Advances in cancer vaccines for immunotherapy of prostate cancer / 中南大学学报(医学版)

Prostate cancer is currently one of the most common malignancies that endanger the lives and health of elderly men. In recent years, immunotherapy, which exploits the activation of anti-cancer host immune cells to accomplish tumor-killing effects, has emerged as a new study avenue in the treatment of prostate cancer. As an important component of immunotherapy, cancer vaccines have a unique position in the precision treatment of malignant tumors. Monocyte cell vaccines, dendritic cell vaccines, viral vaccines, peptide vaccines, and DNA/mRNA vaccines are the most often used prostate cancer vaccines. Among them, Sipuleucel-T, as a monocyte cell-based cancer vaccine, is the only FDA-approved therapeutic vaccine for prostate cancer, and has a unique position and role in advancing the development of immunotherapy for prostate cancer. However, due to its own limitations, Sipuleucel-T has not been widely adopted. Meanwhile, owing to the complexity of immunotherapy and the specificity of prostate cancer, the remaining prostate cancer vaccines have not shown good clinical benefit in large randomized phase II and phase III trials, and further in-depth studies are still needed.

Research progress on proactive healthy lifestyle and disease immunoprevention / 中华预防医学杂志

The paradox of increasing health needs and limited health resources prompted a change in the traditional concept of disease prevention and control, and the concept of proactive health has emerged. Proactive health aimed to prevent and control disease and improve the body's immunity by using controlled methods and means to activate the body's self-healing ability and to identify foreign harmful substances as well as damage factors and tumor cells that the body itself may produce while giving full play to individual initiative. With the continuous development of science, people could maintain and improve their immune system from many aspects, which could be roughly divided into nonpharmaceutical interventions and pharmaceutical interventions. Nonpharmacological interventions included changing lifestyles and habits, adjusting the nutritional structure and intake of food, regulating mindsets and emotions, and improving the living and working environment, etc. This review systematically elaborated on the functions and molecular mechanisms of nutrition, exercise, sleep, and emotion in regulating immunity, to provide some scientific evidence and theoretical support for proactive health.

Clinical research progress and implications of therapeutic vaccines for cervical cancer and precancerous lesions: a qualitative systematic review / 中华肿瘤杂志

Objective: To systematically summarize and analyze the clinical research progress of therapeutic vaccines for cervical cancer or precancerous lesions. Methods: English databases (PubMed, Embase, Web of Science, Cochrane library, Proquest, and ClinicalTrails.gov) and Chinese databases (SinoMed, CNKI, WanFang, and VIP Database) were systematically searched to collect literature on therapeutic vaccines for cervical cancer or precancerous lesions from inception to February 18, 2021. After screening, we evaluated the risk of bias of included studies, and combed the basic information of the literature, research designs, information of vaccines, study patients, outcome indicators and so on, qualitatively summarized the clinical research progress. Results: A total of 71 studies were included in this systematic review, including 14 random controlled trials, 15 quasi-random controlled trials, 4 cohort studies, 1 case-control study, 34 case series studies and 3 case reports. The study patients included women aged 15~79 with cervical cancer or precancerous lesions in 18 countries from 1989 to 2021. On the one hand, there were 40 studies on therapeutic vaccines for cervical precancerous lesions (22 867 participants), involving 21 kinds of vaccines in 6 categories. Results showed 3 marketed vaccines (Cervarix, Gardasil, Gardasil 9) as adjuvant immunotherapies were significant effective in preventing the recurrence of precancerous lesions compared with the conization only. In addition, MVA E2 vaccine had been in phase Ⅲ clinical trials as a specific therapeutic vaccine, with relative literature showing it could eliminate most high-grade precancerous lesions. Therapeutic vaccines for precancerous lesions all showed good safety. On the other hand, there were 31 studies on therapeutic vaccines for cervical cancer (781 participants), involving 19 kinds of vaccines in 7categories, with none had been marketed. 25 studies were with no control group, showing the vaccines could effectively eliminate solid tumors, prevent recurrence, and prolong the median survival time. However, the vaccines effectiveness couldn't be statistically calculated due to the lack of a control group. As for the safety of therapeutic vaccines for cervical cancer, 9 studies showed that patients experienced serious adverse events after treatments, where 7 studies reported that serious adverse events occurred in patients couldn't be ruled out as the results of therapeutic vaccines. Conclusions: The literature review shows that the literature evidence for the therapeutic vaccines for cervical precancerous lesions is relatively mature compared with the therapeutic vaccines for cervical cancer. The four kinds of vaccines on the market are all therapeutic vaccines for precancerous lesions, but they are generally used as vaginal infection treatments or adjuvant immunotherapies for cervical precancerous lesions, not used for the specific treatments of cervical precancerous lesions. Other specific therapeutic vaccines are in the early stage of clinical trials, mainly phase Ⅰ/Ⅱ clinical trials with small sample size. The effectiveness and safety data are limited, and further research is still needed.

Evaluación de la calidad de vida de pacientes con cáncer de pulmón de células no pequeñas tratados con la vacuna CIMAvaxEGF® / Evaluation of quality of life in patients with non-small cell lung cancer treated with CIMAvaxEGF® vaccine

Este reporte corresponde al análisis de la calidad de vida de los pacientes que se incluyeron en el ensayo clínico fase III de evaluación de la vacuna CIMAvaxEGF® en cáncer de pulmón de células no pequeñas. La calidad de vida se evaluó empleando los cuestionarios EORTC QLQ-C30 y QLQ-C13, al inicio y cada 3 meses hasta el fallecimiento del paciente a criterio del investigador. Para comparar las medianas entre los dos grupos se utilizó la prueba no paramétrica de Mann-Whitney. Las comparaciones entre el nivel basal y los diferentes tiempos de seguimiento se realizaron a través de la prueba no paramétrica de Wilcoxon. El cuestionario QLQ-C30 evidenció un beneficio en cuanto a calidad de vida para el grupo vacunado con la vacuna CIMAvaxEGF® en las escalas funcionales (global, rol y social), en las escalas de síntomas de la enfermedad y del tratamiento (dolor) se observó que mejora la calidad de los mismos a favor de los pacientes tratados con la vacuna CIMAvaxEGF®. El cuestionario QLQ-C13, también evidenció ventajas para el grupo vacunado desde el punto de vista de beneficio clínico en los síntomas (disnea, disfagia, alopecia y dolor en el pecho). Se señala como significativo que disminuye la hemoptisis y la tos en el grupo vacunado, observándose un empeoramiento en el grupo control(AU)

This report corresponds to quality of life analysis of patient with non-small cell lung cancer included in the phase III clinical trials Evaluation of CIMAvaxEGF® vaccine in lung cancer. The quality of life was evaluate using the EORTC questionnaires QLQ-C30 y QLQ-C13, at the beginning and every 3 months. To compare the median between two groups the Mann-Whitney non-parametric test was used. To compare the baseline and different follows times the Wilcoxon non-parametric test was used. The QLQ-C30 questionnaire showed a benefit in terms of the quality of life for the CIMAvaxEGF® vaccine group on the functional scores (global, role and social) and symptoms of the disease (pain). The QLQ-LC13 questionnaire showed a benefit in terms of the quality of life for the CIMAvaxEGF® vaccine group on the symptoms scores (dyspnea, dysphagia, alopecia and chest pain). It is noted as significant that the hemoptysis decreases in the group vaccinated as well as the dysphagia, the cough and the dyspnea observing a worsening in the control group(AU)

Emerging immunological strategies: recent advances and future directions / 医学前沿

Immunotherapy plays a compelling role in cancer treatment and has already made remarkable progress. However, many patients receiving immune checkpoint inhibitors fail to achieve clinical benefits, and the response rates vary among tumor types. New approaches that promote anti-tumor immunity have recently been developed, such as small molecules, bispecific antibodies, chimeric antigen receptor T cell products, and cancer vaccines. Small molecule drugs include agonists and inhibitors that can reach the intracellular or extracellular targets of immune cells participating in innate or adaptive immune pathways. Bispecific antibodies, which bind two different antigens or one antigen with two different epitopes, are of great interest. Chimeric antigen receptor T cell products and cancer vaccines have also been investigated. This review explores the recent progress and challenges of different forms of immunotherapy agents and provides an insight into future immunotherapeutic strategies.

Clinical Trial Progress and Application of Immune Checkpoint Inhibitors in the Treatment of Small Cell Lung Cancer / 中国肺癌杂志

Small cell lung cancer (SCLC) is a neuroendocrine tumor with fast progression, high malignancy, easy recurrence, and extremely poor prognosis. In the past 30 years, the clinical treatment strategy of SCLC has been mainly chemotherapy and radiotherapy, but the curative effect is not significant; the current immunotherapy of SCLC has gradually entered the clinic and has made certain progress. Tumor immunotherapy includes immune checkpoint inhibitors, tumor vaccines, cytokines, chimeric antigen receptor T-cell immunotherapy (CAR-T) therapy, etc. Currently, immune checkpoint inhibitors are the most widely used. This article summarizes the principles of immune checkpoint inhibitors and related drugs, summarizes their domestic and foreign clinical trials progress in SCLC treatment, reviews the biomarkers used in the therapy, and discusses its future development direction.
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LMP2-DC Vaccine Elicits Specific EBV-LMP2 Response to Effectively Improve Immunotherapy in Patients with Nasopharyngeal Cancer / 生物医学与环境科学（英文）

Objective@#To evaluate the safety and effectiveness of a vaccine based on latent membrane protein 2 (LMP2) modified dendritic cells (DCs) that boosts specific responses of cytotoxic T lymphocytes (CTLs) to LMP2 before and after intradermal injection in patients with nasopharyngeal carcinoma (NPC).@*Methods@#DCs were derived from peripheral blood monocytes of patients with NPC. We prepared LMP2-DCs infected by recombinant adenovirus vector expressing LMP2 (rAd-LMP2). NPC patients were immunized with 2 × 10 @*Results@#We demonstrated that DCs derived from monocytes displayed typical DC morphologies; the expression of LMP2 in the LMP2-DCs vaccine was confirmed by immunocytochemical assay. Twenty-nine patients with NPC were enrolled in this clinical trial. The LMP2-DCs vaccine was well tolerated in all of the patients. Boosted responses to LMP2 peptide sub-pools were observed in 18 of the 29 patients with NPC. The follow-up data of 29 immunized patients from April, 2010 to April 2015 indicated a five-year survival rate of 94.4% in responders and 45.5% in non-responders.@*Conclusion@#In this pilot study, we demonstrated that the LMP2-DCs vaccine is safe and effective in patients with NPC. Specific CTLs responses to LMP2 play a certain role in controlling and preventing the recurrence and metastasis of NPC, which warrants further clinical testing.

Uso de la vacuna CIMAvax-EGF® como práctica médica habitual / Use of the vaccine CIMAvax-EGF® as habitual medical practice

Se realizó un estudio descriptivo y longitudinal de 58 pacientes con cáncer de pulmón de células no pequeñas, atendidos en la consulta de Sombras Pulmonares correspondiente al Servicio de Neumología del Hospital General Docente Dr Juan Bruno Zayas Alfonso de Santiago de Cuba, desde enero del 2013 hasta igual mes del 2018, quienes eran tratados con CIMAvax-EGF® como práctica médica habitual, con vistas a determinar las características clinicoepidemiológicas de estos. En la serie primaron el sexo masculino y las edades de 60 a 79 años; asimismo, resultaron más frecuentes la etapa IV de la enfermedad y el adenocarcinoma como variedad histológica. Con el uso de la vacuna la mayoría de los pacientes presentaron una supervivencia de 12,9 meses y una respuesta terapéutica de enfermedad no progresora

A descriptive and longitudinal study of 58 patients with lung cancer of non small cells, assisted in the service of Lung Shades corresponding to the Pneumology Service of Dr Juan Bruno Zayas Alfonso Teaching General Hospital was carried out in Santiago de Cuba, from January, 2013 to the same month of 2018, who were treated with CIMAvax-EGF® as habitual medical practice, with the aim of determining the clinical and epidemiological characteristics of them. The male sex and ages from 60 to 79 years prevailed in the series; also, stage IV of the disease and the adenocarcinoma as histological variety were more frequent. With the use of the vaccine most of the patients presented a survival of 12.9 months and a therapeutic response of the non progressive disease

Recent Advances in Immunotherapy for Acute Myeloid Leukemia --Review / 中国实验血液学杂志

Currently, the traditional chemotherapeutic drugs for acute myeloid leukemia (AML) showed significant curative efficacy, including the improving long-term prognosis and the life quality of the patients, however the traditional chemotherapeuatic drugs showed the some limitatious in the aspects of enhancing the complete remission rate of newly diagnosed AML patients, overcoming the relapse after remission,as well as the primary and secondary drug-resstance to chemotherapeutics. In order to improve the long-term prognisis of patients, the immuno therapy will the best choice for these patients. This review sammarizes the main current advance of immunotherapy of AML at home and abroad, such as antibody-drug conjugate(ADC), bispecific T cell engager (BiTE), chimeric type of antigen receptor T cell (CAR-T) therapy, checkpoint inhibitors; dendritic cell vaccination and peptide vaccines; natural killer cell (NK) therapy and so on.

Progress in immunotherapy for hepatocellular carcinoma / 生物工程学报

Hepatocellular carcinoma (HCC) is one of the malignant tumors with the highest morbidity and mortality in the world. The morbidity and mortality of HCC are increasing every year. Liver cancer is a serious threat to public health in China and the death rate of patients with liver cancer in China is the highest in the world. Beyond surgery, chemotherapy and radiotherapy, immunotherapy is an emerging treatment for cancer, which could control and kill tumor cells by relieving the inhibitory status of immune cells in the tumor microenvironment and activating the immune function of the body. Immune checkpoint inhibitors, adoptive immunotherapy and tumor vaccine are the major treatments of immunotherapy. Compared with traditional therapy methods, immunotherapy could enhance immune function, delay tumor progression, prolong the survival time of patients, and becomes a hotspot in the basic and clinical cancer research. This article reviews the research progress of immunotherapy for liver cancer.

Distinct features of dendritic cell-based immunotherapy as cancer vaccines

Dendritic cells (DCs) are the most professional antigen presenting cells that play important roles in connection between innate and adaptive immune responses. Numerous studies revealed that the functions of DCs are related with the capture and processing of antigen as well as the migration to lymphoid tissues for the presenting antigens to T cells. These unique features of DCs allow them to be considered as therapeutic vaccines that can induce immune responses and anti-tumor activity. Here, we discuss and understand the immunological basis of DCs and presume the possibilities of DC-based vaccines for the promising cancer therapy.

Current Approaches in Development of Immunotherapeutic Vaccines for Breast Cancer / 한국유방암학회지

Cancer is the leading cause of death worldwide. In developed as well as developing countries, breast cancer is the most common cancer found among women. Currently, treatment of breast cancer consists mainly of surgery, chemotherapy, hormone therapy, and radiotherapy. In recent years, because of increased understanding of the therapeutic potential of immunotherapy in cancer prevention, cancer vaccines have gained importance. Here, we review various immunotherapeutic breast cancer vaccines including peptide-based vaccines, whole tumor cell vaccines, gene-based vaccines, and dendritic cell vaccines. We also discuss novel nanotechnology-based approaches to improving breast cancer vaccine efficiency.

Immunological-based approaches for cancer therapy

The immunologic landscape of tumors has been continuously unveiled, providing a new look at the interactions between cancer cells and the immune system. Emerging tumor cells are constantly eliminated by the immune system, but some cells establish a long-term equilibrium phase leading to tumor immunoediting and, eventually, evasion. During this process, tumor cells tend to acquire more mutations. Bearing a high mutation burden leads to a greater number of neoantigens with the potential to initiate an immune response. Although many tumors evoke an immune response, tumor clearance by the immune system does not occur due to a suppressive tumor microenvironment. The mechanisms by which tumors achieve the ability to evade immunologic control vary. Understanding these differences is crucial for the improvement and application of new immune-based therapies. Much effort has been placed in developing in silico algorithms to predict tumor immunogenicity and to characterize the microenvironment via high-throughput sequencing and gene expression techniques. Each sequencing source, transcriptomics, and genomics yields a distinct level of data, helping to elucidate the tumor-based immune responses and guiding the fine-tuning of current and upcoming immune-based therapies. In this review, we explore some of the immunological concepts behind the new immunotherapies and the bioinformatic tools to study the immunological aspects of tumors, focusing on neoantigen determination and microenvironment deconvolution. We further discuss the immune-based therapies already in clinical use, those underway for future clinical application, the next steps in immunotherapy, and how the characterization of the tumor immune contexture can impact therapies aiming to promote or unleash immune-based tumor elimination.

Immunotherapy for Non-small-cell Lung Cancer: Current Status and Future Obstacles

Lung cancer is one of the leading causes of death worldwide. There are 2 major subtypes of lung cancer, non-small-cell lung cancer (NSCLC) and small-cell lung cancer (SCLC). Studies show that NSCLC is the more prevalent type of lung cancer that accounts for approximately 80%–85% of cases. Although, various treatment methods, such as chemotherapy, surgery, and radiation therapy have been used to treat lung cancer patients, there is an emergent need to develop more effective approaches to deal with advanced stages of tumors. Recently, immunotherapy has emerged as a new approach to combat with such tumors. The development and success of programmed cell death 1 (PD-1)/program death-ligand 1 (PD-L1) inhibitors and cytotoxic T-lymphocyte antigen 4 (CTLA-4) blockades in treating metastatic cancers opens a new pavement for the future research. The current mini review discusses the significance of immune checkpoint inhibitors in promoting the death of tumor cells. Additionally, this review also addresses the importance of tumor-specific antigens (neoantigens) in the development of cancer vaccines and major challenges associated with this therapy. Immunotherapy can be a promising approach to treat NSCLC because it stimulates host's own immune system to recognize cancer cells. Therefore, future research should focus on the development of new methodologies to identify novel checkpoint inhibitors and potential neoantigens.

Vacunas terapéuticas antitumorales basadas en células dendríticas / Dendritic cell-based therapeutic cancer vaccines

En los últimos años la inmunoterapia ha revolucionado el tratamiento de pacientes con cáncer avanzado. El mayor conocimiento de la biología tumoral y de la inmunología ha permitido desarrollar tratamientos racionales manipulando el sistema inmunitario con importante impacto clínico. Entre otras estrategias de inmunoterapia contra el cáncer se ha explorado el uso de vacunas terapéuticas basadas en células dendríticas (CD). Las CD son células de origen hematopoyético, que expresan constitutivamente moléculas presentadoras de antígeno, y son funcionalmente las inductoras más potentes de la activación y proliferación de linfocitos T a los que presentan antígenos. Los linfocitos T CD8+ proliferan y adquieren capacidad citotóxica cuando reconocen su antígeno específico presentado en la superficie de CD, aunque solo algunos tipos de CD pueden presentar antígenos internalizados desde el exterior celular a precursores de linfocitos T citotóxicos (a esta función se la llama presentación cruzada). Explotar la inducción de una respuesta inmunitaria adaptativa eficaz se considera una buena opción por su especificidad y prolongada duración de la respuesta. Las CD, gracias a su particular capacidad de presentación antigénica y de estimulación linfocitaria, son capaces de revertir la respuesta inmunitaria antitumoral deficiente que presentan algunos pacientes con cáncer. Las CD se pueden obtener a partir de distintas fuentes, empleando diversos protocolos para generar diferenciación y maduración, y se administran por diversas vías como son subcutánea, intravenosa o intranodal. La gran variedad de protocolos en los que se aplican las CD explica los resultados clínicos tan heterogéneos que se han comunicado hasta la fecha.

In recent years immunotherapy has revolutionized the treatment of patients with advanced cancer. The increased knowledge in the tumor immune-biology has allowed developing rational treatments by manipulation of the immune system with significant clinical impact. This rapid development has significantly changed the prognosis of many tumors without treatment options up to date. Other strategies have explored the use of therapeutic vaccines based on dendritic cells (DC) by inducing antitumor immunity. DC are cells of hematopoietic origin, constitutively expressing molecules capable to present antigens, that are functionally the most potent inducers of the activation and proliferation of antigen specific T lymphocytes. The CD8+ T cells proliferate and acquire cytotoxic capacity after recognizing their specific antigen presented on the surface of DC, although only some types of DC can present antigens internalized from outside the cell to precursors of cytotoxic T lymphocytes (this function is called cross-presentation) requiring translocation mechanisms of complex antigens. The induction of an effective adaptive immune response is considered a good option given its specificity, and prolonged duration of response. The DC, thanks to its particular ability of antigen presentation and lymphocyte stimulation, are able to reverse the poor antitumor immune response experienced by patients with cancer. The DC can be obtained from various sources, using different protocols to generate differentiation and maturation, and are administered by various routes such as subcutaneous, intravenous or intranodal. The wide variety of protocols resulted in heterogeneous clinical responses.

A modified method by differential adhesion for enrichment of bladder cancer stem cells

ABSTRACT Purpose: In a previous study the vaccine was effective against bladder cancer in a mouse model. However, a small portion of tumors regrew because the vaccine could not eliminate bladder cancer stem cells (CSCs). In this study, we showed a modified method for the isolation of bladder CSCs using a combination of differential adhesion method and serum-free culture medium (SFM) method. Materials and Methods: Trypsin-resistant cells and trypsin-sensitive cells were isolated from MB49, EJ and 5637 cells by a combination of differential adhesion method and SFM method. The CSCs characterizations of trypsin-resistant cells were verified by the flow cytometry, the western blotting, the quantitative polymerase chain reaction, the resistance to chemotherapy assay, the transwell assay, and the tumor xenograft formation assay. Results: Trypsin-resistant cells were isolated and identified in CSCs characters, with high expression of CSCs markers, higher resistance to chemotherapy, greater migration in vitro, and stronger tumorigenicity in vivo. Conclusion: Trypsin-resistant cells displayed specific CSCs properties. Our study showed trypsin-resistant cells were isolated successfully with a modified method using a combination of differential adhesion method and SFM method.

Supervivencia en pacientes con cáncer pulmonar de células no pequeñas vacunados con CIMAvax-EGF / Survival in patients with non-small cell lung cancer vaccinated with CIMAvax-EGF

Se realizó un estudio observacional, descriptivo y longitudinal en un primer momento, y analítico de cohorte en un segundo tiempo, de 95 pacientes con cáncer de pulmón de células no pequeñas en estadios avanzados, asistidos en el Hospital Provincial Docente Clinicoquirúrgico "Saturnino Lora Torres" y en 4 policlínicos de la ciudad de Santiago de Cuba, durante el período 2006-2013, a fin de estimar la supervivencia en ellos luego de la vacunación con CIMAvax-EGF e identificar los factores asociados a la mortalidad, para lo cual se empleó el método de Kaplan-Meier y el de regresión de Cox, respectivamente. La supervivencia global a los 2 años fue de 20,7 %, con una mediana de 13 meses, en tanto la supervivencia al año de aplicada la vacuna fue de 36,5 %. Por su parte, el estadio IIIB, la respuesta favorable a la primera línea de tratamiento, la combinación quimioterapia-radioterapia-vacuna y la inmunización en 4 o más ocasiones, posibilitaron una supervivencia significativamente mayor. La reacción desfavorable a la primera línea terapéutica constituyó un factor pronóstico del incremento del riesgo de muerte en la población de afectados.

An observational, descriptive and cross-sectional study in a first moment, and cohort analytic in a second time, of 95 patients with non-small cell lung cancer in advanced stages, assisted at "Saturnino Lora Torres" Teaching Clinical Surgical Provincial Hospital and in 4 polyclinics of Santiago de Cuba, was carried out during the period 2006-2013, in order to estimate the survival in them after the vaccination with CIMAvax-EGF and to identify the factors associated to the mortality, for which Kaplan-Meier method and Cox regression were used, respectively. The global survival in 2 years was 20.7%, with a median of 13 months, as long as the survival a year after applying the vaccine was 36.5%. On the other hand, in the stage IIIB, the favorable response to the first line treatment, the chemotherapy-radiotherapy-vaccine combination and the immunization in 4 or more occasions, facilitated a significantly higher survival. The unfavorable reaction to the first therapeutic line constituted a prediction factor of death risk increase in the population affected.

Construction and characterization of an attenuated recombinant Listeria monocytogenes vector vaccine delivering HPV16 E7 / 生物工程学报

Listeria monocytogenes (L. monocytogenes, LM) is an excellent tumor vaccine vector. In this study, recombinant LM vaccine candidate expressing human papillomavirus type 16 (HPV16) E7 protein was constructed and its charactericts were determined. Through homologous recombination, E7 gene was cloned in frame with the LM4 Phly promoter-signal sequence, and introduced into the chromosome of LM4. The recombinant strain named LM4△hly::E7 with the plasmid-free and antibiotic-resistant gene-free was constructed. LM4△hly::E7 could express and secrete E7-LLO fusion protein; its size is 66 kDa and has immunological activity. Furthermore, LM4△hly::E7 could multiply in RAW264.7 macrophages by confocal laser scanning microscope. Additionally, LM4△hly::E7 could induce specific antibodies against E7 in immunized mice in ELISA. Also, the 50% lethal dose (LD₅₀) of LM4△hly::E7 strain was 3.863×10⁹ CFU (Colony-Forming Units) in C57BL/6 mice with intraperitoneal immunization, which was more attenuated than wild type LM4. Mice immunized with LM4△hly::E7 did not show obvious pathological change. These data show that LM4△hly::E7 expressing E7-LLO fusion protein has good safety, which may provide the materials for research of antitumor effect and would be a promising vaccine candidate for cervical cancer.

Construction of a fusion plasmid containing the PSCA gene and cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) and its anti-tumor effect in an animal model of prostate cancer

Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is a negative regulator of T cell activation, which competes with CD28 for B7.1/B7.2 binding, and which has a greater affinity. Fusion of specific antigens to extracellular domain of CTLA4 represents a promising approach to increase the immunogenicity of DNA vaccines. In this study, we evaluated this interesting approach for CTLA4 enhancement on prostate stem cell antigen (PSCA)-specific immune responses and its anti-tumor effects in a prostate cancer mouse model. Consequently, we constructed a DNA vaccine containing the PSCA and the CTLA-4 gene. Vaccination with the CTLA4-fused DNA not only induced a much higher level of anti-PSCA antibody, but also increased PSCA-specific T cell response in mice. To evaluate the anti-tumor efficacy of the plasmids, murine models with PSCA-expressing tumors were generated. After injection of the tumor-bearing mouse model, the plasmid carrying the CTLA4 and PSCA fusion gene showed stronger inhibition of tumor growth than the plasmid expressing PSCA alone. These observations emphasize the potential of the CTLA4-fused DNA vaccine, which could represent a promising approach for tumor immunotherapy.