Prevention of Cervical Cancer Through Papillomavirus Vaccination

A subset of human papillomaviruses (HPVs) promote anogenital malignancy, including cervical cancer, and prevention and treatment strategies that reflect the causal role of HPV are being developed. Vaccines based on HPV virus-like particles induce genotype-specific virus-neutralizing antibody and prevent infection with HPV1. Persistent papillomavirus infection is required for the development of papillomavirus-associated cancer and, therefore, therapeutic vaccines are being developed to eliminate established papillomavirus infection. Such vaccines test principles for the growing field of tumour-antigen-specific immunotherapy. This article reviews progress in the field and draws conclusions for the development of future prophylactic and therapeutic viral vaccines.

ISCOMATRIX (TM) adjuvant: An adjuvant suitable for use in anticancer vaccines

Human Papillomavirus type 16 (HPV16) E6 and E7 oncoproteins are associated with cervical cancer development and progression and can therefore be used as target antigens for cancer immunotherapy. In this study we evaluated the immunogenicity in mice, of different vaccine formulations using recombinant HPV16 derived E6E7 or E7GST fusion proteins. When co-administered with ISCOMATRIX(TM) adjuvant, these E6E7 proteins consistently induced E7 specific CTL, in vivo tumor protection, antibody and DTH responses. ISCOMATRIX(TM) adjuvant has been developed for use in the formulation of novel human vaccines and has been evaluated for safety and toxicity in human trials. A formulation containing aluminum hydroxide (Al(OH)(3)) gave a lesser degree of E7 specific antibody, and no local E7 specific CTL response but similar DTH and tumor protection. These findings demonstrate the potential of ISCOMATRIX(TM) adjuvant to stimulate both cellular and humoral immune responses to endogenously processed target antigens, and hence is the preferred adjuvant when CTL responses are desirable. (C) 2004 Elsevier Ltd. All rights reserved.

The cytoskeleton and motor proteins of human schistosomes and their roles in surface maintenance and host-parasite interactions

Schistosomes are parasitic blood flukes, responsible for significant human disease in tropical and developing nations. Here we review information on the organization of the cytoskeleton and associated motor proteins of schistosomes, with particular reference to the organization of the syncytial tegument, a unique cellular adaptation of these and other neodermatan flatworms. Extensive EST databases show that the molecular constituents of the cytoskeleton and associated molecular systems are likely to be similar to those of other eukaryotes, although there are potentially some molecules unique to schistosomes and platyhelminths. The biology of some components, particular those contributing to host-parasite interactions as well as chemotherapy and immunotherapy are discussed. Unresolved questions in relation to the structure and function of the tegument relate to dynamic organization of the syncytial layer. (C) 2004 Wiley Periodicals, Inc.

DC therapy for prostate cancer

The wide range of currently available treatments for metastatic prostate cancer have demonstrated a modest palliative effect, but none to date has shown an increase in overall survival. The immune system has evolved to protect against infection, however, the modulation of this system represents the possibility of allowing it to identify and destroy cancer cells. The immune system is capable of inciting a powerful immune response against tissues, in the form of transplant rejection, and the potential exists to harness these powers to fight against tumors. Modest clinical responses have been seen in patients with metastatic prostate cancer treated with DC therapies; however, no increase in overall survival has been demonstrated. The current state of DC immunotherapy for prostate cancer is reviewed.

Either interleukin-12 or interferon-gamma can correct the dendritic cell defect induced by transforming growth factor beta(1) in patients with myeloma

The poor response to immunotherapy in patients with multiple myeloma (MM) indicates that a better understanding of any defects in the immune response in these patients is required before effective therapeutic strategies can be developed. Recently we reported that high potency (CMRF44(+)) dendritic cells (DC) in the peripheral blood of patients with MM failed to significantly up-regulate the expression of the B7 co-stimulatory molecules, CD80 and CD86, in response to an appropriate signal from soluble trimeric human CD40 ligand. This defect was caused by transforming growth factor beta(1) (TGFbeta(1)) and interleukin (IL)-10, produced by malignant plasma cells, and the defect was neutralized in vitro with anti-TGFbeta(1). As this defect could impact on immunotherapeutic strategies and may be a major cause of the failure of recent trials, it was important to identify a more clinically useful agent that could correct the defect in vivo. In this study of 59 MM patients, the relative and absolute numbers of blood DC were only significantly decreased in patients with stage III disease and CD80 up-regulation was reduced in both stage I and stage III. It was demonstrated that both IL-12 and interferon-gamma neutralized the failure to stimulate CD80 up-regulation by huCD40LT in vitro. IL-12 did not cause a change in the distribution of DC subsets that were predominantly myeloid (CD11c+ and CDw123-) suggesting that there would be a predominantly T-helper cell type response. The addition of IL-12 or interferon-gamma to future immunotherapy trials involving these patients should be considered.

Interaction between conventional dendritic cells and natural killer cells is integral to the activation of effective antiviral immunity

Dendritic cells (DCs) regulate various aspects of innate immunity, including natural killer (NK) cell function. Here we define the mechanisms involved in DC - NK cell interactions during viral infection. NK cells were efficiently activated by murine cytomegalovirus ( MCMV) - infected CD11b(+) DCs. NK cell cytotoxicity required interferon-alpha and interactions between the NKG2D activating receptor and NKG2D ligand, whereas the production of interferon-gamma by NK cells relied mainly on DC-derived interleukin 18. Although Toll-like receptor 9 contributes to antiviral immunity, we found that signaling pathways independent of Toll-like receptor 9 were important in generating immune responses to MCMV, including the production of interferon-alpha and the induction of NK cell cytotoxicity. Notably, adoptive transfer of MCMV-activated CD11b(+) DCs resulted in improved control of MCMV infection, indicating that these cells participate in controlling viral replication in vivo.

Generation and maturation of dendritic cells for clinical application under serum-free conditions

Monocyte-derived dendritic cells (MoDCs) in clinical use for cancer immunotherapy are ideally generated in serum-free medium (SFM) with inclusion of a suitable maturation factor toward the end of the incubation period. Three good manfacturing practice (GMP) grade SFMs (AIM-V, X-VIVO 15, and X-VIVO 20) were compared with RPMI-1640, supplemented with 10% fetal bovine serum or 10% human serum. DCs generated for 7 days in SFM were less mature and secreted less interleukin (IL) 12p70 and IL-10 than DCs generated in 10% serum. DC yield was comparable in SFMs, and a greater proportion of cells was viable after maturation. Toll-like receptor (TLR) ligands were compared for their ability to induce cytokine secretion under serum-free conditions in the presence of interferon (IFN) gamma. With the exception of Poly I:C, TLR ligands stimulated high levels of IL-10 secretion. High levels of IL-12p70 were induced by two TLR4-mediated stimuli, lipopolysaccharide and Ribomunyl, a clinical-grade bacterial extract. When T-cell responses were compared in allogeneic mixed leukocyte reaction, DCs stimulated with Ribomunyl induced higher levels of IFN gamma than DCs stimulated with the cytokine cocktail: tumor necrosis factor-alpha, IL-1 beta, IL-6, and prostaglandin E-2. In the presence of IL-10 neutralizing antibodies, DC IL-12p70 production and T-cell IFN gamma were increased in vitro. Similarly, DCs stimulated with Ribomunyl, IFN gamma, and anti-IL-10 induced high levels of tetanus toxoid-specific T-cell proliferation and IFN gamma secretion. Thus, MoDCs generated ill SFM efficiently stimulate T-cell IFN gamma production after maturation in the presence of a clinical-grade TLR4 agonist and IL-10 neutralization.

Analysis of the effect of different NKT cell subpopulations on the activation of CD4 and CD8 T cells, NK cells, and B cells

Objective. NKT cells have diverse immune regulatory functions including activation of cells involved in Th1- and Th2-type immune activities. Most previous studies have investigated the functions of NKT cells as a single family but more recent evidence indicates the distinct functional properties of NKT cell subpopulation. This study aims to determine whether NKT cell subpopulations have different stimulatory activities on other immune cells that may affect the outcome of NKT cell-based immunotherapy. Methods. NKT cells and NKT cell subpopulations (CD4(+)CD8(-), CD4(-)CD8(+), CD4(-)CD8(+)) were cocultured with PBMC and their activities on immune cells including CD4(+) and CD8(+) T cells, NK cells, and B cells were assessed by flow cytometry. The production of cytokines in culture was measured by enzyme-linked immunsorbent assay. Results. The CD4(+)CD8(-) NKT cells demonstrated substantially greater stimulatory activities on CD4(+) T cells, NK cells, and B cells than other NKT cell subsets. The CD4(-)CD8(+) NKT cells showed the greatest activity on CD8(+) T cells, and were the only NKT cell subset that activated these immune cells. The CD4(-)CD8(-) NKT cells showed moderate stimulatory activity on CD4(+) T cells and the least activity on other immune cells. Conclusion. The results here suggest that NKT cell subpopulations differ in their abilities to stimulate other immune cells. This highlights the potential importance of manipulating specific NKT cell subpopulations for particular therapeutic situations and of evaluating subpopulations, rather than NKT cells as a group, during investigation of a possible role of NKT cells in various disease settings. (c) 2006 International Society for Experimental Hematology. Published by Elsevier Inc.

Clinical features and management of tumors affecting the lacrimal drainage apparatus

Purpose: To report the clinical features of a series of patients with lacrimal drainage apparatus tumors and present guidelines for management based on histopathology. Methods: A noncomparative retrospective chart review of the clinical, imaging, and pathologic findings of 37 patients presenting to four regional orbital Surgery departments with tumors affecting the lacrimal drainage apparatus between 1990 and 2004. Results: There were 37 patients, of whom 62% were male. The mean age at referral was 54 years. Epiphora, a palpable mass, and dacryocystitis were the most common presentations. Two thirds of the tumors were epithelial. with carcinomas being the most frequent (38%). followed by papillomas (27%). Lymphomas were the most common nonepithelial malignancy (30%). Epithelial tumors were more common in men (87%), whereas lymphomas were more common in women (57%). Treatment modalities included surgery, in addition to radiotherapy and/or chemotherapy and immunotherapy. Mean follow-up was 38 months. Thirty-three patients (89%) remain alive without evidence of disease and 4 patients died of recurrence and/or metastases. Conclusions: Lacrimal drainage apparatus tumors require careful initial management to ensure adequate local and systemic disease control. Atypical mucosa encountered during dacryocystorhinostomy should be biopsied and small papillomas or pedunculated tumors excised and analyzed with frozen sections. If a diffuse or infiltrative mass is encountered, it should be biopsied and managed on the basis of histopathology and extent of disease. Lymphomas should be treated according to protocols. whereas noninvasive carcinoma and extensive papillomas require complete excision of the system. Invasive disease requires en bloc excision. Long-term follow-up is essential for early detection of recurrence.

Engineered T cell receptors and their potential in molecular medicine

T cell receptors are among the most specific biological structures found in nature and are therefore excellent candidates for the molecular targeting of antigen. It is becoming increasingly apparent that common sets of T cell receptors are frequently used in humans to combat pathogen and cancer derived threats. Given that many of these conserved T cell receptors have high affinity for their target ligands, there is potential to amass virtual banks of “off-the-shelf” receptors for use in a wide range of immunotherapeutic strategies. Additionally, such T cell receptors could become basic blueprints for artificial enhancement through mutagenesis, thereby creating an even better 3-dimensional fit for their cognate targets. Indeed, preliminary approaches using both “natural” and “supernatural” T cell receptors have shown promise in treating autoimmunity and malignancy. This review will discuss these studies and other approaches through which T cell receptors can be exploited in immunodiagnostics, pathogen control and gene therapy.

Expression of human DEC-205 (CD205) multilectin receptor on leukocytes

DEC-205 (CD205) belongs to the macrophage mannose receptor family of C-type lectin endocytic receptors and behaves as an antigen uptake/processing receptor for dendritic cells (DC). To investigate DEC-205 tissue distribution in human leukocytes, we generated a series of anti-human DEC-205 monoclonal antibodies (MMRI-5, 6 and 7), which recognized epitopes within the C-type lectin-like domains 1 and 2, and the MMRI-7 immunoprecipitated a single similar to 200 kDa band, identified as DEC-205 by mass spectrometry. MMRI-7 and another DEC-205 mAb (MG38), which recognized the epitope within the DEC-205 cysteine-rich and fibronectin type II domain, were used to examine DEC-205 expression by human leukocytes. Unlike mouse DEC-205, which is reported to have predominant expression on DC, human DEC-205 was detected by flow cytometry at relatively high levels on myeloid blood DC and monocytes, at moderate levels on B lymphocytes and at low levels on NK cells, plasmacytoid blood DC and T lymphocytes. MMRI-7 F(ab')(2) also labeled monocytes, B lymphocytes and NK cells similarly excluding reactivity due to non-specific binding of the mAb to Fc gamma R. Tonsil mononuclear cells showed a similar distribution of DEC-205 staining on the leukocytes. DEC-205-specific semiquantitative immunoprecipitation/western blot and quantitative reverse transcriptase-PCR analysis established that these leukocyte populations expressed DEC-205 protein and the cognate mRNA. Thus, human DEC-205 is expressed on more leukocyte populations than that were previously assumed based on mouse DEC-205 tissue localization studies. The broader DEC-205 tissue expression in man is relevant to clinical DC targeting strategies and DEC-205 functional studies.

IL10 and IL12B polymorphisms each influence IL-12p70 secretion by dendritic cells in response to LPS

Dendritic cells (DC) are the main producers of the cytokine IL-12p70, through which they play a direct role in the development of IFN-gamma-secreting Th1 cells, costimulation of CTL differentiation and NK-cell activation. In contrast, IL-10, which is also produced by DC, negatively regulates IL-12 production. IL-12p70 production varies widely between individuals, and several polymorphisms in the gene encoding IL-12p40 (IL12B) have been identified that influence susceptibility and severity of infectious, autoimmune and neoplastic disease. Here we show that polymorphisms not only of IL12B, but also in the IL10 promoter, influence IL-12p70 secretion by monocyte-derived DC in response to LPS. Although IL12B promoter homozygotes were prone to making more IL-12p70, presence of the IL10 high genotype restricted IL-12p70 production in these individuals. These observations provide a further genetic control of IL-12p70 regulation and emphasize the complexity of production of this cytokine. They also suggest genotypes that might influence the outcome of DC immunotherapy.

Overcoming original antigenic sin to generate new CD8 T cell IFN-gamma responses in an antigen-experienced host

The failure to mount effective immunity to virus variants in a previously virus-infected host is known as original antigenic sin. We have previously shown that prior immunity to a virus capsid protein inhibits induction by immunization of an IFN-gamma CD8(+) T cell response to an epitope linked to the capsid protein. We now demonstrate that capsid protein-primed CD4(+) T cells secrete IL-10 in response to capsid protein presented by dendritic cells, and deviate CD8+ T cells responding to a linked MHC class I-restricted epitope to reduce IFN-gamma production. Neutralizing IL-10 while delivering further linked epitope, either in vitro or in vivo, restores induction by immunization of an Ag-specific IFN-gamma response to the epitope. This finding demonstrates a strategy for overcoming inhibition of MHC class I epitopes upon immunization of a host already primed to Ag, which may facilitate immunotherapy for chronic viral infection or cancer.

The key role of CD40 ligand in overcoming tumor-induced dendritic cell dysfunction

Overcoming dendritic cell (DC) dysfunction is a prerequisite for successful active immunotherapy against breast cancer. CD40 ligand (CD40L), a key molecule in the interface between T-lymphocytes and DCs, seems to be instrumental in achieving that goal. Commenting on our data that CD40L protects circulating DCs from apoptosis induced by breast tumor products, Lenahan and Avigan highlighted the potential of CD40L for immunotherapy. We expand on that argument by pointing to additional findings that CD40L not only rescues genuine DCs but also functionally improves populations of immature antigen-presenting cells that fill the DC compartment in patients with breast cancer.