Presence of interleukin-2 in urine of superficial bladder cancer patients after intravesical treatment with bacillus Calmette-Guérin

Summary Urine samples were obtained from patients with superficial bladder cancer after immunotherapy with bacillus Calmette-Guérin (BCG). The patients were repeatedly (once a week for 6 consecutive weeks) treated with intravesical administration of approximately 5 × 10⁸ culturable particles of BCG. Some patients received more than six BCG instillations. The urine samples were investigated for the presence of interleukin-2 (IL-2) in an in vitro bioassay using a murine cytotoxic T cell line (CTTL-16) that shows IL-2-dependent growth. Preliminary experiments indicated the presence of inhibitory factors in the urine. This inhibitory activity was abolished after 24 h dialysis. In a neutralization assay with both polyvalent and monoclonal anti-(human IL-2) antibody it was demonstrated that there was indeed IL-2 in the urine samples. In 8 of 11 patients the presence of IL-2 in the urine was demonstrated. The IL-2 production was directly related to the BCG administration as samples obtained just before the BCG instillation were always negative. In IL-2-positive samples a maximum level of IL-2 was observed between 2 h and 6 h after the BCG instillation. In urine samples obtained 24 h after the BCG IL-2 was not detected. In most patients the urine became positive after the third or fourth BCG instillation     

Presence of activated lymphocytes in the urine of patients with superficial bladder cancer after intravesical immunotherapy with bacillus Calmette-Guérin

Summary To study the mode of action of intravesical bacillus Calmette-Guérin (BCG) immunotherapy in the prevention and cure of superficial bladder cancer, flow-cytofluorometric analysis of the cellular immunological reaction in the urine of patients was performed. Fresh urinederived leucocytes were obtained from eight patients before (t ₀) and 24 h (t ₂₄) and 48 h (t ₄₈) after repeated intravesical BCG instillations (at least 5 instillations). For two patients urine-derived leucocytes were investigated at the first BCG instillation. The number of leucocytes in the urine was markedly increased 24 h after repeated BCG instillations, indicating a local cellular immunological reaction induced by BCG. The mean number of cells per milliliter of urine at that time was 2.9×10⁶±3.6×10⁶ (n = 8). These leucocytes consisted mainly of granulocytes (75±11%,n = 8). In addition monocytes/macrophages (4±2%,n = 8) and T lymphocytes were present (1±1%,n = 5). The relative increase of monocytes/macrophages in the urine after BCG application tended to be higher compared to the other leucocyte subtypes. As T lymphocytes may play an important role in the BCG-mediated antitumour activity, subsets of lymphocytes were further characterized att ₀,t ₂₄, andt ₄₈ after repeated BCG instillations. The lymphocyte population consisted mainly of T cells (86% CD3⁺,t ₀). Most of the T cells were CD4⁺ (helper/inducer) and were significantly decreased at 48 h (62±9% att ₀ vs 49±6% att ₄₈). Lymphocytes partly expressed HLA-DR antigens (44%,t ₀). The percentage of lymphocytes with interleukin-2 (IL-2) receptors (CD25⁺) was significantly increased at 24 h and 48 h, compared to pre-instillation values (19±11% and 10±4% vs 3±3% respectively). Natural killer cells (CD 16⁺ and/or CD56⁺) and B cells (CD 19⁺) were less numerous (10% and 19% att ₀ respectively). After the first BCG instillation the increase in the number of leucocytes in urine seemed to be less compared to the numbers after repeated BCG instillations. Lymphocytes could not be detected in the urine collected before or after the first BCG instillation. In conclusion, we demonstrated the presence of considerable numbers of leucocytes in the urine 24 h after repeated BCG instillations, i.e. shortly after immunological activation. The antigen expression of the lymphocytes suggested that they may represent the lymphocytes in the bladder wall. Expression of HLA-DR and IL-2 receptors on lymphocytes indicated activation of T cells by the intravesical BCG treatment. These leucocytes may be useful for functional studies, which are essential to elucidate the actual effector mechanism(s) in the mode of action of BCG against superficial bladder cancer in man.     

DNA ploidy and immunomarking of bladder urothelial tumors before and after intravesical bacillus Calmette-Guérin treatment

OBJECTIVE: To investigate DNA ploidy and immunoexpression of Ki-67 and p53 as predictivefactors in cases of superficial urothelial cell carcinoma (UCC) treated with bacillus Calmette-Guérin (BCG). STUDY DESIGN: Samples were obtained from 66 patients with UCC (pTa grade 3 or high grade and pT1 independent of grade or with concomitant carcinoma in situ) before and after intravesical BCG treatment. DNA ploidy analysis (ploidy balance, degree of hyperploidy and aneuploidy, proliferation index) was done by static cytometry. Ki-67 and p53 were analyzed immunohistochemically in paraffin-embedded tissue, and their quantification was carried out using an image analysis system. RESULTS: During a mean follow-up of 63.8 months, 31 of the 66 patients developed recurrent tumors (46.9%). DNA ploidy analysis showed that ploidy balance as well as degree of hyperploidy and aneuploidy were not statistically different between recurrent and nonrecurrent tumors. Only proliferation index was statistically significant between recurrent and nonrecurrent tumors. No statistically significant difference was observed in the percentage of Ki-67- and p53-positive cells between primary tumors that recurred and those that did not. CONCLUSION: These findings suggest that only proliferation index has predictive value for recurrence and progression in UCC treated with BCG.     

Induction of urinary interleukin-1 (IL-1), IL-2, IL-6, and tumour necrosis factor during intravesical immunotherapy with bacillus Calmette-Guérin in superficial bladder cancer

Summary To study the local immunological effects of intravesical bacillus Calmette-Guérin (BCG) therapy in superficial bladder cancer patients, the production of interleukin-1 (IL-1), IL-2, IL-6, tumour necrosis factor (TNF), and interferon (IFN) was investigated in the urine. Urine specimens were collected during the six weekly BCG instillations, before instillation, and 2, 4, 6, 8, and 24 h thereafter. Results were standardized to urine creatinine. In general, the concentration of IL-1 increased markedly during the first three BCG instillations, reaching a plateau from instillations 3 to 6. IL-2 was not detected after the first BCG instillation, but from the second instillation onwards the mean IL-2 concentration increased rapidly. With respect to IL-6, patients had relatively high levels in the urine after the first BCG instillation. A relatively moderate increase of the IL-6 concentration was observed during the following weeks. Like IL-2, TNF was only detected after repeated BCG instillations. Generally the highest TNF levels were found after BCG instillation 5. The presence of IFN could not be demonstrated. With respect to the occurrence of the cytokines during the first 24 h after the BCG instillation, TNF, IL-2, and IL-6 were detectable 2 h after the instillation. In contrast, IL-1 seemed to appear later, i.e. from 4 h onwards. TNF decreased most rapidly; it was nearly absent in 6-h samples. Generally IL-2 was not detectable in the 8-h samples, whereas IL-1 and IL-6 were present up to 8 h after instillation of BCG. The presence of TNF was found less frequently than the presence of IL-1, IL-2, and IL-6. Neutralization experiments indicated that most of the IL-1 present in the urine after BCG treatment was IL-1. In conclusion, activation of BCG-specific T cells was indicated by the detection of IL-2. The presence of IL-1, IL-6, and TNF might suggest activation of macrophages by intravesically administered BCG, although production by other cell types cannot be excluded. It is suggested that these cytokines, in combination with the leucocytes that are known to be recruited to the bladder in reaction to the BCG treatment, may play an important role in the antitumour activity of BCG against bladder cancer. For monitoring purposes, collection of urine might be performed during the first 6 h after BCG instillations 4–6. A correlation between the presence of cytokines in the urine and the clinical response has yet to be evaluated.     

Immune reactions in patients with superficial bladder cancer after intradermal and intravesical treatment with bacillus Calmette-Guérin

Summary The immune reactivity of patients with strongly recurrent superficial bladder cancer was followed after combined intravesical and intradermal bacillus Calmette-Guérin (BCG) immunotherapy. All patients in this study were previously treated without success with intravesical chemotherapy. The BCG treatment regimen consisted of weekly administrations with BCG (RIVM) for six consecutive weeks, both intravesically and intradermally. In this study, sera and peripheral blood leukocytes (PBL) of patients were tested serially. Besides BCG-antigen-specific reactions, e.g. skin reactivity to purified protein derivatives of Mycobacterium tuberculosis (PPD), antibody formation and antigen stimulation of PBL in vitro, non-antigen-specific immune reactivities were also measured, e.g. mitogen response and spontaneous cytotoxic activity of PBL. In addition the antibody response to bladder carcinoma antigens and the cytotoxic activity of PBL for the bladder carcinoma cell line T24 and the natural-killer-sensitive K562 cell line were investigated. The results obtained from the various assays were evaluated for their prognostic value in relation to the length of the tumor-free interval after the BCG treatment. Because sera and PBL were only obtained during the first 6 months after the BCG treatment, the immune reactivity was compared to the clinical results at that same time. At 6 months after therapy 12 out of 40 BCG-treated patients were tumor-free whereas 28 out of 40 showed a recurrence. Skin reactivity to tuberculin PPD was measured in 40 patients during a period of 3–6 months after therapy. Of patients who showed a recurrence of the tumor within 6 months, 48% of them showed a transient response or developed no response at all to PPD. In the group of patients with a longer tumor-free period (n=10), only one patient lost the response to tuberculin PPD. Although PBL of a limited number of patients were tested, it was observed that the cytotoxicity to the bladder carcinoma cell line T24, and the natural-killer-sensitive K562 cell line increased in a number of the patients (7 out of 14, and 9 out of 14 respectively). Reactivity of PBL to mitogens and subset distribution (ratio T-helper: T-suppressor/cytotoxic) were not influenced by the BCG treatment. Antibody response to mycobacterial antigen was detected in 9 out of 23 patients investigated. Of these 9 patients, 8 belonged to the group with a recurrence of the tumor within 6 months (n=17). There was no correlation between the skin reactivity and the antibody response to tuberculin PPD. Furthermore, none of the 25 patients showed an antibody response to bladder carcinoma antigens. Sera of bladder carcinoma patients (n=19) reduced the mitogen-induced proliferation of lymphocytes, compared to sera of healthy controls (n=13), indicating the presence of circulating suppressor factor(s). Our results indicate that the absence of a Mantoux conversion or the presence of transient reaction to tuberculin PPD were highly related (91%) to a relapse of the disease. On the other hand, the cytotoxic activity of PBL to T24 and K562 cell lines, or their reactivity to tuberculin PPD or mitogens, gives no predictive information about the clinical results (tumor-free interval) of the BCG therapy. Abbreviations used: BCG, bacillus Calmette-Guérin; NK, natural killer; PBL, peripheral blood leukocytes; PPD, purified protein derivative of Mycobacterium tuberculosis; ELISA, enzyme-linked immunosorbent assay     

Antiproliferative effects of bacillus Calmette-Guérin and interferon α2b on human bladder cancer cells in vitro

Direct inhibitory effects of bacillus Calmette-Guérin (BCG) and interferon 2b (IFN2b) on six human bladder carcinoma cell lines, UCRU-BL-13, UCRU-BL-17, UCRU-BL-28, 5637, T24 and J82, were studied using an in vitro proliferation assay. Effects on proliferation following exposure to BCG or IFN2b were analysed by [³H]thymidine incorporation over 7 days. BCG had an antiproliferative effect on all bladder lines, while sensitivity to IFN2b varied greatly, being as remarkably low as 1 U/ml for some lines. The antiproliferative effect was greatest when cells were exposed continuously to either agent, but was still evident with a limited exposure. When clinical concentrations were simulated in vitro, BCG+IFN2b was more effective than BCG alone and as effective as a double BCG concentration. We conclude that, in addition to their immunomodulatory effects, BCG and IFN2b directly inhibit the proliferation of human bladder cancer cells, and often at extremely low concentrations.     

Association of polymorphisms in oxidative stress genes with clinical outcomes for bladder cancer treated with Bacillus Calmette-Guérin

Genetic polymorphisms in oxidative stress pathway genes may contribute to carcinogenesis, disease recurrence, treatment response, and clinical outcomes. We applied a pathway-based approach to determine the effects of multiple single nucleotide polymorphisms (SNPs) within this pathway on clinical outcomes in non-muscle-invasive bladder cancer (NMIBC) patients treated with Bacillus Calmette-Guérin (BCG). We genotyped 276 SNPs in 38 genes and evaluated their associations with clinical outcomes in 421 NMIBC patients. Twenty-eight SNPs were associated with recurrence in the BCG-treated group (P<0.05). Six SNPs, including five in NEIL2 gene from the overall and BCG group remained significantly associated with recurrence after multiple comparison adjustments (q<0.1). Cumulative unfavorable genotype analysis showed that the risk of recurrence increased with increasing number of unfavorable genotypes. In the analysis of risk factors associated with progression to disease, rs3890995 in UNG, remained significant after adjustment for multiple comparison (q<0.1). These results support the hypothesis that genetic variations in host oxidative stress genes in NMIBC patients may affect response to therapy with BCG.     

Cytokine-mediated antitumor effect of bacillus Calmette-Guérin on tumor cells in vitro

Intravesical instillation therapy of bacillus Calmette-Guérin (BCG) is a useful modality for recurrent superficial transitional-cell carcinoma (TCC) of the urinary bladder. The mechanism of BCG effect has not yet been well characterized. BCG was tested in vitro for cytokine-mediated antiproliferative activity against T24 and KK47 cells (cell lines established from human TCC of the urinary bladder), and ACHN cells (cell line established from human renal cell carcinoma) using a modified human tumor clonogenic assay. Continuous exposure of cells to BCG at concentrations of more than 5 g/ml in the presence of peripheral blood mononuclear cells (PBMC) consisting of a mixture of 5×10⁴ monocytes/dish and 5×10⁵ lymphocytes/dish, obtained from healthy donors, significantly inhibited colony formation of T24 and ACHN cells in comparison with growth inhibition in the absence of PBMC (P<0.05). Slightly inhibited colony formation was observed with KK47 cells under the same conditions. At the same time various cytokines were measured in supernatants when BCG and the same conditioned PBMC were co-cultured. Tumor necrosis factor (TNF) and interleukin-1 (IL-1) were detected at markedly high levels at 24 h, and interferon (IFN) was detected at 120 h. IL-2 and macrophage-colony-stimulating factor were not detected. Neutralizing anti-TNF monoclonal antibody significantly reduced the anti-proliferative activity of ACHN cells, and anti-IFN antibody reduced that of T24 cells. The results obtained suggest that cytokines mediated by BCG play an important role in the antitumor activity of BCG and that the sensitivity of bladder cancer cells to the cytokines induced by BCG may differ considerably.     

Mycobacterium bovis bacillus Calmette-Guérin induces TLR2-mediated formation of lipid bodies: intracellular domains for eicosanoid synthesis in vivo

Differentiation of macrophages into foamy (lipid-laden) macrophages is a common pathological observation in tuberculous granulomas both in experimental settings as well as in clinical conditions; however, the mechanisms that regulate intracellular lipid accumulation in the course of mycobacterial infection and their significance to pathophysiology of tuberculosis are not well understood. In this study, we investigated the mechanisms of formation and function of lipid-laden macrophages in a murine model of tuberculosis. Mycobacterium bovis bacillus Calmette-Guérin (BCG), but not Mycobacterium smegmatis, induced a dose- and time-dependent increase in lipid body-inducible nonmembrane-bound cytoplasmic lipid domain size and numbers. Lipid body formation was drastically inhibited in TLR2-, but not in TLR4-deficient mice, indicating a role for TLR2 in BCG recognition and signaling to form lipid bodies. Increase in lipid bodies during infection correlated with increased generation of PGE2 and localization of cyclooxygenase-2 within lipid bodies. Moreover, we demonstrated by intracellular immunofluorescent localization of newly formed eicosanoid that lipid bodies were the predominant sites of PGE2 synthesis in activated macrophages. Our findings demonstrated that BCG-induced lipid body formation is TLR2 mediated and these structures function as signaling platforms in inflammatory mediator production, because compartmentalization of substrate and key enzymes within lipid bodies has impact on the capacity of activated leukocytes to generate increased amounts of eicosanoids during experimental infection by BCG.     

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.     

Identification of novel proteins in culture filtrates of Mycobacterium bovis bacillus Calmette-Guérin in the isoelectric point range 6-11

Two-dimensional gel electrophoresis and mass spectrometry were used to identify proteins in the isoelectric point range 6-11 in culture filtrates of Mycobacterium bovis bacillus Calmette-Guérin (BCG). Twelve proteins were identified, three of which had not been described previously. The expression of the identified proteins was comparatively analyzed in culture filtrates of BCG in different growth phases and culture conditions. For some of these proteins, the relative protein abundance in the different culture filtrate preparations was significantly different. The differential expression of the identified proteins is discussed in relation to their putative localization and/or biological function.     

Role of apoptosis-regulating signal kinase 1 in innate immune responses by Mycobacterium bovis bacillus Calmette-Guérin

Mycobacterium bovis bacillus Calmette-Guérin (BCG) induces innate immune responses through Toll-like receptor (TLR) 2 and TLR4. We investigated the role of apoptosis-regulating signal kinase (ASK) 1 in reactive oxygen species (ROS)-mediated innate immune responses induced by BCG mycobacterial infection. In macrophages, M. bovis BCG stimulation resulted in rapid activation of mitogen-activated protein kinases (MAPKs), secretion of inflammatory cytokines, such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-6, and ROS generation in a TLR2- and TLR4-dependent manner. M. bovis BCG-induced ROS production led to robust activation of ASK1 upstream of the c-jun-N-terminal kinase and p38 MAPK, but not extracellular-regulated kinase 1/2. Blocking ASK1 activity markedly attenuated M. bovis BCG-induced TNF-alpha and IL-6 production by macrophages. Both TLR2 and TLR4 were required for optimal activation of ASK1 in response to M. bovis BCG. Furthermore, we present evidence that TNF receptor-associated factor (TRAF) 6 activities were essential for ROS-mediated ASK1 activation by M. bovis BCG. Finally, ASK1 activities were required for effective control of intracellular mycobacterial survival. Thus, the results of this study suggest a novel role of the TLR-ROS-TRAF6-ASK1 axis in the innate immune response to mycobacteria as a signaling intermediate.     

Bacillus Calmette-Guérin potentiates monocyte responses to lipopolysaccharide-induced tumor necrosis factor and interleukin-1, but not interleukin-6 in bladder cancer patients

During the past decade, particular attention has been focused on treatment of bladder cancer patients with the bacterial agent bacillus Calmette-Guérin (BCG). In these studies, bladder cancer patients were instilled with BCG (75mg/50ml) once per week for 6 weeks, 1–2 weeks following trans-urethreal resection of the bladder. Cystoscopy was performed after 6 weeks and, unless tumor progression was present, monthly treatments were given for 1 year. Blood was drawn 2 h after the last instillation, and monocytes were isolated (5×10⁶ cells/ml) and treated, or not, with lipopolysaccharide (LPS) (20 g/ml) for tumor necrosis factor (TNF), interleukin-1 (IL-1) and interleukin-6 (IL-6) release. The levels of monokines were determined by a monokine-specific enzyme-linked immunosorbent assay. Out results clearly show that, after 18 h incubation, macrophages from BCG-treated bladder cancer patients produced from 2.8- to 1.9-fold and from 2.0- to 1.3-fold greater amounts of TNF and IL-1 respectively, compared to macrophages from healthy controls, 5-fold higher than bladder cancer patients not treated with BCG. IL-6 was not affected. In another set of experiments macrophages (5×10⁶ cells/ml) from healthy subjects were pretreated, or not, with BCG (100 g/ml) overnight and treated, or not, with LPS 20 g/ml alone and in combination with interleukin-1 receptor antagonist (IL-1ra) 250 ng/ml. Macrophages treated with BCG had a strong stimulatory effect on IL-1 release (9.45 ng/ml) while LPS was less effective (3.59 ng/ml). The combination of BCG plus LPS produced an additive effect on IL-1 release (13.71 ng/ml) compared to the effect of the compound alone. The addition of IL-1ra (250 ng/ml) to BCG was not effective, while when IL-1ra was added to BCG plus LPS only a partial inhibition of IL-1 release was found (9.83 ng/ml), compared to BCG plus LPS without IL-1ra (13.71 ng/ml). These effects seem to be related to the inhibition of IL-1 stimulated with LPS, but not BCG. The priming effect of BCG exerted on LPS-stimulated monocyte production of TNF and IL-1 from bladder cancer patients led us to study the possible modulation of fibrinogen and C-reactive protein in the serum of BCG-treated cancer patients. The plasma levels of fibrinogen and C-reactive protein were higher (approximately twice) in BCG-treated patients compared to values obtained in untreated patients or healthy controls. We conclude that the beneficial immunotherapeutic effects of BCG in bladder cancer patients are related to its capacity to prime macrophages to enhance the release of TNF and IL-1, but not IL-6 in response to physiological secondary stimuli, or through the direct stimulation of BCG on IL-1 or TNF, which are directly involved in the killing of cancer cells. Moreover, the increase of IL-1 or TNF in BCG bladder cancer patients may lead to high plasma levels of fibrinogen and C-reactive protein, two proteins responsible for the acute-phase response.     

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)-α 2B secreting recombinant (r) BCG (rBCG-IFN-α). We demonstrated that rBCG-IFN-α augmented T helper type 1 (Th1) cytokine IFN-γ production by PBMC. In this study, we further investigated whether rBCG-IFN-α 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-α or control MV261 BCG, and used as effector cells in ⁵¹Cr-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-α as well as endogenously expressed IFN-γ and IL-2 in inducing the cytotoxicity, PBMC were stimulated with rBCG-IFN-α in the presence of neutralizing antibodies to IFN-α, IFN-γ 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 ⁵¹Cr-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-α further increased the PBMC cytotoxicity by up to 2-fold. Elevated production of IFN-γ and IL-2 by PBMC was observed after rBCG-IFN-α stimulation. Blockage of IFN-α, IFN-γ or IL-2 by neutralizing antibodies during rBCG-IFN-α 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-α with the former cell type being more predominant. Conclusions  rBCG-IFN-α 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.     

Influence of T-lymphocyte deprivation on the antileukemic effect of bacillus calmette-guérin in vivo

Summary The effect in AKR mice of T-lymphocyte deprivation in vivo, obtained by adult thymectomy plus/minus whole-body irradiation and bone-marrow reconstitution, was studied in the growth of grafted leukemia cells obtained from spontaneous AKR leukemia. Both thymectomized mice and mice subjected to thymectomy, whole-body irradiation, and bone-marrow reconstitution (B) had a lower take-frequency of graft leukemia than conventional mice. Growth of graft leukemia was inhibited by BCG treatment both in thymectomized mice and in B mice. Concomitant with the increased inhibition of leukemia growth, an increased incidence of wasting-like disease was observed. In vitro cytotoxicity studies revealed that spleen lymphoid cells from nonleukemic mice were cytotoxic to AKR leukemia cells, to nonmalignant AKR fibroblasts, and to other nonmalignant cells with H-2^k haplotype. The activity of this self-directed cytotoxicity was most marked in AKR mice with wasting-like disease. The presence of autocytotoxic cells was frequently associated with a positive direct Coombs' test. Immunofluorescence studies showed, further, that the cytotoxic activity was independent of retrovirus antigens as tested by indirect immunofluorescence with anti-MuLV antibodies. Adult thymectomy of AKR mice confers an increased antitumoral immune potential, but also an increased risk of development of serious autoimmune disease.     

Bacillus Calmette-Guérin vaccination reduces the severity and progression of tuberculosis in badgers

Control of bovine tuberculosis (TB) in cattle has proven particularly challenging where reservoirs of infection exist in wildlife populations. In Britain and Ireland, control is hampered by a reservoir of infection in Eurasian badgers (Meles meles). Badger culling has positive and negative effects on bovine TB in cattle and is difficult, costly and controversial. Here we show that Bacillus Calmette-Guérin (BCG) vaccination of captive badgers reduced the progression, severity and excretion of Mycobacterium bovis infection after experimental challenge. In a clinical field study, BCG vaccination of free-living badgers reduced the incidence of positive serological test results by 73.8 per cent. In common with other species, BCG did not appear to prevent infection of badgers subjected to experimental challenge, but did significantly reduce the overall disease burden. BCG vaccination of badgers could comprise an important component of a comprehensive programme of measures to control bovine TB in cattle.     

Immunological properties of recombinant Mycobacterium bovis bacillus Calmette-Guérin strain expressing fusion protein IL-2-ESAT-6

The live vaccine Mycobacterium bovis bacillus Calmette-Guérin (BCG) provides variable efficacy against adult pulmonary tuberculosis (TB). Recombinant BCG, expressing either immunodominant antigens or Th1 cytokines, is a promising strategy for developing a new TB vaccine. However, not much is known about whether the introduction of cytokine and specific antigen genes concurrently into the BCG strain could improve the immunogenicity of BCG. In this study, a recombinant BCG strain (rBCG) expressing the fusion protein human interleukin (IL)-2 and ESAT-6 (early secreted antigenic target-6 kDa) antigen of Mycobacterium tuberculosis was constructed. Six weeks after BALB/c mice (H-2d) were immunized with 106 colony forming units (CFUs) BCG or rBCG, splenocyte proliferation was determined with MTT [3-(4,5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide] assay, IL-4 and interferon (IFN)-gamma produced by splenocytes were tested by enzyme linked immunosorbent assay (ELISA,) and the cytotoxicity of splenocytes from immunized mice to P815 cells (H-2d) expressing ESAT-6 protein was measured using CytoTox 96 Non-Radioactive Cytotoxicity Assay. Compared with native BCG-vaccinated mice, rBCG induced stronger Th1 responses that were confirmed by high lymphoproliferative responses and IFN-gamma production to culture filtrate protein (CFP) or ESAT-6 protein. Moreover, rBCG induced significant enhanced CTL responses against P815-ESAT-6 cells. Results from rBCG-immunized mice demonstrated that introducing the il-2 and esat-6 genes into BCG could enhance Th1 type immune responses to ESAT-6. Further investigation is needed by introducing other Th1 cytokines and antigens into BCG to optimize the protective efficacy against TB.     

Catalytically inactive cyclooxygenase 2 and absence of prostaglandin E2 biosynthesis in murine peritoneal macrophages following in vivo phagocytosis of heat-killed Mycobacterium bovis bacillus Calmette-Guérin

Over 25 years ago, it was observed that peritoneal macrophages (Mphi) isolated from mice given heat-killed Mycobacterium bovis bacillus Calmette-Guérin (HK-BCG) i.p. did not release PGE(2). However, when peritoneal Mphi from untreated mice are treated with HK-BCG in vitro, cyclooxygenase 2 (COX-2), a rate-limiting enzyme for PGE(2) biosynthesis, is expressed and the release of PGE(2) is increased. The present study of peritoneal Mphi obtained from C57BL/6 mice and treated either in vitro or in vivo with HK-BCG was undertaken to further characterize the cellular responses that result in suppression of PGE(2) release. The results indicate that Mphi treated with HK-BCG in vivo express constitutive COX-1 and inducible COX-2 that are catalytically inactive, are localized subcellularly in the cytoplasm, and are not associated with the nuclear envelope (NE). In contrast, Mphi treated in vitro express catalytically active COX-1 and COX-2 that are localized in the NE and diffusely in the cytoplasm. Thus, for local Mphi activated in vivo by HK-BCG, the results indicate that COX-1 and COX-2 dissociated from the NE are catalytically inactive, which accounts for the lack of PGE(2) production by local Mphi activated in vivo with HK-BCG. Our studies further indicate that the formation of catalytically inactive COX-2 is associated with in vivo phagocytosis of HK-BCG, and is not dependent on extracellular mediators produced by in vivo HK-BCG treatment. This attenuation of PGE(2) production may enhance Mphi-mediated innate and Th1-acquired immune responses against intracellular infections which are suppressed by PGE(2).     

Immunotherapy of bovine ocular squamous cell carcinoma by repeated intralesional injections of live bacillus Calmette-Guérin (BCG) or BCG cell walls

Summary Thirty cows of the Dutch Friesian and the Maas-Rijn-Ijssel breed with histologically confirmed ocular squamous cell carcinoma were treated by repeated intralesional injection of live bacillus Calmette-Guérin (BCG) (n = 14) or a BCG cell-wall vaccine (n = 16). Complete regression of the primary tumour was observed in 64% and 57% of the animals respectively. In the 2-year follow-up period there was no recurrence of primary tumours. This sharply contrasts with the recurrence frequency (40%–50%) after complete remission induced by a single intralesional injection with BCG, observed in an earlier study. In 1 animal a new primary tumour developed. At necropsy metastases were present in 33% of the treated animals: in 3 of 17 animals that showed complete regression of the primary tumour and in 7 of 13 animals with partial regression or progressive disease. This did not differ significantly from results obtained after a single treatment (27%). Delayed-type hypersensitivity toM. bovis purified protein derivative (PPD) was more persistent in animals showing regression of the primary tumour than in non-responding animals. Of the animals with a positive PPD response 6 months after treatment, 79% showed tumour regression. Regression was observed in only 28% of the animals not responding to PPD after the same period of time. In conclusion: (a) recurrence of the primary tumour was not observed after repeated BCG treatment; (b) the frequency of metastases was not decreased compared to results obtained with a single treatment; (c) regression was correlated with a positive delayed-type hypersensitivity reaction to PPD (P <0.05) 6 months after treatment; (d) no significant differences were observed when the clinical results of treatment with live BCG and the BCG cell wall vaccine were compared.