Cell mediated immune responses against human prion protein

Vaccination approaches that may provide protection against the abnormal form of prion protein (PrPSc) have recently focused on the ability of antibodies to prevent PrPSc propagation. Progress has been hampered due to the difficulty in generating antibody responses in wild type mice, which is believed to be a consequence of T cell tolerance to the normal form of prion protein (PrPC). The problem of tolerance can be avoided using transgenic mice unable to express PrPC. This study examines active PrP specific T cell responses that can be produced in PrP null (PrP 0/0) mice using simple peptide vaccination procedures. Spleenocytes recovered from vaccinated PrP 0/0 mice were tested in vitro for their specificity with T cell recognition demonstrated through a proliferative response to the peptide. Analysis of mRNA also indicates the stimulation of a heterogenous population of T cells with an increase in cytokines and cytotoxicity associated mRNA. Responsive T cells were expanded using a T cell cloning procedure and demonstrated an ability to recognize the mature human prion protein. These clones may potentially be used to negate the problem of T cell tolerance in wild type mice.     

Myelopeptide-5 Abolishes Virus-Induced Immunosuppression by Restoring T Cell Functions

Myelopeptide-5 (MP-5; synthetic analog of endogenous low-molecular-weight peptide Val-Val-Tyr-Pro-Asp) neutralized the immunosuppressive effects of antiviral vaccines (influenza, measles, and measles/parotitis) and stimulated their immunogenicity by restoring functional activity of T cells, suppressed by the viruses. Specific binding of MP-5 to CD4⁺ lymphocyte (its target cell) was studied using [³H]MP-5 (dissociation constant 2.03×10^—7 M). Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 147, No. 1, pp. 62-66, January, 2009     

Human Dendritic Cell Subsets for Vaccination

TProtective immunity results from the interplay of antigen (Ag)-nonspecific innate immunity and Ag-specific adaptive immunity. The cells and molecules of the innate system employ non-clonal recognition pathways such as lectins and TLRs. B and T lymphocytes of the adaptive immune system employ clonal receptors recognizing Ag or peptides in a highly specific manner. An essential link between innate and adaptive immunity is provided by dendritic cells (DCs). As a component of the innate immunc system, DC organize and transfer information from the outside world to the cells of the adaptive immune system. DC can induce such contrasting states as active immune responsiveness or immunological tolerance. Recent years have brought a wealth of information regarding DC biology and pathophysiology that shows the complexity of this cell system. Thus, presentation of antigen by immature (non-activated) DCs leads to tolerance, whereas mature, antigen-loaded DCs are geared towards the launching of antigen-specific immunity. Furthermore, DCs are composed of multiple subsets with distinct functions at the interface of the innate and adaptive immunity. Our increased understanding of DC pathophysiologywill permit their rational manipulation for therapy such as vaccination to improve immunity.     

Human Dendritic Cell Interactions with Whole Recombinant Yeast: Implications for HIV-1 Vaccine Development

Defects in number and function of dendritic cells (DCs) have been observed during HIV-1 infection, so therapeutic HIV-1 vaccine approaches that target or activate DCs may improve vaccine immunogenicity. To determine the potential of recombinant Saccharomyces cerevisiae yeast as an HIV-1 vaccine, we investigated interactions between yeast and human DCs. Yeast induced direct phenotypic maturation of monocyte-derived DCs (MDDCs) and enriched blood myeloid DCs (mDCs), but only indirectly matured blood plasmacytoid DCs (pDCs). Yeast-pulsed MDDCs and blood mDCs produced inflammatory cytokines and stimulated strong allo-reactive T cell proliferation. Both blood DC subsets internalized yeast, and when pulsed with yeast recombinant for HIV-1 Gag protein, both stimulated in vitro expansion of Gag-specific CD8⁺ memory T cells. These results suggest that S. cerevisiae yeast have potent adjuvant effects on human DCs. Furthermore, recombinant yeast-derived antigens are processed by human blood DCs for MHC class-I cross-presentation. These DC-targeting characteristics of yeast suggest that it may be an effective vaccine vector for induction of HIV-1-specific cellular immune responses.     

Cell culture modeling of specialized tissue: identification of genes expressed specifically by follicle-associated epithelium of Peyer's patch by expression profiling of Caco-2/Raji co-cultures

Peyer's patch follicle-associated epithelium (FAE) regulates intestinal antigen access to the immune system in part through the action of microfold (M) cells which mediate transcytosis of antigens and microorganisms. Studies on M cells have been limited by the difficulties in isolating purified cells, so we applied TOGA mRNA expression profiling to identify genes associated with the in vitro induction of M cell-like features in Caco-2 cells and tested them against normal Peyer's patch tissue for their expression in FAE. Among the genes identified by this method, laminin beta3, a matrix metalloproteinase and a tetraspan family member, showed enriched expression in FAE of mouse Peyer's patches. Moreover, the C. perfringens enterotoxin receptor (CPE-R) appeared to be expressed more strongly by UEA-1(+) M cells relative to neighboring FAE. Expression of the tetraspan TM4SF3 gene and CPE-R was also confirmed in human Peyer's patch FAE. Our results suggest that while the Caco-2 differentiation model is associated with some functional features of M cells, the genes induced may instead reflect the acquisition of a more general FAE phenotype, sharing only select features with the M cell subset.     

同种特异T细胞疫苗诱导移植物存活期延长的研究——Ⅰ.同种特异T细胞疫苗诱导的细胞免疫水平低下

在体外实验中观察了同种特异T细胞疫苗（TCV）免疫鼠T淋巴细胞对同种抗原和有丝分裂原（ConA）的反应能力。B6同种抗原特异TCV免疫的BALB/c小鼠对B6同种抗原的反应（MLR）能力明显变抑制,对无关第三者同种抗原AKR的反应能力也显著下降,表明存在抗原非特异性的抑制作用。在BALB/c同种抗原特异TCV免疫的B6小鼠中,获得一致的结果。在观察两组TCV免疫动物T细胞对Cond诱导的淋巴细胞增殖实验中,与正常小鼠 T细胞反应性比较,TCV免疫动物 T细胞的增殖能力显著下降,表现为抗原非特异作用。此与MLR中ConA-T细胞免疫动物的结果相一致。在CML实验里,同种抗原特异TCV免疫小鼠的脾细胞体外诱导同种CTL活性明显受到抑制,CTL 活性十分低下。体外实验结果表明:同种特异TCV免疫小鼠可诱发同种抗原反应和对ConA诱发的增殖反应能力显著低下,表现为抗原非特异性作用。     

同种特异T细胞疫苗诱导移植物存活期延长的研究——Ⅱ.抗独特型T细胞免疫反应

同种特异T细胞疫苗(TCV)免疫诱导出同种免疫反应低下,同种移植物存活时间显著延长,推测其作用机制可能是同种特异TCV免疫诱导机体抗同种特异TCV(独特型)T细胞的上调.实验证实了“抗TCV-T细胞”的存在.以同种特异TCV免疫动物可诱导出对TCV特异的细胞增殖反应.TCV免疫小鼠淋巴细胞能特异杀伤TCV细胞.将TCV免疫小鼠脾细胞作为调节细胞,观察到它能显著地抑制同种MLR,表明它是一“抑制性T细胞”.这些结果提示,同种特异TCV免疫可诱导机体免疫网络中独特型-抗独特型的上调,产生了同种反应T细胞的独特型T细胞,从而保护同种移植物免受同种反应性T细胞的攻击使同种移植物存活时间显著延长.     

T细胞接种对SLE样小鼠防治作用的探讨

本文在空肠弯曲菌（CJ-S131）免疫诱导的小鬼SLE样综合征模型上,观察了T细胞接种（T CellVaccination,TCV）的预防和治疗作用。用于 TCV的细胞为 CJ-S131预致敏的同系小鼠 T细胞。结果显示TCV可明显地抑制CJ-S131诱导的特异性迟发型超敏反应,相反却显著地增强抗dsDNA抗体和抗外膜蛋白抗体生成。因此TCV对SLE样小鼠没有预防及治疗作用。本文对此现象进行了讨论。     

Immunogenicity and protective efficacy of the Mycobacterium tuberculosis fadD26 mutant

The Mycobacterium tuberculosis fadD26 mutant has impaired synthesis of phthiocerol dimycocerosates (DIM) and is attenuated in BALB/c mice. Survival analysis following direct intratracheal infection confirmed the attenuation: 60% survival at 4 months post-infection versus 100% mortality at 9 weeks post-infection with the wild-type strain. The fadD26 mutant induced less pneumonia and larger DTH reactions. It induced lower but progressive production of interferon (IFN)-gamma, interleukin (IL)-4 and tumour necrosis factor (TNF)-alpha. Used as a subcutaneous vaccine 60 days before intratracheal challenge with a hypervirulent strain of M. tuberculosis (Beijing code 9501000), the mutant induced a higher level of protection than did Bacille Calmette-Guérin (BCG). Seventy per cent of the mice vaccinated with the fadD26 mutant survived at 16 weeks after challenge compared to 30% of those vaccinated with BCG. Similarly, there was less tissue damage (pneumonia) and lower colony-forming units (CFU) in the mice vaccinated with the fadD26 mutant compared to the findings in mice vaccinated with BCG. These data suggest that DIM synthesis is important for the pathogenicity of M. tuberculosis, and that inactivation of DIM synthesis can increase the immunogenicity of live vaccines, and increase their ability to protect against tuberculosis.     

Influenza vaccination in patients with asthma: why is the uptake so low?

BACKGROUND: Patients with asthma are particularly susceptible to serious complications from influenza. The Chief Medical Officer recommends annual influenza vaccination for adult patients with asthma. The uptake of influenza vaccination by patients with asthma is only 40% and, unlike other high-risk groups, has failed to increase in recent years. AIM: To investigate the contribution of sociodemographic factors, asthma morbidity, and health beliefs to influenza vaccination uptake in patients with asthma. Design of study: Cross-sectional questionnaire study. SETTING: Single urban British general practice, Exeter, UK. METHOD: A questionnaire survey was sent to adult patients with asthma. Participants were aged 16-65 years, were receiving beta(2) agonists and inhaled steroids, and had been invited for influenza vaccination in September 2003. Data were examined using univariate analysis and logistic regression. RESULTS: A total of 136/204 (66.7%) patients responded to the survey. Influenza vaccination uptake in the study population was 40%. Younger patients were less likely to have undergone vaccination than older patients. There was no difference in vaccination uptake rates between groups of patients defined by other sociodemographic factors. Asthma morbidity was similar in vaccinated and non-vaccinated groups of patients. Vaccinated individuals had a greater belief in the efficacy of the vaccination and medical advice regarding the vaccination, and felt more susceptible to influenza and its complications when compared with non-vaccinated individuals. A fear of side-effects was associated with declining the invitation for vaccination. These health beliefs were the only independent predictors of uptake of influenza vaccination among this group of patients with asthma. CONCLUSION: Improving vaccination uptake in patients with asthma is unlikely unless individual health beliefs are taken into account.     

Resetting the Adaptive Immune System After Autologous Stem Cell Transplantation: Lessons from Responses to Vaccines

Autologous stem cell transplantation (ASCT) to treat autoimmune diseases (AID) is thought to reset immunological memory directed against autoantigens. This hypothesis can only be studied indirectly because the exact nature of the pathogenetic autoantigens is unknown in most AID. Therefore, 19 children with juvenile idiopathic arthritis (JIA) or systemic lupus erythematodes (SLE) and 10 adults with multiple sclerosis (MS) were vaccinated with the T-cell-dependent neoantigen rabies and the recall antigen tetanus toxoid after, respectively before, bone marrow harvest. Both vaccinations were repeated after ASCT. All except two of the responders mounted a primary antibody response to rabies after revaccination, and 44% of the responders mounted a primary antibody response to tetanus boost after ASCT. These data show that immunological memory to a neoantigen is lost in most patients with AID after immunoablative pretreatment; however, memory to a recall antigen boosted before bone marrow harvest is only lost in part of the patients. Disease progression was arrested in all patients with JIA/SLE except one, but only in a minority of MS patients. Clinical outcome on a per case basis was not associated with the profile of the immune response toward the vaccination antigens after ASCT.     

Successful postexposure vaccination against hepatitis B in chimpanzees

To study the effect of postexposure vaccination, four chimpanzees were vaccinated with hepatitis B (HB) vaccine 4, 8, 48, and 72 hr, respectively, after intravenous injection of an infectious hepatitis B virus (HBV) inoculum. The second and third vaccine inoculations were given 2 and 6 weeks later, i.e., at considerably shorter intervals than recommended either for ordinary prophylactic vaccination or for postexposure vaccination in combination with hepatitis B immune globulin (HBIG). The chimpanzees were followed for 1 year. None showed HBs-antigenemia, liver enzyme elevation (ALT), or histopathological alterations in liver biopsies. Late appearance of anti-HBc was observed only in the serum of the animal whose series of vaccination started 72 hr after HBV inoculation. An unvaccinated control chimpanzee, which received the HBV inoculum only, developed clinical hepatitis B with ALT-elevations and HBs-antigenemia within 2 months of the experimental HBV inoculation. These results indicate that postexposure vaccination against hepatitis B begun within 48 hr after HBV exposure, with short intervals between the vaccine injections, can protect against hepatitis B infection also when concomitant HBIG-prophylaxis is not given.     

Different immune responses after intradermal and intramuscular administration of vaccine against tick-borne encephalitis virus

A single multisite intradermal (ID) administration of the same dose used for regular intramuscular (IM) immunisation with vaccine against tick-borne encephalitis virus (TBEV) resulted in seroconversion of all vaccinees within three weeks: with the regular IM schedule, two vaccinations were necessary for all vaccinees to seroconvert. After the first ID vaccination, antibodies of the IgM class against TBEV (anti-TBEV-IgM) were observed in all vaccinees; after the first IM vaccination, only three out of nine vaccinees showed an IgM response. The geometric mean titer (GMT) of anti-TBEV-IgM in seropositives was 5–20-fold higher in the ID group and similar to that after natural infection. The GMT of antibodies of the IgG class against TBEV (anti-TBEV-IgG) was also higher in the ID group but with a less marked difference. Hemagglutination-inhibiting (HI) antibodies appeared earlier and persisted longer after one or two ID injections; after a third vaccination, HI antibody levels were similar in both groups. Side effects after ID vaccination were limited to local reactions. These results indicate that follow-up injections may be omitted or at least reduced after ID administration of the vaccine dose usually used for IM vaccination schedules. However, additional studies in larger groups of vaccinees are necessary before ID vaccination can be recommended for general use.     

广州市2009年与2003年预防接种门诊状况比较

目的了解广州市预防接种门诊规范化建设现状,为政府制定免疫规划策略提供依据。方法参照《广东省预防接种门诊规范化建设标准》,对2009年广州市210间预防接种规范化门诊进行调查,并与2003年广州市174间预防接种门诊的免疫规划基础年报进行比较。结果 2009年门诊总面积达标率为98.1%,2003年总面积达标率为的41.1%,差异有统计学意义（χ^2=153.16,P〈0.01）。2009年免疫接种人员配置由2003年的服务总人口万分之1.29增加到万分之1.70。2009年平均每个免疫预防人员每年接种疫苗的人次数由2003年的1517人次增加到2415人次。结论广州市预防接种规范化门诊建设正逐步完善,为适应免疫规划新形势的需要,仍需加大工作力度。     

2006-2010年清远市狂犬病流行特征与防制策略分析

目的了解清远市狂犬病流行病学特征,探讨预防控制策略。方法收集2006-2010年清远市狂犬病个案调查及疫情报告资料进行统计分析。结果 2006-2010年清远市共报告狂犬病280例,年发病率介于1.24/10万～2.11/10万之间,病死率100%,发病率呈逐年上升趋势;疫情以清远北部农村地区较为严重,10月为全年发病最高峰,≥50岁人群报告发病占52.14%,职业以农民和学生为主;90.09%的病例由犬伤引起,59.05%的病例未对伤口进行任何处理,93.53%的病例未注射狂犬病疫苗。结论近年来清远市狂犬病疫情由较偏远的县（市）向市内中心区域迅速扩散,农村是重点防控地区,加强宣传教育以及落实狂犬病综合防制措施是今后的工作重点。     

地震灾后儿童群体性免疫预防实施情况分析

目的及时总结“5．12”汶川大地震灾后甲肝、乙脑疫苗预防接种工作经验，为自然灾害后开展群体性免疫预防工作提供参考。方法按照《江油市地震后甲肝、乙脑预防接种实施方案》开展群体性接种工作。对彰明镇等4个乡镇实施技术指导、现场督导和接种率快速评估。结果4个乡镇甲肝疫苗报告接种率为97．2％（3666／3773），乙脑疫苗报告接种率为99．2％（1389／1400）。快速评估共调查180名儿童，甲肝疫苗接种率为98．1％（155／158），乙脑疫苗接种率为97.3％（73／75）。快速评估结果与报告接种率基本一致。结论本次地震灾后群体性接种活动进展顺利，达到预期指标。灾后开展群体性预防接种需加强调配和培训医务人员，做好接种对象摸底工作．确保安全的接种场所．提供足够疫苗和冷链设备等。     

Acquired immune responses to the seasonal trivalent influenza vaccination in COPD

Epidemiological data suggest that influenza vaccination protects against all-cause mortality in chronic obstructive pulmonary disease (COPD) patients. However, recent work has suggested there is a defect in the ability of some COPD patients to mount an adequate humoral response to influenza vaccination. The aim of our study was to investigate humoral and cell-mediated vaccine responses to the seasonal trivalent influenza vaccination (TIV) in COPD subjects and healthy controls. Forty-seven subjects were enrolled into the study; 23 COPD patients, 13 age-matched healthy controls (HC ≥ 50) and 11 young healthy control subjects (YC ≤ 40). Serum and peripheral blood mononuclear cells (PBMC) were isolated pre-TIV vaccination and at days 7 and 28 and 6 months post-vaccine for haemagglutinin inhibition (HAI) titre, antigen-specific T cell and antibody-secreting cell analysis. The kinetics of the vaccine response were similar between YC, HC and COPD patients and there was no significant difference in antibody titres between these groups at 28 days post-vaccine. As we observed no disease-dependent differences in either humoral or cellular responses, we investigated if there was any association of these measures with age. H1N1 (r = −0·4253, P = 0·0036) and influenza B (r = −0·344, P = 0·0192) antibody titre at 28 days negatively correlated with age, as did H1N1-specific CD4⁺ T helper cells (r = −0·4276, P = 0·0034). These results suggest that age is the primary determinant of response to trivalent vaccine and that COPD is not a driver of deficient responses per se. These data support the continued use of the yearly trivalent vaccine as an adjunct to COPD disease management.     

Hepatitis B in Italy: where we are ten years after the introduction of mass vaccination

In Italy, a program of vaccination against hepatitis B targeted at the immunisation of persons at high risk began in 1983. In 1991, vaccination became mandatory for all newborns and adolescents. Since then, the vaccine has been given to more than 10 million children, with an outstanding record of safety and efficacy. The coverage rate is globally around 94%, with differences between the Northern and Southern regions, with the latter having the lower acceptance rate. According to the National Surveillance System (SEIEVA), the incidence of acute hepatitis B per 10(5) inhabitants declined from 5.4 in 1990 to 2 in 2000. The reduction was even greater among 15-24-year-old individuals, where the incidence rate per 10(5) decreased from 17.3 to 2 in the same period. In parallel with the decline of hepatitis B, hepatitis delta has also declined significantly. Catch-up immunisation of unvaccinated adolescents, as well as an effort to improve the vaccination coverage rate in high-risk groups, are required to ameliorate the efficacy of the vaccination campaign. Routine administration of booster doses of vaccine is not considered necessary to sustain immunity in immunocompetent persons.     

Turkeys are protected from infection with Chlamydia psittaci by plasmid DNA vaccination against the major outer membrane protein.

Plasmid DNA expressing the major outer membrane protein (MOMP) of an avian Chlamydia psittaci serovar A strain has been tested for its ability to raise an immune response and induce protection against challenge with the same serovar. A combined parenteral (intramuscular injection) and mucosal route (DNA drops administered to the nares) of DNA inoculation was compared with gene gun-based immunization. The gene gun delivery of pcDNA1/MOMP as well as the intramuscular-intranasal DNA delivery primed both T-helper and B cell memory, although rMOMP-expressing cells did not induce high antibody responses. Evidence for the priming of the memory was provided by the fact that the pcDNA1/MOMP inoculations raised antibodies belonging to the IgG and not IgM isotype. However, in response to challenge only five out of 15 vaccinated turkeys showed four-fold increases in serum IgG after challenge. By contrast, evidence for the priming of T cell memory in response to challenge was found in all vaccinated turkeys, as shown by the significantly heightened proliferative responses of peripheral blood lymphocytes following vaccination. Both immunization methods produced similar serological and lymphocyte proliferative responses. Notwithstanding the immunization method, a significant level of protection was observed in all pcDNA1/MOMP-immunized turkeys. The efficacy of MOMP-based DNA vaccination as a means of preventing severe clinical signs, lesions and chlamydia excretion in a turkey model of C. psittaci infection was demonstrated.