Ubiquitin基因介导下的PRRSV GP5基因免疫特性研究

目的：探讨泛素基因对GP5基因免疫的影响。泛素-蛋白酶体途径是一种高效蛋白降解途径,主要负责真核细胞内蛋白选择性降解。方法：本研究将ORF5DNA片段克隆到含泛素（Ub）基因的表达载体pCMV-Ub和pCMV载体,构建成重组质粒pCMV—Ub-GP5和pCMV-GP5。两种质粒DNA肌肉注射免疫BALb／c小鼠后,分别检测体液免疫反应和细胞免疫反应,比较GP5单基因和Ub—GP5融合基因DNA免疫所诱生免疫应答的强度。结果：二者均可诱生PRRSVELISA抗体和中和抗体,其抗体水平无明显差别,但Ub-GP5融合基因诱生的淋巴细胞反应和CTL反应明显高于GP5基因。结论：泛素基因可以促进GP5诱生细胞免疫反应。     

泛素基因介导下的猪繁殖与呼吸综合征病毒M基因对小鼠的免疫试验

摘要：【目的】获得猪繁殖与呼吸综合征病毒（Porcine Reproductive and Respiratory Syndrome virus, PRRSV）M蛋白基因及其与泛素（Ubiquitin, Ub）基因融合的真核表达质粒,并进一步研究Ub对M基因免疫效果的影响。【方法】利用RT-PCR技术以PRRSV CH-1a株和BALB/c小鼠脾脏组织总RNA为模板,分别扩增出PRRSV M蛋白基因与小鼠的Ub基因,利用SOE技术将PRRSV M基因与小鼠Ub基因进行融合,最终构建真核表达质粒pVAX1-M与pVAX1-U-M。以两种真核表达质粒DNA肌肉免疫BALB/c小鼠后,分别检测体液免疫反应与细胞免疫反应,比较M单基因与Ub-M融合基因DNA免疫所诱生的免疫应答强度【结果】IFA试验表明,pVAX1-M与pVAX1-U-M均能BHK-21细胞内成功表达目的基因;两种重组质粒免疫小鼠后均可诱生PRRSV ELISA抗体与细胞免疫反应,但是pVAX1-U-M诱导的细胞免疫反应明显高于pVAX1-M,差异显著（P<0.05）;而其诱导的抗体水平明显低于pVAX1-M,二者差异也显著（P<0.05）。【结论】泛素在一定程度上可以促进PRRSV M基因诱导细胞免疫反应,但对体液免疫未见到同样作用。     

HBV包膜-核心蛋白融合基因DNA疫苗诱导小鼠持久的细胞免疫应答

构建编码HBV包膜-核心蛋白融合基因的DNA疫苗pSC、pSS1S2C和编码HBV包膜蛋白或核心蛋白基因的DNA疫苗pHBs、pHBc,分别肌肉注射免疫BALB/c小鼠,检测小鼠的血清抗体、T细胞增殖和细胞毒性T淋巴细胞反应,比较融合基因DNA疫苗与单基因DNA疫苗诱生免疫应答的强度,发现融合基因DNA疫苗诱生抗体的效率明显不及单基因DNA疫苗,但其能诱导更强、更持久的细胞免疫应答,表明HBV包膜-核心蛋白融合基因DNA疫苗对于治疗慢性乙型肝炎可能比单基因DNA疫苗更为有效.     

EB病毒核抗原1羧基端的原核表达、纯化及其免疫学特性

为进一步研究EB病毒核抗原 1(EBNA1)的功能及提高EB病毒 (EBV)相关疾病辅助诊断的特异性 ,对EBNA1基因 3′端的部分片段进行了原核表达、纯化并初步研究其免疫学特性 .采用PCR法扩增了EBNA1基因编码区 ,经酶切鉴定、序列分析后 ,将其 3′端 5 73bp片段克隆至原核表达载体pET30a中 ,得到重组质粒pET30a SS5 80 .该重组质粒转化大肠杆菌BL2 1(DE3)感受态细胞并经异丙基 β D 硫代半乳糖苷 (IPTG)诱导表达出分子量约 2 5kD的融合蛋白 (2 5 kDEBNA1) .该蛋白以包涵体和可溶形式存在 ,均可用Ni2 + 离子亲和柱纯化 .Western印迹结果显示 ,该蛋白能与鼻咽癌 (NPC)病人血清发生特异性反应 .纯化的 2 5kDEBNA1蛋白免疫BALB c小鼠后 ,经ELISA检测获得了高效价的多克隆抗体 .免疫印迹和间接免疫荧光结果显示制备的免疫小鼠血清能够与HeLa细胞中瞬时表达的EBNA1蛋白发生特异性反应 ,且特异性优于鼻咽癌病人血清 .以上结果表明成功构建了EBNA1羧基端的原核表达质粒 ,并在大肠杆菌中高效表达了 2 5kDEBNA1蛋白 ,该蛋白具有良好的抗原性和免疫原性     

HIV-2gag-gp105嵌合基因DNA疫苗对小鼠的免疫原性研究

利用真核表达载体pVAX1构建HIV-2 gag-gp105嵌合基因的重组质粒pVAX1gag-gp105,将其转入BHK21细胞中,利用间接免疫荧光方法检测其表达情况.进一步分别将核酸疫苗质粒pVAX1gag-gp105、对照组质粒pVAX1和PBS溶液经肌肉注射免疫BALB/c小鼠,检测免疫小鼠脾CD4+、CD8+T细胞亚群的数量,脾特异性CTL杀伤活性和血清抗体滴度.结果显示,重组核酸疫苗质粒pVAX1gag-gp105疫组小鼠脾CD4+、CD8+T细胞亚群的数值均比对照组高(P＜0.01),脾特异性CTL杀伤活性与对照组相比差异极显著(P＜0.01),血清抗体滴度显著高于对照组(P＜0.01).以上结果表明,HIV-2 gag-gp105嵌合基因DNA疫苗对BALB/c小鼠具有良好的体液和细胞免疫原性.     

猪Ⅱ型圆环病毒ORF2与猪GM-CSF基因重组腺病毒共表达及免疫效果分析

旨在构建含融合基因pGMCSF-ORF2的重组腺病毒,并对其表达水平和免疫效果进行分析.运用PCR方法扩增PCV2 ORF2和pGM-CSF基因,拼接后克隆入pMD18-T载体,然后再亚克隆入腺病毒穿梭质粒pShuttle-CMV中,阳性穿梭质粒经PmeⅠ酶线性化后电转化含腺病毒基因组(AdEasy-1)的大肠杆菌细胞BJ5183-Ad-1,成功获得了重组腺病毒DNA.将纯化后的重组腺病毒DNA转染AD293细胞,经过病毒基因组的PCR和转录水平的RT-PCR及Western blot等方面对融合蛋白的表达进行了鉴定.以该病毒免疫Babl/c小白鼠,对免疫小鼠血清中PCV2抗体进行检测.结果显示,获得了pGMCSF-ORF2重组基因,重组腺病毒载体构建成功,获得了表达pGMCSF-ORF2融合蛋白的重组腺病毒.该病毒免疫小鼠后,在小鼠血清中检测到了PCV2的特异性抗体.获得的重组腺病毒能有效表达pGMCSF-ORF2融合蛋白,且可诱导小鼠产生针对PCV2的特异性抗体.     

HIV-2 gag-gp105嵌合基因DNA疫苗对小鼠的免疫原性研究

利用真核表达载体 pVAX1 构建 HIV-2 gag-gp105 嵌合基因的重组质粒 pVAX1gag-gp105,将其转入 BHK21细胞中,利用间接免疫荧光方法检测其表达情况。进一步分别将核酸疫苗质粒 pVAX1gag-gp105、对照组质粒pVAX1 和 PBS 溶液经肌肉注射免疫 BALB/c 小鼠,检测免疫小鼠脾 CD4 、CD8 T 细胞亚群的数量,脾特异性 CTL杀伤活性和血清抗体滴度。结果显示,重组核酸疫苗质粒 pVAX1gag-gp105 疫组小鼠脾 CD4 、CD8 T 细胞亚群的数值均比对照组高( P<0.01),脾特异性 CTL 杀伤活性与对照组相比差异极显著(P<0.01),血清抗体滴度显著高于对照组(P<0.01) 。以上结果表明,HIV-2 gag-gp105 嵌合基因 DNA 疫苗对 BALB/c 小鼠具有良好的体液和细胞免疫原性。     

HIV-1结构蛋白gag-gp120与白细胞介素2联合基因免疫

在真核表达载体pVAX1中的CMV启动子下游插入IL-2基因,构建真核表达质粒pVAXIL2.将它与表达I型人免疫缺陷病毒(Human immunodeficiency virus 1, HIV-1) gag-gp120的核酸疫苗质粒pVAXGE共同肌肉注射BALB/c小鼠,免疫3次后,以ELISA法检测免疫小鼠血清中抗HIV-1抗体水平,结果显示联合免疫组小鼠在免疫2周后已有抗体产生,6周后进入高峰.乳酸脱氢酶释放法检测免疫小鼠脾特异性CTL杀伤活性,结果显示联合免疫组小鼠脾特异性CTL杀伤活性显著高于pVAXGE单独免疫组(P<0.05)和载体质粒pVAX1对照组(P<0.01).以上结果表明HIV-1核酸疫苗质粒pVAXGE与真核表达质粒pVAXIL2联合免疫可诱导特异性体液免疫和细胞免疫应答,且免疫应答水平高于pVAXGE单独免疫组,IL-2发挥了免疫佐剂的作用,增强了核酸疫苗的免疫原性.     

尼帕病毒融合蛋白和受体结合蛋白基因DNA免疫的研究

构建了表达哺乳动物密码子优化的NiV囊膜蛋白F和G基因的真核表达质粒pCAGG-NiV-F和pCAGG-NiV-G.细胞融合试验表明,重组NiV融合蛋白F和受体结合蛋白G在pCAGG-NiV-F、pCAGG-NiV-G共转染BHK细胞中获得表达,并具有良好生物学活性.真核表达质粒pCAGG-NiV-F、pCAGG-NiV-G和pCAGG-NiV-F pCAGG-NiV-G DNA分别按100μg/只的剂量肌肉注射免疫6周龄BALB/c小鼠,间隔4周加强免疫,第二次加强免疫3周后采血,分离血清备用.分别以重组杆状病毒感染Sf9细胞表达的重组NiV融合蛋白(rNF)和受体结合蛋白(rNG)为包被抗原,应用间接ELISA检测上述质粒DNA免疫血清中的特异性抗体,具有较高的敏感性和特异性.另外,中和试验结果表明,DNA免疫小鼠产生的特异抗体可有效中和NiV囊膜蛋白F和G介导的伪型VSV重组病毒侵入NiV易感宿主细胞的感染性,并且受体结合蛋白G基因DNA诱导中和抗体的滴度高于融合蛋白F基因DNA.结果表明,DNA疫苗具有防制尼帕病毒性脑炎的潜力.     

HIV-1 gagpol病毒样颗粒疫苗免疫小鼠的实验研究

目的:为构建含中国流行株HIV*1核心蛋白(gag、pol)基因的病毒样颗粒疫苗(VIP疫苗),并评价其诱导的体液和细胞免疫反应效果.方法:将重组质粒pcDNA3.1/gagpol稳定转染HEK293细胞,上清液经蔗糖垫层超速离心纯化后,用收获的VLP疫苗免疫小鼠,通过ELLSA检测免疫小鼠的特异性抗体和IFN-γ,通过乳酸脱氢酶(LDH)实验检测小鼠特异性细胞毒性T淋巴细胞(CTL)反应.结果:VLP疫苗免疫组小鼠血清的抗HIV-1 gp160抗体滴度和IFN-γ均升高(P<0.01).其特异性CTL活性均高于PBS对照组(P<0.01).结论:构建的VLP疫苗免疫小鼠可以诱导特异性体液和细胞免疫应答,为进一步研制HIV治疗性疫苗奠定基础.     

Targeting of hepatitis C virus core protein for MHC I or MHC II presentation does not enhance induction of immune responses to DNA vaccination.

We analyzed different vaccine approaches aimed at enhancing CD4(+)- and CD8(+)-dependent responses against hepatitis C virus (HCV) core antigen. Specific DNA vectors expressing various forms of the core in fusion with the ubiquitin or the lysosome-associated membrane protein (LAMP) were generated. These expressed the full-length wildtype core; the full-length core expressed as a covalent fusion with the ubiquitin; the full-length core expressed as a noncovalent fusion with the ubiquitin and containing a N-stabilizing or N-destabilizing residue; and the full-length core expressed as a fusion with the LAMP sequence. In vitro expression levels of the different plasmids differed by as much as tenfold. After injection into mice, none of the plasmids yielded a detectable antibody response, whereas core-specific cytotoxic T-lymphocyte (CTL) activity could be observed with all plasmids as long as 21 weeks postimmunization. No increase in CTL activity (ranging from 7% to 34% specific lysis) was observed with the ubiquitin-fusion-expressed core antigens compared with the wildtype core. The lowest CTL activity (< 5% specific lysis) was observed with the LAMP fusion. This vector was nonetheless unable to induce a detectable proliferative response. Screening of 10 different putative CTL peptide epitopes failed to reveal newly targeted epitopes when the core-fusion plasmids were used compared with the wildtype core-expressing plasmid. These data underline the difficulty in optimizing anti-core cellular immune response using molecular targeting strategies in DNA-based vaccination.     

Suppression of murine cytomegalovirus (MCMV) replication with a DNA vaccine encoding MCMV M84 (a homolog of human cytomegalovirus pp65)

The cytotoxic T-lymphocyte (CTL) response against the murine cytomegalovirus (MCMV) immediate-early gene 1 (IE1) 89-kDa phosphoprotein pp89 plays a major role in protecting BALB/c mice against the lethal effects of the viral infection. CTL populations specific to MCMV early-phase and structural antigens are also generated during infection, but the identities of these antigens and their relative contributions to overall immunity against MCMV are not known. We previously demonstrated that DNA vaccination with a pp89-expressing plasmid effectively generated a CTL response and conferred protection against infection (J. C. Gonzalez Armas, C. S. Morello, L. D. Cranmer, and D. H. Spector, J. Virol. 70:7921-7928, 1996). In this report, we have sought (i) to identify other viral antigens that contribute to immunity against MCMV and (ii) to determine whether the protective response is haplotype specific. DNA immunization was used to test the protective efficacies of plasmids encoding MCMV homologs of human cytomegalovirus (HCMV) tegument (M32, M48, M56, M82, M83, M69, and M99), capsid (M85 and M86), and nonstructural antigens (IE1-pp89 and M84). BALB/c (H-2(d)) and C3H/HeN (H-2(k)) mice were immunized by intradermal injection of either single plasmids or cocktails of up to four expression plasmids and then challenged with sublethal doses of virulent MCMV administered intraperitoneally. In this way, we identified a new viral gene product, M84, that conferred protection against viral replication in the spleens of BALB/c mice. M84 is expressed early in the infection and encodes a nonstructural protein that shares significant amino acid homology with the HCMV UL83-pp65 tegument protein, a major target of protective CTLs in humans. Specificity of the immune response to the M84 protein was confirmed by showing that immunization with pp89 DNA, but not M84 DNA, protected mice against subsequent infection with an MCMV deletion mutant lacking the M84 gene. The other MCMV genes tested did not generate a protective response even when mice were immunized with vaccinia viruses expressing the viral proteins. However, the M84 plasmid was protective when injected in combination with nonprotective plasmids, and coimmunization of BALB/c mice with pp89 and M84 provided a synergistic level of protection in the spleen. Viral titers in the salivary glands were also reduced, but not to the same extent as observed in the spleen, and the decrease was seen only when the BALB/c mice were immunized with pp89 plus M84 or with pp89 alone. The experiments with the C3H/HeN mice showed that the immunity conferred by DNA vaccination was haplotype dependent. In this strain of mice, only pp89 elicited a protective response as measured by a reduction in spleen titer. These results suggest that DNA immunization with the appropriate combination of CMV genes may provide a strategy for improving vaccine efficacy.     

Genetic Immunization of Wild-Type and Hepatitis C Virus Transgenic Mice Reveals a Hierarchy of Cellular Immune Response and Tolerance Induction against Hepatitis C Virus Structural Proteins

To study the effect of genetic immunization on transgenic expression of hepatitis C virus (HCV) proteins, we evaluated the immunological response of HCV transgenic mice to HCV expression plasmids. FVB/n transgenic mice expressing HCV structural proteins (core, E1, and E2) and wild-type (WT) FVB/n mice were immunized intramuscularly with plasmids expressing core (pHCVcore) or core/E1/E2 (pHCVSt). After immunization, HCV-specific humoral and cellular immune response was studied. Both WT and transgenic mice immunized with either HCV construct produced antibodies and exhibited T-cell proliferative responses against core or envelope. In WT mice immunized with pHCVSt, cytotoxic T-lymphocyte (CTL) activities were detected against E2 but not against core or E1, whereas strong CTL activities against core could be detected in WT mice immunized with pHCVcore. In pHCVSt-immunized, transgenic mice, CTL activities against the core or envelope were completely absent, but core-specific CTL activities could be detected in pHCVcore-immunized transgenic mice. A similar pattern of immune responses was also observed in other mouse strains, including a transgenic line expressing human HLA-A2.1 molecules (AAD mice). Despite the presence of a peripheral cellular immunity against HCV, no liver pathology or lymphocytic infiltrate was observed in these transgenic mice. Our study suggests a hierarchy of CTL response against the HCV structural proteins (E2 > core > E1) in vivo when the proteins are expressed as a polyprotein. The HCV transgenic mice can be induced by DNA immunization to generate anti-HCV antibodies and anticore CTLs. However, they are tolerant at the CTL level against the E2 protein despite DNA immunization.     

中国HIV-1流行毒株的DNA疫苗的初步研究

为研制针对我国ＨＩＶ－１流行毒株的艾滋病毒疫苗,构建了具有代表性的ｇａｇ和ｇｐ１２０核酸疫苗,进行了初步的小鼠免疫实验。结果初步显示：（１）免疫Ｂａｌｂ／Ｃ小鼠可以产生ＨＩＶ－１特异性的体液和细胞免疫;（２）ｇａｇ和ｇｐ１２０基因联合免疫可以同时诱发针对ｇａｇ和ｇｐ１２０的细胞和体液免疫反应,而且效果比各自单独免疫要好;（３）Ｂ亚型ｇｐ１２０基因免疫可以诱发识别Ｃ亚型ｇｐ１２０抗原的ＣＴＬ反应。本     

Targeting of EBNA1 for rapid intracellular degradation overrides the inhibitory effects of the Gly-Ala repeat domain and restores CD8+ T cell recognition.

Epstein-Barr virus (EBV)-encoded nuclear antigen 1 (EBNA1) includes a unique glycine-alanine repeat domain that inhibits the endogenous presentation of cytotoxic T lymphocyte (CTL) epitopes through the class I pathway by blocking proteasome-dependent degradation of this antigen. This immune evasion mechanism has been implicated in the pathogenesis of EBV-associated diseases. Here, we show that cotranslational ubiquitination combined with N-end rule targeting enhances the intracellular degradation of EBNA1, thus resulting in a dramatic reduction in the half-life of the antigen. Using DNA expression vectors encoding different forms of ubiquitinated EBNA1 for in vivo studies revealed that this rapid degradation, remarkably, leads to induction of a very strong CTL response to an EBNA1-specific CTL epitope. Furthermore, this targeting also restored the endogenous processing of HLA class I-restricted CTL epitopes within EBNA1 for immune recognition by human EBV-specific CTLs. These observations provide, for the first time, evidence that the glycine-alanine repeat-mediated proteasomal block on EBNA1 can be reversed by specifically targeting this antigen for rapid degradation resulting in enhanced CD8+ T cell-mediated recognition in vitro and in vivo.     

Epstein-Barr virus nuclear antigen 2 transactivates the long terminal repeat of human immunodeficiency virus type 1.

Human immunodeficiency virus type 1 (HIV-1)-infected subjects show a high incidence of Epstein-Barr virus (EBV) infection. This suggests that EBV may function as a cofactor that affects HIV-1 activation and may play a major role in the progression of AIDS. To test this hypothesis, we generated two EBV-negative human B-cell lines that stably express the EBNA2 gene of EBV. These EBNA2-positive cell lines were transiently transfected with plasmids that carry either the wild type or deletion mutants of the HIV-1 long terminal repeat (LTR) fused to the chloramphenicol acetyltransferase (CAT) gene. There was a consistently higher HIV-1 LTR activation in EBNA2-expressing cells than in control cells, which suggested that EBNA2 proteins could activate the HIV-1 promoter, possibly by inducing nuclear factors binding to HIV-1 cis-regulatory sequences. To test this possibility, we used CAT-based plasmids carrying deletions of the NF-kappa B (pNFA-CAT), Sp1 (pSpA-CAT), or TAR (pTAR-CAT) region of the HIV-1 LTR and retardation assays in which nuclear proteins from EBNA2-expressing cells were challenged with oligonucleotides encompassing the NF-kappa B or Sp1 region of the HIV-1 LTR. We found that both the NF-kappa B and the Sp1 sites of the HIV-1 LTR are necessary for EBNA2 transactivation and that increased expression resulted from the induction of NF-kappa B-like factors. Moreover, experiments with the TAR-deleted pTAR-CAT and with the tat-expressing pAR-TAT plasmids indicated that endogenous Tat-like proteins could participate in EBNA2-mediated activation of the HIV-1 LTR and that EBNA2 proteins can synergize with the viral tat transactivator. Transfection experiments with plasmids expressing the EBNA1, EBNA3, and EBNALP genes did not cause a significant HIV-1 LTR activation. Thus, it appears that among the latent EBV genes tested, EBNA2 was the only EBV gene active on the HIV-1 LTR. The transactivation function of EBNA2 was also observed in the HeLa epithelial cell line, which suggests that EBV and HIV-1 infection of non-B cells may result in HIV-1 promoter activation. Therefore, a specific gene product of EBV, EBNA2, can transactivate HIV-1 and possibly contribute to the clinical progression of AIDS.     

Different patterns of Epstein-Barr virus gene expression and of cytotoxic T-cell recognition in B-cell lines infected with transforming (B95.8) or nontransforming (P3HR1) virus strains

Epstein-Barr virus (EBV)-negative Burkitt's lymphoma (BL) cell lines have been converted to EBV genome positivity by in vitro infection with the transforming EBV strain B95.8 and with the nontransforming mutant strain P3HR1, which has a deletion in the gene encoding the nuclear antigen EBNA2. These B95.8- and P3HR1-converted lines have been compared for their patterns of expression of EBV latent genes (i.e., those viral genes constitutively expressed in all EBV-transformed lines of normal B-cell origin) and for their recognition by EBV-specific cytotoxic T lymphocytes (CTLs), in an effort to identify which latent gene products provide target antigens for the T-cell response. B95.8-converted lines on several different EBV-negative BL-cell backgrounds all showed detectable expression of the nuclear antigens EBNA1, EBNA2, and EBNA3 and of the latent membrane protein (LMP); such converts were also clearly recognized by EBV-specific CTL preparations with restriction through selected human leukocyte antigen (HLA) class I antigens on the target cell surface. The corresponding P3HR1-converted lines (lacking an EBNA2 gene) expressed EBNA1 and EBNA3 but, surprisingly, showed no detectable LMP; furthermore, these converts were not recognized by EBV-specific CTLs. Such differences in T-cell recognition were not due to any differences in expression of the relevant HLA-restricting determinants between the two types of convert, as shown by binding of specific monoclonal antibodies and by the susceptibility of both B95.8 and P3HR1 converts to allospecific CTLs directed against these same HLA molecules. The results suggest that in the normal infectious cycle, EBNA2 may be required for subsequent expression of LMP and that both EBNA2 and LMP (but not EBNA1 or EBNA3) may provide target antigens for the EBV-specific T-cell response.     

Effects of Antigen and Genetic Adjuvants on Immune Responses to Human Immunodeficiency Virus DNA Vaccines in Mice

The effects of genetic adjuvants on humoral and cell-mediated immunity to two human immunodeficiency virus antigens, Env and Nef, have been examined in mice. Despite similar levels of gene expression and the same gene delivery vector, the immune responses to these two gene products differed following DNA immunization. Intramuscular immunization with a Nef expression vector plasmid generated a humoral response and antigen-specific gamma interferon (IFN-gamma) production but little cytotoxic-T-lymphocyte (CTL) immunity. In contrast, immunization with an Env vector stimulated CTL activity but did not induce a high-titer antibody response. The ability to modify these antigen-specific immune responses was investigated by coinjection of DNA plasmids encoding cytokine and/or hematopoietic growth factors, interleukin-2 (IL-2), IL-12, IL-15, Flt3 ligand (FL), and granulocyte-macrophage colony-stimulating factor (GM-CSF). Coadministration of these genes largely altered the immune responses quantitatively but not qualitatively. IL-12 induced the greatest increase in IFN-gamma and immunoglobulin G responses to Nef, and GM-CSF induced the strongest IFN-gamma and CTL responses to Env. A dual approach of expanding innate immunity by administering the FL gene, together with a cytokine that enhances adaptive immune responses, IL-2, IL-12, or IL-15, generated the most potent immune response at the lowest doses of Nef antigen. These findings suggest that intrinsic properties of the antigen determine the character of immune reactivity for this method of immunization and that specific combination of innate and adaptive immune cytokine genes can increase the magnitude of the response to DNA vaccines.