转染肿瘤总RNA的DC疫苗诱导抗肝癌特异性免疫

目的：探讨转染人肝癌总RNA的树突状细胞(DC) 疫苗体外诱导特异性细胞毒性T淋巴细胞(CTL)的作用。 方法： 采用原发性肝癌（HCC）病人外周血单核细胞（PBMC），在粒/巨细胞集落刺激因子(GM-CSF)和白细胞介素-4(IL-4) 刺激下增殖分化为DC细胞；从人肝癌细胞中体外扩增肝癌RNA。以HCCRNA转染DC细胞，并与PBMC混合培养诱导扩增CTL。MTT法测定CTL的杀瘤活性。 结果： 转染HCCRNA 48 h后， DC表面分子CD83、CD86和HLA-DR表达明显增高。转染HepG-2细胞HCCRNA的DC和病人HCCRNA诱导的CTL对HepG-2细胞和病人HCC细胞的杀瘤活性均明显高于正常肝细胞RNA+DC、脂质体+DC、Opti-MEM+DC以及空白对照组；而对胃癌SGC-7901细胞无杀伤活性。 结论： 以肝癌RNA为肿瘤抗原，DC作为疫苗的抗原提呈细胞，体外冲击致敏DCs，能诱导肝癌特异性CTL。本研究为HCC术后复发和转移的防治提供一种可能有效的疫苗治疗方法。     

HPV 16 E6E7基因修饰树突状细胞疫苗诱导CTL致CaSki细胞凋亡体外实验研究

目的:采用人乳头状瘤-16(HPV-16)E6E7重组腺病毒(pAd-E6E7)转染树突状细胞(Dendritic cell,DC),观察基因修饰的DC疫苗诱导细胞毒性T淋巴细胞(Cytotoxic Tlymphocyte,CTL)致使CaSki细胞凋亡的效果。方法:将pAd-E6E7转染体外培养的小鼠未成熟树突状细胞制备DC疫苗,激光共聚焦显微镜观察转染的小鼠未成熟树突状细胞绿色荧光蛋白表达,流式细胞术检测转染前后小鼠树突状细胞表面标志物(CD40、CD86、MHCⅡ和CD11C)。DC疫苗诱导产生特异性细胞毒性T淋巴细胞,与CaSki细胞共培养后,采用DAPI、TUNEL及流式细胞术检测CaSki细胞凋亡情况。结果:pAd-E6E7成功转染体外培养的小鼠未成熟树突状细胞,体外转染效率约为40%～50%,成功制备了HPV16 E6E7基因修饰树突状细胞疫苗,诱导产生细胞毒性T淋巴细胞,经DAPI、TUNEL及流式细胞术检测证明CaSki出现凋亡。结论:以带有HPV16 E6E7基因的重组腺病毒载体转染DC制备基因修饰的DC疫苗,诱导CTL致使CaSki细胞出现凋亡。     

Foxp3转染对哮喘小鼠脾淋巴细胞功能的影响

目的: 转染Foxp3至哮喘小鼠脾淋巴细胞,探讨Foxp3表达对脾淋巴细胞功能的影响。方法: 卵白蛋白(OVA)致敏激发制作哮喘小鼠模型,收集培养脾脏淋巴细胞;使用电穿孔法转染真核表达载体pcDNA3.1(-)-Foxp3至脾脏淋巴细胞,并设转染空质粒组和对照组;RT-PCR和Western blotting检测Foxp3的表达;流式细胞术检测转染后CD4⁺CD25⁺ Treg细胞/CD4⁺细胞比例;MTT法检测转染后的脾脏淋巴细胞增殖反应,ELISA检测脾淋巴细胞上清中白细胞介素4(IL-4)和干扰素γ(IFN-γ)的含量。结果: 转染组Foxp3 mRNA 和蛋白的表达水平显著高于空质粒组和对照组;转染Foxp3后CD4⁺CD25⁺ Treg细胞/CD4⁺细胞比例显著高于空质粒组和对照组;与空质粒组和对照组相比,转染pcDNA3.1(-)-Foxp3质粒明显抑制了脾淋巴细胞增殖;转染组细胞上清中IL-4和IFN-γ含量低于空质粒组和对照组。结论: 转染pcDNA3.1(-)-Foxp3至哮喘小鼠脾淋巴细胞,Foxp3得到有效表达。Foxp3的高表达能增加CD4⁺CD25⁺ T细胞的数量,抑制哮喘小鼠脾淋巴细胞的增殖以及Th1和Th2细胞因子的产生。     

ΔNp73α基因转染树突状细胞抗乳腺癌细胞的免疫效应

目的:研究ΔNp73α基因转染树突状细胞(DC)诱导的特异性抗乳腺癌免疫效应。方法:人脐带血细胞经GM-CSF、IL-4、TNF-α等细胞因子诱导培养DC,流式细胞仪(FCM)检测DC成熟前后CD1a、CD83的表达变化情况。脂质体法将pc DNA-HA/ΔNp73α转染至DC,经Western blot检测转染情况。转染DC与自体T细胞共培养诱导特异性CTL。MTT法测定T细胞增殖能力;ELISA法检测IFN-γ的分泌水平;LDH释放法检测T细胞对乳腺癌细胞MDA-MB-231的杀伤作用。结果:DC诱导成熟后,CD1a表达约占56%,CD83约占74%,与未成熟DC(CD1a 19%,CD83 13%)比较,差异有显著统计学意义(P0.01)。Western blot检测到DC-ΔNp73α组有一特异条带表达。DC-ΔNp73α组诱导的特异性CTL对MDA-MB-231杀伤作用高于DC组(P0.05),而且刺激T细胞增殖能力增强,分泌IFN-γ的水平升高,与空载体DC-pc DNA组及DC组比较有显著统计学意义(P0.01)。结论:以ΔNp73α转染DC制备的DC疫苗,具有显著诱导CTL杀伤乳腺癌细胞的作用。     

MCF-7 乳腺癌细胞培养上清对树突状细胞抑制作用的研究

目的:应用MCF-7乳腺癌细胞分泌的上清液培养正常外周血树突状细胞,探讨MCF-7乳腺癌细胞分泌因子对正常树突状细胞分化、成熟及功能的影响.方法:应用MCF-7 乳腺癌细胞的培养上清和GM-CSF、IL-4及TNF-α培养正常外周血单个核细胞,检测所诱导的树突状细胞(DC)及其致敏的CTL活性.结果:MCF-7 乳腺癌细胞培养上清能够明显抑制正常树突状细胞的分化成熟及抗原提呈能力,CD80、CD83、CD86和HLA-DR的表达明显降低,与正常对照差异显著(P＜0.01);CTL对MCF-7细胞杀伤活性为17.35%与对照组56.14%比较差异显著(P＜0.01);IL-12分泌和共刺激T淋巴细胞所分泌的IFN-γ明显降低(P＜0.01).结论:MCF-7 乳腺癌细胞上清明显抑制所共培养的树突状细胞的分化、成熟及抗原提呈能力.     

瘦素预处理的MSC 体外调节SLE 患者淋巴细胞亚群的初步研究

目的:前期研究证实系统性红斑狼疮(SLE)患者血清异常升高的瘦素可加剧间充质干细胞(MSC)衰老,本研究旨在探讨瘦素预处理MSC 对淋巴细胞亚群免疫调节的变化情况。方法:分离脐带MSC,并收集SLE 患者外周血单个核细胞(PBMC),分为三组:PBMC 组,MSC+PBMC,瘦素(100 ng/ ml)预处理MSC 3 d+PBMC,1 .10 共培养3 d,收集悬浮细胞。流式细胞仪检测淋巴细胞亚群:CD4+ CD25+ Foxp3+调节性T(Treg)细胞、CD4+ IL-17+ Th17 细胞、CD4+ CXCR5+ PD-1+滤泡辅助T(Tfh)细胞、CD19+ B 细胞,并检测CD3+ T 细胞、CD19+ B 细胞表面CD25、CD69 平均荧光强度(MFI)。结果:与对照组相比,瘦素预处理的MSC 对Treg 细胞上调作用受损[(8.53±2.33)% vs (6.79±2.14)%,P<0.01],对Th17 细胞下调亦受影响[(1.28±0.70)%vs (1.64±0.55)%,P<0.01],Tfh 细胞比例有增加的趋势,但差异无统计学意义[(1.48±1.36) % vs (2.08±1.52)%,P =0.051]。与MSC 组比较,瘦素预处理组T 细胞活化分子CD25、CD69 表达增加。而在B 淋巴细胞活化指标,瘦素预处理后CD25 MFI 较前有升高[(19.16±3.62) vs (21.05±2.36),P<0.05],但对CD69 影响则无统计学差异。结论:瘦素体外作用于MSC,不仅使加剧其细胞衰老,亦损伤其对T、B 淋巴细胞的免疫调节能力。     

Flt3L与CCL5细胞因子佐剂对HBc抗原DNA疫苗特异性免疫应答的促进作用

观察真核重组表达质粒pFlt3L及pCCL5对携带HBc抗原的DNA疫苗诱导的抗原特异性免疫应答的促进作用。将pFlt3L及pCCL5分别用脂质体的方法转染Hep G2细胞,然后采用骨髓细胞增殖及趋化小室实验检测细胞上清Flt3L及CCL5两种细胞因子的生物学活性。将pFlt3L和pCCL5两种重组质粒单独或联合使用与携带HBc抗原的DNA疫苗经肌内注射法免疫小鼠,采用MTT法检测脾淋巴细胞增殖、流式细胞仪检测脾CD8+T淋巴细胞中IFN-γ表达、ELISA法检测脾淋巴细胞培养上清IL-4含量及乳酸脱氢酶(LDH)释放法检测特异性CTL杀伤活性。结果:骨髓细胞增殖及趋化实验证实了Flt3L及CCL5均有生物学活性。pFlt3L和pCCL5单独或联合使用均可促进特异性淋巴细胞增殖反应(P<0.05),提高小鼠脾脏CD8+T淋巴细胞中IFN-γ表达量(P<0.05或P<0.01),IL-4表达水平在各组无显著区别(P>0.05),Flt3L+CCL5组小鼠脾细胞特异性CTL活性显著高于其他各组(P<0.05)。pFlt3L和pCCL5表达质粒联用可显著促进小鼠Th1型细胞因子的表达,并对带HBc抗原的DNA疫苗的免疫应答具有促进作用。     

慢性乙肝患者树突状细胞对Th1/Th2分化的影响

探讨慢性乙肝患者树突状细胞(dendritic cells,DC)对CD4+Th细胞亚群分化的影响。分离慢性乙肝患者外周血单个核细胞(PBMC),以rhIL-4(50 ng/ml)、rhGM-CSF(10 ng/ml)和rhTNF-α(100 u/ml)诱导培养DC。以流式细胞仪检测DC表面CD1a、CD83、CD80、CD86、HLA-DR分子表达情况。MTT法检测DC刺激同种异体淋巴细胞增殖能力。免疫磁珠分离外周血CD4+T细胞亚群,PMA+Ionomycin刺激后胞内荧光染色,流式细胞仪检测辅助性T细胞(helper T cell,Th)内特征性细胞因子IFN-γ/IL-4以判断Th1/Th2分化。ELISA法检测DC或Th细胞培养上清中IL-6、IL-12、IFN-γ和IL-4的含量。结果:慢性乙肝患者的DC表达CD1a、CD83、CD80、CD86、HLA-DR分子水平明显低于正常人(P<0.01);培养至第7天,慢性乙肝患者DC分泌的IL-12水平低于正常人(P<0.01),而分泌的IL-6水平增高(P<0.05)。与正常人相比,慢性乙肝患者外周血中Th1细胞占CD4+T细胞的百分比较低(P<0.01),其Th细胞培养上清中IFN-γ的量也较低(P<0.01)。患者DC与同种异体的健康人Th细胞共培养,刺激Th1型细胞因子IFN-γ产生的能力低于正常人(P<0.01)。慢性乙肝患者体内DC功能的异常可能导致了外周血Th1细胞分化不足。     

重组质粒pchIL-18-MAGE转染树突状细胞疫苗体外杀伤肝癌细胞的研究

目的:探讨重组质粒pch IL-18-MAGE转染DC细胞在体外对肝癌细胞的杀伤作用。方法:构建共表达质粒pchIL-18-MAGE,体外培养树突状细胞,将以上重组质粒转染树突状细胞。RT-PCR和Western blot方法验证IL-18和MAGE-1基因在转染DC中的表达。应用流式细胞术检测转染后DC细胞的表型变化。以转染重组质粒DC刺激的淋巴细胞作为效应细胞,单纯淋巴细胞和未经转染DC刺激的淋巴细胞为对照,检测其对肝癌靶细胞的体外杀伤作用。ELISA法检测INF-γ的分泌。结果:pchIL-18-MAGE转染后DC细胞高表达CD83、CD1a、CD86、CD80、HLA-DR等抗原,表现为成熟DC表型特征。共表达质粒转染的DC细胞诱导的CTL对肝癌细胞杀伤作用最强(P<0.05)。结论:pchIL-18-MAGE转染DC细胞对MAGE+肝癌细胞杀伤作用明显。     

Induction of Cell-Mediated Immunity against Mycobacterium tuberculosis Using DNA Vaccines Encoding Cytotoxic and Helper T-Cell Epitopes of the 38-Kilodalton Protein

Cell-mediated immune responses are crucial in the protection against tuberculosis. In this study, we constructed DNA vaccines encoding cytotoxic T lymphocytes (CTL) and T helper cell (Th) epitopes of the 38-kDa lipoglycoprotein of Mycobacterium tuberculosis and analyzed and compared their immunogenicities with that of pXJ38, a DNA vaccine encoding the entire 38-kDa protein (X. Zhu, N. Venkataprasad, H. S. Thangaraj, M. Hill, M. Singh, J. Ivanyi, and H. M. Vordermeier, J. Immunol. 158:5921-5926, 1997). Plasmid DNAs encoding a CTL epitope, P3 (pP3), a Th epitope (vTh), or both the Th and the P3 epitopes (pThP3) were prepared and tested in C57BL6/J (H-2(b)) mice. Our results confirmed that DNA immunization with pXJ38 induces strong CD8(+) CTL and Th1 responses (high gamma interferon [IFN-gamma], low interleukin-4 [IL-4]). Coadministration of plasmid DNAs encoding a Th epitope with those encoding a CTL epitope (vTh+pP3) elicited both antigen-specific CD8(+) CTL and Th1 responses. High levels of IFN-gamma were secreted by spleen cells from all plasmid DNA-vaccinated mice after in vitro stimulation with the recombinant 38-kDa protein. Small or undetectable amounts of IL-4 were observed, which indicates the induction of a Th1-like response. Multiple-epitope vaccination by vTh+pP3 or pThP3 resulted in a broader Th1 response to peptide or epitopes than the single-epitope plasmid DNAs. Antigen-specific immunoglobulin G2a was only detected in sera from mice immunized with the plasmid pXJ38, and not in mice immunized with the epitope-based DNA vaccines. Thus, the absence of an antibody response after immunization with epitope plasmid DNAs and their ability to trigger only a specific cellular immune response may prove to be important advantages for a vaccine against tuberculosis.     

Identification of a promiscuous HLA DR-restricted T-cell epitope derived from the inhibitor of apoptosis protein survivin

The inhibitor of apoptosis protein survivin is a promising tumor-associated antigen specifically recognized by CD8+ cytotoxic effector T-lymphocytes (CTL). To improve current vaccines that aim to induce survivin-specific CTL, it is necessary to study the role of CD4+ T-helper (TH) and CD4+ T-regulatory (Treg) cells. Because both TH and Treg cells recognize antigens in the context of HLA-class II molecules, identification of HLA class II-associated peptide epitopes from survivin is required. Here, we analyzed T-cell responses against survivin using synthetic peptides predicted to serve as HLA-DR-restricted epitopes. Six peptides were shown to induce CD4+ T-cell responses, restricted by HLA-DR molecules. For one peptide epitope, SVN10, T-cell clones were demonstrated to be capable of recognizing naturally processed antigen. SVN10-specific T cells could be stimulated from the blood of healthy individuals and cancer patients with multiple HLA-DR genotypes. Thus the identified SVN10 epitope can be used to study the role of CD4+ TH and Treg cells in immune responses and possibly be included in a multivalent peptide vaccine against survivin.     

Cooperation of human tumor-reactive CD4+ and CD8+ T cells after redirection of their specificity by a high-affinity p53A2.1-specific TCR

Efficient immune attack of malignant disease requires the concerted action of both CD8+ CTL and CD4+ Th cells. We used human leukocyte antigen (HLA)-A*0201 (A2.1) transgenic mice, in which the mouse CD8 molecule cannot efficiently interact with the alpha3 domain of A2.1, to generate a high-affinity, CD8-independent T cell receptor (TCR) specific for a commonly expressed, tumor-associated cytotoxic T lymphocyte (CTL) epitope derived from the human p53 tumor suppressor protein. Retroviral expression of this CD8-independent, p53-specific TCR into human T cells imparted the CD8+ T lymphocytes with broad tumor-specific CTL activity and turned CD4+ T cells into potent tumor-reactive, p53A2.1-specific Th cells. Both T cell subsets were cooperative and interacted synergistically with dendritic cell intermediates and tumor targets. The intentional redirection of both CD4+ Th cells and CD8+ CTL by the same high-affinity, CD8-independent, tumor-specific TCR could provide the basis for novel broad-spectrum cancer immunotherapeutics.     

Effective therapeutic anticancer vaccines based on precision guiding of cytolytic T lymphocytes

Summary: In natural immune responses CD4⁺ T helper (Th) cells, reactive with peptide antigens presented by major histocompatibility complex (MHC) class II molecules on dendritic cells (DC), can drive the maturation of DC that is required for induction of CD8⁺ cytolytic T‐lymphocyte (CTL) immunity. Proper induction, expansion and maintenance of CTL responses are achieved through delicate interactions between CD4⁺ T cells, DC and CD8⁺ T cells involving several ligand–receptor pairs. Th cells to a large extent operate through up‐regulation of CD40L, which then interacts with CD40 on DC to cause DC maturation. Subsequent CTL induction by activated DC requires CD80/CD86 on the DC to interact with the CD28 costimulatory receptor on CD8⁺ T cells. For maintenance and full expansion of CTL, interaction of the DC‐expressed 4–1BB ligand with its receptor 4–1BB on CTL is also important. Alternative molecular triggers of DC activation that can support induction of powerful CTL responses include agonistic anti‐CD40 antibody or ligands of Toll‐like receptors (TLR) such as LPS (TLR4 ligand) or oligodeoxynucleotides containing CpG‐motifs (TLR9 ligand). The combination of CpG adjuvant with a 35 amino acid long synthetic peptide comprising both tumor‐specific CTL and Th epitopes proved to be a highly effective vaccine formulation capable of inducing therapeutic immunity against human papillomavirus‐induced mouse tumors. The recently acquired insights into antigen presentation and costimulatory signals have made possible the development of a new generation of therapeutic anticancer vaccines.     

Acquired pMHC I Complexes Greatly Enhance CD4~+ Th Cell’s Stimulatory Effect on CD8~+ T Cell-Mediated Diabetes in Transgenic RIP-mOVA Mice

CD4+ helper T (Th) cells play pivotal roles in induction of CD8+ CTL immunity. However, the mechanism of CD4+ T cell help delivery to CD8+ T cells in vivo is still elusive. In this study, we used ovalbumin (OVA)-pulsed dendritic cells (DCOVA) to activate OT-II mouse CD4+ T cells, and then studied the help effect of these CD4+ T cells on CD8+ cytotoxic T lymphocyte (CTL) responses. We also examined CTL mediated islet β cell destruction which led to diabetes in wild-type C57BL/6 mice and transgenic rat insuli...     

DNA sequences encoding CD4+ and CD8+ T-cell epitopes are important for efficient protective immunity induced by DNA vaccination with a Trypanosoma cruzi gene

Immunization of BALB/c mice with a plasmid containing the gene for Trypanosoma cruzi trans-sialidase (TS) induced antibodies that inhibited TS enzymatic activity, CD4+ Th1 and CD8+ Tc1 cells, and protective immunity against infection. We used this model to obtain basic information on the requirement of CD4 or CD8 or B-cell epitopes for an effective DNA-induced immunity against T. cruzi infection. For that purpose, mice were immunized with plasmids containing DNA sequences encoding (i) the entire TS protein, (ii) the TS enzymatic domain, (iii) the TS CD4+ T-cell epitopes, (iv) the TS CD8+ T-cell epitope, or (v) TS CD4+ and CD8+ T-cell epitopes. Plasmids expressing the entire TS or its enzymatic domain elicited similar levels of TS-inhibitory antibodies, gamma interferon (IFN-gamma)-producing T cells, and protective immunity against infection. Although the plasmid expressing TS CD4 epitopes was immunogenic, its protective efficacy against experimental infection was limited. The plasmid expressing the CD8 epitope was poorly immunogenic and provided little protective immunity. The reason for the limited priming of CD8+ T cells was due to a requirement for CD4+ T cells. To circumvent this problem, a plasmid expressing both CD4+ and CD8+ T-cell epitopes was produced. This plasmid generated levels of IFN-gamma-producing T cells and protective immunity comparable to that of the plasmid expressing the entire catalytic domain of TS. Our observations suggest that plasmids expressing epitopes recognized by CD4+ and CD8+ T cells may have a better protective potential against infection with T. cruzi.     

High frequency of CD4+ T cells specific for the TB10.4 protein correlates with protection against Mycobacterium tuberculosis infection

TB10.4 is a newly identified antigen of Mycobacterium tuberculosis recognized by human and murine T cells upon mycobacterial infection. Here, we show that immunization with Mycobacterium bovis BCG induces a strong, genetically controlled, Th1 immune response against TB10.4 in mice. BALB/c and C57BL/6 strains behave as high and low responders to TB10.4 protein, respectively. The TB10.4:74-88 peptide was identified as an immunodominant CD4+ T-cell epitope for H-2d mice. Since recent results, as well as the present study, have raised interest in TB10.4 as a subunit vaccine, we analyzed immune responses induced by this antigen delivered by a new vector, the adenylate cyclase (CyaA) of Bordetella pertussis. CyaA is able to target dendritic cells and to deliver CD4+ or CD8+ T-cell epitopes to the major histocompatibility complex class II/I molecule presentation pathways, triggering specific Th1 or cytotoxic T-lymphocyte (CTL) responses. Several CyaA harboring either the entire TB10.4 protein or various subfragments containing the TB10.4:20-28 CTL epitope were shown to induce TB10.4-specific Th1 CD4+ and CD8+ T-cell responses. However, none of the recombinant CyaA, injected in the absence of adjuvant, was able to induce protection against M. tuberculosis infection. In contrast, TB10.4 protein administered with a cocktail of strong adjuvants that triggered a strong Th1 CD4+ T-cell response induced significant protection against M. tuberculosis challenge. These results confirm the potential value of the TB10.4 protein as a candidate vaccine and show that the presence of high frequencies of CD4+ T cells specific to this strong immunogen correlates with protection against M. tuberculosis infection.     

Functionally distinct helper T-cell epitopes of HCV and their role in modulation of NS3-specific,CD8+/tetramer positive CTL

Hepatitis C virus specific (HCV-specific) CD8+ cytotoxic T cells play a critical role in viral clearance. Low HCV-specific cytotoxic T lymphocyte (CTL) responses in chronic HCV infection may favor the persistence of virus, whereas stimulation and expansion of HCV-specific CTL activity may assist elimination of HCV infection. Helper T cells control the intensity of CD8+ T-cell responses and helper T-cell responses are known to be compromised in chronic carriers of HCV. In this study, we wanted to ascertain if strengthening the Th response could increase the intensity of CTL activity against HCV target antigens. We selected a synthetic CTL peptide NS3(1073-1081)), two Th1 epitopes, peptide NS3(358-375) and NS5B(155-172), and one Th2 epitope, peptide NS3(505-521). By using the four peptides alone or in combinations, we stimulated peripheral blood cells isolated from a chronic hepatitis C patient in vitro and then analyzed CD8 T cells specific for the NS3(1073-1081) CTL epitope in A2 tetramer staining and cytotoxicity assays. The results demonstrated that CTL responses could be augmented by helper T-cell epitopes NS3(358-375) and NS5B(155-172). Th2 epitope NS3(505-521) inhibited augmentation of CTL activity by Th1 epitopes. This inhibitory effect could be overcome by combining the two Th1 epitopes NS3(358-375) and NS5B(155-172) together with NS3(505-521). Under such conditions, CTL frequency was restored, but cytotoxic activity remained low suggesting that the help provided under these cultures was sufficient to drive proliferation of CTL, but not sufficient to drive differentiation into mature killer cells. These results may provide some insights into compromised CTL activity in HCV viral persistence.     

A synergistic effect of a combined bivalent DNA-protein anti-HIV-1 vaccine containing multiple T- and B-cell epitopes of HIV-1 proteins

Immunogenic properties of the combined vaccine CombiHIVvac, comprising polyepitope HIV-1 immunogens, one being the artificial polyepitope protein TBI, containing the T- and B-cell epitopes from Env and Gag proteins, and the DNA vaccine construct pcDNA-TCI coding for the artificial protein TCI, carrying over 80 T-cell epitopes (both CD4+ CTL and CD8+ Th) from Env, Gag, Pol, and Nef proteins, are studied in this work. The data reported demonstrate clearly that a combination of two B- and T-cell immunogens (TBI and TCI) in one construct results in a synergistic increase in the antibody response to both TBI protein and the proteins from HIV-1 lysate. The level of antibodies induced by immunization with the constructs containing either immunogen alone (TBI protein or the plasmid pcDNA-TCI) was significantly lower as compared to that induced by the combined vaccine. The analysis performed suggests that the presence of CD4+ T-helper epitopes, which can be presented by MHC class II, in the protein TCI may be the main reason underlying the increased synthesis of antibodies to TBI protein due to a CD4-mediated stimulation of B-cell proliferation and differentiation.