Teaching vaccine safety communication to medical students and health professionals.

Not only the general public, but also those studying to become health professionals, are struggling to keep up with a growing body of evidence and increasingly complex information about the many different types of vaccines available to date. At the same time, a number of increasingly complex subjects of study are competing for their attention during undergraduate and graduate education. In many medical school curricula in German-speaking countries, the subject of vaccines has been entirely omitted, or is regarded a minor subtopic. During the studies, most medical school curricula in German-speaking countries do not offer obligatory courses and/ or hands-on training vaccinology in vaccination. In Germany, private pediatricians administer the majority of immunizations. Even during postgraduate training programs in pediatrics, which are largely hospital-based, vaccinations are rarely a topic, and vaccinology remains a "hobby" and a "field without lobby" lacking specific certification requirements. Studies of acceptance of vaccines among health professionals and medical students have shown that many may still have their own doubts and uncertainties about vaccines revealing a number of unanswered questions during their studies and postgraduate training.

A design thinking approach to effective vaccine safety communication.

The highly complex and controversial topic of vaccine safety communication warrants innovative, user-centered solutions that would start with gaining mutual respect while taking into account the needs, concerns and underlying motives of patients, parents and physicians. To this end, a non-profit collaborative project was conducted by The Vienna Vaccine Safety Initiative, an international think tank aiming to promote vaccine safety research and communication, and the School of Design Thinking in Potsdam, Germany, the first school for innovation in Europe. The revolutionary concept of the Design Thinking approach is to group students in small multi-disciplinary teams. As a result they can generate ground-breaking ideas by combining their expertise and different points of view. The team agreed to address the following design challenge question: "How might we enable physicians to encourage parents and children to prevent infectious diseases?" The current article describes, step-by step, the ideation and innovation process as well as first tangible outcomes of the project.

Awareness and utilization of reporting pathways for adverse events following immunization: online survey among pediatricians in Russia and Germany.

OBJECTIVES: Vaccine safety surveillance is highly dependent on accurate reporting of adverse events following immunization (AEFI). An online survey was conducted to assess the utilization of AEFI reporting standards and pathways among pediatricians in Germany, and in Russia where pediatric specialization begins in medical school. METHODS: In May 2011, a 31-item online questionnaire was sent to members of the German Professional Association for Pediatricians (BVKJ) and the Union of Pediatricians of Russia (UPR), capturing information on vaccine safety training, awareness of AEFI reporting pathways, and use of standardized case definitions for the ascertainment of AEFI. A convenience sample of 1,632 completed online surveys was analyzed. RESULTS: Participating pediatricians reported spending approximately 50 min per 8-hour workday on vaccine safety consultations, but only 42 % (56 % UPR, 26 % BVKJ) have ever received any formal vaccine safety training. Two-thirds reported having observed AEFI in their practice, but only one-third utilized standardized case definitions for case ascertainment. Only 35 % of participants named accurate AEFI reporting pathways. Every second pediatrician would report AEFI to institutions that are not primarily in charge of vaccine safety surveillance; the remaining reports would either be lost or delayed. Pediatricians who had received formal vaccine safety training were significantly more likely to apply international safety standards and to report adequately, both at the p < 0.05 level. CONCLUSION: Pediatricians play a key role in the post-marketing surveillance of vaccine safety. The lack of training represents a missed opportunity. There may be a role for professional societies to improve vaccine safety training.

Quality of life in childhood immune thrombocytopenia: international validation of the kids' ITP tools.

BACKGROUND: The Kids ITP Tools (KIT) is a disease-specific measure of health-related quality of life for children with immune thrombocytopenia (ITP). To facilitate use in international trials it has been cross-culturally adapted for France, Germany, the United Kingdom and Uruguay. This study assessed the validity and reliability of the translated KIT in comparison to generic quality of life measures. METHODS: Children 2-18 years of age with ITP and their parents were recruited in France, Germany, the United Kingdom and Uruguay. Participants completed the KIT, PedsQL and KINDL. We examined the Pearson's correlation between these measures for our pooled sample and estimated the reliability over a 2-week time period. Findings were further explored by country. RESULTS: A total of 127 families (81 children self-reported) participated. Mean child-reported scores were: KIT 74.3 (SD = 15.3), PedsQL 81.3 (SD = 13.0), and KINDL 70.5 (SD = 14.3). Corresponding mean parent proxy-reported scores were: 70.6 (SD = 18.1), 75.7 (SD = 16.8) and 72.3 (SD = 12.7), respectively. Correlation between KIT and the generic measures was consistent with our a priori hypothesis (PedsQL r = 0.54, KINDL r = 0.48, both P < 0.0001). Child KIT scores for newly diagnosed ITP patients were significantly lower than for chronic ITP patients (67.3 vs. 77.3; P = 0.005). There was a significant correlation (P < 0.001) between the child and parent proxy KIT scores (ICC = 0.52). Child KIT test-retest reliability was acceptable at 0.71. CONCLUSIONS: The cross-culturally translated KIT is valid and reliable with acceptable correlation to the PedsQL and KINDL. There is a significant difference in child self-reported KIT scores between newly diagnosed and chronic ITP.

Two patterns of thrombopoietin signaling suggest no coupling between platelet production and thrombopoietin reactivity in thrombocytopenia-absent radii syndrome.

BACKGROUND: Thrombocytopenia with absent radii syndrome is defined by bilateral radius aplasia and thrombocytopenia. Due to impaired thrombopoietin signaling there are only few bone marrow megakaryocytes and these are immature; the resulting platelet production defect improves somewhat over time. A microdeletion on chromosome 1q21 is present in all patients but is not sufficient to form thrombocytopenia with absent radii syndrome. We aimed to refine the signaling defect in this syndrome. DESIGN AND METHODS: We report an extended study of 23 pediatric and adult patients suffering from thrombocytopenia with absent radii syndrome in order to scrutinize thrombopoietin signal transduction by immunoblotting and gel electrophoretic shift assays. In addition, platelet immunotyping and reactivity were analyzed by flow cytometry. Results were correlated with clinical data including age and platelet counts. RESULTS: Two distinct signaling patterns were identified. Juvenile patients showed abrogated thrombopoietin signaling (pattern #1), which is restored in adults (pattern #2). Phosphorylated Jak2 was indicative of activation of STAT1, 3 and 5, Tyk2, ERK, and Akt, showing its pivotal role in distinct thrombopoietin-dependent pathways. Jak2 cDNA was not mutated and the thrombopoietin receptor was present on platelets. All platelets of patients expressed normal levels of CD41/61, CD49b, and CD49f receptors, while CD42a/b and CD29 were slightly reduced and the fibronectin receptor CD49e markedly reduced. Lysosomal granule release in response to thrombin receptor activating peptide was diminished. CONCLUSIONS: We show a combined defect of platelet production and function in thrombocytopenia with absent radii syndrome. The rise in platelets that most patients have during the first years of life preceded the restored thrombopoietin signaling detected at a much later age, implying that these events are uncoupled and that an unknown factor mediates the improvement of platelet production.

Immature platelet count: a simple parameter for distinguishing thrombocytopenia in pediatric acute lymphocytic leukemia from immune thrombocytopenia.

BACKGROUND: Platelet counts below normal values define thrombocytopenia. However, platelet counts alone do not reveal the underlying pathomechanism. New blood cell counters provide additional information on platelet size and volume, and enable the distinction of sub-populations. In this preliminary study, we evaluate whether one of these markers can be used for diagnosis of isolated thrombocytopenia in children. PROCEDURE: We provide normal values for mean platelet volume (MPV), platelet distribution width (PDW), plateletcrit (PCT), platelet large cell ratio (P-LCR), platelet mean-frequent volume (P-MFV), relative immature platelet fraction (IPF%), and absolute IPF (IPF#) for 100 healthy children and analyzed 87 children with thrombocytopenia. RESULTS: In children with platelet production defects, IPF% was low, while in acute immune thrombocytopenia (ITP), IPF% was markedly increased (median 25.2%, P < 0.01), representing accelerated platelet turnover. Interestingly, children diagnosed with acute lymphocytic leukemia (ALL) also had elevated IPF% (median 10%, P < 0.01), suggesting that thrombopoiesis is stimulated despite virtual absence of bone marrow progenitors. Low IPF# was only found in patients with acute ITP. CONCLUSIONS: IPF% is a marker for thrombocytopenia due to defective platelet production while IPF#, representing the immature platelet count, might become a practical parameter to distinguish acute ITP from thrombocytopenia in children with newly diagnosed ALL (P < 0.01).

Continuous veno-venous single-pass albumin hemodiafiltration in children with acute liver failure.

OBJECTIVE: To investigate the applicability, efficacy, and safety of single-pass albumin dialysis in children. DESIGN: Retrospective data review of uncontrolled clinical data. SETTING: University-based pediatric intensive care unit collaborating with a local center for liver transplantation. PATIENTS: Nine children, aged 2 to 15 yrs, who were treated with single-pass albumin dialysis for acute liver failure of various origins under a compassionate-use protocol between 2000 and 2006. All patients met high-urgency liver transplantation criteria. INTERVENTIONS: Single-pass albumin dialysis was performed as rescue therapy for children with acute liver failure. MEASUREMENTS AND MAIN RESULTS: The decrease in hepatic encephalopathy (grades 1-4) and the serum levels of bilirubin, bile acids, and ammonium were measured to assess the efficacy of detoxification. As a measure of liver synthesis function, thromboplastin time and fibrinogen were analyzed. The safety of the procedure was assessed by documenting adverse effects on mean arterial blood pressure, platelet count, and clinical course. Seven out of nine patients were bridged successfully to either native organ recovery (n = 1) or liver transplantation (n = 6), one of them twice. Six out of nine patients undergoing single-pass albumin dialysis (ten treatments) survived. In six patients, hepatic encephalopathy could be reduced at least by one degree. Ammonium, bilirubin, and bile acid levels decreased in all patients. One patient had an allergic reaction to albumin. CONCLUSIONS: In childhood acute liver failure, treatment with single-pass albumin dialysis was generally well tolerated and seems to be effective in detoxification and in improving blood pressure, thus stabilizing the critical condition of children before liver transplantation and facilitating bridging to liver transplantation. It may be beneficial in avoiding severe neurologic sequelae after acute liver failure and thereby improve survival. Single-pass albumin dialysis is an inexpensive albumin-based detoxification system that is easy to set up and requires little training. Whether and to what extent single-pass albumin dialysis can support children with acute liver failure until native liver recovery remains unclear.

Systematic amino acid substitutions improved efficiency of GD2-peptide mimotope vaccination against neuroblastoma.

The likelihood of identifying peptides of sufficient quality for the development of effective cancer vaccines by screening of phage display libraries is low. Here, we introduce the sequential application of systematic amino acid substitution by SPOT synthesis. After the substitution of two amino acids within the sequence of a phage display-derived mimotope of disialoganglioside GD2 (mimotope MA), the novel mimotope C3 showed improved GD2 mimicry in vitro. Peptide vaccination with the C3 mimotope induced an 18-fold increased anti-GD2 serum response associated with reduction of primary tumour growth and spontaneous metastasis in contrast to MA mimotope controls in a syngeneic neuroblastoma model. In summary, SPOT provides an ideal optimisation tool for the development of phage display-derived cancer vaccines.

Xenogeneic immunization with human tyrosine hydroxylase DNA vaccines suppresses growth of established neuroblastoma.

Neuroblastoma (NB) is a challenging malignancy of the sympathetic nervous tissue characterized by a very poor prognosis. One important marker for NB is the expression of tyrosine hydroxylase (TH), the first-step enzyme of catecholamine biosynthesis. We could show stable and high TH gene expression in 67 NB samples independent of the clinical stage. Based on this observation, we addressed the question of whether xenogeneic TH DNA vaccination is effective in inducing an anti-NB immune response. For this purpose, we generated three DNA vaccines based on pCMV-F3Ub and pBUD-CE4.1 plasmids encoding for human (h)THcDNA (A), hTH minigene (B), and hTHcDNA in combination with the proinflammatory cytokine interleukin 12 (C), and tested prophylactic and therapeutic efficacy to suppress primary tumor growth and spontaneous metastasis. Here we report that xenogeneic TH DNA vaccination was effective in eradicating established primary tumors and inhibiting metastasis. Interestingly, this effect could not be enhanced by adding the Th1 cytokine interleukin 12. However, increased IFN-gamma production and NB cytotoxicity of effector cells harvested from vaccinated mice suggested the participation of tumor-specific CTLs in the immune response. The depletion of CD8(+)T cells completely abrogated the hTH vaccine-mediated anti-NB immune response. Furthermore, rechallenging of surviving mice resulted in reduced primary tumor growth, indicating the induction of a memory immune response. In conclusion, xenogeneic immunization with TH-derived DNA vaccines is effective against NB, and may open a new venue for a novel and effective immunotherapeutic strategy against this challenging childhood tumor.

Eradication of CD19+ leukemia by targeted calicheamicin θ.

Children with relapsed and refractory acute lymphoblastic leukemia (ALL) still face a critical prognosis. We tested the hypothesis that targeted calicheamicin theta (θ) using an anti-CD19-immunoconjugate may provide an effective treatment strategy for CD19(+) ALL. Calicheamicin θ is a rationally designed prodrug of the natural enediyene calicheamicin γ, obtained by total synthesis. It offers the advantage of increased in vivo stability and 1000-fold higher antitumor potency over calicheamicin γ. First, we demonstrate efficacy of calicheamicin θ against primary pre-B leukemic cells and multidrug-resistant leukemia cell lines (IC(50) = 10(-9) to 10(-12) M). Second, conjugation of calicheamicin θ to an internalizing murine anti-CD19 monoclonal antibody was demonstrated to affect neither calicheamicin θ mediated cytotoxicity nor binding of the antibody to the target molecule. Third, anti-CD19-calicheamicin θ immunoconjugate revealed a maximum tolerated dose of 10 µg/kg and CD19-specific and long-lasting eradication of established leukemia was demonstrated in a xenograft model. Finally, we show that the antileukemic effect of anti-CD19-calicheamicin θ is mediated by induction of apoptosis proceeding through the caspase-mediated mitochondrial pathway. On the basis of these results, we conclude that anti-CD19-calicheamicin θ immunoconjugates may offer a novel and effective approach for the treatment of relapsed CD19(+) ALL.

Survivin minigene DNA vaccination is effective against neuroblastoma.

The inhibitor of apoptosis protein survivin is highly expressed in neuroblastoma (NB) and survivin-specific T cells were identified in Stage 4 patients. Therefore, we generated a novel survivin minigene DNA vaccine (pUS-high) encoding exclusively for survivin-derived peptides with superior MHC class I (H2-K(k)) binding affinities and tested its efficacy to suppress tumor growth and metastases in a syngeneic NB mouse model. Vaccination was performed by oral gavage of attenuated Salmonella typhimurium SL7207 carrying pUS-high. Mice receiving the pUS-high in the prophylactic setting presented a 48-52% reduction in s.c. tumor volume, weight and liver metastasis level in contrast to empty vector controls. This response was as effective as a survivin full-length vaccine and was associated with an increased target cell lysis, increased presence of CD8(+) T-cells at the primary tumor site and enhanced production of proinflammatory cytokines by systemic CD8(+) T cells. Furthermore, depletion of CD8(+) but not CD4(+) T-cells completely abrogated the pUS-high mediated primary tumor growth suppression, demonstrating a CD8(+) T-cell mediated effect. Therapeutic vaccination with pUS-high led to complete NB eradication in over 50% of immunized mice and surviving mice showed an over 80% reduction in primary tumor growth upon rechallenge in contrast to controls. In summary, survivin-based DNA vaccination is effective against NB and the rational minigene design provides a promising approach to circumvent potentially hazardous effects of using full length antiapoptotic genes as DNA vaccines.

A rationally designed tyrosine hydroxylase DNA vaccine induces specific antineuroblastoma immunity.

Therapeutic vaccination against tumor antigens without induction of autoimmunity remains a major challenge in cancer immunotherapy. Here, we show for the first time effective therapeutic vaccination followed by suppression of established spontaneous neuroblastoma metastases using a tyrosine hydroxylase (TH) DNA minigene vaccine. We identified three novel mouse TH (mTH3) derived peptides with high predicted binding affinity to MHC class I antigen H2-K(k) according to the prediction program SYFPEITHI and computer modeling of epitopes into the MHC class I antigen binding groove. Subsequently, a DNA minigene vaccine was generated based on the expression vector pCMV-F3Ub encoding mutated ubiquitin (Gly(76) to Ala(76)) and mTH3. Prophylactic and therapeutic efficacies of this vaccine were established following oral delivery with attenuated Salmonella typhimurium SL7207. Only mice immunized with mTH3 were free of spontaneous liver metastases. This effect was clearly dependent on ubiquitin and high affinity of the mTH epitopes to MHC class I antigens. Specifically, we showed a crucial role for minigene expression as a stable ubiquitin-Ala(76) fusion peptide for vaccine efficacy. The immune response following the mTH3 DNA minigene vaccination was mediated by CD8(+) T cells as indicated by infiltration of primary tumors and TH-specific cytolytic activity in vitro. Importantly, no cell infiltration was detectable in TH-expressing adrenal medulla, indicating the absence of autoimmunity. In summary, we show effective therapeutic vaccination against neuroblastoma with a novel rationally designed TH minigene vaccine without induction of autoimmunity providing an important baseline for future clinical application of this strategy.

Primary ciliary dyskinesia associated with normal axoneme ultrastructure is caused by DNAH11 mutations.

Primary ciliary dyskinesia (PCD) is an inherited disorder characterized by perturbed or absent beating of motile cilia, which is referred to as Kartagener syndrome (KS) when associated with situs inversus. We present a German family in which five individuals have PCD and one has KS. PCD was confirmed by analysis of native and cultured respiratory ciliated epithelia with high-speed video microscopy. Respiratory ciliated cells from the affected individuals showed an abnormal nonflexible beating pattern with a reduced cilium bending capacity and a hyperkinetic beat. Interestingly, the axonemal ultrastructure of these respiratory cilia was normal and outer dynein arms were intact, as shown by electron microscopy and immunohistochemistry. Microsatellite analysis indicated genetic linkage to the dynein heavy chain DNAH11 on chromosome 7p21. All affected individuals carried the compound heterozygous DNAH11 mutations c.12384C>G and c.13552_13608del. Both mutations are located in the C-terminal domain and predict a truncated DNAH11 protein (p.Y4128X, p.A4518_A4523delinsQ). The mutations described here were not present in a cohort of 96 PCD patients. In conclusion, our findings support the view that DNAH11 mutations indeed cause PCD and KS, and that the reported DNAH11 nonsense mutations are associated with a normal axonemal ultrastructure and are compatible with normal male fertility.

Nutrient mixture including vitamin C, L-lysine, L-proline, and epigallocatechin is ineffective against tumor growth and metastasis in a syngeneic neuroblastoma model.

BACKGROUND: The replacement of established evidence-based cancer therapy protocols (mainstream therapy) by unevaluated complementary and alternative medicine (CAM) is a challenge in pediatric oncology. We tested the hypothesis that oral application of L-lysine and ascorbic acid (Lysin C Drink) in combination with epigallocatechin-gallate (EGCG) and amino-acids (Epican forte) is effective in a preclinical model of neuroblastoma. METHODS: Primary tumors and spontaneous metastases were induced in A/J mice by injection of NXS2 neuroblastoma cells. Mice were treated by daily oral gavage with L-lysine and ascorbic acid (Lysin C Drink) (equivalent to 150 mg ascorbic acid/day/mouse) (treatment A) or with EGCG plus ascorbic- and amino-acids (Epican forte) (9.2 mg/mouse) (treatment B). Treatment A was started in the prophylactic setting (7 days before tumor cell injection) as well as in the therapeutic setting (1 day after tumor cell inoculation). Finally, treatment B was evaluated alone and in combination with treatment A in the therapeutic setting. The effect on primary tumor growth and the development of spontaneous liver metastases was evaluated. RESULTS: L-lysine and ascorbic acid (Lysin C Drink) and EGCG plus ascorbic- and amino-acids (Epican forte) are ineffective in reduction of primary tumor growth and prevention of spontaneous liver metastases in this model. CONCLUSIONS: Neither a formal clinical development nor the use of these substances can be recommended for neuroblastoma.

Atypical tetanus in a completely immunized 14-year-old boy.

We report the uncommon clinical course of tetanus in a completely immunized 14-year-old boy. His initial symptoms, which included a flaccid paralysis, supported a diagnosis of botulism. Preliminary mouse-test results with combined botulinum antitoxins A, B, and E, obtained from tetanus-immunized horses, backed this diagnosis. The change in his clinical course from paralysis to rigor and the negative, more specific, botulinum mouse test with isolated botulinum antitoxins A, B, and E, obtained from nonvaccinated rabbits, disproved the diagnosis of botulism. Tetanus was suspected despite complete vaccination. The final results of a positive mouse test performed with isolated tetanus antitoxin confirmed the diagnosis. Adequate treatment was begun, and the boy recovered completely.

Fractalkine (CX3CL1)- and interleukin-2-enriched neuroblastoma microenvironment induces eradication of metastases mediated by T cells and natural killer cells.

Fractalkine (FKN) is a unique CX3C chemokine (CX3CL1) known to induce both adhesion and migration of leukocytes mediated by a membrane-bound and a soluble form, respectively. Its function is mediated through CX3C receptor (CX3CR), which is expressed by T(H)1 immune cells including T cells and natural killer (NK) cells. FKN was shown to be expressed in >90% of 68 neuroblastoma samples as determined by cDNA microarray analysis. Here, we characterized the effect of FKN in the neuroblastoma microenvironment using a syngeneic model genetically engineered to secrete FKN. We show FKN-mediated migration, adhesion, and IFN-gamma secretion of immune effector cells, but limited antineuroblastoma activity, in vitro and in vivo. Therefore, we tested the hypothesis that a combined increase of FKN and interleukin-2 (IL-2) in the neuroblastoma microenvironment induces an effective antitumor immune response. For this purpose, IL-2 was targeted to ganglioside GD2, which is highly expressed on neuroblastoma tissue, using an anti-GD2 antibody IL-2 immunocytokine (ch14.18-IL-2). Only mice bearing FKN- and IL-2-enriched neuroblastoma tumors exhibited a reduction in primary tumor growth and a complete eradication of experimental liver metastases. The depletion of T cells and NK cells in vivo abrogated the effect, and these effector cells showed the highest cytolytic activity in vitro. Finally, only the FKN- and IL-2-enriched neuroblastoma microenvironment resulted in T-cell activation and the release of proinflammatory cytokines. In summary, we showed for the first time the immunologic mechanisms by which targeted IL-2 treatment of neuroblastoma with an FKN-rich microenvironment induces an effective antitumor response.

Pulmonary hypertension in a case of Hb-Mainz hemolytic anemia.

The development of pulmonary arterial hypertension (PAH) is the leading cause of mortality in patients with thalassemia and sickle cell anemia and was reported to occur in hemolytic anemias such as hereditary stomatocytosis, and paroxysmal nocturnal hemoglobinuria. Here, we report for the first time on the development of PAH in a patient with Hb-Mainz hemolytic anemia. Hb-Mainz is an unstable hemoglobin variant resulting from mutations at codon 98 of the beta chain gene (Val>Glu) characterized by severe chronic hemolytic anemia. The development of PAH in this patient further supports the contention that there is a clinical syndrome of hemolysis-associated development of PAH.

Characterization of GD2 peptide mimotope DNA vaccines effective against spontaneous neuroblastoma metastases.

Disialoganglioside GD2 is an established target for immunotherapy in neuroblastoma. We tested the hypothesis that active immunization against the glycolipid GD2 using DNA vaccines encoding for cyclic GD2-mimicking decapeptides (i.e., GD2 mimotopes) is effective against neuroblastoma. For this purpose, two GD2 peptide mimotopes (MA and MD) were selected based on docking experiments to anti-GD2 antibody ch14.18 (binding free energy: -41.23 kJ/mol for MA and -48.06 kJ/mol for MD) and Biacore analysis (K(d) = 12.3 x 10(-5) mol/L for MA and 5.3 x 10(-5) mol/L for MD), showing a higher affinity of MD over MA. These sequences were selected for DNA vaccine design based on pSecTag2-A (pSA) also including a T-cell helper epitope. GD2 mimicry was shown following transfection of CHO-1 cells with pSA-MA and pSA-MD DNA vaccines, with twice-higher signal intensity for cells expressing MD over MA. Finally, these DNA vaccines were tested for induction of tumor protective immunity in a syngeneic neuroblastoma model following oral DNA vaccine delivery with attenuated Salmonella typhimurium (SL 7207). Only mice receiving the DNA vaccines revealed a reduction of spontaneous liver metastases. The highest anti-GD2 humoral immune response and natural killer cell activation was observed in mice immunized with the pSA-MD, a finding consistent with superior calculated binding free energy, dissociation constant, and GD2 mimicry potential for GD2 mimotope MD over MA. In summary, we show that DNA immunization with pSA-MD may provide a useful strategy for active immunization against neuroblastoma.