Interleukin 10 induced augmentation of delayed-type hypersensitivity (DTH) enhances Mycobacterium bovis bacillus Calmette-Guérin (BCG) mediated antitumour activity

The double-sided effects of Mycobacterium Bovis bacillus Calmette-Guérin vaccine

Bacillus Calmette-Guérin (BCG), the only vaccine proven to be effective against tuberculosis (TB), is the most commonly used vaccine globally. In addition to its effects on mycobacterial diseases, an increasing amount of epidemiological and experimental evidence accumulated since its introduction in 1921 has shown that BCG also exerts non-specific effects against a number of diseases, such as non-mycobacterial infections, allergies and certain malignancies. Recent Corona Virus Disease 2019 (COVID-19) outbreak has put BCG, a classic vaccine with significant non-specific protection, into the spotlight again. This literature review briefly covers the diverse facets of BCG vaccine, providing new perspectives in terms of specific and non-specific protection mechanisms of this old, multifaceted, and controversial vaccine.

Identification of Secreted O-Mannosylated Proteins From BCG and Characterization of Immunodominant Antigens BCG_0470 and BCG_0980

Bacterial glycoproteins have been investigated as vaccine candidates as well as diagnostic biomarkers. However, they are poorly understood in Mycobacterium bovis strain bacille Calmette-Guérin (BCG), a non-pathogenic model of Mycobacterium tuberculosis. To understand the roles of secreted O-mannosylated glycoproteins in BCG, we conducted a ConA lectin-affinity chromatography and mass spectra analysis to identify O-mannosylated proteins in BCG culture filtrate. Subsequent screening of antigens was performed using polyclonal antibodies obtained from a BCG-immunized mouse, with 15 endogenous O-mannosylated proteins eventually identified. Of these, BCG_0470 and BCG_0980 (PstS3) were revealed as the immunodominant antigens. To examine the protective effects of the antigens, recombinant antigens proteins were first expressed in Mycobacterium smegmatis and Escherichia coli, with the purified proteins then used to boost BCG primed-mice. Overall, the treated mice showed a greater delayed-type hypersensitivity response in vivo, as well as stronger Th1 responses, including higher level of IFN-γ, TNF-α, and specific-IgG. Therefore, mannosylated proteins BCG_0470 and BCG_0980 effectively amplified the immune responses induced by BCG in mice. Together, our results suggest that the oligosaccharide chains containing mannose are the antigenic determinants of glycoproteins, providing key insight for future vaccine optimization and design.

Genomic and Therapeutic Landscape of Non-muscle-invasive Bladder Cancer

Non-muscle-invasive bladder cancer (NMIBC) is heterogeneous, but current diagnostic and treatment strategies rely primarily on clinical parameters, lacking individualization to tumor and host genetics and biology. The heterogeneity of NMIBCs is derived from mutations, mutation signatures, chromosomal loss, and disruption of molecular pathways, which ultimately affects tumor progression, recurrence, and responsiveness to intravesical and systemic chemotherapy. Although research is still underway, advances in sequencing technology, insight into differential bacillus Calmette-Guérin responses, and new investigational treatment targets will soon offer clinicians new, precision-based tools to risk stratify and determine treatment regimens for future patients with bladder cancer.

Predictors of Response to Intravesical Therapy

Despite the 40-year reign of bacillus Calmette-Guérin (BCG) as the most effective immunotherapy in urologic cancers, a lack of clinical tools to predict treatment response has hampered progress in the field. Acting as an immunostimulatory agent against a multitude of phenotypically diverse non-muscle-invasive bladder cancers, response to BCG likely depends on both tumor characteristics as well as host factors. With a deeper understanding of the tumor biology as well as the mechanism of action underpinning immunotherapy, newer and more effective clinical tools are being constructed to improve patient selection.

Anti-IL-10-mediated Enhancement of Antitumor Efficacy of a Dendritic Cell-targeting MIP3α-gp100 Vaccine in the B16F10 Mouse Melanoma Model Is Dependent on Type I Interferons

The chemokine MIP3α (CCL20) binds to CCR6 on immature dendritic cells. Vaccines fusing MIP3α to gp100 have been shown to be effective in therapeutically reducing melanoma tumor burden and prolonging survival in a mouse model. Other studies have provided evidence that interleukin-10 (IL-10) neutralizing antibodies (αIL-10) enhance immunologic melanoma therapies by modulating the tolerogenic tumor microenvironment. In the current study, we have utilized the B16F10 syngeneic mouse melanoma model to demonstrate for the first time that a therapy neutralizing IL-10 enhances the antitumor efficacy of a MIP3α-gp100 DNA vaccine, leading to significantly smaller tumors, slower growing tumors, and overall increases in mouse survival. The additive effects of αIL-10 were not shown to be correlated to vaccine-specific tumor-infiltrating lymphocytes (TILs), total TILs, or regulatory T cells. However, we discovered an upregulation of IFNα-4 transcripts in tumors and a correlation of increased plasmacytoid dendritic cell numbers with reduced tumor burden in αIL-10-treated mice. Interferon α receptor knockout (IFNαR1) mice received no benefit from αIL-10 treatment, demonstrating that the additional therapeutic value of αIL-10 is primarily mediated by type I IFNs. Efficient targeting of antigen to immature dendritic cells with a chemokine-fusion vaccine provides an effective anticancer therapeutic. Combining this approach with an IL-10 neutralizing antibody therapy enhances the antitumor efficacy of the therapy in a manner dependent upon the activity of type I IFNs. This combination of a vaccine and immunomodulatory agent provides direction for future optimization of a novel cancer vaccine therapy.

Immunotherapy and Radiation - A New Combined Treatment Approach for Bladder Cancer?

Recently, immunotherapy with checkpoint inhibitors has been showing promise in clinical trials for stage IV bladder cancer. Herein, we review the literature regarding the role for radiation therapy, the role for immunotherapy, and the potential synergy of these treatments combined in bladder cancer. There is ample pre-clinical data in a number of different tumor models, coupled with a growing body of clinical evidence in melanoma and other malignancies to suggest combining radiation and immunotherapy could lead to substantial advances in treatment outcomes for bladder cancer. Yet, these data for bladder cancer remain at the pre-clinical stage, and further study is needed.

Immunotherapy for urothelial cancer: from BCG to checkpoint inhibitors and beyond

Since its introduction almost 40 years ago, intravesical BCG for non-muscle invasive bladder cancer remains one of the most successful cancer immunotherapies. However, up to 40% of patients will progress after BCG therapy and develop invasive bladder cancer. Despite its extensive clinical use, we are only beginning to understand how BCG works. Here we review preclinical and clinical data that implicate BCG-induced Th1 and cytotoxic cellular immune responses in cancer regression. We propose that future immunotherapies should aim to augment Th1 and/or cellular responses in those that fail BCG therapy. We review clinical trials of immunotherapy in bladder cancer with a focus on the promising role of checkpoint blockade inhibitors that target the programmed cell death 1/programmed death-ligand 1 (PD-L1) axis and/or cytotoxic T lymphocyte antigen 4.

Inflammation and Urothelial Bladder Cancer: What we Need to Known? (Review)

 The association between inflammation and bladder cancer has been debated in several studies, highlighting that inflammation may be a crucial component both in tumor development or progression. On the other hand, several authors suggest that the presence of an inflammatory cell infiltrate within the urothelial bladder cancer is a good prognostic predictor in terms of recurrence-free survival time. The question is: What is the prognostic role of inflammation in patients affected by urothelial bladder cancer? On one hand, chronic inflammation should be considered a risk factor in developing bladder cancer, as demonstrated by Schistosoma haematobium infection and, on the other hand, the inflammation induced by the Bacillus Calmette-Guérin intravesical therapy has a protective effect on cancer recurrence. Recently, some authors highlight that the presence of an inflammatory cell infiltrate within the urothelial bladder cancer is a good prognostic predictor in terms of recurrence-free survival time, due to the host generating angiogenic stimulation of a local inflammatory reaction against cancer. This is probably due to the angiogenetic stimulation of a local inflammatory reaction generated by the host against superficial bladder cancer. However, the debate is still open. This review will summarize recent data regarding inflammation and urothelial cell carcinoma, with special emphasis on the role that the inflammatory response is likely to have on recurrence risk and progression in superficial bladder cancer patients.

Anti-interleukin-10R1 monoclonal antibody in combination with bacillus Calmette--Guérin is protective against bladder cancer metastasis in a murine orthotopic tumour model and demonstrates systemic specific anti-tumour immunity

Effective treatment of bladder cancer with bacillus Calmette-Guérin (BCG) depends on the induction of a T helper type (Th) 1 immune response. Interleukin (IL)-10 down-regulates the Th1 response and is associated with BCG failure. In this study, we investigated whether blocking IL-10 signalling could enhance the BCG-induced Th1 response and anti-tumour immunity in a murine orthotopic tumour model. Treatment with BCG and anti-IL-10 receptor 1 monoclonal antibody (anti-IL-10R1 mAb) increased the interferon (IFN)-γ to IL-10 ratio in both splenocyte cultures and urine. Mice bearing luciferase-expressing MB49 (MB49-Luc) tumours were treated and followed for tumour growth by bioluminescent imaging, bladder weight and histology. Mice treated with phosphate-buffered saline (PBS) (group 1), BCG plus control immunoglobulin (Ig)G1 (group 2) or BCG plus anti-IL-10R1 mAb (group 3) showed 0, 6 and 22% tumour regression, respectively. The mean bladder weight of group 3 mice was substantially lower than those of groups 1 and 2 mice. Remarkably, 36% of group 1 and 53% of group 2 mice but no group 3 mice developed lung metastasis (P = 0·02). To investigate the mechanisms underlying the effect of combination therapy, splenocytes were stimulated with S12 peptide (serine mutation at codon 12 of the K-ras oncogene) known to be expressed in MB49-Luc cells. Induction of ras mutation-specific IFN-γ and cytotoxicity was observed in mice treated with combination therapy. These observations indicate that BCG, in combination with anti-IL-10R1 mAb, induces enhanced anti-tumour immunity that is protective against lung metastasis. Anti-IL-10R1 mAb demonstrates systemic effects and may prove useful in clinical practice for treating bladder cancer in high-risk patients.

Construction of a recombinant-BCG containing the LMP2A and BZLF1 genes and its significance in the Epstein-Barr virus positive gastric carcinoma

The signal peptide Ag85B of Bacillus Chalmette-Guerin (BCG) was used to construct a recombinant plasmid of BCG. The BCG-Ag85B gene and fused EBV LMP2A and BZLF1 genes were amplified and successively inserted into the Escherichia coli-BCG shuttle-vector pMV261. The recombinant plasmids were then amplified in E. coli DH5α and transformed into competent BCG. The expression of BZLF1 and LMP2A fusion proteins in recombinant-BCG (rBCG) was shown by Western blot. After the injection of recombinant-BCG into mice, antibodies against the fusion protein BZLF1 and LMP2A were measured by ELISA, and the cellular immune effects were determined by the lactate dehydrogenate (LDH) release assays. The results confirmed that the cloned genes of BCG-Ag85B and Z2A were correctly inserted into the vector pMV261. The recombinant plasmid pMVZ2A expressed Z2A in BCG effectively after transformation. The rBCG proteins were recognized by the BZLF1 (LMP2A) antibody. An ELISA demonstrated that rBCG could stimulate the generation of antibody against the fusion protein. The fusion gene was constructed successfully, and the rBCG induced humoral and cellular immune response in mice.

Combined bacillus Calmette–Guerin and interferon use in superficial bladder cancer

Due to its high rate of local recurrence after transurethral surgery, superficial bladder cancer is often treated with adjuvant topical intravesical chemotherapy or biological agents, such as bacillus Calmette-Guerin or interferon-alpha. Recent laboratory testing has revealed that combination interferon-alpha with bacillus Calmette-Guerin results in remarkable synergy, affecting not only bladder tumors directly but also enhancing the immune response to bacillus Calmette-Guerin by orders of magnitude. Clinical studies are now demonstrating lower toxicity with combination low-dose bacillus Calmette-Guerin/interferon regimens, while providing a much needed salvage option for previous bacillus Calmette-Guerin failures.

Immunotherapeutic strategies for bladder cancer

Bladder cancer is a common urologic malignancy with rising incidence in the elderly population. In most cases, bladder cancer is non-muscle-invasive at diagnosis and shows dramatically high recurrence rates, although current treatments often reduce the risk of disease progression. Immunotherapy using intravesical instillation of Bacillus Calmette-Guérin (BCG) remains the most effective therapy for patients with high risk tumors. However, BCG-therapy has important limitations including substantial adverse events and frequent treatment failure. Thus, it appears crucial to either improve or replace current therapy using new immunotherapeutic strategies. Here, we discuss the clinical trials that assessed therapeutic vaccination of bladder cancer patients using tumor associated antigens and we also argue for novel approaches arising from murine models. Vaccination routes to induce appropriate T-cell homing in the tumor site as well as the use of local immunostimulation to enhance recruitment of vaccine-induced T cells are discussed to highlight what we believe is a promising therapeutic vaccination strategy for patients with non-muscle-invasive bladder cancer.

From infection to immunotherapy: host immune responses to bacteria at the bladder mucosa

The pathogenesis of urinary tract infection and mechanisms of the protective effect of Bacillus Calmette-Guerin (BCG) therapy for bladder cancer highlight the importance of studying the bladder as a unique mucosal surface. Innate responses to bacteria are reviewed, and although our collective knowledge remains incomplete, we discuss how adaptive immunity may be generated following bacterial challenge in the bladder microenvironment. Interestingly, the widely held belief that the bladder is sterile has been challenged recently, indicating the need for further study of the impact of commensal microorganisms on the immune response to uropathogen infection or intentional instillation of BCG. This review addresses the aspects of bladder biology that have been well explored and defines what still must be discovered about the immunobiology of this understudied organ.

Experience with newer intravesical chemotherapy for high-risk non-muscle-invasive bladder cancer

The definitive treatment for patients with high-risk non-muscle-invasive bladder cancer (NMIBC) who fail to respond to intravesical bacillus Calmette-Guérin (BCG) is cystectomy. However, many patients who experience recurrence after BCG are either poor operative candidates or refuse surgery due to the long-term impact on their quality of life. In the last decade, there has been an increased interest in alternative intravesical therapies, and several novel chemotherapeutics have emerged as promising agents for high-risk NMIBC patients unable or unwilling to undergo cystectomy. Additionally, extended treatment regimens with combined induction and maintenance therapy have been investigated, and may increase the durability of response to these new agents, as has been shown for conventional intravesical therapy.

The immunological effect of revaccination with Bacille Calmette-Guérin vaccine at 19 months of age

BACKGROUND

Bacille Calmette-Guérin (BCG) vaccination has important non-specific immune effects. In a randomized trial in Guinea-Bissau, BCG revaccination was associated with significantly increased survival in children who received diphtheria-tetanus-pertussis (DTP)-booster vaccine before enrolment and in children who did not receive micronutrient supplementation (MN). Within the trial we assessed the immunological effects of BCG revaccination.

METHODS

Children were randomized to BCG or nothing. Blood was sampled 6-11 weeks after randomization (early sample group) or 5-9 months later (late sample group). In vitro cytokine responses (interferon (IFN)-γ, interleukin (IL)-13, tumor-necrosis-factor (TNF)-α, and IL-10) were assessed in whole blood cultures stimulated with lipopolysaccharide (LPS), purified protein derivative (PPD) or phytohaemagglutinin (PHA). Effect-modification by sex, DTP-booster vaccination and MN was studied.

RESULTS

Cytokines were measured in 345 infants. BCG was associated with significantly increased IFN-γ (geometric mean ratio (GMR)=4.54 (95% confidence interval: 3.13-6.58)) and IL-13 (GMR=1.43 (1.00-2.05)) PPD responses, the effect being strongest in the early sample group. Across all three conditions BCG tended to increase IL-10 (LPS, PHA, PPD: GMR=1.20, 1.12, 1.20), most pronounced in the late sample group. BCG reduced the TNF-α/IL-10 ratio in boys with DTP-booster at bleeding and increased it in those without (interaction test: p=0.03). In children without MN, BCG was associated with reduced TNF-α response in the early sample group (p=0.006), and increased IL-10 in the late sample group (p=0.03).

CONCLUSION

BCG revaccination resulted in a strong IFN-γ response to PPD, which waned slightly over time. BCG also affected the pro-/anti-inflammatory balance, with reduced TNF-α and increased IL-10 responses to LPS, PHA and PPD. This effect depended on sex, DTP-booster vaccination and micronutrient supplementation, being most pronounced in children who had received DTP-booster before enrolment and children who had not received MN, i.e. the group of children which also had lower mortality after BCG revaccination.

Bacillus Calmette-Guerin (BCG) immunotherapy for bladder cancer: current understanding and perspectives on engineered BCG vaccine

Since the first report in 1976, accumulated clinical evidence has supported intravesical Bacillus Calmette-Guerin (BCG) therapy as one of the standard methods of management of intermediate- and high-risk non-muscle invasive bladder cancer. Despite its efficacy, intravesical BCG therapy is associated with a variety of adverse events (AEs), most of which are tolerable or controllable with supportive care. However, some patients receiving intravesical BCG therapy may experience uncommon but severe AEs, leading to cessation of BCG therapy. Not all, but most severe AEs result from either local or systemic infection with live BCG. Intravesical instillation of BCG elicits multiple immune reactions, although the precise immunological mechanism of BCG therapy is not clear. It is convenient to separate the complex reactions into the following three categories: infection of urothelial cells or bladder cancer cells, induction of immune reactions, and induction of antitumor effects. Recently, our knowledge about each category has increased. Based on this understanding, predictors of the efficacy of intravesical BCG therapy, such as urinary cytokine measurement and cytokine gene polymorphism, have been investigated. Recently, preclinical studies using a novel engineered mycobacterium vaccine have been conducted to overcome the limitations of BCG therapy. One approach is Th1 cytokine-expressing recombinant forms of BCG; another approach is development of non-live bacterial agents to avoid AEs due to live BCG infection. We also briefly describe our approach using an octaarginine-modified liposome-incorporating BCG cell wall component to develop future substitutes for live BCG.

Blocking IL-10 enhances bacillus Calmette-Guérin induced T helper Type 1 immune responses and anti-bladder cancer immunity

Proper induction of Th1 immunity is required for effective immunotherapy of bladder cancer with the bacillus Calmette-Guérin (BCG). Interleukin-10 (IL-10) downregulates the Th1 immune response and is associated with BCG therapy failure. We evaluated BCG plus IL-10 blocking antibodies and found that this combination therapy induces enhanced Th1 immune responses and anti-bladder cancer immunity in preclinical animal models.

Prediction of response to bacillus Calmette-Guérin treatment in non-muscle invasive bladder cancer patients through interleukin-6 and interleukin-10 ratio

This study aimed to evaluate whether the interleukin-6 (IL-6) and interleukin-10 (IL-10) ratio (IL-6/IL-10) can be used as a prognostic marker of recurrence following bacillus Calmette-Guérin (BCG) therapy in patients with high-risk non-muscle invasive bladder cancer (NMIBC). One hundred and twenty-one consecutive urological patients (72 affected by high-risk NMIBC and 49 controls) were selected for this prospective study. Urine samples for dipstick and interleukin analyses were collected from each subject before surgery. All patients underwent transurethral resection of bladder tumours (TUR-BT), followed by six weekly BCG instillations. IL-6 and IL-10 concentrations in urine were determined by solid phase ELISA Quantikine IL-6 and IL-10 Immunoassay. Patients with NMIBC were stratified in accordance with IL-6/IL-10: group A ≤0.09 and group B >0.10. The main outcome measures were time to first recurrence and recurrence rate following BCG therapy. At enrolment, IL-6/IL-10 was not statistically different between patients and controls (p=0.763, degrees of freedom (df)=1, F-test result (F)=0.092). Of the 72 patients with NMIBC, 38 (52.7%) had an IL-6/IL-10 of ≤0.09 (group A), while 34 (47.3%) had an IL-6/IL-10 of >0.10 (group B). A significant difference between IL-6/IL-10 and status at follow-up was found (p=0.016, df=1, χ²=5.800). The Kaplan-Meier curves demonstrated that group B patients had a significantly higher probability of being recurrence-free than group A patients [p=0.003; recurrence rate (RR)=3.1]. At multivariate analysis, IL-6/IL-10 (p<0.003) and the number of lesions (p<0.001) were identified as independent predictors of BCG response probability. In conclusion, this study highlights the feasible role of IL-6/IL-10 in predicting recurrence following BCG therapy in high-risk NMIBC.

Bladder Cancer Immunotherapy: BCG and Beyond

Mycobacterium bovis bacillus Calmette-Guérin (BCG) has become the predominant conservative treatment for nonmuscle invasive bladder cancer. Its mechanism of action continues to be defined but has been shown to involve a T helper type 1 (Th1) immunomodulatory response. While BCG treatment is the current standard of care, a significant proportion of patients fails or do not tolerate treatment. Therefore, many efforts have been made to identify other intravesical and immunomodulating therapeutics to use alone or in conjunction with BCG. This paper reviews the progress of basic science and clinical experience with several immunotherapeutic agents including IFN-α, IL-2, IL-12, and IL-10.

Th1 cytokine-secreting recombinant Mycobacterium bovis bacillus Calmette-Guérin and prospective use in immunotherapy of bladder cancer

Intravesical instillation of Mycobacterium bovis bacillus Calmette-Guérin (BCG) has been used for treating bladder cancer for 3 decades. However, BCG therapy is ineffective in approximately 30–40% of cases. Since evidence supports the T helper type 1 (Th1) response to be essential in BCG-induced tumor destruction, studies have focused on enhancing BCG induction of Th1 immune responses. Although BCG in combination with Th1 cytokines (e.g., interferon-α) has demonstrated improved efficacy, combination therapy requires multiple applications and a large quantity of cytokines. On the other hand, genetic manipulation of BCG to secrete Th1 cytokines continues to be pursued with considerable interest. To date, a number of recombinant BCG (rBCG) strains capable of secreting functional Th1 cytokines have been developed and demonstrated to be superior to BCG. This paper discusses current rBCG research, concerns, and future directions with an intention to inspire the development of this very promising immunotherapeutic modality for bladder cancer.

Re-inventing intratumoral immunotherapy for melanoma

Immunotherapeutics have been applied intratumorally to manage accessible lesions and to induce systemic immunity in malignant melanoma. Intratumoral bacillus Calmette-Guérin (BCG) has been used for 40 years, and intratumoral BCG, IL-2, IFN-α and imiquimod are recommended as treatment options for patients with in-transit melanoma metastases. Regression of cutaneous metastases can be achieved. Subcutaneous metastases are more refractory, and regression of uninjected, visceral metastases is infrequent. Other microbial products, cytokines, chemicals, immune cells, antibody and viral and plasmid vectors expressing immunologically active molecules have been tested. Antitumor activity has not been demonstrated to be superior to that of intratumoral BCG. There are few controlled trials, and whether survival is impacted with any approach has not yet been established. The immunotherapeutics applied and the intratumoral administration procedure itself can activate responses that are immune inhibitory. More rigorous clinical testing and improved understanding and modulation of regulatory immune responses are necessary.

Mycobacterium bovis bacillus Calmette-Guérin-induced macrophage cytotoxicity against bladder cancer cells

Many details of the molecular and cellular mechanisms involved in Mycobacterium bovis bacillus Calmette-Guérin (BCG) immunotherapy of bladder cancer have been discovered in the past decades. However, information on a potential role for macrophage cytotoxicity as an effector mechanism is limited. Macrophages play pivotal roles in the host innate immunity and serve as a first line of defense in mycobacterial infection. In addition to their function as professional antigen-presenting cells, the tumoricidal activity of macrophages has also been studied with considerable interest. Studies have shown that activated macrophages are potent in killing malignant cells of various tissue origins. This review summarizes the current understanding of the BCG-induced macrophage cytotoxicity toward bladder cancer cells with an intention to inspire investigation on this important but underdeveloped research field.

The tuberculin skin test (TST) is affected by recent BCG vaccination but not by exposure to non-tuberculosis mycobacteria (NTM) during early life

The tuberculin skin test (TST) is widely used in TB clinics to aid Mycobacterium tuberculosis (M.tb) diagnosis, but the definition and the significance of a positive test in very young children is still unclear. This study compared the TST in Gambian children at 4½ months of age who either received BCG vaccination at birth (Group 1) or were BCG naïve (Group 2) in order to examine the role of BCG vaccination and/or exposure to environmental mycobacteria in TST reactivity at this age. Nearly half of the BCG vaccinated children had a positive TST (≥5 mm) whereas all the BCG naïve children were non-reactive, confirming that recent BCG vaccination affects TST reactivity. The BCG naïve children demonstrated in vitro PPD responses in peripheral blood in the absence of TST reactivity, supporting exposure to and priming by environmental mycobacterial antigens. Group 2 were then vaccinated at 4½ months of age and a repeat TST was performed at 20–28 months of age. Positive reactivity (≥5 mm) was evident in 11.1% and 12.5% infants from Group 1 and Group 2 respectively suggesting that the timing of BCG vaccination had little effect by this age. We further assessed for immune correlates in peripheral blood at 4½ months of age. Mycobacterial specific IFNγ responses were greater in TST responders than in non-responders, although the size of induration did not correlate with IFNγ. However the IFNγ: IL-10 ratio positively correlated with TST induration suggesting that the relationship between PPD induced IFNγ and IL-10 in the peripheral blood may be important in controlling TST reactivity. Collectively these data provide further insights into how the TST is regulated in early life, and how a positive response might be interpreted.

Thymic stromal lymphopoietin plays an adjuvant role in BCG-mediated CD8(+) cytotoxic T cell responses through dendritic cell activation

Although Bacillus Calmette-Guérin (BCG) has historically emerged as a potent adjuvant in cancer immunization through dendritic cell (DC) activation, the efficacy of its antitumor effect has been limited. Therefore, the strategy of adjuvant therapy using BCG needs to be improved by adding enhancers. Here we found that thymic stromal lymphopoietin (TSLP) acts as an enhancer for the BCG-mediated antitumor effect. While BCG-stimulated DCs induced CD8(+) T cell production of IFN-gamma without strong cell expansion, TSLP-stimulated DCs induced robust CD8(+) T cell expansion without high quantities of IFN-gamma production. Notably, DCs stimulated with both BCG and TSLP induced robust expansion of CD8(+) T cells that produced a large amount of IFN-gamma with a potent cytolytic activity related to granzyme B expression. Our data suggest that TSLP is a good adjuvant to enhance the BCG-mediated cytotoxic T cell effect through DC activation, and provide a functional basis for a novel strategy for antitumor immune-based therapy.

Emerging targeted therapies for bladder cancer: a disease waiting for a drug

Urothelial cell carcinoma is the fifth most common cancer and the costliest to treat. This is largely because of all new cases, about 70% present as superficial disease and this while rarely fatal, tends to recur, requiring long-term follow-up and repeat interventions. The standard of care, intravesical chemo- and immunotherapy, while effective, is associated with a considerable side-effect profile and approximately 30% of patients either fail to respond to treatment or suffer recurrent disease within 5 years. Muscle-invasive bladder cancer is life threatening, showing modest chemosensitivity, and usually requires radical cystectomy. Although bladder cancer is fairly well-genetically characterized, clinical trials with molecularly targeted agents have, in comparison to other solid tumors such as lung, breast and prostate, been few in number and largely unsuccessful, with no new agents being registered in the last 20 years. Hence, bladder cancer represents a considerable opportunity and challenge for molecularly targeted therapy.

Interleukin-10 inhibits Mycobacterium bovis bacillus Calmette-Guérin (BCG)-induced macrophage cytotoxicity against bladder cancer cells

The mechanisms underlying bacillus Calmette-Guérin (BCG) immunotherapy of bladder cancer currently remain elusive. Previously, we demonstrated that macrophages were cytotoxic to bladder cancer cells upon BCG stimulation in vitro. However, macrophages from C57BL/6 mice were less potent than those from C3H/HeN mice for the killing of bladder cancer cells. This study was to determine whether interleukin (IL)-10 produced by macrophages in response to BCG is a causative factor for the reduced cytotoxicity in BCG-stimulated C57BL/6 macrophages. Thioglycollate-elicited peritoneal macrophages were prepared and analysed for the BCG induction of cytotoxicity, cytokines and nitric oxide (NO) in vitro. Compared to BCG-stimulated C3H/HeN macrophages, BCG-stimulated C57BL/6 macrophages exhibited reduced killing of bladder cancer MBT-2 cells and MB49 cells. Studies demonstrated further that BCG-stimulated C57BL/6 macrophages produced a high level of IL-10, which correlated with reduced production of tumour necrosis factor (TNF)-alpha, IL-6 and NO. Neutralizing endogenous IL-10 during BCG stimulation increased C57BL/6 macrophage cytotoxicity against MB49 cells by 3.2-fold, along with increased production of TNF-alpha by 6.4-fold and NO by 3.6-fold, respectively. Macrophages from C57BL/6 IL-10(-/-) mice also exhibited increased killing of MB49 cells and production of TNF-alpha and NO upon BCG stimulation. In addition, supplementation of exogenous recombinant IL-10 reduced BCG-induced C3H/HeN macrophage cytotoxicity against both MBT-2 cells and MB49 cells in a dose-dependent manner. These results reveal the inhibitory role of IL-10 in BCG-induced macrophage cytotoxicity, suggesting that blockage of IL-10 may potentially enhance the effect of BCG in the treatment of bladder cancer patients.

Recombinant bacillus Calmette-Guérin (BCG) expressing interferon-alpha 2B enhances human mononuclear cell cytotoxicity against bladder cancer cell lines in vitro

PURPOSE

The proper induction of cellular immunity is required for effective bacillus Calmette-Guérin (BCG) immunotherapy of bladder cancer. It has been known that BCG stimulation of human peripheral blood mononuclear cells (PBMC) leads to the generation of effector cells cytotoxic to bladder cancer cells in vitro. To improve BCG therapy, we previously developed human interferon (IFN)-alpha 2B secreting recombinant (r) BCG (rBCG-IFN-alpha). We demonstrated that rBCG-IFN-alpha augmented T helper type 1 (Th1) cytokine IFN-gamma production by PBMC. In this study, we further investigated whether rBCG-IFN-alpha could also enhance PBMC cytotoxicity toward bladder cancer cells.

MATERIALS AND METHODS

PBMC were prepared from healthy individuals, left alone or stimulated with rBCG-IFN-alpha or control MV261 BCG, and used as effector cells in (51)Cr-release assays. Human bladder cancer cell lines T24, J82, 5637, TCCSUP, and UMUC-3 were used as target cells. To determine the role of secreted rIFN-alpha as well as endogenously expressed IFN-gamma and IL-2 in inducing the cytotoxicity, PBMC were stimulated with rBCG-IFN-alpha in the presence of neutralizing antibodies to IFN-alpha, IFN-gamma or IL-2. To determine the role of natural killer (NK) and CD8(+) T cells in inducing the cytotoxicity, both cell types were isolated after BCG stimulation of PBMC and used as effector cells in (51)Cr-release assays.

RESULTS

Non-stimulated PBMC showed basal levels of cytotoxicity against all target cell lines tested. MV261 BCG increased the PBMC cytotoxicity by 1.8- to 4.2-fold. rBCG-IFN-alpha further increased the PBMC cytotoxicity by up to 2-fold. Elevated production of IFN-gamma and IL-2 by PBMC was observed after rBCG-IFN-alpha stimulation. Blockage of IFN-alpha, IFN-gamma or IL-2 by neutralizing antibodies during rBCG-IFN-alpha stimulation reduced or abolished the induction of PBMC cytotoxicity. Both NK and CD8(+) T cells were found to be responsible for the enhanced PBMC cytotoxicity induced by rBCG-IFN-alpha with the former cell type being more predominant.

CONCLUSIONS

rBCG-IFN-alpha is an improved BCG agent that induces enhanced PBMC cytotoxicity against bladder cancer cells in vitro. This rBCG strain may serve as an alternative to BCG for the treatment of superficial bladder cancer.

Immunomodulatory effects of recombinant BCG expressing pertussis toxin on TNF-alpha and IL-10 in a bladder cancer model

BACKGROUND

Since successful treatment of superficial bladder cancer with BCG requires proper induction of Th1 immunity, we have developed a rBCG-S1PT strain that induced a stronger cellular immune response than BCG. This preclinical study was designed to compare the modulatory effects of BCG and rBCG-S1PT on bladder TNF-alpha and IL-10 expression and to evaluate antitumour activity.

METHODS

For Experiment I, the MB49 bladder cancer cell line was used in C57BL/6 mice. Chemical cauterization of the bladder was performed to promote intravesical tumor implantation. Mice were treated by intravesical instillation with BCG, rBCG-S1PT or PBS once a week for four weeks. After 35 days the bladders were removed and weighed. TNF- and IL-10 cytokine responses were measured by qPCR. Experiment II was performed in the same manner as Experiment I, except the animals were not challenged with MB49 tumor cells.

RESULTS

rBCG-S1PT immunotherapy resulted in bladder weight reduction, compared to the BCG and control group. There were increases in TNF-alpha in the BCG-treated group, as well as increases in TNF-alpha and IL-10 mRNA in the rBCG-S1PT group.

CONCLUSION

These data indicate a significant reduction of bladder tumor volume for the rBCG group, compared to the BCG and PBS groups. This suggests that rBCG could be a useful substitute for wild-type BCG and that the potential modulation between TNF-alpha and IL-10 cytokine productions may have therapeutic value.

The fibronectin attachment protein of bacillus Calmette-Guerin (BCG) mediates antitumor activity

PURPOSE

The receptor responsible for the attachment of bacillus Calmette-Guerin (BCG) to fibronectin, fibronectin attachment protein (FAP), has been cloned. Studies targeting FAP as an inducer of immunity in mycobacterial infections suggest that FAP is a highly immunogenic protein. In light of these findings and the need to find effective alternatives to BCG treatment for bladder cancer, we tested the ability of FAP to induce antitumor activity.

MATERIALS AND METHODS

The ability of FAP to bind to bladder tumor cells and the bladder wall was established using (125)I-FAP. For testing antitumor activity in vivo, mice were catheterized and 5 x 10(4) MB-49 bladder tumor cells were implanted orthotopically on day 0. Test groups were treated with PBS only, FAP, or BCG on day 1 and day 8. A subset of mice was preimmunized with FAP prior to treatment.

RESULTS

FAP was observed to bind to bladder tumor cells in a fibronectin-dependent manner. Attachment of FAP within the bladder followed the pattern established for BCG binding. Antitumor studies showed a significant reduction in tumor growth in FAP-treated mice that had been preimmunized with FAP. Tumor growth was not inhibited in naïve mice treated with FAP. Dose-response studies showed that FAP-induced antitumor activity is dose dependent, and experiments comparing BCG with FAP showed equivalent antitumor effects. In vitro experiments showed antigen-specific lymphocyte proliferation and a cytokine profile indicative of Th-1 polarization of the FAP-induced immune response. CD8+ T cells and natural killer cells were found to be required for the FAP-induced antitumor response.

CONCLUSIONS

FAP is an effective antitumor agent that inhibits tumor growth at a level equivalent to that observed for BCG. This protein may thus provide an alternative to BCG for treatment of superficial bladder cancer.

Celecoxib has potent antitumour effects as a single agent and in combination with BCG immunotherapy in a model of urothelial cell carcinoma

OBJECTIVES

Prostaglandin E2 (PGE2) is a potent immune modulator and known to suppress both tumour antigen-specific helper T (TH1) cells and the generation of cytotoxic T lymphocytes (CTLs). We hypothesised that a combination of the cyclooxygenase 2 (COX-2) selective inhibitor celecoxib and intravesical bacillus Calmette-Guérin (BCG), an effective tumour immunoprophylaxis and ablative therapy for non-muscle-invasive bladder cancer, would be more effective than BCG alone.

METHODS

We assessed urinary levels of PGE2 in humans receiving BCG and in a murine model of urothelial cell carcinoma (UCC). The cytokine response to BCG plus celecoxib was assessed in murine dendritic cells (DCs) in vitro and tumour ablation was assessed in an orthotopic MBT2 murine bladder cancer model.

RESULTS

Administration of intravesical BCG resulted in elevated urinary PGE2 levels in patients with high-grade superficial UCC and in a mouse model of UCC. In vitro, activation of DCs with BCG stimulated COX-2 up-regulation and release of the archetypal tolerogenic factors, PGE2 and interleukin 10. In a superficial mouse model of UCC, combination of celecoxib and intravesical BCG therapy resulted in increased tumour infiltration of CD4+ T cells and improved efficacy when compared to BCG alone. Further, celecoxib demonstrated marked antitumour efficacy when administered in the absence of BCG immunotherapy.

CONCLUSIONS

This study demonstrates that a combination strategy involving BCG immunotherapy and celecoxib may be more therapeutically beneficial than stand-alone intravesical therapy.

Interleukin-6/10 Ratio as a Prognostic Marker of Recurrence in Patients With Intermediate Risk Urothelial Bladder Carcinoma

PURPOSE

Several potential markers have been investigated to improve the noninvasive diagnosis of recurrent superficial bladder carcinoma. We evaluated the role of the interleukin-6/10 ratio as a prognostic marker of recurrence in patients with intermediate risk superficial bladder carcinoma.

MATERIALS AND METHODS

A total of 65 consecutive urological patients seen in the office, including 41 with intermediate risk superficial bladder carcinoma and 24 controls, were selected for this prospective study. Five urine samples for urinary cytology and interleukin analyses were collected from each subject at baseline, and 3, 6, 9 and 12 months after surgery, respectively. Interleukin-6 and 10 were determined in urine by the Quantikine solid phase interleukin-6 and 10 enzyme-linked immunosorbent assay, respectively. Sensitivity, specificity, and positive and negative predictive values of the method were calculated.

RESULTS

At baseline sample collection the interleukin-6/10 ratio was not statistically different between patients and controls (p = 0.58). Interleukin-6/10 was statistically different between patients with vs without recurrence 3 (0.009 vs 0.408), 6 (0.011 vs 0.268), 9 (0.012 vs 0.288) and 12 months (0.009 vs 0.302) after pre-transurethral bladder tumor resection (each p <0.001). Multivariate analysis indicated that interleukin-6/10 was an independent prognostic factor of recurrence (HR 3.62, 95% CI 2.80-4.92, p <0.001). Test sensitivity and specificity were 0.83% (95% CI 0.57-0.95) and 0.76% (95% CI 0.45-0.93), respectively.

CONCLUSIONS

The current study highlights the feasible role of the interleukin-6/10 ratio for predicting intermediate risk superficial bladder carcinoma recurrence. However, clinical trials with a greater number of patients are needed to consider its use in clinical urological practice.

Dose-dependent synergy of Th1-stimulating cytokines on bacille Calmette-Guérin-induced interferon-gamma production by human mononuclear cells

Successful bacille Calmette-Guérin (BCG) immunotherapy of bladder cancer depends on the proper induction of a T helper-type 1 (Th1) immune response. In this study we investigated the possible involvement of Th1-stimulating cytokines in BCG-induced interferon (IFN)-gamma production as well as their potential roles in enhancing BCG-induced IFN-gamma from human peripheral blood mononuclear cells (PBMCs). BCG efficiently induced IFN-gamma production by PBMCs in a dose-dependent manner. Neutralization of endogenous cytokines interleukin (IL)-2, IL-12 and IFN-alpha reduced BCG-induced IFN-gamma by 38%, 67% and 49%, respectively. Although single recombinant (r) IL-2, rIL-12 and rIFN-alpha induced no or a marginal amount of IFN-gamma, a combination of any two or three cytokines increased IFN-gamma production. When BCG (a subsaturated dose) was combined with mono, dual or triple cytokines, a synergy on IFN-gamma production was observed. Such a synergy was readily achievable even when minimal or low doses of cytokines were used. No saturation of IFN-gamma production was observed even when a subsaturated BCG dose was combined with very high doses of cytokines. A robust IFN-gamma production was also observed when a minimal BCG dose was combined with minimal doses of triple cytokines. In addition, we demonstrated that IL-2- and IFN-alpha-expressing rBCGs were superior to wild-type BCG for PBMC IFN-gamma induction and that combination of both rBCGs showed a synergy in IFN-gamma production. Taken together, these results suggest that combination of BCG with certain exogenous or endogenous (expressed by rBCGs) Th1-stimulating cytokines is a rational candidate for further study in bladder cancer treatment.

Discriminators of mouse bladder response to intravesical Bacillus Calmette-Guerin (BCG)

Background

Intravesical Bacillus Calmette-Guerin (BCG) is an effective treatment for bladder superficial carcinoma and it is being tested in interstitial cystitis patients, but its precise mechanism of action remains poorly understood. It is not clear whether BCG induces the release of a unique set of cytokines apart from its pro-inflammatory effects. Therefore, we quantified bladder inflammatory responses and alterations in urinary cytokine protein induced by intravesical BCG and compared the results to non-specific pro-inflammatory stimuli (LPS and TNF-α). We went further to determine whether BCG treatment alters cytokine gene expression in the urinary bladder.

Methods

C57BL/6 female mice received four weekly instillations of BCG, LPS, or TNF-α. Morphometric analyses were conducted in bladders isolated from all groups and urine was collected for multiplex analysis of 18 cytokines. In addition, chromatin immune precipitation combined with real-time polymerase chain reaction assay (CHIP/Q-PCR) was used to test whether intravesical BCG would alter bladder cytokine gene expression.

Results

Acute BCG instillation induced edema which was progressively replaced by an inflammatory infiltrate, composed primarily of neutrophils, in response to weekly administrations. Our morphological analysis suggests that these polymorphonuclear neutrophils are of prime importance for the bladder responses to BCG. Overall, the inflammation induced by BCG was higher than LPS or TNF-α treatment but the major difference observed was the unique granuloma formation in response to BCG. Among the cytokines measured, this study highlighted the importance of IL-1β, IL-2, IL-3, IL-4, IL-6, IL-10, IL-17, GM-CSF, KC, and Rantes as discriminators between generalized inflammation and BCG-specific inflammatory responses. CHIP/Q-PCR indicates that acute BCG instillation induced an up-regulation of IL-17A, IL-17B, and IL-17RA, whereas chronic BCG induced IL-17B, IL-17RA, and IL-17RB.

Conclusion

To the best of our knowledge, the present work is the first to report that BCG induces an increase in the IL-17 family genes. In addition, BCG induces a unique type of persisting bladder inflammation different from TNF-α, LPS, and, most likely, other classical pro-inflammatory stimuli.

Mycobacterium bovis bacillus Calmette-Guérin (BCG) induces human CC- and CXC-chemokines in vitro and in vivo

Both CC- and CXC-chemokines are known to be potent leucocyte activators and chemoattractants and play important roles in inflammatory responses. However, chemokine response to bacillus Calmette-Guérin (BCG) infection remains incompletely defined. In this study, we investigated human CC- [macrophage-derived chemokine (MDC), monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha and eosinophil chemoattractant activity (eotaxin)] and CXC-interferon-inducible protein (IP)-10 chemokine production in response to BCG stimulation. BCG efficiently induced all chemokines tested in the urine of four bladder cancer patients undergoing intravesical BCG immunotherapy. The peak urinary chemokine responses occurred generally between the fourth and sixth weekly treatment, except eotaxin, which was less predictable. To evaluate the effect of BCG on induction of chemokines in vitro, urothelial cell lines and peripheral blood mononuclear cells (PBMCs) were used. Although BCG induced no or marginal chemokines from urothelial SV-HUC-1, RT4 and T24 cells, BCG-derived cytokines [interleukin (IL)-1beta, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha] induced all chemokines tested except eotaxin from these cell lines. BCG also efficiently induced all chemokines tested except eotaxin from PBMCs of both BCG-naive and BCG-vaccinated subjects. MCP-1 and MIP-1alpha emerged at 4-5 h post-BCG exposure (early chemokines); IP-10 elevated at day 1 and peaked at day 2 (intermediate chemokine); and MDC elevated at day 1 and peaked at day 7 (late chemokine). This kinetic pattern was paralleled with that of BCG-induced cytokines [early: TNF-alpha; intermediate: IL-6 and IL-10; and late: IFN-gamma and granulocyte-macrophage colony-stimulating factor (GM-CSF)]. Taken together, these results indicate that BCG directly or indirectly induces human CC- and CXC-chemokine production, which may represent one of the mechanisms by which BCG exerts its anti-tumour activity.

Cytokine gene polymorphisms can alter the effect of Bacillus Calmette-Guérin (BCG) immunotherapy

Various types of cancer are more frequent in men than women, and bladder cancer is one of the most common of these. Intravesical instillation of Bacillus Calmette-Guérin (BCG) after transurethral resection is the most effective treatment for superficial bladder cancers. The main aim of this study was to investigate for possible links between cytokine gene polymorphisms and different outcomes after BCG immunotherapy. Sixty patients who had been diagnosed with transitional cell cancer were investigated. All genotyping experiments were performed using polymerase chain reaction sequence-specific primers and a commercially available kit. The genes investigated were those that code for interleukin (IL)-1alpha, IL-1beta, IL-1R, IL-1RA, IL-4RA, IL-2, IL-4, IL-6, IL-10, IL-12, interferon-gamma (IFN-gamma), transforming growth factor-beta (TGF-beta), and tumor necrosis factor-alpha (TNF-alpha). Analyses of the data identified TGF-beta codon 25 GG (92.85% vs. 64.44%, p=0.04, OR=7.17), IL-4 -1098 GG (16.6% vs. 0.0%, p=0.05, OR=18.33), IL-10 -1082 GG (28.5% vs. 6.8%, p=0.05, OR=5.47), and IL-10 -1082 GCC/GCC (28.57% vs. 4.5%, p=0.025, OR=8.4) polymorphisms as risk factors for progression of bladder cancer.

Uroepithelial cells can directly respond to Mycobacterium bovis bacillus Calmette-Guérin through Toll-like receptor signalling

OBJECTIVE

To investigate, in a human urinary tract cell line, the interaction of Toll-like receptor (TLR) signals with cytoplasmic adapter proteins MyD88 and bacillus Calmette-Guérin (BCG), and evaluate the epithelial cytokine response to BCG infection. Intravesical BCG therapy is effective against carcinoma in situ and as prophylaxis for recurrence, but although immunological mechanisms have been assumed, the mechanisms of the antitumour effects of BCG have not been completely elucidated.

MATERIALS AND METHODS

The cell line was first screened for TLR expression by reverse transcription-polymerase chain reaction (RT-PCR). Total RNA was isolated from a human urinary cell line, Hu35E6E7, and cDNA synthesised. PCR was used to measure the gene expression of TLR-2, -3, -4, -5, -9, MyD88, MD-2, CD14 and interleukin-8 and -6. The Hu35E6E7 cell line was cultured in keratinocyte serum-free medium, and BCG was added to the cell culture. After Hu35E6E7 cells were stimulated by BCG for various periods, the total RNA of the cells was extracted. Quantitative real-time PCR was conducted for MyD88 using appropriate probes, and the expression of MyD88 analysed. The cell supernatant was collected, and the levels of interferon-gamma, tumour necrosis factor-alpha, interleukin-2, -12, -4, -6, -10, -8 and -1beta were assayed using an enzyme-linked immunosorbent assay.

RESULTS

Uroepithelial cells expressed TLR-2, -3, -4 and -9, and MyD88, MD2, CD14, interleukin-6 and -8 were also detected. At 3, 6, 9 and 12 h after adding BCG, quantitative PCR assay showed that the expression of MyD88 was maximal at 6 h. The presence of BCG stimulated the release only of interleukin-6 and -8 from Hu35E6E7 cells after 6 h. By contrast, interferon-gamma, tumour necrosis factor-alpha, interleukin-2, -12, -4, -10 and -1beta were not detected in the culture supernatant.

CONCLUSION

These results show that uroepithelial cells, but not immune cells, responded directly to BCG through TLR signalling. Further investigation is needed to determine the role of cytokines released from uroepithelial cells after BCG infection.

AdCD40LGene Therapy Counteracts T Regulatory Cells and Cures Aggressive Tumors in an Orthotopic Bladder Cancer Model

PURPOSE

The aim of this study was to develop an immunostimulating gene therapy for the treatment of orthotopic bladder carcinoma by transferring the gene for CD40L into the tumor site. CD40L stimulation of dendritic cells induces interleukin-12 expression that drives Th1 type of immune responses with activation of cytotoxic T cells.

EXPERIMENTAL DESIGN

The gene for murine CD40L was transferred into bladders of tumor-bearing mice using an adenoviral vector construct. To facilitate viral uptake, the bladders were pretreated with Clorpactin. Survival of mice as well as transgene expression and immunologic effect, such as resistance to tumor challenge and presence of T regulatory cells, were monitored.

RESULTS

On viral vector instillation, CD40L expression could be detected by reverse transcription-PCR. As a sign of transgene function, interleukin-12 (IL-12) expression was significantly increased. AdCD40L gene therapy cured 60% of mice with preestablished tumors. The cured mice were completely resistant to subcutaneous challenge with MB49 tumor cells, whereas the growth of a syngeneic irrelevant tumor was unaltered. Furthermore, the mRNA expression level of the T regulatory cell transcription factor Foxp3 was evaluated both in tumor biopsies and lymph nodes. There were no differences within the tumors of the different treatment groups. However, Foxp3 mRNA levels were down-regulated in the lymph nodes of AdCD40L-treated mice. Correspondingly, T cells from AdCD40L-treated mice were not able to inhibit proliferation of naive T cells as opposed to T cells from control-treated, tumor-bearing mice.

CONCLUSIONS

AdCD40L gene therapy evokes Th1 cytokine responses and counteracts T regulatory cell development and/or function.

DNA vaccination using bacillus Calmette-Guerin-DNA as an adjuvant to enhance immune response to three kinds of swine diseases

In order to enhance the immune efficacy of DNA vaccination, experiments were conducted to investigate the regulating effects of Bacillus Calmette-Guerin (BCG)-DNA as an adjuvant on immune responses of mice against foot-and-mouth disease (FMD), Aujeszky's disease (AjD) and classical swine fever (CSF). BCG-DNA was purified from BCG by ion-exchange chromatography. Three DNA vaccines (pVSG, pVgD and pVE2) against the respective infection were constructed, and BCG-DNA was coimmunized to mice by muscle injection. The results showed that titres of specific immunoglobulin (Ig)G to the vaccines mounted remarkably in the sera of the adjuvant covaccinated mice (P < 0.01). Antibody isotype IgG2a and IgG1 also increased, respectively, in mice coimmunized with BCG-DNA compared with those of the control groups (P < 0.01). Cellular immune cytokine interferon-gamma and cytotoxic T lymphocytes were detected in coimmunized BCG-DNA groups (P < 0.05). Whereas interleukin-4, humoral immune cytokine, was not significant (P > 0.05). These results suggest that codelivery of BCG-DNA with DNA vaccines against FMD, AjD and CSF can enhance the induction of antigen-specific, especially, cell-mediated immunity.

The immunotherapy of prostate and bladder cancer

The role of the immune system in controlling the growth of tumour cells is highly complex and has been extensively debated. It is well documented that the immune system controls virally induced cancers, and there is evidence for a role of specific immunity in other types of tumours. The greater understanding of the regulation and optimization of adoptive, specific immune responses, and the better characterization of tumour-associated antigens indicate the way for active specific vaccination and cell therapy in urological tumours. Currently, bacille Calmette Guerin immunotherapy is established for localized bladder cancer and many experimental immunotherapies are under evaluation. Here we review some timely aspects of tumour immunology, and describe the current status and development of immunotherapy in prostate and bladder cancer.

Cyclooxygenase-2 inhibition: a potential mechanism for increasing the efficacy of bacillus calmette-guerin immunotherapy for bladder cancer

PURPOSE

Intravesical bacillus Calmette-Guerin (BCG) therapy is the principal treatment for high risk, noninvasive urothelial carcinoma and carcinoma in situ of the bladder. However, up to 40% of patients fail to respond to this treatment. In this study the potential for inhibition of PGE2 production by BCG treated dendritic cells (DCs) was studied in the context of preferential polarization of the immune response toward a cancer clearing T-helper type 1 immune response.

MATERIALS AND METHODS

Murine bone marrow derived DCs were cultured with interleukin (IL)-4 and granulocyte-macrophage colony-stimulating factor. After 7 days the cells were stimulated with BCG. Cell surface expression of co-stimulatory molecules and phagocytic ability were measured by flow cytometry analysis to verify cell activation. The production of IL-10 and IL-12 was measured after DC stimulation with BCG in the presence of IL-10, prostaglandin E2(Cayman Chemical, Ann Arbor, Michigan), antiIL-10 antibody (Insight Biotechnology, Wembley, United Kingdom), NS-398 and indomethacin (Sigma, Poole, United Kingdom).

RESULTS

Prostaglandin E2 stimulated a dose dependent increase in the levels of IL-10 produced by BCG activated DCs (p <0.01). IL-10 significantly decreased IL-12 production (p <0.001), while IL-10 blockade significantly increased IL-12 levels (p <0.05). The COX-2 selective inhibitor NS-398 caused a dose dependent increase in the concentration of IL-12 produced by BCG activated DCs (p <0.01). This effect was also seen with the partially selective COX-1 inhibitor indomethacin (p <0.05).

CONCLUSIONS

The inhibition of PGE2 synthesis by COX inhibition favored the production of IL-12 by BCG activated DC. This potentially will result in the generation of a T-helper type 1, polarized T-cell response that may improve the efficacy of BCG therapy.

Role of urothelial cells in BCG immunotherapy for superficial bladder cancer

Intravesical instillation of Bacillus Calmette-Guérin (BCG) is used for the treatment of superficial bladder cancer, both to reduce the recurrence rate of bladder tumour and to diminish the risk of progression. Since its first therapeutic application in 1976, major research efforts have been directed to decipher the exact mechanism of action of the BCG-associated antitumour effect. Bacillus Calmette-Guérin causes an extensive local inflammatory reaction in the bladder wall. Of this, the massive appearance of cytokines in the urine of BCG-treated patients stands out. Activated lymphocytes and macrophages are the most likely sources of these cytokines, but at present other cellular sources such as urothelial tumour cells cannot be ruled out. Bacillus Calmette-Guérin is internalised and processed both by professional antigen-presenting cells and urothelial tumour cells, resulting in an altered gene expression of these cells that accumulates in the presentation of BCG antigens and secretion of particular cytokines.

Interim results from a national multicenter phase II trial of combination bacillus Calmette-Guerin plus interferon alfa-2b for superficial bladder cancer

PURPOSE

Interim results are provided from a large multicenter trial of combination bacillus Calmette-Guerin (BCG) plus interferon (IFN) alfa-2b for BCG naive (BCG-N) and previous BCG failure (BCG-F) cases of superficial bladder cancer.

MATERIALS AND METHODS

A total of 490 patients enrolled from May 1999 to May 2000 with a median of 24 months of followup were analyzed. The BCG-N group (259) was treated with a 6-week induction course of standard dose BCG plus 50 million units of IFN followed by 3, 3-week maintenance cycles of reduced dose BCG (1/3 to 1/10) plus 50 million units IFN at 3, 9 and 15 months after induction. The BCG-F group (231) was treated similarly except induction therapy began at a decreased (1/3 to 1/10) BCG dose.

RESULTS

The simple tumor recurrence rates for BCG-N and BCG-F groups were 40% and 52%, and the Kaplan-Meier estimates for disease freedom at 24 months were 57% and 42%, respectively. Progression to muscle invasion occurred in 5% and 4.3% while metastasis occurred in 2.3% and 2.6%, respectively. In each group 3.9% of patients underwent cystectomy and 2 patients in each group died of bladder cancer. Serious adverse events occurred in 5.5% with infection related serious adverse events being less prevalent in the BCG-F group (2.6% vs 5.4%). Toxicity related dropout, treatment delay and/or further BCG dose reduction, and need for symptomatic drugs were similar. Moderate to severe local side effects during induction were higher in the BCG-F group (6.2% vs 16.9%) but equilibrated during maintenance therapy. Systemic reactions were rare.

CONCLUSIONS

This multicenter trial provides a benchmark for the efficacy and safety of combination BCG and IFN as up front and salvage therapy. The incremental value of IFN cannot be determined from this study.

Recombinant Mycobacterium bovis bacillus Calmette-Guérin (BCG) expressing mouse IL-18 augments Th1 immunity and macrophage cytotoxicity

Interleukin-18 (IL-18) has been demonstrated to synergize with BCG for induction of a T-helper-type 1 (Th1) immune response. Since successful treatment of superficial bladder cancer with BCG requires proper induction of Th1 immunity, we have developed a recombinant (r) BCG strain that functionally secretes mouse (m) IL-18. This rBCG-mIL-18 strain significantly increased production of the major Th1 cytokine IFN-gamma in splenocyte cultures, at levels comparable to that elicited by control BCG plus exogenous rIL-18. IFN-gamma production by splenocytes was eliminated by addition of neutralizing anti-IL-18 antibody. Endogenous IL-12 played a favourable role whereas IL-10 played an adverse role in rBCG-mIL-18-induced IFN-gamma production. Enhanced host antimycobacterial immunity was observed in mice infected with rBCG-mIL-18 which showed less splenic enlargement and reduced bacterial load compared to control mice infected with BCG. Further, splenocytes from rBCG-mIL-18-infected mice, in response to BCG antigen, displayed increased production of IFN-gamma and GMCSF, decreased production of IL-10, elevated cellular proliferation and higher differentiation of IFN-gamma-secreting cells. rBCG-mIL-18 also enhanced BCG-induced macrophage cytotoxicity against bladder cancer MBT-2 cells in a dose-dependent manner. Neutralizing all endogenous macrophage-derived cytokines tested (IL-12, IL-18 and TNF-alpha) as well as IFN-gamma severely diminished the rBCG-mIL-18-induced macrophage cytolytic activity, indicating a critical role for these cytokines in this process. Cytokine analysis for supernatants of macrophage-BCG mixture cultures manifested higher levels of IFN-gamma and TNF-alpha in rBCG-mIL-18 cultures than in control BCG cultures. Taken together, this rBCG-mIL-18 strain augments BCG's immunostimulatory property and may serve as a better agent for bladder cancer immunotherapy and antimycobacterial immunization.