钩端螺旋体疫苗的接种反应和血清学效果观察

为统一中国钩体疫苗的菌数 (浓度 ) ,保障人群预防接种的安全与有效 ,用上海、武汉和成都生物制品研究所生产钩体疫苗 ,观察了 4种不同菌数、4种不同接种剂量 8个不同组别对 2 0 37人的免疫效果。所有接种者全身反应轻微 ,中强反应不超过 3%。局部反应各所间有差别 ,上海所最轻 (9.6 8% ) ,武汉所居中(17.93% ) ,成都所最重 (38.78% )。血清阳转率和GMT水平 1个月达高峰 ,3个月似有下降。随着钩体疫苗接种总量的增大 ,人群抗体的阳转率和GMT水平有所提高 ,尤其是赖型抗原。 3个所疫苗的抗体阳转率和GMT有明显差别 ,以成都所为最高。根据实验结果 ,建议 :① 5价 (含 5价 )以下钩体疫苗 ,每型菌数不低于1.5亿 /mL ;② 6价 (含 6价 )以上 ,每型含菌数不应低于 1亿 /mL ,但疫苗的总菌数不超过 12 .5亿 /mL ;③全程接种 2次 ,首次 0 .5mL ,再次 1mL ,间隔 5～ 7d。该建议已被 1990版《中国生物制品规程》(钩体疫苗制检规程 )所采纳 ,并一直沿用至今。     

问号钩端螺旋体疫苗候选基因LB061的抗原性和保守性研究

目的 克隆表达和鉴定问号钩端螺旋体黄疸出血群赖型赖株中疫苗候选基因LB061,研究LB061的免疫原性和在不同血清型钩端螺旋体菌中的保守性。方法 生物信息学软件分析预测LB061的特征。构建原核表达质粒pQE31-LB061,经IPTG诱导后用SDS-PAGE及Western印迹法鉴定表达情况。用表达的重组蛋白免疫BALB/c小鼠,Western印迹法检测其抗原性和在不同血清型钩端螺旋体中的保守性。Western印迹法检测钩端螺旋体全菌兔抗血清中的LB061抗体。结果 生物信息学预测结果显示,LB061含有DUF839家族结构域。成功克隆了重组质粒pQE31-LB061,表达的重组蛋白能刺激BALB/c小鼠产生抗体(效价为1∶32000),并能与相应抗体反应,具有良好的抗原性。在16株不同血清型的钩端螺旋体中均可检测到LB061蛋白的表达,并在钩端螺旋体赖株全菌兔抗血清中检测到其抗体。结论 LB061蛋白可以作为外膜蛋白刺激宿主免疫系统产生抗体,具有良好的抗原性和保守性。本研究为其作为疫苗候选基因的研究奠定了基础。     

问号钩端螺旋体中一个新的OmpA家族蛋白抗原性及保守性研究

目的克隆表达和鉴定问号钩端螺旋体(L.interrogans)黄疸出血群赖型赖株中一个新的外膜蛋白(Omp)A家族基因LA0301,研究LA0301编码蛋白的抗原性和在15个钩端螺旋体(简称钩体)血清群代表株中的保守性,探讨其在疫苗研究中的意义。方法生物信息学软件分析预测LA0301的特征。构建原核表达重组体pQE31-LA0301,经IPTG诱导后用十二烷基磺酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)及蛋白质印迹法(Western blot)鉴定表达情况。用表达的重组蛋白免疫BALB/c小鼠,Western印迹检测其免疫反应性和在不同血清型钩体中的保守性。酶联免疫吸附试验(ELISA)和Western印迹检测兔抗钩体全菌血清中的LA0301编码蛋白的抗体。结果生物信息学预测结果显示,LA0301具有OmpA家族的结构域。克隆表达了重组质粒pQE31-LA0301,重组蛋白能刺激BALB/c小鼠产生特异性抗体,效价为1:32000。在兔抗钩体全菌血清中检测到特异的LA0301蛋白抗体,并在15个血清群的代表株钩体中均可检测到LA0301蛋白。结论LA0301蛋白是问号钩体中一个新的OmpA家族蛋白,具有良好的抗原性和保守性,并且能在钩体感染的过程中刺激机体产生相应的抗体。为进一步研究钩体新型疫苗候选基因奠定了基础。     

钩端螺旋体外膜菌苗的研究I．菌苗的制备、性质及免疫原性

本文报道有关钩端螺旋体外膜菌苗的研究结果。通过不同孔径微孔滤膜收集盐变细胞(0．85～1．2微米)及纯化外膜(0.45微米),方法简便、省时,且不需贵重仪器,为大量制备钩端螺旋体(以下简称钩体)外膜菌苗提供了新的途径。黄疸出血群及波摩那群钩体外膜,在电子显微镜下的形态大多里圆形成不规则形。其化学组成黄疽出血群外膜中含蛋白质3 7．77％,碳水化合物22．21％及类脂质1 7．77％;后者则含蛋白质59．7 2％,碳水化合物13．69％,类脂质¨．90％。除强碱相似文献   

伤寒杆菌感染后IgG和IgM抗体消长规律的初步观察

本文报道了以试管凝集、SpA菌体吸收和2ME处理血清的方法对感染动物和部分伤寒病人血清中的IgG和IgM抗体的消长规律的观察结果。初次注射伤寒杆菌在3～30天中均为IgM抗体,再次注射后仍然以IgM抗体首先回升,然后才有IgG抗体的出现。在再次注射后所观察的期间,IgM抗体仍然维持较高的滴度。在观察的10例伤寒病人(6至30日病程)中,其抗体类型也是IgM。伤寒病人的血清学诊断,目前主要用肥达氏反应。本文以试管凝集、SpA菌体吸收和2ME处理血清的方法对感染动物血清和部分伤寒病人血清中的IgG和IgM抗体的消长规律进行了初步观察。     

钩端螺旋体遗传物质和毒力因子的研究进展

钩端螺旋体可引起人、兽共患疾病--钩端螺旋体病,其基本结构由圆柱形菌体、鞭毛和外膜组成.经血清型分类法将该体分为24个血清群200多种血清型.该体由大、小两个染色体组成,基因组共约5000kb,推测含4 768个基因.结构基因编码的鞭毛蛋白、溶血素、脂蛋白、脂多糖等可作为毒力因子,在钩端螺旋体致病过程中起主要作用.     

阳离子脂质体DOTAP佐剂对H5N1流感病毒裂解疫苗免疫效果的影响

目的研究阳离子脂质体DOTAP佐剂对H5N1型流感病毒裂解疫苗免疫效果的影响。方法制备DOTAP阳离子脂质体流感病毒裂解疫苗(简称DOTAP流感裂解疫苗),检测其包封率。将BALB/c小鼠分为13组,分别用含0.1、1.0、10.0μg HA/只剂量以DOTAP、Al(OH)3、CPG-ODN为佐剂以及不含佐剂的流感裂解疫苗于0、21天皮下免疫,PBS作为对照组,用血凝抑制试验检测小鼠初次免疫后21、42天血清HI抗体滴度;用ELISA检测初次免疫后21、42天血清特异性IgG抗体、IgG1、IgG2a亚类抗体滴度,以及初次免疫后42天小鼠脾脏单个核细胞体外经抗原刺激后细胞因子IL-2、IL-4、IFN-γ的分泌水平。将BALB/c小鼠分为3组,分别用含不同DOTAP剂量(100、300、600μg/只)的DOTAP流感裂解疫苗于0、21天皮下免疫,检测初次免疫后21、42天小鼠血清HI抗体滴度和IgG抗体滴度。结果 DOTAP流感裂解疫苗粒径在300~400 nm,带正电荷,包封率在50%以上;DOTAP流感裂解疫苗诱导的HI抗体水平和特异性IgG抗体水平均高于流感裂解疫苗,而与铝佐剂和Cp G-ODN佐剂间差异无统计学意义;DOTAP流感裂解疫苗产生的抗体仍以IgG1亚类抗体为主,免疫后42天诱导的IgG2a亚类抗体水平高于流感裂解疫苗和铝佐剂,低于Cp G-ODN佐剂;DOTAP流感裂解疫苗免疫后既分泌高水平Th1型细胞因子IFN-γ,同时也分泌高水平Th2型细胞因子IL-4;不同DOTAP剂量的DOTAP流感裂解疫苗免疫后,其HI抗体滴度和IgG抗体滴度在低、中、高剂量组之间存在明显的量效关系。结论 DOTAP作为H5N1型流感病毒裂解疫苗的佐剂可显著提高流感裂解疫苗的免疫原性,其对体液免疫应答的增强作用不低于铝佐剂和Cp G-ODN佐剂,并具有诱导细胞免疫应答的能力。     

问号钩端螺旋体属特异性OmpL1s抗原膜定位及其自然抗体应答

为了确定问号钩端螺旋体(简称钩体)属特异性OmpL1s抗原膜定位及其自然抗体应答情况和抗体类型,为OmpL1s用于研制通用性钩体基因工程疫苗及检测试剂盒抗原提供依据。采用显微镜凝集试验(MAT)检测四川地区156份钩体病人血清标本。用PCR和核苷酸序列分析,了解中国流行的钩体主要血清群ompL1基因型。采用常规基因工程技术构建ompL1/1和ompL1/2主要基因型原核表达系统,Ni-NTA亲和层析法提纯目的重组表达产物rOmpL1/1和rOmpL1/2。采用胶体金免疫电镜技术,对OmpL1s进行膜定位。建立了基于rOmpL1s的ELISAs,检测钩体病人血清中特异性抗体水平及其类型。试验结果表明,黄疸出血群钩体仍然是四川地区最主要的优势钩体血清群。中国流行的钩体主要血清群ompL1基因可有ompL1/1和ompL1/2两个基因型,两者核苷酸和氨基酸序列相似性之间有较明显的差异。OmpL1s是位于钩体外膜表面的蛋白分子。不同稀释度的156例钩体病人血清标本中,rOmpL1/1和rOmpL1/2特异性IgM阳性率分别为67.9%～79.5%和75.0%～75.6%,特异性IgG阳性率分别为71.8%～79.5%和75.0%～76.9%。上述试验结果提示,OmpL1s是位于钩体表面属特异性蛋白抗原。自然感染钩体时,rOmpL1/1和rOmpL1/2均可诱导机体体液免疫应答并产生IgM和IgG两类血清抗体,且两者之间有广泛的抗原交叉反应。rOmpL1/1和rOmpL1/2可作为研制通用性钩体基因工程疫苗和检测试剂盒的候选抗原。     

流行性出血热(EHF)双价纯化灭活疫苗——I 期临床观察

根据卫生部药审(91)特申体第02号文件,本品纯化灭活双价疫苗92年完成了Ⅰ期人体反应及血清学效果观察。91001批双价疫苗以0,1,2月和0,14,35天程序免疫,91002批以0,1,2月程序免疫,各接种15人。接种后未出现任何不良反应,与Ⅰ型,Ⅱ型单价疫苗相同,是安全可靠的。两种免疫程序,二针次免疫后皆能产生较高免疫抗体,接种后半年仍保持一定抗体水平。中和抗体(PRNT)均在1∶10～1∶20,ELISA1∶478～1∶549(GMT),阳转率100％,再次证明本型纯化疫苗安全有效,并具有较高免疫活性,本型疫苗也可采用二针次(0,1月),总量2ml免疫。     

七日热群钩端螺旋体的两个新血清型

本文报告七日热群钩端螺旋体的两个新血清型。A10株钩端螺旋体系I 962年自勐腊县钩端螺旋体病患者分离,命名为云南型钩端螺旋体(Leptospira interrogans serovar yunnan)H27株钩端螺旋体系1964年自河口县钩端螺旋体病患者分离,命名为河口型钩端螺旋体(Le-ptospira interrogans serovar hekou)。     

Evaluation of the Protective Immunity of a Novel Subunit Fusion Vaccine in a Murine Model of Systemic MRSA Infection

Staphylococcus aureus is a common commensal organism in humans and a major cause of bacteremia and hospital acquired infection. Because of the spread of strains resistant to antibiotics, these infections are becoming more difficult to treat. Therefore, exploration of anti-staphylococcal vaccines is currently a high priority. Iron surface determinant B (IsdB) is an iron-regulated cell wall-anchored surface protein of S. aureus. Alpha-toxin (Hla) is a secreted cytolytic pore-forming toxin. Previous studies reported that immunization with IsdB or Hla protected animals against S. aureus infection. To develop a broadly protective vaccine, we constructed chimeric vaccines based on IsdB and Hla. Immunization with the chimeric bivalent vaccine induced strong antibody and T cell responses. When the protective efficacy of the chimeric bivalent vaccine was compared to that of individual proteins in a murine model of systemic S. aureus infection, the bivalent vaccine showed a stronger protective immune response than the individual proteins (IsdB or Hla). Based on the results presented here, the chimeric bivalent vaccine affords higher levels of protection against S. aureus and has potential as a more effective candidate vaccine.     

Enhanced potency of individual and bivalent DNA replicon vaccines or conventional DNA vaccines by formulation with aluminum phosphate

DNA vaccines against botulinum neurotoxin (BoNTs) induce protective humoral immune responses in mouse model, but when compared with conventional vaccines such as toxoid and protein vaccines, DNA vaccines often induce lower antibody level and protective efficacy and are still necessary to increase their potency. In this study we evaluated the potency of aluminum phosphate as an adjuvant of DNA vaccines to enhance antibody responses and protective efficacy against botulinum neurotoxin serotypes A and B in Balb/c mice. The administration of these individual and bivalent plasmid DNA replicon vaccines against botulinum neurotoxin serotypes A and B in the presence of aluminum phosphate improved both antibody responses and protective efficacy. Furthermore, formulation of conventional plasmid DNA vaccines encoding the same Hc domains of botulinum neurotoxin serotypes A and B with aluminum phosphate adjuvant increased both antibody responses and protective efficacy. These results indicate aluminum phosphate is an effective adjuvant for these two types of DNA vaccines (i.e., plasmid DNA replicon vaccines and conventional plasmid DNA vaccines), and the vaccine formulation described here may be an excellent candidate for further vaccine development against botulinum neurotoxins.     

Immunogenicity and Protective Efficacy of a Vero Cell Culture-Derived Whole-Virus H7N9 Vaccine in Mice and Guinea Pigs

BackgroundA novel avian H7N9 virus with a high case fatality rate in humans emerged in China in 2013. We evaluated the immunogenicity and protective efficacy of a candidate Vero cell culture-derived whole-virus H7N9 vaccine in small animal models.MethodsAntibody responses induced in immunized DBA/2J mice and guinea pigs were evaluated by hemagglutination inhibition (HI), microneutralization (MN), and neuraminidase inhibition (NAi) assays. T-helper cell responses and IgG subclass responses in mice were analyzed by ELISPOT and ELISA, respectively. Vaccine efficacy against lethal challenge with wild-type H7N9 virus was evaluated in immunized mice. H7N9-specific antibody responses induced in mice and guinea pigs were compared to those induced by a licensed whole-virus pandemic H1N1 (H1N1pdm09) vaccine.ResultsThe whole-virus H7N9 vaccine induced dose-dependent H7N9-specific HI, MN and NAi antibodies in mice and guinea pigs. Evaluation of T-helper cell responses and IgG subclasses indicated the induction of a balanced Th1/Th2 response. Immunized mice were protected against lethal H7N9 challenge in a dose-dependent manner. H7N9 and H1N1pdm09 vaccines were similarly immunogenic.ConclusionsThe induction of H7N9-specific antibody and T cell responses and protection against lethal challenge suggest that the Vero cell culture-derived whole-virus vaccine would provide an effective intervention against the H7N9 virus.     

Immunogenicity of Bivalent Human Papillomavirus DNA Vaccine Using Human Endogenous Retrovirus Envelope-Coated Baculoviral Vectors in Mice and Pigs

Human papillomavirus is known to be the major pathogen of cervical cancer. Here, we report the efficacy of a bivalent human papillomavirus type 16 and 18 DNA vaccine system following repeated dosing in mice and pigs using a recombinant baculovirus bearing human endogenous retrovirus envelope protein (AcHERV) as a vector. The intramuscular administration of AcHERV-based HPV16L1 and HPV18L1 DNA vaccines induced antigen-specific serum IgG, vaginal IgA, and neutralizing antibodies to levels comparable to those achieved using the commercially marketed vaccine Cervarix. Similar to Cervarix, AcHERV-based bivalent vaccinations completely blocked subsequent vaginal challenge with HPV type-specific pseudovirions. However, AcHERV-based bivalent vaccinations induced significantly higher cell-mediated immune responses than Cervarix, promoting 4.5- (HPV16L1) and 3.9-(HPV18L1) fold higher interferon-γ production in splenocytes upon stimulation with antigen type-specific pseudovirions. Repeated dosing did not affect the immunogenicity of AcHERV DNA vaccines. Three sequential immunizations with AcHERV-HP18L1 DNA vaccine followed by three repeated dosing with AcHERV-HP16L1 over 11 weeks induced an initial production of anti-HPV18L1 antibody followed by subsequent induction of anti-HPV16L1 antibody. Finally, AcHERV-based bivalent DNA vaccination induced antigen-specific serum IgG immune responses in pigs. These results support the further development of AcHERV as a bivalent human papillomavirus DNA vaccine system for use in preventing the viral infection as well as treating the infected women by inducing both humoral and cell-mediated immune responses. Moreover, the possibility of repeated dosing indicates the utility of AcHERV system for reusable vectors of other viral pathogen vaccines.     

Whole inactivated SIV virion vaccines with functional envelope glycoproteins: safety,immunogenicity, and activity against intrarectal challenge

A novel type of whole inactivated simian immunodeficiency virus (SIV) virion vaccine immunogen with functional envelope glycoproteins was evaluated, without adjuvant, in rhesus macaques. Immunogens included purified inactivated virions of SIVmac239, a designed mutant of SIVmac239 with gp120 carbohydrate attachment sites deleted (SIVmac239 g4,5), and SIVmneE11S. The vaccines were noninfectious, safe, and immunogenic, inducing antibody responses and cellular responses, including responses by CD8+ lymphocytes. Interpretation of protective efficacy following intrarectal challenge was complicated by incomplete take of the challenge in some SIV na?ve controls.     

A novel recombinant multisubunit vaccine against Chlamydia

The administration of an efficacious vaccine is the most effective long-term measure to control the oculogenital infections caused by Chlamydia trachomatis in humans. Chlamydia genome sequencing has identified a number of potential vaccine candidates, and the current challenge is to develop an effective delivery vehicle for induction of a high level of mucosal T and complementary B cell responses. Vibrio cholerae ghosts (VCG) are nontoxic, effective delivery vehicles with potent adjuvant properties, and are capable of inducing both T cell and Ab responses in mucosal tissues. We investigated the hypothesis that rVCG could serve as effective delivery vehicles for single or multiple subunit chlamydial vaccines to induce a high level of protective immunity. rVCG-expressing chlamydial outer membrane proteins were produced by a two-step genetic process, involving cloning of Omp genes in V. cholerae, followed by gene E-mediated lysis of the cells. The immunogenicity and vaccine efficacy of rVCG-expressing single and multiple subunits were compared. Immunologic analysis indicated that i.m. immunization of mice with either vaccine construct induced a strong mucosal and systemic specific Th1 response against the whole chlamydial organism. However, there was an immunogenic advantage associated with the multiple subunit vaccine that induced a higher frequency of Th1 cells and a relatively greater ability to confer protective immunity, compared with the single subunit construct. These results support the operational theory that the ability of a vaccine to confer protective immunity against Chlamydia is a function of the level of Th1 response elicited.     

Effectiveness of bivalent vaccines against Aeromonas hydrophila and Lactococcus garvieae infections in rainbow trout Oncorhynchus mykiss (Walbaum)

Lactococcus garvieae and Aeromonas hydrophila are bacterial pathogens affecting salmonids and other fish species and cause of heavy losses in aquaculture. Diseases caused by these bacteria can be controlled satisfactory by immunization using monovalent vaccines. In this study, the protective efficacy of two bivalent vaccines against L. garvieae and A. hydrophila was evaluated in rainbow trout (Oncorhynchus mykiss). Bivalent formulations, containing formalin-inactivated bacteria, were prepared as an aqueous bacterin and as an adjuvanted vaccine using montanide ISA-763. Protection against L. garvieae and A. hydrophila was tested at day 30 and 90 post-vaccination. High levels of protection were achieved for the aqueous and adjuvanted bivalent vaccines against L. garvieae (RPS of 100% and 95.3%) and A. hydrophila (RPS of 100% and 95.3%) at day 30 post-vaccination. Significant differences (p < 0.05) were found between the RPS at days 30 and 90 post-immunization with a decrease in the protection levels for the aqueous bivalent vaccine against L. garvieae (RPS 76.2%) and A. hydrophila (RPS 85%), but not for the adjuvanted vaccine (RPS of 90% against L. garvieae and 95% against A. hydrophila). In addition, high antibody levels were observed in the vaccinated fish at day 15 post-immunization using both vaccines. Our results demonstrate that these bivalent vaccines can effectively protect rainbow trout against L. garvieae and A. hydrophila and could offer an appropriate strategy to prevent these infections in rainbow trout farms.     

A Whole Virus Pandemic Influenza H1N1 Vaccine Is Highly Immunogenic and Protective in Active Immunization and Passive Protection Mouse Models

The recent emergence and rapid spread of a novel swine-derived H1N1 influenza virus has resulted in the first influenza pandemic of this century. Monovalent vaccines have undergone preclinical and clinical development prior to initiation of mass immunization campaigns. We have carried out a series of immunogenicity and protection studies following active immunization of mice, which indicate that a whole virus, nonadjuvanted vaccine is immunogenic at low doses and protects against live virus challenge. The immunogenicity in this model was comparable to that of a whole virus H5N1 vaccine, which had previously been demonstrated to induce high levels of seroprotection in clinical studies. The efficacy of the H1N1 pandemic vaccine in protecting against live virus challenge was also seen to be equivalent to that of the H5N1 vaccine. The protective efficacy of the H1N1 vaccine was also confirmed using a severe combined immunodeficient (SCID) mouse model. It was demonstrated that mouse and guinea pig immune sera elicited following active H1N1 vaccination resulted in 100% protection of SCID mice following passive transfer of immune sera and lethal challenge. The immune responses to a whole virus pandemic H1N1 and a split seasonal H1N1 vaccine were also compared in this study. It was demonstrated that the whole virus vaccine induced a balanced Th-1 and Th-2 response in mice, whereas the split vaccine induced mainly a Th-2 response and only minimal levels of Th-1 responses. These data supported the initiation of clinical studies with the same low doses of whole virus vaccine that had previously been demonstrated to be immunogenic in clinical studies with a whole virus H5N1 vaccine.     

Antibody Persistence in Adults Two Years after Vaccination with an H1N1 2009 Pandemic Influenza Virus-Like Particle Vaccine

The influenza virus is a human pathogen that causes epidemics every year, as well as potential pandemic outbreaks, as occurred in 2009. Vaccination has proven to be sufficient in the prevention and containment of viral spreading. In addition to the current egg-based vaccines, new and promising vaccine platforms, such as cell culture-derived vaccines that include virus-like particles (VLPs), have been developed. VLPs have been shown to be both safe and immunogenic against influenza infections. Although antibody persistence has been studied in traditional egg-based influenza vaccines, studies on antibody response durations induced by VLP influenza vaccines in humans are scarce. Here, we show that subjects vaccinated with an insect cell-derived VLP vaccine, in the midst of the 2009 H1N1 influenza pandemic outbreak in Mexico City, showed antibody persistence up to 24 months post-vaccination. Additionally, we found that subjects that reported being revaccinated with a subsequent inactivated influenza virus vaccine showed higher antibody titres to the pandemic influenza virus than those who were not revaccinated. These findings provide insights into the duration of the antibody responses elicited by an insect cell-derived pandemic influenza VLP vaccine and the possible effects of subsequent influenza vaccination on antibody persistence induced by this VLP vaccine in humans.     

Characterization of antigen-specific immune responses induced by canarypox virus vaccines

Avipoxvirus-based vectors, such as recombinant canarypox virus ALVAC, are studied extensively as delivery vehicles for vaccines against cancer and infectious diseases. Effective use of such vaccines is expected to benefit from proper understanding of the interaction between these viral vectors and the host immune system. We performed preclinical vaccination experiments in a murine tumor model to analyze the immunogenic properties of an ALVAC-based vaccine against carcinoembryonic Ag (ALVAC-CEA), a tumor-associated autoantigen commonly overexpressed in colorectal cancers. The protective CEA-specific immunity induced by this vaccine consisted of CD4(+) T cell responses with a mixed Th1/Th2 cytokine profile that were accompanied by potent humoral responses, but not by CEA-specific CD8(+) CTL immunity. In contrast, protective immunity induced by a CEA-specific DNA vaccine (DNA-CEA) consisted of Th1 and CTL responses. Modification of the ALVAC-CEA vaccine through coinjection of DNA-CEA, admixture with CpG oligodeoxynucleotides, or supplementation with additional transgenes encoding a triad of costimulatory molecules (TRICOM) did not result in induction of CEA-specific CTL responses. Even though these results suggested that ALVAC does not elicit Ag-specific CTLs, immunization with ALVAC vaccines against other Ags efficiently induced CTL responses. Our data show that the capacity of ALVAC vaccines to elicit CTL immunity against transgene-encoded Ags critically depends on the presence of highly immunogenic CTL epitopes in these Ags. This consideration needs to be taken into account with respect to the design and evaluation of vaccination strategies that use ALVAC-based vaccine.