包裹天然骨架CpG ODN和HBsAg的非磷脂脂质体疫苗的免疫效果

非磷脂脂质体NovasomeR○(Np )是由Brij5 2、胆固醇和油酸组成 ,可作为同时传递佐剂和抗原的载体。我们将HBsAg与天然骨架CpGODN (phosphodiesterCpGODN ,pdCpGODN )包裹于Np后免疫BALB/c小鼠 ,检测其免疫效果。结果显示 ,包裹pdCpGODN和HBsAg的Np在小鼠中诱导了很高滴度的抗 HBs抗体产生并诱生了HBsAgS2 8 3 9特异性的CTL ,而铝佐剂组和仅包裹HBsAg的Np组诱生的抗体滴度较低 ,未检测到CTL活力。抗体亚类分析结果表明包裹pdCpGODN和HBsAg的Np诱生的免疫应答类型与pdCpGODN剂量有关 ,较低剂量 (2 4 μgpdCpGODN )诱生的为IgG2a为主的Th1型应答 ,而较高剂量(4 7μgpdCpGODN )诱生的是Th1/Th2混合型应答。铝佐剂和仅包裹HBsAg的Np组诱生的是以IgG1为主的Th2型应答。此外 ,包裹pdCpGODN和HBsAg的Np免疫小鼠脾淋巴细胞在体外HBsAg刺激培养后特异性增殖并分泌高水平的IFN γ。这些结果表明包裹pdCpGODN和HBsAg的Np能增强HBsAg的免疫原性 ,诱生体液 /细胞免疫均衡应答 ,有可能发展为慢性乙肝的治疗性疫苗     

Coencapsulation of CpG oligodeoxynucleotides with recombinant Leishmania major stress-inducible protein 1 in liposome enhances immune response and protection against leishmaniasis in immunized BALB/c mice

CpG oligodeoxynucleotides (CpG ODN) have been shown to have potent adjuvant activity for a wide range of antigens. The purpose of this study was to determine the potential benefit of using liposomes as a delivery vehicle to enhance the adjuvant activity of CpG ODN with Leishmania major stress-inducible protein 1 (LmSTI1) antigen in induction of the Th1 response in a murine model of leishmaniasis. BALB/c mice were immunized subcutaneously three times in 3-week intervals with liposomal recombinant LmSTI1 (Lip-rLmSTI1), rLmSTI1 coencapsulated with CpG ODN in a liposome (Lip-rLmSTI1-CpG ODN), rLmSTI1 plus CpG ODN in phosphate-buffered saline (PBS), rLmSTI1 plus non-CpG ODN in PBS, rLmSTI1 in PBS, empty liposome, or PBS. The intensity of infection induced by L. major promastigote challenge was measured by footpad swelling. A significant (P < 0.001) inhibition of infection in mice immunized with Lip-rLmSTI1-CpG ODN was shown compared to the other groups, and no parasite was detected in the spleens of this group 14 weeks after challenge. The highest immunoglobulin G2a (IgG2a) titer and the highest IgG2a/IgG1 ratio were also shown in the sera of mice immunized with Lip-rLmSTI1-CpG ODN before and 14 weeks after challenge. The results indicated the superiority of CpG ODN in its liposomal form over its soluble form to induce the Th1 response when used in association with rLmSTI1 antigen. It seems that using a liposome delivery system carrying CpG ODN as an adjuvant coencapsulated with Leishmania antigen plays an important role in vaccine development strategies against leishmaniasis.     

CpG oligodeoxynucleotide and Montanide ISA 51 adjuvant combination enhanced the protective efficacy of a subunit malaria vaccine

Unmethylated CpG dinucleotide motifs present in bacterial genomes or synthetic oligodeoxynucleotides (ODNs) serve as strong immunostimulatory agents in mice, monkeys and humans. We determined the adjuvant effect of murine CpG ODN 1826 on the immunogenicity and protective efficacy of the Saccharomyces cerevisiae-expressed 19-kDa C-terminal region of merozoite surface protein 1 (yMSP1(19)) of the murine malaria parasite Plasmodium yoelii. We found that in C57BL/6 mice, following sporozoite challenge, the degree of protective immunity against malaria induced by yMSP1(19) in a formulation of Montanide ISA 51 (ISA) plus CpG ODN 1826 was similar or superior to that conferred by yMSP1(19) emulsified in complete Freund's adjuvant (CFA/incomplete Freund's adjuvant). In total, among mice immunized with yMSP1(19), 22 of 32 (68.7%) with ISA plus CpG 1826, 0 of 4 (0%) with CFA/incomplete Freund's adjuvant, 0 of 4 (0%) with CpG 1826 mixed with ISA (no yMSP1(19)), and 0 of 11 (0%) with CpG 1826 alone were completely protected against development of erythrocytic stage infection after sporozoite challenge. The adjuvant effect of CpG ODN 1826 was manifested as both significantly improved complete protection from malaria (defined as the absence of detectable erythrocytic form parasites) (P = 0.007, chi square) and reduced parasite burden in infected mice. In vivo depletions of interleukin-12 and gamma interferon cytokines and CD4+ and CD8+ T cells in vaccinated mice had no significant effect on immunity. On the other hand, immunoglobulin G (IgG) isotype levels appeared to correlate with protection. Inclusion of CpG ODN 1826 in the yMSP1(19) plus ISA vaccine contributed towards the induction of higher levels of IgG2a and IgG2b (Th1 type) antibodies, suggesting that CpG ODN 1826 caused a shift towards a Th1 type of immune response that could be responsible for the higher degree of protective immunity. Our results indicate that this potent adjuvant formulation should be further evaluated for use in clinical trials of recombinant malarial vaccine candidates.     

Immunization against hepatitis B virus by mucosal administration of antigen-antibody complexes

Antigen-antibody complexes have been shown to enhance immune responses against several antigens given by parenteral immunization. Herein, we have evaluated the potential of administering such immunostimulatory complexes by a mucosal route. Hepatitis B surface antigen (HBsAg) complexed with antibodies against HBsAg (anti-HBs) (HBsAg/Ab) was administered to BALB/c mice by intranasal inhalation. HBsAg by itself did not induce immune responses, whereas with HBsAg/Ab complexes, both systemic and mucosal immune responses were observed and these could be modulated by adjuvants. With HBsAg/Ab (1 or 10 microg), anti-HBs antibodies induced were predominantly of the IgG1 isotype (Th2-like). In contrast, anti-HBs induced by HBsAg/Ab plus cholera toxin (CT) or oligodeoxynucleotides (ODN) containing immunostimulatory CpG motifs (CpG) (1 microg each) were predominantly IgG2a (Th1-like). Results from this study indicate that HBsAg/Ab complexes can induce strong humoral immune responses when delivered by a noninvasive route, whether used alone or in combination with other mucosal adjuvants.     

Phosphodiester CpG oligonucleotides as adjuvants: polyguanosine runs enhance cellular uptake and improve immunostimulative activity of phosphodiester CpG oligonucleotides in vitro and in vivo

Bacterial DNA and oligonucleotides (ODN) containing CpG-motifs strongly activate cells of the immune system. Accordingly CpG-DNA is a powerful adjuvant in vaccination protocols for B-cell as well as for cytotoxic T-cell responses. A decisive propensity of CpG-DNA is its capacity to induce preferentially T helper type 1 (Th1)-dominated immune responses. To exert its function CpG-DNA has to be taken up by responsive cells, e.g. antigen-presenting cells (APC). The rate of uptake is influenced by the DNA's backbone modification and critically determines activity of CpG-DNA. CpG ODN with a phosphothioate backbone (PTO) are currently used for most in vivo and in vitro studies, since PTO modification protects ODN from the attack of nucleases. However, after administration of PTO-modified CpG-ODN long-lasting effects including lymphadenopathy as well as sustained local interferon-gamma (IFN-gamma) and interleukin-12 (IL-12) production have been reported. To circumvent these restrictions we investigated the effects of DNA sequence as well as DNA backbone modification on cellular uptake and resulting immunostimulation. We show here that uptake of phosphodiester (PO)-CpG-ODN can be strongly enhanced by poly guanosine runs added at the 3' end of the ODN. In addition these ODN showed an improved immunostimulatory activity in vivo and in vitro. This included protection of mice against lethal Th2-dependent leishmaniasis as well as priming of antigen specific Th1 responses. More importantly, guanosine-rich PO-CpG-ODN neither induced lymphadenopathy nor prolonged cytokine production after local administration. Since these improved PO ODN are efficient in vitro and in vivo and lack long lasting undesired effects they could be used preferably as adjuvants in vaccination protocols.     

Immunostimulatory DNA as an Adjuvant in Vaccination against Leishmania major

Oligodeoxynucleotides (ODN) which contain immunostimulatory CG motifs (CpG ODN) can promote T helper 1 (Th1) responses, an adjuvant activity that is desirable for vaccination against leishmaniasis. To test this, susceptible BALB/c mice were vaccinated with soluble leishmanial antigen (SLA) with or without CpG ODN as adjuvant and then challenged with Leishmania major metacyclic promastigotes. CpG ODN alone gave partial protection when injected up to 5 weeks prior to infection, and longer if the ODN was bound to alum. To demonstrate an antigen-specific adjuvant effect, a minimum of 6 weeks between vaccination and infection was required. Subcutaneous administration of SLA alone, SLA plus alum, or SLA plus non-CpG ODN resulted in exacerbated disease compared to unvaccinated mice. Mice receiving SLA plus CpG ODN showed a highly significant (P < 5 x 10(-5)) reduction in swelling compared to SLA-vaccinated mice and enhanced survival compared to unvaccinated mice. The modulation of the response to SLA by CpG ODN was maintained even when mice were infected 6 months after vaccination. CpG ODN was not an effective adjuvant for antibody production in response to SLA unless given together with alum, when it promoted production of immunoglobulin G2a, a Th1-associated isotype. Our results suggest that with an appropriate antigen, CpG ODN would provide a stable, cost-effective adjuvant for use in vaccination against leishmaniasis.     

Immunomodulation of Japanese encephalitis vaccine through CpG oligodeoxynucleotides in mice

Synthetic oligodeoxynucleotides (ODN) containing unmethylated cytosine guanine (CpG) dinucleotides motifs act as immune adjuvant and provide means of modulation to immune responses when co-delivered with antigens. They stimulate both innate and adaptive immune responses and induce T helper 1 (Th1) immune responses. We investigated the immunomodulation of Japanese encephalitis (JE) vaccine using CpG ODN as an adjuvant. Mice were immunized with one dose of JE vaccine 0.1 ml with different concentrations (10, 25 and 100 microg) of CpG ODN. The serum antibody level and cytokines were evaluated and compared with mice immunized with two doses of JE vaccine alone. Our studies revealed that anti-JE antibody level in mice immunized with single dose of 0.1 ml JE vaccine and 100 microg CpG ODN were almost equal to mice immunized with two doses of JE vaccine alone. Furthermore, CpG ODN enhanced the production of TNF-alpha and Th1-mediated cytokines, including IFN-gamma and IL-2 compared with JE vaccine alone. In addition, absence of any significant changes in biochemical, haematological and histological studies suggest that CpG ODN are safe adjuvants for JE vaccine. Therefore, it is inferred that CpG ODN are effective and improve the efficacy of JE vaccine.     

新型CpG ODN增强乙肝疫苗诱导IgG2a类抗体产生的实验研究

目的：寻找能增强乙肝疫苗刺激IgG2a类抗体产生，使机体处于Th1样免疫环境的新型乙肝疫苗佐剂。方法：选用自行设计的A、B、C型CpGODN，并以发表的A、B型CpGODN作为阳性对照，与重组乙肝疫苗混合后于第0．4周免疫BALB／C小鼠，用ELISA法检测免疫小鼠血清中HBsAb水平及种类。结果：各型CpGODN都能增强乙肝疫苗刺激HBsAb的产生水平，CpGODN＋乙肝疫苗免疫的小鼠血清中HBsAb类型为IgG2a〉〉IgG1，而单独应用商品化重组乙型肝炎疫苗的小鼠血清中HBsAb类型为IgG1〉〉IgG2a。结论：各型CpGODN对重组乙型肝炎疫苗[含AI（OH）3佐剂]均具有增效作用，而且可以诱导机体产生倾向于Th1途径的免疫应答反应。     

The immunodominant T helper 2 (Th2) response elicited in BALB/c mice by the Leishmania LiP2a and LiP2b acidic ribosomal proteins cannot be reverted by strong Th1 inducers

The search for disease-associated T helper 2 (Th2) Leishmania antigens and the induction of a Th1 immune response to them using defined vaccination protocols is a potential strategy to induce protection against Leishmania infection. Leishmania infantum LiP2a and LiP2b acidic ribosomal protein (P proteins) have been described as prominent antigens during human and canine visceral leishmaniasis. In this study we demonstrate that BALB/c mice infected with Leishmania major develop a Th2-like humoral response against Leishmania LiP2a and LiP2b proteins and that the same response is induced in BALB/c mice when the parasite P proteins are immunized as recombinant molecules without adjuvant. The genetic immunization of BALB/c mice with eukaryotic expression plasmids coding for these proteins was unable to redirect the Th2-like response induced by these antigens, and only the co-administration of the recombinant P proteins with CpG oligodeoxynucleotides (CpG ODN) promoted a mixed Th1/Th2 immune response. According to the preponderance of a Th2 or mixed Th1/Th2 responses elicited by the different regimens of immunization tested, no evidence of protection was observed in mice after challenge with L. major. Although alterations of the clinical outcome were not detected in mice presensitized with the P proteins, the enhanced IgG1 and interleukin (IL)-4 response against total Leishmania antigens in these mice may indicate an exacerbation of the disease.     

人工合成免疫刺激DNA联合HBsAg DNA疫苗在HBV转基因鼠的免疫应答研究

目的 :探讨免疫刺激DNA序列联合基因免疫在HBV转基因鼠的免疫应答。方法 :用人工合成硫代修饰的免疫刺激DNA寡核苷酸 (CpGODN)与HBVS区基因真核表达载体 (V HBs)联合免疫HBsAg转基因鼠 ,通过ELISA观察小鼠血清HBsAg及抗 HBs抗体水平 ,并用免疫组化 (SP法 )及病理HE染色观察小鼠肝组织HBsAg表达量的改变及肝组织炎症活动度。结果 :V HBs联合CpGODN组 6只免疫鼠中有 2只血清抗 HBs抗体阳性 ,其平均效价为 (5 6 2 1± 15 16 )mU ml,血清HBsAg浓度在免疫后第 8周时有 2只转阴 ,而单用V HBs组及V 10 12对照组小鼠血清抗 HBs抗体均阴性、HBsAg含量无明显降低。V HBs +CpGODN组肝组织HBsAg的表达量低于V HBs组及对照组 ,并可见大量炎细胞浸润 ,炎症组织活动度积分明显高于V HBs组及对照组。结论 :CpGODN联合V HBs可增强其免疫应答及抗病毒效应。     

T helper 2 immunity to hepatitis B surface antigen primed by gene-gun-mediated DNA vaccination can be shifted towards T helper 1 immunity by codelivery of CpG motif-containing oligodeoxynucleotides

Gene-gun-mediated DNA immunization usually induces predominant T helper 2 (Th2) type immune response. As oligodeoxynucleotides (ODN)-containing unmethylated CpG motifs can activate the innate immune system in a Th1-biased way, the potential of codelivery of CpG motifs-containing ODN (CpG-ODN) with plasmid DNA to switch the gene-gun-mediated Th2 immune response was evaluated in this study. Here we show that codelivery of CpG-ODN with plasmid DNA at certain ratio (10/1) can enhance the Th1 humoral and cell-mediated immune responses in gene-gun-mediated DNA immunization in BALB/c mice, including increasing the hepatitis B surface antigen-specific total immunoglobulin G (IgG), IgG2a subclass, cytotoxic T-cell lymphocyte activity as well as interferon-gamma (IFN-gamma) secretion. Taken together, these results demonstrate that codelivery of CpG-ODN with recombinant plasmid DNA by gene gun can shift the gene-gun-mediated DNA immune response from Th2 towards Th1.     

The adjuvant effect of CpG oligodeoxynucleotide linked to the non-toxic B subunit of cholera toxin for induction of immunity against H. pylori in mice

The present study was carried out to test the immunostimulatory and adjuvant effects of the non-toxic B subunit of cholera toxin (CTB), CpG oligodeoxynucleotide (ODN) and CpG ODN linked to CTB (CTB–CpG) for generation of immunity against H. pylori in mice. Herein, we showed that CTB–CpG induces more potent proinflammatory cytokine and chemokine responses in the cervical and the mesenteric lymph nodes (CLN and MLN, respectively) cells in vitro compared with those of CTB and CpG ODN. The adjuvant effects of these agents were examined following intranasal immunization of C57Bl/6 mice with H. pylori lysate in combination with CpG ODN, CTB or CTB–CpG. All three immunization regimes resulted in high H. pylori -specific IgG antibody responses; however, only the CTB–CpG and, to some extent, the CpG ODN immunized mice mounted a sustainable IgG2c antibody response. Importantly, mice immunized with H. pylori antigen and CTB–CpG or CpG ODN, but not CTB, developed strong H. pylori -specific proliferative and IFN-γ responses in their MLN CD4⁺ T cells upon recall antigen stimulation in vitro . These mice also had significantly lower bacterial load compared with the control-infected mice. Furthermore, the CTB–CpG and the CpG ODN immunized mice developed increased specific IgA antibody responses in their gastrointestinal tracts following H. pylori challenge. These results imply that CTB–CpG and CpG ODN, but not CTB, could serve as nasal adjuvants for induction of a H. pylori -specific Th1 type immunity in MLN and also a specific mucosal IgA antibody response in the gastrointestinal tract upon H. pylori challenge.     

Bacterial DNA and CpG-containing oligodeoxynucleotides activate cutaneous dendritic cells and induce IL-12 production: implications for the augmentation of Th1 responses

BACKGROUND: Unmethylated CpG sequences in bacterial DNA act as adjuvants selectively inducing Th1 predominant immune responses during genetic vaccination or when used in conjunction with protein Ag. The precise mechanism of this adjuvant effect is unknown. Because dendritic cells (DC) are thought to be crucially involved in T cell priming and Th1/Th2 education during vaccination via skin, we characterized the effects of bacterial DNA and CpG-containing oligodeoxynucleotides (CpG ODN) on cutaneous DC. METHODS AND RESULTS: Stimulation with CpG ODN 1826 (6 micrograms/ml) induced activation of immature Langerhans cell (LC)-like DC as determined by an increased expression of MHC class II and costimulatory molecules, loss of E-cadherin-mediated adhesion and increased ability to stimulate allogeneic T cells. Composition-matched control ODN 1911 lacking CpG sequences at equal concentrations was without effect. In comparison to LPS and ODN 1911, CpG ODN 1826 selectively stimulated DC to release large amounts of IL-12 (p40) and little IL-6 or TNF-alpha within 18 h and detectable levels of IL-12 p70 within 72 h. Stimulation with Escherichia coli DNA, but not calf thymus DNA, similarly induced DC maturation and IL-12 p40 production. Injection of CpG ODN into murine dermis induced enhanced expression of MHC class II and CD86 by LC in the overlying epidermis and intracytoplasmic IL-12 p40 accumulation in a subpopulation of activated LC. CONCLUSION: Bacterial DNA and CpG ODN stimulate DC in vitro and in vivo and may preferentially elicit Th1-predominant immune responses because they can activate and mobilize DC, inducing them to produce IL-12.     

Systemic Th1 immunization of mice against Helicobacter pylori infection with CpG oligodeoxynucleotides as adjuvants does not protect from infection but enhances gastritis

Recent reports have suggested that oral vaccination of mice against Helicobacter pylori is dependent on a Th1-mediated immune response. However, oral vaccination in mice neither induces sterilizing immunity nor leads to complete protection from disease. Therefore, in this study we investigated whether a systemic subcutaneous immunization against H. pylori by using CpG oligodeoxynucleotides as a Th1 adjuvant could achieve protection in a mouse model of H. pylori infection. CpG oligodeoxynucleotides are known for their ability to induce nearly entirely Th1-biased immune responses and may be approved for human use in future. Immunization of mice with H. pylori lysate and CpG induced a strong local and systemic Th1 immune response. Despite this strong Th1 response, mice were not protected from infection with H. pylori yet had a 10-fold reduction in the number of H. pylori in the gastric mucosa compared to nonimmunized mice. Of note, reduction of the bacterial density in immunized mice was accompanied by a significantly enhanced gastritis. Hence, systemic Th1 immunization of mice, even though being able to reduce the bacterial load in the stomach, is associated with aggravated pathology.     

Co-administration of porcine-specific CpG oligodeoxynucleotide enhances the immune responses to pseudorabies attenuated virus vaccine in newborn piglets in vivo

Oligonucleotides containing CpG motifs (CpG ODN) are strong adjuvants for humoral and cellular immune responses in mice, but data on immune responses in piglets are scarce. In this report, porcine-specific CpG ODN were used as immunoadjuvants to enhance the immune responses of the newborn piglets to Pseudorabies attenuated virus (PRV) vaccine. The titres of specific antibodies and serum IgG1/IgG2 ratio to PRV vaccine, the proliferation of peripheral blood mononuclear cells (PBMCs), IL-4 and interferon-gamma(IFN-gamma) in piglets serum were examined to identify the immune response of the newborn piglets. The results showed that piglets immunized with PRV vaccine and CpG ODN presented high titers of PRV-specific antibodies and IgG2 isotype, a Th1-dominated (IFN-gamma) cytokine profile, together with inducing higher proliferation of PBMCs. All these data indicate that CpG ODN are potential effective adjuvants for the PRV vaccine in newborn piglets.     

Oligodeoxynucleotides lacking CpG dinucleotides mediate Toll-like receptor 9 dependent T helper type 2 biased immune stimulation

Oligodeoxynucleotides (ODN) with unmethylated CpG dinucleotides mimic the immune stimulatory activity of bacterial DNA in vertebrates and are recognized by Toll-like receptor 9 (TLR9). It is also possible to detect immune activation with certain phosphorothioate sequences that lack CpG motifs. These ODN are less potent than CpG ODN and the mechanism by which they stimulate mammalian leucocytes is not understood. We here provide several lines of evidence demonstrating that the effects induced by non-CpG ODN are mediated by TLR9. First, non-CpG ODN could not stimulate cytokine secretion from the splenocytes of TLR9-deficient (TLR9(-/-)) mice. Second, immunization of TLR9(+/+) but not TLR9(-/-) mice with non-CpG ODN enhanced antigen-specific antibody responses, although these were T helper type 2 (Th2)-biased. Third, reactivity to non-CpG ODN could be reconstituted by transfection of human TLR9 into non-responsive cells. In addition, we define a new efficient immune stimulatory motif aside from the CpG dinucleotide that consists of a 5'-TC dinucleotide in a thymidine-rich background. Non-CpG ODN containing this motif induced activation of human B cells, but lacked stimulation of Th1-like cytokines and chemokines. Our study indicates that TLR9 can mediate either efficient Th1- or Th2-dominated effects depending on whether it is stimulated by CpG or certain non-CpG ODN.     

Interleukin-12- and gamma interferon-dependent protection against malaria conferred by CpG oligodeoxynucleotide in mice

Unmethylated CpG dinucleotides in bacterial DNA or synthetic oligodeoxynucleotides (ODNs) cause B-cell proliferation and immunoglobulin secretion, monocyte cytokine secretion, and activation of natural killer (NK) cell lytic activity and gamma interferon (IFN-gamma) secretion in vivo and in vitro. The potent Th1-like immune activation by CpG ODNs suggests a possible utility for enhancing innate immunity against infectious pathogens. We therefore investigated whether the innate immune response could protect against malaria. Treatment of mice with CpG ODN 1826 (TCCATGACGTTCCTGACGTT, with the CpG dinucleotides underlined) or 1585 (ggGGTCAACGTTGAgggggG, with g representing diester linkages and phosphorothioate linkages being to the right of lowercase letters) in the absence of antigen 1 to 2 days prior to challenge with Plasmodium yoelii sporozoites conferred sterile protection against infection. A higher level of protection was consistently induced by CpG ODN 1826 compared with CpG ODN 1585. The protective effects of both CpG ODNs were dependent on interleukin-12, as well as IFN-gamma. Moreover, CD8+ T cells (but not CD4+ T cells), NK cells, and nitric oxide were implicated in the CpG ODN 1585-induced protection. These data establish that the protective mechanism induced by administration of CpG ODN 1585 in the absence of parasite antigen is similar in nature to the mechanism induced by immunization with radiation-attenuated P. yoelii sporozoites or with plasmid DNA encoding preerythrocytic-stage P. yoelii antigens. We were unable to confirm whether CD8+ T cells, NK cells, or nitric oxide were required for the CpG ODN 1826-induced protection, but this may reflect differences in the potency of the ODNs rather than a real difference in the mechanism of action of the two ODNs. This is the first report that stimulation of the innate immune system by CpG immunostimulatory motifs can confer sterile protection against malaria.     

CpG motifs as possible adjuvants for the treatment of allergic diseases

DNA containing unmethylated CpG motifs and synthetic oligodeoxynucleotides derived thereof (CpG ODN) have intensively been investigated for their immunostimulatory properties in the recent past. CpG ODN were shown to induce strong Th1 immune responses in mammals. The downregulation of the antigen-driven Th2 response of type I allergies represents one important therapeutic goal of specific immunotherapy (SIT). Hence, CpG ODN represent promising substances which support the modification of the pathogenic Th2 immune profile toward a Th1 profile when used as adjuvants for SIT. This article discusses how the use of CpG ODN in immunotherapeutics could improve the treatment of type I allergy.     

Characterization of three CpG oligodeoxynucleotide classes with distinct immunostimulatory activities

Oligodeoxynucleotides (ODN) with unmethylated deoxycytidyl-deoxyguanosine (CpG) dinucleotides (CpG ODN) mimic the immunostimulatory activity of bacterial DNA and are recognized by the Toll-like receptor 9 (TLR9). CpG ODN of the B-Class stimulate strong B cell and NK cell activation and cytokine production. The highest degrees of NK stimulation as well as IFN-alpha secretion by plasmacytoid DC were found to occur only with A-Class ODN. A third class of CpG ODN combines the immune effects of A- and B-Class CpG ODN. C-Class ODN strongly stimulate B cell or NK cell activation and IFN-alpha production. In contrast to the A-Class, the C-Class is wholly phosphorothioate, has no poly-G stretches, but has palindromic sequences combined with stimulatory CpG motifs. All classes stimulate TLR9-dependent signaling, but with strikingly different dose-response relationships that are quite in contrast to those observed for IFN-alpha. Effects similar to those on human cells were observed on mouse splenocytes. In contrast, splenocytes from TLR9-deficient mice did not show any response to the three CpG ODN classes. In vivo studies demonstrate that C-Class ODN are very potent Th1 adjuvants. C-Class ODN may represent new therapeutic drugs that combine the effects of A- and B-Class ODN for broad applications in infectious disease or cancer therapy.