Vaccination against HPV-16 oncoproteins for vulvar intraepithelial neoplasia

Safety and immunogenicity of long HSV-2 peptides complexed with rhHsc70 in HSV-2 seropositive persons

HSV-2, the primary causative agent of genital herpes, establishes latency in sensory ganglia and reactivates causing recurrent lesions and viral shedding. Induction or expansion of CD4(+) and CD8(+) T cell responses are expected to be important for a successful therapeutic vaccine against HSV-2. A candidate vaccine consisting of 32 synthetic 35mer HSV-2 peptides non-covalently complexed with recombinant human Hsc70 protein (named HerpV, formerly AG-707) was tested for safety and immunogenicity in a Phase I study. These peptides are derived from 22 HSV-2 proteins representative of all phases of viral replication. Thirty-five HSV-2 infected participants were randomized and treated in one of four groups: HerpV+QS-21 (saponin adjuvant), HerpV, QS-21, or vehicle. The vaccine was well tolerated and safe. All seven participants with evaluable samples who were administered HerpV with QS-21 demonstrated a statistically significant CD4(+) T cell response to HSV-2 antigens, and the majority of such participants demonstrated a statistically significant CD8(+) T cell response as well. To our knowledge, this is the first candidate vaccine against HSV-2 to demonstrate a broad CD4(+) and CD8(+) T cell response in HSV-2(+) participants, and the first HSP-based vaccine to show immune responses against viral antigens in humans.

Identification of novel immunogenic human leukocyte antigen-A 2402-binding epitopes of human papillomavirus type 16 E7 for immunotherapy against human cervical cancer

BACKGROUND

A study was undertaken to identify new immunogenic human leukocyte antigen (HLA)-A 2402-restricted epitopes from human papillomavirus (HPV) type 16 E7 protein for immunotherapy against cervical cancer.

METHODS

Synthetic overlapping peptides were screened by measuring the frequency of CD8(+) cytotoxic T lymphocytes (CTLs) producing intracellular interferon-γ (IFN-γ) using flow cytometry and were validated in SiHa cells with a Cr release cytotoxicity assay. In vivo antitumor effects of peptide-sensitized peripheral blood mononuclear cells (PBMCs) and isolated CD8(+) CTLs were evaluated using BALB/c nude mice with SiHa cell xenotransplants.

RESULTS

Among 14 overlapping 15-amino acid peptides, E7(61-75) (CDSTLRLCVQSTHVD) and E7(67-81) (LCVQSTHVDIRTLED) induced significantly higher IFN-γ production (P < .05) and showed higher in vitro cytotoxicity against SiHa cells than did cells sensitized with the negative control. To determine the exact HLA-A 2402-restricted epitopes, a total of 25 overlapping 9- or 10-amino acid peptides spanning E7(61-75) and E7(67-81) were synthesized. E7(61-69) (CDSTLRLCV) and E7(67-76) (LCVQSTHVDI) induced significantly greater IFN-γ production as well as increased in vitro cytotoxicity against SiHa cells compared with those of other peptides and the negative control (P < .01), and the antitumor effects of these peptide-sensitized PBMCs were induced by CD8(+) CTLs. E7(61-69) -sensitized and E7(67-76) -sensitized PBMCs and isolated CD8(+) CTLs showed a much greater suppression of tumor growth in vivo compared with that of control groups treated with PBS (P < .01). The authors also confirmed the synergistic antitumor effect of cisplatin followed by E7(67-76) -sensitized PBMCs in vivo.

CONCLUSIONS

E7(61-69) and E7(67-76) were identified as novel HPV type 16 E7 epitopes for HLA-A 2402, which could be used for immunotherapy against cervical cancer.

Generating HPV specific T helper cells for the treatment of HPV induced malignancies using TCR gene transfer

Background

Infection with high risk Human Papilloma Virus (HPV) is associated with cancer of the cervix, vagina, penis, vulva, anus and some cases of head and neck carcinomas. The HPV derived oncoproteins E6 and E7 are constitutively expressed in tumor cells and therefore potential targets for T cell mediated adoptive immunotherapy. Effective immunotherapy is dependent on the presence of both CD4+ and CD8+ T cells. However, low precursor frequencies of HPV16 specific T cells in patients and healthy donors hampers routine isolation of these cells for adoptive transfer purposes. An alternative to generate HPV specific CD4+ and CD8+ T cells is TCR gene transfer.

Methods

HPV specific CD4+ T cells were generated using either a MHC class I or MHC class II restricted TCR (from clones A9 and 24.101 respectively) directed against HPV16 antigens. Functional analysis was performed by interferon-γ secretion, proliferation and cytokine production assays.

Results

Introduction of HPV16 specific TCRs into blood derived CD4+ recipient T cells resulted in recognition of the relevant HPV16 epitope as determined by IFN-γ secretion. Importantly, we also show recognition of the endogenously processed and HLA-DP1 presented HPV16E6 epitope by 24.101 TCR transgenic CD4+ T cells and recognition of the HLA-A2 presented HPV16E7 epitope by A9 TCR transgenic CD4+ T cells.

Conclusion

Our data indicate that TCR transfer is feasible as an alternative strategy to generate human HPV16 specific CD4+ T helper cells for the treatment of patients suffering from cervical cancer and other HPV16 induced malignancies.

New Approaches to Immunotherapy for HPV Associated Cancers

Cervical cancer is the second most common cancer of women worldwide and is the first cancer shown to be entirely induced by a virus, the human papillomavirus (HPV, major oncogenic genotypes HPV-16 and -18). Two recently developed prophylactic cervical cancer vaccines, using virus-like particles (VLP) technology, have the potential to prevent a large proportion of cervical cancer associated with HPV infection and to ensure long-term protection. However, prophylactic HPV vaccines do not have therapeutic effects against pre-existing HPV infections and do not prevent their progression to HPV-associated malignancy. In animal models, therapeutic vaccines for persisting HPV infection can eliminate transplantable tumors expressing HPV antigens, but are of limited efficacy in inducing rejection of skin grafts expressing the same antigens. In humans, clinical trials have reported successful immunotherapy of HPV lesions, providing hope and further interest. This review discusses possible new approaches to immunotherapy for HPV associated cancer, based on recent advances in our knowledge of the immunobiology of HPV infection, of epithelial immunology and of immunoregulation, with a brief overview on previous and current HPV vaccine clinical trials.

The present and future of peptide vaccines for cancer: single or multiple, long or short, alone or in combination?

Peptide vaccines incorporate one or more short or long amino acid sequences as tumor antigens, combined with a vaccine adjuvant. Thus, they fall broadly into the category of defined antigen vaccines, along with vaccines using protein, protein subunits, DNA, or RNA. They remain one of the most immunogenic approaches, based on measures of T-cell response in the blood or in draining lymph nodes. However, existing peptide vaccines have had limited success at inducing clinical tumor regressions, despite reliable induction of T-cell responses. Several new developments offer promise for improving peptide vaccines, including use of long peptides, optimization of adjuvants including toll-like receptor agonists, and combination with systemic therapies that may reduce tumor-associated immune dysfunction, such as blockade of PD-1/PD-L1 interactions. To apply these new approaches optimally, it will be critical to study their effects in the context of defined antigens, for which peptide vaccines are optimal.

A novel, broad spectrum therapeutic HPV vaccine targeting the E7 proteins of HPV16, 18, 31, 45 and 52 that elicits potent E7-specific CD8T cell immunity and regression of large, established, E7-expressing TC-1 tumors

Persistent infection by high risk genotypes of human papillomavirus (HPV) is the cause of cervical cancer, which remains one of the most common cancers among women worldwide. In addition, there is a growing appreciation that high risk HPVs are associated with a number of other cancers including anogenital cancers as well as a subset of head and neck cancers. Recently, prophylactic HPV vaccines targeting the two most prevalent high risk HPVs (HPV16 and HPV18) have been deployed in large-scale vaccination campaigns. However, the extent to which these prophylactic vaccines confer protection against other high risk HPV genotypes is largely unknown and prophylactic vaccines have been shown to be ineffective against pre-existing infection. Thus there continues to be an urgent need for effective therapeutic vaccines against HPV. The E7 protein of HPV16 has been widely studied as a target for therapeutic vaccines in HPV-associated cancer settings because HPV16 is the most prevalent of the high risk HPV genotypes. However, HPV16 accounts for only about 50% of cervical cancers and there are at least 15 other high risk HPVs that are known to be oncogenic. We have developed a novel, broad-spectrum, therapeutic vaccine (Pentarix) directed at the E7 proteins from five of the most prevalent high-risk genotypes of HPV worldwide (HPV16, 18, 31, 45 and 52) that together account for more than 80% of all HPV-associated cancers. Pentarix is a recombinant protein-based vaccine that elicits strong, multi-genotype specific CD8 T cell immunity when administered to mice in combination with adjuvants comprised of agonists of the TLR3 or TLR9 family of innate immune receptors. Furthermore, large, established E7-expressing TC-1 tumors undergo rapid and complete regression after therapeutic vaccination of mice with Pentarix. Together, these data suggest that Pentarix may be of clinical value for patients with E7-positive, HPV-associated precancerous lesions or malignant disease.

Parenteral is more efficient than mucosal immunization to induce regression of human papillomavirus-associated genital tumors

Cervical cancer is a public health concern as it represents the second cause of cancer death in women worldwide. High-risk human papillomaviruses (HPV) are the etiologic agents, and HPV E6 and/or E7 oncogene-specific therapeutic vaccines are under development to treat HPV-related lesions in women. Whether the use of mucosal routes of immunization may be preferable for inducing cell-mediated immune responses able to eradicate genital tumors is still debated because of the uniqueness of the female genital mucosa (GM) and the limited experimentation. Here, we compared the protective activity resulting from immunization of mice via intranasal (i.n.), intravaginal (IVAG) or subcutaneous (s.c.) routes with an adjuvanted HPV type 16 E7 polypeptide vaccine. Our data show that s.c. and i.n. immunizations elicited similar frequencies and avidity of TetE71CD81 and E7-specific Interferon-gamma-secreting cells in the GM, whereas slightly lower immune responses were induced by IVAG immunization. In a novel orthotopic murine model, both s.c. and i.n. immunizations allowed for complete long-term protection against genital E7-expressing tumor challenge. However, only s.c. immunization induced complete regression of already established genital tumors. This suggests that the higher E7-specific systemic response observed after s.c. immunization may contribute to the regression of growing genital tumors, whereas local immune responses may be sufficient to impede genital challenges. Thus, our data show that for an efficiently adjuvanted protein-based vaccine, parenteral vaccination route is superior to mucosal vaccination route for inducing regression of established genital tumors in a murine model of HPV-associated genital cancer.

ELISpot for measuring human immune responses to vaccines

The enzyme-linked immunosorbent spot (ELISpot) assay is one of the most commonly used methods to measure antigen-specific T cells in both mice and humans. Some of the primary reasons for the popularity of the method are that ELISpot is highly quantitative, can measure a broad range of magnitudes of response and is capable of assessing critical cellular immune-related activities such as IFN-γ secretion and granzyme B release. Furthermore, ELISpot is adaptable not only to the evaluation of a variety of T-cell functions, but also to B cells and innate immune cells. It is no wonder that ELISpot has evolved from a research tool to a clinical assay. Recent Phase I and II studies of cancer vaccines, tested in a variety of malignancies, have suggested that ELISpot may be a useful biomarker assay to predict clinical benefit after therapeutic immune modulation. This article will discuss the most common applications of ELISpot, overview the efforts that have been undertaken to standardize the assay and apply the method in the analysis of human clinical trials, and describe some important steps in the process of developing a clinical-grade ELISpot.

Summit on cell therapy for cancer: The importance of the interaction of multiple disciplines to advance clinical therapy

The field of cellular therapy of cancer is moving quickly and the issues involved with its advancement are complex and wide ranging. The growing clinical applications and success of adoptive cellular therapy of cancer has been due to the rapid evolution of immunology, cancer biology, gene therapy and stem cell biology and the translation of advances in these fields from the research laboratory to the clinic. The continued development of this field is dependent on the exchange of ideas across these diverse disciplines, the testing of new ideas in the research laboratory and in animal models, the development of new cellular therapies and GMP methods to produce these therapies, and the testing of new adoptive cell therapies in clinical trials. The Summit on Cell Therapy for Cancer to held on November 1 and 2, 2011 at the National Institutes of Health (NIH) campus will include a mix of perspectives, concepts and ideas related to adoptive cellular therapy that are not normally presented together at any single meeting. This novel assembly will generate new ideas and new collaborations and possibly increase the rate of advancement of this field.

Pathway profiling and rational trial design for studies in advanced stage cervical carcinoma: a review and a perspective

Multiple genetic abnormalities will have occurred in advanced cervical cancer and multiple targeting is likely to be needed to control tumor growth. To date, dominant therapeutic targets under scrutiny for cervical cancer treatment have been EGFR pathway and angiogenesis inhibition as well as anti-HPV vaccines. The potentially most effective targets to be blocked may be downstream from the membrane receptor or at the level of the nucleus. Alterations of the pathways involved in DNA repair and in checkpoint activations, as well as the specific site of HPV genome integration, appear worth assessing. For genetic mutational analysis, complete exon sequencing may become the norm in the future but at this stage frequent mutations (that matter) can be verified by PCR analysis. A precise documentation of relevant alterations of a large spectrum of protein biomarkers can be carried out by reverse phase protein array (RPPA) or by multiplex analysis. Clinical decision-making on the drug(s) of choice as a function of the biological alteration will need input from bio-informatics platforms as well as novel statistical designs. Endpoints are yet to be defined such as the loss (or reappearance) of a predictive biomarker. Single or dual targeting needs to be explored first in relevant preclinical animal and in xenograft models prior to clinical deployment.

Tumor immunology: basic and clinical advances

The third in a series of AACR conferences, entitled "Tumor Immunology: Basic and Clinical Advances," was held in Miami Beach, Florida from November 30 to December 3, 2010. The overall objective of this meeting was to discuss rapid developments in the understanding of basic principles of antitumor immunity and strategies for increasing the success rate of cancer immunotherapy. The key findings that emerged from the meeting included (i) that integrated approaches are required for the development of effective cancer immunotherapies and (ii) attention should be on multiple cellular and molecular components and their broader networks rather than on a single pathway or cell type.

Immune parameters affecting the efficacy of chemotherapeutic regimens

The outcome of chemotherapy can be influenced by the host immune system at multiple levels. Chemotherapy can kill cancer cells by causing them to elicit an immune response or alternatively, by increasing their susceptibility to immune attack. In addition, chemotherapy can stimulate anticancer immune effectors either in a direct fashion or by subverting immunosuppressive mechanisms. Beyond cancer-cell-intrinsic factors that determine the cytotoxic or cytostatic response, as well as the potential immunogenicity of tumor cells, the functional state of the host immune system has a major prognostic and predictive impact on the fate of cancer patients treated with conventional or targeted chemotherapies. In this Review, we surmise that immune-relevant biomarkers may guide personalized therapeutic interventions including compensatory measures to restore or improve anticancer immune responses.

Prevention and treatment of papillomavirus-related cancers through immunization

Cervical and other anogenital cancers are initiated by infection with one of a small group of human papillomaviruses (HPV). Virus-like particle-based vaccines have recently been developed to prevent infection with two cancer-associated HPV genotypes (HPV16, HPV18) and have been ∼95% effective at preventing HPV-associated disease caused by these genotypes in virus-naive subjects. Although immunization induces virus-neutralizing antibody sufficient to prevent infection, persistence of antibody as measured by current assays does not appear necessary to maintain protection over time. Investigators have not identified a reliable surrogate immunological marker of protection against disease following immunization. The prophylactic vaccines are not therapeutic for existing infection. Trials of HPV-specific immunotherapy have shown some efficacy for existing disease, although animal modeling suggests that a combination of immunization and local enhancement of innate immunity may be necessary for optimal therapeutic outcome. HPV prophylactic vaccines are the first vaccines designed to prevent a human cancer and are the practical outcome of a global collaborative effort between basic and applied scientists, clinicians, and industry.

Electroporation delivery of DNA vaccines: prospects for success

A number of noteworthy technology advances in DNA vaccines research and development over the past few years have led to the resurgence of this field as a viable vaccine modality. Notably, these include--optimization of DNA constructs; development of new DNA manufacturing processes and formulations; augmentation of immune responses with novel encoded molecular adjuvants; and the improvement in new in vivo delivery strategies including electroporation (EP). Of these, EP mediated delivery has generated considerable enthusiasm and appears to have had a great impact in vaccine immunogenicity and efficacy by increasing antigen delivery upto a 1000 fold over naked DNA delivery alone. This increased delivery has resulted in an improved in vivo immune response magnitude as well as response rates relative to DNA delivery by direct injection alone. Indeed the immune responses and protection from pathogen challenge observed following DNA administration via EP in many cases are comparable or superior to other well studied vaccine platforms including viral vectors and live/attenuated/inactivated virus vaccines. Significantly, the early promise of EP delivery shown in numerous pre-clinical animal models of many different infectious diseases and cancer are now translating into equally enhanced immune responses in human clinical trials making the prospects for this vaccine approach to impact diverse disease targets tangible.

Immunosuppressive tumor microenvironment in cervical cancer patients

Cervical cancer is caused by Human papillomavirus (HPV) in virtually all cases. These HPV-induced cancers express the viral oncogenes E6 and E7 and are therefore potentially recognized by the immune system. Despite the abundant presence of these foreign antigens, the immune system is unable to cope with the tumor. Due to the constant immunological pressure, cervical cancers can evolve different immune evasion strategies, which will be described in the current review. Several approaches for immunotherapy of cervical cancer are currently under development, which aim at inducing strong HPV-specific immunity. Besides the reinforcement of potent anti-tumor immune responses, immunotherapy could also enhance HPV-specific T regulatory cells. Supplementary strategies that neutralize an immunosuppressive milieu may have great potential. These strategies are discussed as well.

Immunomodulatory effects of cyclophosphamide and implementations for vaccine design

Drug repositioning refers to the utilization of a known compound in a novel indication underscoring a new mode of action that predicts innovative therapeutic options. Since 1959, alkylating agents, such as the lead compound cyclophosphamide (CTX), have always been conceived, at high dosages, as potent cytotoxic and lymphoablative drugs, indispensable for dose intensity and immunosuppressive regimen in the oncological and internal medicine armamentarium. However, more recent work highlighted the immunostimulatory and/or antiangiogenic effects of low dosing CTX (also called "metronomic CTX") opening up novel indications in the field of cancer immunotherapy. CTX markedly influences dendritic cell homeostasis and promotes IFN type I secretion, contributing to the induction of antitumor cytotoxic T lymphocytes and/or the proliferation of adoptively transferred T cells, to the polarization of CD4(+) T cells into TH1 and/or TH17 lymphocytes eventually affecting the Treg/Teffector ratio in favor of tumor regression. Moreover, CTX has intrinsic "pro-immunogenic" activities on tumor cells, inducing the hallmarks of immunogenic cell death on a variety of tumor types. Fifty years after its Food and Drug Administration approval, CTX remains a safe and affordable compound endowed with multifaceted properties and plethora of clinical indications. Here we review its immunomodulatory effects and advocate why low dosing CTX could be successfully combined to new-generation cancer vaccines.

A novel mucosal orthotopic murine model of human papillomavirus-associated genital cancers

Cervical cancer results from infection with high-risk type human papillomaviruses (HPV). Therapeutic vaccines aiming at controlling existing genital HPV infections and associated lesions are usually tested in mice with HPV-expressing tumor cells subcutaneously implanted into their flank. However, effective vaccine-induced regression of these ectopic tumors strongly contrasts with the poor clinical results of these vaccines produced in patients with HPV-associated genital neoplasia. To assess HPV therapeutic vaccines in a more relevant setting, we have, here, established an orthotopic mouse model where tumors in the genital mucosa (GM) develop after an intravaginal instillation of HPV16 E6/E7-expressing tumor cells transduced with a luciferase-encoding lentiviral vector for in vivo imaging of tumor growth. Tumor take was 80-90% after nonoxynol-9 induced damage of the epithelium. Tumors remained localized in the genital tract, and histological analysis showed that most tumors grew within the squamous epithelium of the vaginal wall. Those tumors induced (i) E7-specific CD8 T cells restricted to the GM and draining lymph nodes, in agreement with their mucosal location and (ii) high Foxp3+ CD4+ infiltrates, similarly to those found in natural non-regressing HPV lesions. This novel genital HPV-tumor model by requiring GM homing of vaccine-induced immune responses able to overcome local immuno-suppression may be more representative of the situation occurring in patients upon therapeutic vaccination.

Recommendations from the iSBTc-SITC/FDA/NCI Workshop on Immunotherapy Biomarkers

PURPOSE

To facilitate development of innovative immunotherapy approaches, especially for treatment concepts exploiting the potential benefits of personalized therapy, there is a need to develop and validate tools to identify patients who can benefit from immunotherapy. Despite substantial effort, we do not yet know which parameters of antitumor immunity to measure and which assays are optimal for those measurements.

EXPERIMENTAL DESIGN

The iSBTc-SITC (International Society for Biological Therapy of Cancer-Society for Immunotherapy of Cancer), FDA (Food and Drug Administration), and NCI (National Cancer Institute) partnered to address these issues for immunotherapy of cancer. Here, we review the major challenges, give examples of approaches and solutions, and present our recommendations.

RESULTS AND CONCLUSIONS

Although specific immune parameters and assays are not yet validated, we recommend following standardized (accurate, precise, and reproducible) protocols and use of functional assays for the primary immunologic readouts of a trial; consideration of central laboratories for immune monitoring of large, multi-institutional trials; and standardized testing of several phenotypic and functional potential potency assays specific to any cellular product. When reporting results, the full QA (quality assessment)/QC (quality control) should be conducted and selected examples of truly representative raw data and assay performance characteristics should be included. Finally, to promote broader analysis of multiple aspects of immunity, and gather data on variability, we recommend that in addition to cells and serum, RNA and DNA samples be banked (under standardized conditions) for later testing. We also recommend that sufficient blood be drawn to allow for planned testing of the primary hypothesis being addressed in the trial, and that additional baseline and posttreatment blood is banked for testing novel hypotheses (or generating new hypotheses) that arise in the field.

[What's new in dermatological treatments?]

Although the isolated clinical cases published are sometimes helpful in individual situations in which the therapeutic options have been exhausted, this type of publication cannot be generalized. For this reason, the selection presented covering the period from November 2009 to October 2010 is to a very large extent based on controlled trials, either because they contribute important information or because they raise great hope for a significant number of patients. For the first time in cutaneous oncology, a treatment (ipilimumab) has significantly increased overall survival in patients with metastatic melanoma (phase III), although this gain remains modest (4-6 months) and adverse immunological effects are frequent (30-40%). A phase I trial with treatment specifically targeting the mutant BRAF protein has shown an objective response in 81% of the patients treated in the metastatic phase of melanoma, thus allowing its development to be pursued. Grouping two studies in a rare tumor such as dermatofibrosarcoma also gives hope with imatinib as a neoadjuvant treatment when the initial tumor is inoperable, with, however, an inconsistent response of approximately 50% and only if the tumor presents reorganization of chromosomes 17 and 22. Cutaneous inflammatory diseases are still dominated by dual therapies in psoriasis, with, notably, an effectiveness trial on etanercept at different doses not showing a difference in efficacy depending on dose for the joint component of psoriasis, but also by the publication of a direct comparison of two dual therapies, ustekinumab versus etanercept. In atopic dermatitis, a controversial article invites one to reflect upon the progress made in the management of children by clinical nurses, as in the Netherlands and in Great Britain, in an attempt to contend with the shortage of dermatologists. Since the use of biotherapies is not the prerogative of psoriasis, infliximab was assessed in a phase II trial in Verneuil disease without demonstrating significant efficacy on the main criterion, but it did show a tendency to reduce the score used. This trial suffered from a weakness both in methodology and statistical power, thus precluding any conclusion. The rarity of therapeutic trials on drug eruptions warrants their mention. A French phase II study gives a glimpse of a trend toward efficacy in terms of survival in the treatment of toxic epidermal necrolysis with cyclosporine. As for infectious dermatosis and sexually transmitted infections, a French multicenter study has shown significantly higher efficacy with ivermectin than with malathion in treating pediculosis without increasing the side effects. Today, however, this systemic treatment cannot be a first-line treatment outside of certain specific situations. A large cohort study (somewhat unsatisfactory in its methodology) has not demonstrated the teratogenicity of antiherpes treatments in 830,000 infants. In prevention of HIV transmission, no microbicidal gel had shown efficacy to date. This has now been accomplished in South Africa with a 1% tenofovir gel. The results of a preliminary trial on therapeutic vaccination against HPV16 proposed to women who are carriers of cervical intraepithelial neoplasia opens the way for wide vaccine therapy of cutaneous virus-induced neoplasia. In conclusion, several articles analyzing the dermatology literature provide an opportunity to reflect on the quality of such articles, Boutron's being absolutely in-dis-pen-sa-ble!

Human papillomaviruses as therapeutic targets in human cancer

Cervical carcinomas are almost universally associated with high-risk human papillomavirus (HPV) infections, and are a leading cause of cancer death in women worldwide. HPV oncoproteins contribute to cancer initiation and progression and their expression is necessary for the maintenance of the transformed state. The fact that the initiating oncogenic insult, infection with a high-risk HPV and viral oncoprotein expression, is common to almost all cervical cancers offers unique opportunities for prevention, early detection, and therapy. The potential for prevention has been realized by introduction of prophylactic vaccines that are to prevent transmission of specific high-risk HPVs. Given, however, that these vaccines have no therapeutic efficacy and HPV-associated cervical cancers arise years if not decades after the initial infection, it has been estimated that there will be no measurable decline of HPV-associated tumors before 2040. Cervical cancer alone will be diagnosed in more than 375,000 US women between now and 2040. Other HPV-associated anogenital and head and neck cancers are predicted to afflict another 700,000 men and women over this time period. Hence, therapeutic efforts to combat high-risk HPV-associated disease remain of critical importance.

Papillomavirus virus like particle-based therapeutic vaccine against human papillomavirus infection related diseases: immunological problems and future directions

Chronic infection with certain types of human papillomaviruses (HPV), especially HPV-16 and HPV-18, leads to the development of cervical cancer. Prophylactic HPV vaccines based on HPV virus like particles (VLPs) have now been developed. The commercial vaccines, Gardasil and Cervarix are clinically effective in preventing HPV infection but do not have a therapeutic effect against existing chronic HPV infections. However, papillomavirus (PV) VLPs elicit strong cytotoxic T cell (CTL) responses and PV VLPs without any adjuvant have therapeutic effects in animal PV infection model. Alum in Gardasil, Alum and 3-O-deacylated-4'-monophosphoryl lipid A (ASO4) in Cervarix may stimulate IL10 production and inhibit the Th1, CTL immune response of immunized individuals. PV VLPs also stimulate the production of IL10 by CD4(+) T cells, which prevent their CTL generation effect as a therapeutic vaccine. Neutralizing IL10 at the time of PV VLPs immunization increases cytotoxic T cell responses. PV VLPs incorporating PV early protein E2, 6 and 7, together with immune stimulator that promote strong type 1 responses, and at the same time blocking the effect of IL10 may have therapeutic effect against HPV infection related diseases and are worth further basic and clinical investigation.

Local activation of CD8 T cells and systemic tumor eradication without toxicity via slow release and local delivery of agonistic CD40 antibody

PURPOSE

Immunotherapy against tumors with anti-CD40 agonistic antibodies has been extensively studied in preclinical animal models and recently also in clinical trials. Although promising results have been obtained, antibody (Ab)-related toxicity has been a limiting factor. We reasoned that strict local activation of tumor-specific CD8 T cells through stimulation of CD40 on the dendritic cells (DC) in the tumor area while excluding systemic stimulation might be sufficient for effective tumor eradication and can limit systemic toxicity.

EXPERIMENTAL DESIGN

Preclinical in vivo models for immunogenic tumors were used to investigate the potential of delivering a nontoxic dose of agonistic anti-CD40 Ab to the tumor region, including draining lymph node, in a slow-release formulation (montanide).

RESULTS

The delivery of anti-CD40 monoclonal Ab, formulated in slow-release Montanide ISA-51, reprograms CTLs by inducing local but not systemic DC activation, resulting in effective tumor-specific CTL responses that eradicate local and distant tumors. Adverse side effects, assayed by organ histology and liver enzymes in the blood, were much lower after local anti-CD40 Ab delivery than systemic administration. The local delivery of anti-CD40 Ab activates only CTLs against antigens presented in the tumor-draining area, because unrelated distant tumors expressing different tumor antigens were not eradicated.

CONCLUSIONS

These results establish a novel therapeutic principle that local delivery and slow release of agonistic anti-CD40 Ab to the tumor-draining area effectively activates local tumor-specific CD8 T cells to become systemic effectors without causing systemic toxicity or nonspecific CTL activation. These findings have important implications for the use of anti-CD40 therapies in patients.

Control of cervicovaginal HPV-16 E7-expressing tumors by the combination of therapeutic HPV vaccination and vascular disrupting agents

Abstract Antigen-specific immunotherapy and vascular disrupting agents, such as 5,6-dimethylxanthenone-4-acetic acid (DMXAA), have emerged as attractive approaches for the treatment of cancers. In the current study, we tested the combination of DMXAA treatment with therapeutic human papillomavirus type 16 (HPV-16) E7 peptide-based vaccination for their ability to generate E7-specific CD8+ T-cell immune responses, as well as their ability to control E7-expressing tumors in a subcutaneous and a cervicovaginal tumor model. We found that the combination of DMXAA treatment with E7 long peptide (amino acids 43-62) vaccination mixed with polyriboinosinic:polyribocytidylic generated significantly stronger E7-specific CD8+ T-cell immune responses and antitumor effects compared with treatment with DMXAA alone or HPV peptide vaccination alone in the subcutaneous model. Additionally, we found that the DMXAA-mediated enhancement of E7-specific CD8+ T-cell immune responses generated by the therapeutic HPV peptide-based vaccine was dependent on the timing of administration of DMXAA. Treatment with DMXAA in tumor-bearing mice was also shown to lead to increased dendritic cell maturation and increased production of inflammatory cytokines in the tumor. Furthermore, we observed that the combination of DMXAA with HPV-16 E7 peptide vaccination generated a significant enhancement in the antitumor effects in the cervicovaginal TC-1 tumor growth model, which closely resembles the tumor microenvironment of cervical cancer. Taken together, our data demonstrated that administration of the vascular disrupting agent, DMXAA, enhances therapeutic HPV vaccine-induced cytotoxic T-lymphocyte responses and antitumor effects against E7-expressing tumors in two different locations. Our study has significant implications for future clinical translation.

A long peptide from MELOE-1 contains multiple HLA class II T cell epitopes in addition to the HLA-A*0201 epitope: an attractive candidate for melanoma vaccination

CD4(+) T cells contribute importantly to the antitumor T cell response, and thus, long peptides comprising CD4 and CD8 epitopes may be efficient cancer vaccines. We have previously identified an overexpressed antigen in melanoma, MELOE-1, presenting a CD8(+) T cell epitope, MELOE-1(36-44), in the HLA-A*0201 context. A T cell repertoire against this epitope is present in HLA-A*0201+ healthy subjects and melanoma patients and the adjuvant injection of TIL containing MELOE-1 specific CD8(+) T cells to melanoma patients was shown to be beneficial. In this study, we looked for CD4(+) T cell epitopes in the vicinity of the HLA-A*0201 epitope. Stimulation of PBMC from healthy subjects with MELOE-1(26-46) revealed CD4 responses in multiple HLA contexts and by cloning responsive CD4(+) T cells, we identified one HLA-DRβ1*1101-restricted and one HLA-DQβ1*0603-restricted epitope. We showed that the two epitopes could be efficiently presented to CD4(+) T cells by MELOE-1-loaded dendritic cells but not by MELOE-1+ melanoma cell-lines. Finally, we showed that the long peptide MELOE-1(22-46), containing the two optimal class II epitopes and the HLA-A*0201 epitope, was efficiently processed by DC to stimulate CD4(+) and CD8(+) T cell responses in vitro, making it a potential candidate for melanoma vaccination.

Immunologic biomarkers as correlates of clinical response to cancer immunotherapy

Over the last few years, several newly developed immune-based cancer therapies have been shown to induce clinical responses in significant numbers of patients. As a result, there is a need to identify immune biomarkers capable of predicting clinical response. If there were laboratory parameters that could define patients with improved disease outcomes after immunomodulation, product development would accelerate, optimization of existing immune-based treatments would be facilitated and patient selection for specific interventions might be optimized. Although there are no validated cancer immunologic biomarkers that are predictive of clinical response currently in widespread use, there is much published literature that has informed investigators as to which markers may be the most promising. Population-based studies of endogenous tumor immune infiltrates and gene expression analyses have identified specific cell populations and phenotypes of immune cells that are most likely to mediate anti-tumor immunity. Further, clinical trials of cancer vaccines and other cancer directed immunotherapy have identified candidate immunologic biomarkers that are statistically associated with beneficial clinical outcomes after immune-based cancer therapies. Biomarkers that measure the magnitude of the Type I immune response generated with immune therapy, epitope spreading, and autoimmunity are readily detected in the peripheral blood and, in clinical trials of cancer immunotherapy, have been associated with response to treatment.

Strategies to counteract MHC-I defects in tumors

Defects in MHC-I antigen presentation represent a common feature of cancer and allow evasion from T cell recognition. Recent findings from immunotherapy in melanoma suggested that irreversible MHC-I defects enable escape from immune pressure. Although loss of antigen presentation is known for many years, strategies to counteract these defects are scarce and largely unexamined. Now that the first forms of T-cell-based immunotherapy show clinical efficacy and reach FDA approval, this issue deserves urgent awareness. Here we describe possible roads leading to corrections of MHC-I defects in tumors and describe a salvage pathway for CTL by targeting novel tumor antigens that we recently uncovered.

Long synthetic peptides for the production of vaccines and drugs: a technological platform coming of age

Long synthetic peptides (LSPs) have a variety of important clinical uses as synthetic vaccines and drugs. Techniques for peptide synthesis were revolutionized in the 1960s and 1980s, after which efficient techniques for purification and characterization of the product were developed. These improved techniques allowed the stepwise synthesis of increasingly longer products at a faster rate, greater purity, and lower cost for clinical use. A synthetic peptide approach, coupled with bioinformatics analysis of genomes, can tremendously expand the search for clinically relevant products. In this Review, we discuss efforts to develop a malaria vaccine from LSPs, among other clinically directed work.

Treatment of vulvar intraepithelial neoplasia with topical imiquimod: seven years median follow-up of a randomized clinical trial

OBJECTIVE

Recently we reported on the efficacy of imiquimod for treating vulvar intraepithelial neoplasia (VIN) in a placebo-controlled, double-blinded randomized clinical trial (RCT). Four weeks after treatment, a complete response was observed in 35% of patients and a partial response in 46%. All complete responders remained disease-free at 12 months follow-up. In the current investigations, we assessed long-term follow-up at least 5 years after the initial RCT.

METHODS

Twenty-four of 26 imiquimod-treated patients who had participated in the initial RCT were seen for follow-up. Primary endpoint was durability of clinical response to imiquimod assessed by naked eye vulvar examination and histology. Long-term clinical response was correlated to lesion size before start of the initial RCT. Secondary endpoints were mental health, global quality of life, body image and sexual function in relation with long-term clinical response.

RESULTS

Median follow-up period was 7.2 years (range 5.6-8.3 years). VIN recurred in one of nine complete responders. Of the initial partial responders, two became disease-free after additional imiquimod treatment. In the other partial responders, VIN recurred at least once after the initial RCT. In long-term complete responders, lesion size at study entry was smaller and these patients had a significantly better global quality of life at follow-up than patients with residual disease and/or recurrence after imiquimod treatment.

CONCLUSIONS

In case of a complete response, imiquimod is effective in the long-term. Furthermore, patients with a long-term complete response had a significantly better global quality of life than patients who recurred after imiquimod treatment.

Immunosurveillance in human non-viral cancers

Immunosurveillance of infections and therefore of viral-induced cancers is well admitted but that of nonviral cancers is a matter of hot debate. In the recent years, data collected from large libraries of human cancers demonstrated that the immune contexture of the primary tumors is an essential prognostic factor for patients' disease-free and overall survival. The location in the tumor's center and invasive margin, the coordination of a memory Th1/cytotoxic T cell infiltrate, and the expression of genes involved in angiogenesis, chemotaxis, and cell adhesion are key factors for an immune control of disease progression. Systems biology predicted markers shaping an efficient immune reaction can serve as tools and targets for novel therapeutic approaches.

Immunotherapy for persistent viral infections and associated disease

Persistent viral infections reflect a failure of the host's immune system to control infection, and in many cases, they are associated with the development of malignancies. So far, vaccines designed to boost viral immunity during chronic infection have not been successful. Infections with high-risk human papilloma viruses (e.g. HPV16) are acquired by a large segment of the population and persist in 5-10% of infected individuals, which causes the development of high-grade pre-malignant lesions. Recently we succeeded in causing regression of HPV16-induced disease in ∼50% of chronically infected patients by a novel therapeutic vaccine. Here, we summarize the parallels in immunity against HPV and other chronic viruses and discuss the general implications of our findings for the immunotherapy of chronic infections.

Immunotherapy as a strategy for the treatment of non-small-cell lung cancer

Positive modulation of a patient's immune system to produce antitumor immunity is an attractive strategy that may improve the dismal outcomes typically associated with non-small-cell lung cancer (NSCLC). Using methods that either augment specific antitumor immunity or positively influence the patient's immune system to allow the de novo generation of immunity to encompass current strategies used in recent clinical trials of NSCLC. Encouraging results of Phase II trials in antigen-specific immunotherapy have led to three subsequent Phase III trials, which are currently enrolling. Results of these trials will improve our understanding of the role that immunotherapy plays in the treatment of NSCLC. Successful application of a humoral vaccine in Cuba led to its approval for the treatment of advanced NSCLC patients in that country. To date, trials involving nonspecific immunotherapeutic interventions have failed to improve outcomes in NSCLC and may indicate a need to combine them with antigen-specific vaccines. Although these trials will greatly advance our knowledge of NSCLC immunotherapy, we believe truly efficacious immunotherapy may only result from implementation of strategies to both augment antitumor immunity and counteract tumor-mediated immunosuppression.

Dendritic cells in cancer immunotherapy

DC initiate and regulate T-cell immunity and are thus the key to optimization of all types of vaccines. Insights into DC biology offer many opportunities to enhance immunogenicity. In this Viewpoint, I discuss some recent developments and findings that are of immediate relevance for the clinical development of cancer vaccines. In addition, I emphasize my personal view that we should explore the potential of adoptively transferred DC (i.e. DC vaccination) as cancer vaccines by performing two-armed trials that address critical variables and by delivering antigens via mRNA-transfected DC.

Programmed cell death-1 (PD-1) at the heart of heterologous prime-boost vaccines and regulation of CD8+ T cell immunity

Developing new vaccination strategies and optimizing current vaccines through heterologous prime-boost carries the promise of integrating the benefits of different yet synergistic vectors. It has been widely thought that the increased immunity afforded by heterologous prime-boost vaccination is mainly due to the minimization of immune responses to the carrier vectors, which allows a progressive build up of immunity against defined epitopes and the subsequent induction of broader immune responses against pathogens. Focusing on CD8⁺ T cells, we put forward a different yet complementary hypothesis based primarily on the systematic analysis of DNA vaccines as priming agents. This hypothesis relies on the finding that during the initiation of immune response, acquisition of co-inhibitory receptors such as programmed cell death-1 (PD-1) is determined by the pattern of antigen exposure in conjunction with Toll-like receptor (TLR)-dependent stimulation, critically affecting the magnitude and profile of secondary immunity. This hypothesis, based upon the acquisition and co-regulation of pivotal inhibitory receptors by CD8⁺ T cells, offers a rationale for gene-based immunization as an effective priming strategy and, in addition, outlines a new dimension to immune homeostasis during immune reaction to pathogens. Finally, this model implies that new and optimized immunization approaches for cancer and certain viral infections must induce highly efficacious T cells, refractory to a broad range of immune-inhibiting mechanisms, rather than solely or primarily focusing on the generation of large pools of vaccine-specific lymphocytes.

E6 and E7 fusion immunoglobulin from human papilloma virus 16 induces dendritic cell maturation and antigen specific activation of T helper 1 response

Human papilloma virus (HPV) 16 causes cervical cancer. Induction of oncogenesis by HPV 16 is primarily dependent on the function of E6 and E7 proteins, which inactivate the function of p53 and pRB, respectively. Thus, blocking the activity of the E6 and E7 proteins from HPV 16 is critical to inhibiting oncogenesis during infection. We have expressed and purified soluble HPV 16 E6 and E7 fusion immunoglobulin (Ig), which were combined with the constant region of an Ig heavy chain, in a mammalian system. To assess whether soluble E6 and E7 fusion Igs induce effective cellular immune responses, immature dendritic cells (DCs) were treated with these fusion proteins. Soluble E6 and E7 fusion Igs effectively induced maturation of DCs. Furthermore, immunization with soluble E6 and E7 fusion Igs in mice resulted in antigen-specific activation of T helper 1 (Th1) cells. This is the first comprehensive study to show the molecular basis of how soluble HPV 16 E6 or E7 fusion Igs induces Th1 responses through the maturation of DCs. In addition, we show that DC therapy using soluble HPV E6 and E7 fusion Igs may be a valuable tool for controlling the progress of cervical cancer.

Repeated PR1 and WT1 peptide vaccination in Montanide-adjuvant fails to induce sustained high-avidity, epitope-specific CD8+ T cells in myeloid malignancies

BACKGROUND

We previously showed that vaccination with one dose of PR1 and WT1 peptides induces transient anti-leukemia immunity. We hypothesized that maintenance of a sustained anti-leukemia response may require frequent boost injections.

DESIGN AND METHODS

Eight patients with myeloid malignancies were enrolled in this phase II study, and 6 completed 6 injections of PR1 and WT1 peptides in Montanide-adjuvant with GM-CSF, every two weeks.

RESULTS

Both high- and low-avidity PR1 or WT1-specific CD8(+) T cells were detected in all evaluable patients after the first vaccine dose. Repeated vaccination led to selective deletion of high avidity PR1- and WT1-specific CD8(+) T cells and was not associated with significant reduction in WT1-expression. Additional boosting failed to increase vaccine-induced CD8(+) T-cell frequencies further and in all patients the response was lost before the 6(th) dose. PR1- or WT1-specific CD8(+) T cells were not detected in bone marrow samples, excluding their preferential localization to this site. Following a booster injection three months after the 6(th) vaccine dose, no high-avidity PR1 or WT1-specific CD8(+) T cells could be detected, whereas low-avidity T cells were readily expanded.

CONCLUSIONS

These data support the immunogenicity of PR1 and WT1 peptide vaccines. However, repeated delivery of peptides with Montanide-adjuvant and GM-CSF leads to rapid loss of high-avidity peptide-specific CD8(+) T cells. These results may offer an explanation for the lack of correlation between immune and clinical responses observed in a number of clinical trials of peptide vaccination. New approaches are needed to induce long-term high-avidity memory responses against leukemia antigens.

Designing vaccines based on biology of human dendritic cell subsets

The effective vaccines developed against a variety of infectious agents, including polio, measles, and hepatitis B, represent major achievements in medicine. These vaccines, usually composed of microbial antigens, are often associated with an adjuvant that activates dendritic cells (DCs). Many infectious diseases are still in need of an effective vaccine including HIV, malaria, hepatitis C, and tuberculosis. In some cases, the induction of cellular rather than humoral responses may be more important because the goal is to control and eliminate the existing infection rather than to prevent it. Our increased understanding of the mechanisms of antigen presentation, particularly with the description of DC subsets with distinct functions, as well as their plasticity in responding to extrinsic signals, represent opportunities to develop novel vaccines. In addition, we foresee that this increased knowledge will permit us to design vaccines that will reprogram the immune system to intervene therapeutically in cancer, allergy, and autoimmunity.

Minimal information about T cell assays: the process of reaching the community of T cell immunologists in cancer and beyond

Many assays to evaluate the nature, breadth, and quality of antigen-specific T cell responses are currently applied in human medicine. In most cases, assay-related protocols are developed on an individual laboratory basis, resulting in a large number of different protocols being applied worldwide. Together with the inherent complexity of cellular assays, this leads to unnecessary limitations in the ability to compare results generated across institutions. Over the past few years a number of critical assay parameters have been identified which influence test performance irrespective of protocol, material, and reagents used. Describing these critical factors as an integral part of any published report will both facilitate the comparison of data generated across institutions and lead to improvements in the assays themselves. To this end, the Minimal Information About T Cell Assays (MIATA) project was initiated. The objective of MIATA is to achieve a broad consensus on which T cell assay parameters should be reported in scientific publications and to propose a mechanism for reporting these in a systematic manner. To add maximum value for the scientific community, a step-wise, open, and field-spanning approach has been taken to achieve technical precision, user-friendliness, adequate incorporation of concerns, and high acceptance among peers. Here, we describe the past, present, and future perspectives of the MIATA project. We suggest that the approach taken can be generically applied to projects in which a broad consensus has to be reached among scientists working in fragmented fields, such as immunology. An additional objective of this undertaking is to engage the broader scientific community to comment on MIATA and to become an active participant in the project.

The application of exosomes as a nanoscale cancer vaccine

Cancer is a leading cause of death globally, and it is predicted and projected to continue rising as life expectancy increases. Although patient survival rates for some forms of cancers are high due to clinical advances in treatment protocols, the search for effective cancer vaccines remains the ultimate Rosetta Stone in oncology. Cervarix^®, Gardasil^®, and hepatitis B vaccines are currently employed in preventing certain forms of viral cancers. However, they are, strictly speaking, not ‘true’ cancer vaccines as they are prophylactic rather than therapeutic, are only effective against the oncogenic viruses, and do not kill the actual cancer cells. On April 2010, a new prostate cancer vaccine Provenge^® (sipuleucel-T) was approved by the US FDA, and it is the first approved therapeutic vaccine that utilizes antigen-presenting cell technology involving dendritic cells in cancer immunotherapy. Recent evidence suggests that the use of nanoscale particles like exosomes in immunotherapy could form a viable basis for the development of novel cancer vaccines, via antigen-presenting cell technology, to prime the immune system to recognize and kill cancer cells. Coupled with nanotechnology, engineered exosomes are emerging as new and novel avenues for cancer vaccine development. Here, we review the current knowledge pertaining to exosome technology in immunotherapy and also seek to address the challenges and future directions associated with it, in hopes of bringing this exciting application a step closer toward an effective clinical reality.

Desirable cell death during anticancer chemotherapy

The concept of immunogenic chemotherapy that has recently emerged relies upon the capacity of a cytotoxic compound to trigger a cell-death modality. This modality elicits cross-priming by dendritic cells of tumor antigen-specific T cells that will contribute to the tumoricidal activity of the compound and protect the host against relapse. In contrast, most anticancer drugs elicit nonimmunogenic apoptosis that is not accompanied with an immunizing property. This review will discuss some molecular and metabolic changes required at the level of the tumor that must engage key pathways at the level of the host for the induction of Tc1 polarized-protective T cell responses during chemotherapy. We will summarize the immune adjuvants that can boost the immunogenicity of cell death to augment the efficacy of chemotherapy.