Therapeutic tumor vaccines-a rising star to benefit cancer patients

Malignant tumors are still a worldwide threat to human health.Tumor treatment strategies are constantly evolving,and the advent of tumor immunotherapy has brought up hope to many types of tumors,especially for those that are refractory to conventional therapies including surgery,radiotherapy,and chemotherapy.Tumor vaccines can initiate or amplify an anti-tumor immune response in tumor patients through active immunization,and therefore occupy an important position in tumor immunotherapy.The main types of tumor vaccines include tumor cell vaccines,dendritic cell vaccines,polypeptide vaccines and nucleic acid vaccines.Due to factors such as poor antigen selection and suppressive tumor microenvironment,earliest tumor vaccines on clinical trials failed to achieve satisfactory clinical effects.However,with the development of second-generation genome sequencing technologies and bioinformatics tools,it is possible to predict neoantigens generated by tumor-specific mutations and therefore prepare personalized vaccines.This article summarizes the global efforts in developing tumor vaccines and highlights several representative tumor vaccines in each category.

Phase Ⅰ clinical study of personalized peptide vaccination combined with radiotherapy for advanced hepatocellular carcinoma

AIM To assess the efficacy and safety of a new treatment modality, cellular immune therapy based on personalized peptide vaccination(PPV-DC-CTL) combined with radiotherapy, for treating advanced hepatocellular carcinoma(HCC). METHODS A total of nine patients with advanced HCC were enrolled. Multidisciplinary consultation confirmed that all the patients definitely had no opportunity of surgery, because four patients had multiple liver metastases(the number of liver lesions > 3), one patient had liver metastases and portal vein tumor thrombosis, one patient had lung and bone metastases, two patients had liver and lung metastases and one patient had liver metastasis and peritoneal metastasis. Patients with metastasis were treated with precise radiotherapy combined with PPV-DC-CTL.RESULTS Following radiotherapy and one to three cycles of PPV-DC-CTL treatment, AFP levels were significantly decreased in six patients and imaging assessment of the lesions showed a partial response(PR) in three patients and stable disease in the other three patients. The response rate was 33% and disease control rate was 66%. This regimen was found to be safe and well tolerated. None of the patients developed liver or kidney side effects. Only one patient developed grade Ⅱ bone marrow suppression and the remaining patients had no significant hematological side effects.CONCLUSION Radiotherapy combined with PPV-DC-CTL provides a new therapeutic strategy for patients with advanced HCC, which is well tolerated, safe, feasible and effective.

HPV16 E5 Peptide Vaccine in Treatment of Cervical Cancer In Vitro and In Vivo

Human papillomavirus （HPV）-induced cervical cancer is the second most common cancer among women worldwide. Despite the encouraging development of the preventive vaccine for HPV, a vaccine for both prevention and therapy or pre-cancerous lesions remains in high priority. Thus far, most of the HPV therapeutic vaccines are focused on HPV E6 and E7 oncogene. However these vaccines could not completely eradicate the lesions. Recently, HPV E5, which is considered as an oncogene, is getting more and more attention. In this study, we predicted the epitopes of HPV16 E5 by bioinformat- ics as candidate peptide, then, evaluated the efficacy and chose an effective one to do the further test. To evaluate the effect of vaccine, rTC-1 （TC-1 cells infected by rAAV-HPV16E5） served as cell tumor model and rTC-1 loading mice as an ectopic tumor model. We prepared vaccine by muscle injection. The vaccine effects were determined by evaluating the function of tumor-specific T cells by cell prolif- eration assay and ELISPOT, calculating the tumor volume in mice and estimating the survival time of mice. Our in vitro and in vivo studies revealed that injection of E5 peptide＋CpG resulted in strong cell-mediated immunity （CMI） and protected mice from tumor growth, meanwhile, prolonged the sur- vival time after tumor cell loading. This study provides new insights into HPV16 E5 as a possible target on the therapeutic strategies about cervical cancer.

New modular platform based on multi-adjuvanted amphiphilic chitosan nanoparticles for efficient lipopeptide vaccine delivery against group A streptococcus

An effective vaccine against group A streptococcus(GAS)is highly desirable for definitive control of GAS infections.In the present study,two variants of amphiphilic chitosan nanoparticles-based GAS vaccines were developed.The vaccines were primarily composed of encapsulated KLH protein(a source of T helper cell epitopes)and lipidated M-protein derived B cell peptide epitope(lipoJ14)within the amphiphilic structure of nanoparticles.The only difference between themwas one of the nanoparticles vaccines received additional surface coating with poly(I:C).The formulated vaccines exhibited nanosized particles within the range of 220–240 nm.Cellular uptake study showed that nanoparticles vaccine without additional poly(I:C)coating has greater uptake by dendritic cells and macrophages compared to nanoparticles vaccine that was functionalized with poly(I:C).Both vaccines were found to be safe in mice and showed negligible cytotoxicity against HEK293 cells.Upon immunization in mice,both nanoparticle vaccines produced high antigen-specific antibodies titres that were regulated by a balanced Th1 and Th2 response compared to physical mixture.These antibodies elicited high opsonic activity against the tested GAS strains.Overall,our data demonstrated that amphiphilic chitosan nanoparticles platform induced a potent immune response even without additional inclusion of poly(I:C).

A Novel Contraceptive Vaccine: Design and Synthesis of the Chimeric Peptide Containing Multivalent Sperm-Specific Epitopes

ve To develop a novel multivalent chimeric peptide vaccine for bisexual fertility regulation

Nasal mucosal inhalation of amyloid-beta peptide 3–10 defective adenovirus attenuates cytotoxicity induced by beta-amyloid(1–42)

Three-month-old Alzheimer＇s disease model transgenic mice were immunized with Aβ1-42, Plp-Adenovirus [Ad]-X-CMV-（Aβ3-10）lo-CpG [AdCpG-（Aβ3-10）1] or AdCpG virus fluid via na- sal mucosal inhalation, respectively. ELISA analysis of serum showed Aβ42 antibody titers were significantly increased in mice immunized with Aβ1-42 and AdCpG-（Aβ3-10）10. Concanavalin A and AdCpG-（Aβ3-10）10 stimulation significantly increased the number of proliferating spleen cells cultured from AdCpG（Aβ3-10）Io and Aβ42 groups compared with the control group. In the AdCp- G（Aβ3-10）10 group, levels of interleukin （IL）-4 and IL-10 were increased, while those of IL-2 and interferon-y were decreased. In the A[342 group, levels of IL-4, IL-10, IL-2 and interferon-y were all increased. Experimental findings indicate that AdCpG-（Aβ3-10）10 vaccine can produce strong T helper 2 （Th2） humoral immune responses in addition to the production of Aβ42 antibody. The cellular immunologic response was weak and avoided Aβ1-42-mediated cytotoxicity.

Prediction, Synthesis and Antigenicity of the Antigenic Peptides of 26kDa Glutathione S-Transferasc of Schistosoma Japonicum (Sj26)

Six antigenic peptides of 26 kDa glutathione S-transferase of Schistosoma japonicum(Sj26) have been predicted according to their hydrophilicity, flexibility. accessibility. chargedistribution and β -turn in the secondary structure by the determination of its primary structure andsynthesized by solid phase method. All of them showed antigenicity with anti-schistosomajaponicum immunoglobulin polyclonal antibody, anti-Sj-lgG PcAb by Dot-ELISA. Three of themshowed good antigenicity. They would serve as candidates of synthetic anti-schistosomal vaccine.

Mapping the Antigenic Peptides of Sm26/2 in Glutathione S-Transferases of Schistosoma Mansoni

Six antigenic peptides of Sm26/2 glutathione S-transferase of schistosoma mansoni have been predicted according to their hydrophilicity, flexibility, accessibility, charge distribution and beta-turn in the secondary structure by the determination of its primary structure, and synthesized by solid phase method. Two of them showed good antigenicity by Dot-ELISA. They would be candidate peptides of synthetic anti-schistosomal vaccine.

Evaluation of NR2B peptide as subunit vaccines against experimental neuropathic pain

Background NR2B containing N-methyI-D-aspartate （NMDA） receptor plays an important role in the facilitation and maintenance of neuropathic pain. The discrete distribution of NR2B subunit in the central nervous system （CNS） may support reduced side effects of agents that act selectively at this site. Therefore, we investigated the hypothesis that a humoral autoimmune response targeting the NR2B subunit of NMDA receptor relieves pain like behaviours produced by peripheral injury. Methods Rats were immunized subcutaneously with NR2B-Keyhole Limpet Hemocyanin （NR2B-KLH） three times at two-week intervals. NR2B specific IgG titres in sera and cerebrospinal fluid were determined by indirect ELISA. Seven days after the third immunization, 2 of the 3 terminal branches of the sciatic nerve （tibial and common peroneal nerves） were tightly ligated. Behavioural testing was carried out on every other day after surgery, until 7 days after surgery. The lumbar spinal cord （L4-6） was removed on day 7 after ligation. The expression of NR2B protein in the lumbar spinal cord was determined using Western blotting. Results After the second vaccination, NR2B specific IgG in sera was detected to be 〉0.5 μg/ml in six of nine rats. After the third vaccination, all the immunized rats had 〉2.2 μg/ml. Titres of NR2B specific IgG in sera peaked 42 days post initial immunization and persisted for over 70 days. No NR2B specific IgG was detected in sera from PBS or KLH group. The behavioural thresholds in NR2B group were significantly higher than those in PBS and KLH groups on day 7 after ligation. NR2B specific IgG in CSF in NR2B group could not be detected on day 1 before spinal dissection; but could be detected on day 7 after surgery. The expression of NR2B protein in group NR2B was significantly lower than in PBS and KLH groups on day 7 after surgery. Conclusion The NR2B peptide could be used as a vaccine against neuropathic pain, which could be associated with reduction of NR2B protein in the lumbar spinal cord.

Three Candidate Peptide-Vaccines in Combination To Induce High Levels of Multiantibodies Against HIV-1

N and C domains of human immunodeficiency virus type 1 (HIV 1) gp41 are demonstrated to play an important role in HIV entry and prevention. In addition, the V3 loop on gp120 was identified as the principal neutralizing determinant (PND). Based on the fact that a combination of several monoclonal antibodies to different neutralizing epitopes showed great protection against intravenous challenge and vaginal transmission of pathogenic HIV 1/Simian immunodeficiency virus (SIV) chimeric virus on macaques, three candidate peptide vaccines were prepared and used in combination to induce high levels of multiantibodies against HIV 1. The three peptides contained important functional regions on HIV 1 gp160. The N domain peptide (P1: aa550 579) and C domain peptide (P2: aa633 662) of gp41 and V3 peptide (P3: aa301 328) of gp120 were conjugated with bovine serum albumin (BSA) using the glutaraldehyde method. After the vaccination course, each of the three candidate peptide vaccines induced strong antibody response in rabbits. The three vaccines used in combination induced high levels of multiantibodies against the peptides of the N and C domains and the V3 loop, with the titer of antibodies up to 1∶64001∶25600 in rabbit sera in comparison with the titer of 1∶8001∶3200 induced by rgp41 or rgp160. Our results indicate that immunogenicities of the N and C domains and the V3 loop in these three candidate peptide vaccines were clearly stronger than those induced by rgp41 or rgp160, and these peptide vaccines used in combination synchronously induced high levels of multiantibodies against HIV 1, suggesting that used in combination they may provide a new vaccine strategy to induce strong multi antiviral activity.

Peptide vaccine against glioblastoma:from bench to bedside

Glioblastoma accounts for almost half of all intracranial primary malignancies and has the worst prognosis.Because of its high malignancy and frequent recurrence after standard therapy,it is of great signifcance to explore new therapy options.Recently immune therapy has taken remarkable progress in a variety of tumors,among which peptide vaccines utilize peptide sequences based on tumor-specifc antigens or tumor-associated antigen targets to activate selfimmune response against tumor cells.However,due to the particularity of intracranial central nervous system tumors,the application of peptide vaccines in glioblastoma still faces challenges.This article mainly reviews the immune basis and important clinical trial results of peptide vaccine therapy for GBM,analyzes the reasons for its poor efcacy,and proposes the development direction of peptide vaccines for the unique challenges of immunotherapy in GBM.An in-depth understanding and elaboration of the application and related issues of peptide vaccine in the treatment of GBM will help to formulate relevant treatment strategies in future clinical and basic research.

Role of T-cell receptor V beta 8.3 peptide vaccine in the prevention of experimental autoimmune uveoretinitis

Background T-cell receptor （TCR） plays an important role in the development of autoimmune diseases. Recently, it was reported that immunization of animals with TCR peptide derived from the pathogenic cells could prevent autoimmune diseases. The aim of this study was to investigate whether vaccination with a synthetic peptide from the hypervariable region of TCR Vβ 8.3, an experimental autoimmune uveoretinitis （EAU）-associated gene, was able to prevent the disease. Methods EAU was induced in Lewis rats by immunization with IRBP R16 peptide emulsified in complete Freund＇s adjuvant （CFA）. The clinical and histological appearances were scored. Delayed type hypersensitivity （DTH） and lymphocyte proliferation were detected. Cytokine levels of aqueous humour, supernatants of cells from spleen and draining lymph nodes were measured by enzyme linked immunosorbent assay （ELISA）. Gene expression of TCR Vβ8.3 on CD4^＋ T cells was examined by real time quantitative polymerase chain reaction （PCR）. Results After vaccination, the intraocular inflammation was significantly mitigated, antigen specific DTH and lymphocyte proliferation responses were suppressed, interleukin （IL）-2 in aqueous humour, interferon （IFN）-γ and IL-2 produced by the spleen and draining lymph node cells were significantly decreased, whereas the production of IL-4 and IL-10 were increased. The response of draining lymph node cells to TCR Vβ 8.3 peptide was enhanced after vaccination. Inoculation with CFA alone did not affect the severity of EAU and the above parameters. The suppression of EAU was much stronger in the group of four fold inoculations than the group of two fold inoculations. The expression of TCR Vβ 8.3 gene was significantly reduced in the group of fourfold inoculations. Conclusion Vaccination with the synthetic TCR Vβ 8.3 peptide could remarkably inhibit the development of EAU.

Specific humoral immune responses in rhesus monkeys vaccinated with the Alzheimer’s disease-associated β-amyloid 1-15 peptide vaccine

Background Alzheimer’s disease(AD) is a neurodegenerative disorder characterized by overproduction of β-amyloid (Aβ), with the subsequent pathologic deposition of Aβ which is important for memory and cognition. Recent studies showed murine models of AD and AD patients inoculated with Aβ 1-42 peptide vaccine had a halted or delayed pathological progression of AD. Unfortunately, the clinical phase Ⅱ a trial of Aβ 1-42 peptide vaccine (AN1792) was halted prematurely because of episodes of menigoencephalitis in 18 of the vaccinated patients. The vaccination of BALB/c or Tg2576 transgenic mouse with Aβ 1-15 peptide vaccine is safe and the immune effects are satisfactory. This study further characterizes the specific humoral immune responses in adult rhesus monkeys induced by Aβ 1-15 peptide vaccine.Methods Five male adult rhesus monkeys were injected intramuscularly with Aβ 1-15 peptide vaccine at baseline and at weeks 2, 6, 10, 14, 18 and 22. The titers and IgG isotypes of the antibody against Aβ 1-42 in serum was measured by Enzyme-linked Immunosorbent Assay (ELISA). The specificity of the antibody against Aβ 1-42 was determined by Western blot. The Aβ plaques in Tg2576 transgenic mouse brain were stained with the antiserum using immunohistochemistry method.Results At the eighth week after the vaccination, antibody against Aβ 1-42 began to develop significantly in serum. The titers of the antibody increased following vaccine boosted and reached 1∶3840 at the twenty-fourth week, then decreased after the termination of inoculation. The IgG1 was accounted for the highest level in the antiserum pool. The antibody against Aβ 1-42 showed high specificity. The Aβ plaques in Tg2576 transgenic mouse brain were labeled with the antiserum.Conclusion Aβ 1-15 vaccine can induce vigorously specific humoral immune responses in adult rhesus monkey.

Phenotypic and Functional Analysis of LCMV gp33-41-Specific CD8 T Cells Elicited by Multiple Peptide Immunization in Mice Revealed the Up-regulation of PD-1 Expression on Antigen-Specific CD8 T Cells

The phenotype and function of antigen-specific CD8 T cells are closely associated with the efficacy of a therapeutic vaccination. Here we showed that multiple immunizations with LCMV gp33-41 peptide （KAV） in Freund＇s adjuvant could induce KAV-specific CD8 T cells with low expression of CD127 and CD62L molecules. The inhibitory receptor PD-1 was also expressed on a substantial part of KAV-specific CD8 T cells, and its expression level on KAV-specific CD8 T cells in spleen and lymph nodes was much higher when compared to those in peripheral blood. Furthermore, KAV-specific CD8 T cells could specifically kill KAV-pulsed target cells in vivo but the efficiency was low. These data suggest that prime-boost vaccination schedule with peptide in Freund＇s adjuvant can elicit antigen-specific CD8 T cells of effector-like phenotype with partial functional exhaustion, which may only provide short-term protection against the pathogen. Cellular ＆ Molecular Immunology.

Candidate Multi-Peptide-Vaccine Against Classical Swine Fever Virus Induces Strong Antibody Response with Predefined Specificity

Previous investigations demonstrated that the envelope glycoprotein E2 (gp55) of classical swine fever virus (CSFV) is the most immunogenic protein. Interestingly, recombinant protein E2 that contains only one structural antigenic unit (unit B/C or A) could protect pigs from a lethal challenge of CSFV. Based on these findings, we designed and prepared five overlapping synthetic peptides that covered the sequence unit B/C (aa 693777) of Shimen E2 and conjugated individual peptides with bovine serum albumin (BSA). After the vaccination, the specificity of the rabbit sera was analyzed in the enzyme linked immunosorbent assay (ELISA) and the fast protein liquid chromatography (FPLC). The results show that each of the five candidate peptide vaccines can successfully induce a high titer of specific antibodies in New Zealand White Rabbits (n=3). Subsequently, the five candidate peptide vaccines were applied in combination for immunization of pigs (n=10) and induced specific and strong humoral responses against all of the five designed peptides in pigs. Our studies indicate that the candidate multi peptide vaccine would prove an excellent marker vaccine against CSFV and provide a model for developing effective synthetic peptide vaccines to stop viral epidemics in humans and animals.