a much larger IgG1 response than do BALB/c B cells transferred simultaneously with GaM delta antibody; 2) B cells that express membrane IgD generate the great majority of this response; 3) differences in the magnitudes of the responses of BALB/c B cells transferred at different times after CB20 mice were injected with GaM delta antibody cannot be explained by differences in homing of the donor B cells to the host spleen or by short survival of donor BALB/c B cells after their transfer; and 4) the response made by donor BALB/c B cells transferred 2 days after CB20 mice were injected with GaM delta is proportionate to donor cell representation in the host spleen 1 day after their transfer, whereas the response made by donor cells transferred simultaneously with GaM delta is disproportionately small. These observations suggest that most of the IgG1 antibody made by GaM delta-injected mice is generated by newly produced, mIgD+ B cells that appear approximately 2 days after GaM delta injection, rather than by those B cells that are present in the spleen at the time of GaM delta injection, and support the view that signals that induce B cell secretion of Ig require an interaction with at least partially activated Th cells.