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Efficacy of the BCG revaccination programme in a cohort given BCG vaccination at birth in Hong Kong.

SETTING: Revaccination of tuberculin-negative school-children is a regular practice in Hong Kong. OBJECTIVE: To assess the efficacy of BCG revaccination guided by tuberculin skin testing. METHOD: A cohort of 303,692 children vaccinated at birth was followed through the tuberculosis notification register for the development of active disease. The percentage of cohort who participated in the BCG revaccination program during primary school was estimated from the vaccination statistics of the Hong Kong Department of Health. The BCG revaccination history of identified cases was ascertained through vaccination cards and clinic records. RESULTS: A total of 85.2% of the cohort participated in the BCG revaccination programme; 79.7% of the participants were tuberculin-negative and revaccinated; 343 developed tuberculosis after the age of 11; 302 were among the participants in the programme while 41 were not. The tuberculosis incidence was 16.5 and 12.9 per 100,000 person-years for participants and non-participants, respectively (RR 1.28, 95%CI 0.92-1.77). Among the participants, tuberculosis incidence was 12.5 and 32.0/100,000 person-years, respectively, for the tuberculin-negative/BCG revaccinated group and the tuberculin-positive/non-revaccinated group (RR 0.39, 95%CI 0.31-0.49). CONCLUSION: This study failed to demonstrate any significant difference in the incidence rates of tuberculosis among participants and non-participants in a school BCG revaccination programme. The increased risk for tuberculosis in the tuberculin-positive group does not support the use of the tuberculin testing for detection of immunity conferred by neonatal BCG vaccination.

Adolescent↗

Pulmonary tuberculosis due to BCG in a technician employed in a BCG laboratory.

X-ray examination of the lungs of a laboratory technician in the BCG Department of the Statens Seruminstitut, Copenhagen revealed a lung tumour and possible signs of tuberculosis. The diagnosis was confirmed by macroscopic and histopathological examination of lung tissue removed by surgery. Subsequent bacteriological examination showed the infection to have been caused by BCG. The possibility is discussed of whether the condition had developed from a metastatic lesion following BCG vaccination, or was the result of an aerogenic infection during the production of BCG vaccine. The simultaneous development of the tuberculous condition and the tumour is remarkable but is not discussed further. The requirements of WHO when signs of tuberculosis are found in a worker in a BCG laboratory were complied with in this instance, but it was not considered necessary to change the routine procedure in the BCG Department.

Animals↗

[BCG sepsis as a fatal complication of BCG vaccination].

Fatal septicemia with Bacillus Calmette-Guérin (BCG) following BCG vaccination is always caused by an underlying defect of immunologic mechanisms. At the Children's Hospital, University of Berne, two cases of BCG septicemia were recently observed. The clinical picture, course, and pathogenesis of the illness are discussed. The harmless complications of BCG vaccination are summarized, and a review of the literature on fatal disseminated BCG infection stresses the different type of immunologic mechanism defect and clinical course. Therapy with antituberculous drugs is ineffective. Other therapeutic measures are mentioned. Immunologic tests must be performed rapidly when fatal disseminated BCG infection is suspected, in order to organize genetic counselling as soon as possible. The question whether newborns should still be vaccinated in spite of the numerous complications is discussed and answered in the affirmative.

Antigen-Antibody Reactions↗

Lysed BCG vaccines. 2. The effect of lysis on the immunogenicity and allergenicity of BCG vaccines.

The authors have attempted to prepare lysed BCG vaccines retaining the protective antigens of the BCG cell wall and yet eliciting in experimental animals limited sensitivity to the tuberculin substances, the advantage sought being to retain the usefulness of the tuberculin following vaccination as an indicator of superinfection.Experimental vaccines were prepared by growing and lysing BCG in both Dubos and Aldridge liquid media with glycine, lysosyme and lithium chloride; vaccines were also prepared by autolysis in Aldridge nitrogen-deficient, chemically defined medium.Glycine, lysozyme and lithium chloride significantly reduced both the protective and allergenic properties of the lysates. The best protection was afforded by BCG cells autolysed in Aldridge medium. Treatment of the BCG autolysates with lysozyme alone did not affect the protective capability of the vaccines and almost completely eliminated the allergenicity. It is suggested that these BCG lysates contain metabolically inactive cells, which do not multiply in vitro but may still provide sufficient antigen in vivo to ensure protection.

Animals↗

Survival of lung cancer patients treated with BCG and/or a soluble BCG fraction (F70) after surgery, radiotherapy and chemotherapy.

243 lung cancer patients treated with routine therapy (surgery 54, radiotherapy 46 and chemotherapy 143) in Plovdiv's District Oncologic Dispensary (PDOD) were submitted to an additional therapy with BCG or with its soluble fraction F70. The survival rate of these patients was compared with the survival rate of 305 lung cancer patients following routine therapy alone (surgery 78, radiotherapy 113 and chemotherapy 114). The two groups were not randomized. Between patients treated and non-treated with BCG(F70) a significant increase of the survival rate was found for patients submitted to BCG(F70) treatment after surgery or radiotherapy in the 2nd and 3rd year survival period and for patients submitted to BCG(F70) treatment after chemotherapy -- in the 1st year survival period of patients with limited disease only. The effect of the additional BCG(F70) treatment was less dependent on the preceding routine therapy than upon the clinical stage of the disease at the moment of BCG(F70) treatment beginning. More salient results were observed in patients with undifferentiated histological forms.

BCG Vaccine↗

[Results of BCG in the treatment of pTa and pT1 bladder tumors. Evaluation of a long protocol using 75 mg of Pasteur strain BCG].

OBJECTIVES: Evaluation of a protocol of intravesical BCG therapy using 75 mg of Pasteur strain BCG with 2 years of maintenance treatment, and a follow-up of up to 60 months. MATERIAL AND METHODS: 189 patients treated by transurethral resection (TUR) for a pTa (N = 80) or pT1 (N = 109) bladder tumour were included in the study. The local and general safety was excellent. We retrospectively compared this series to a group of patients treated by TUR alone (N = 42) another group treated with TUR and Mitomycin C (MMC) (N = 81). The 3 groups were statistically comparable. RESULTS: At 48 months, 62% of patients treated with BCG were recurrence-free, versus only 18% for patients treated with TUR alone and 38% for patients treated with TUR and MMC (p = 0.001). At 42 months, 11% of pT1 tumours treated with BCG had progressed to invasive carcinoma, and this progression occurred during the first 18 months in every case. In comparison, this progression was observed in 25% of pT1 tumours treated by TUR alone and 21% of tumours treated with TUR and MMC. CONCLUSIONS: Our study confirms the efficacy of our BCG protocol ro reduce the potential for recurrence and progression of superficial bladder tumours, despite reduction of the dose to 75 mg. It also suggests the superiority of BCG compared to MMC in terms of recurrence and progression.

Actuarial Analysis↗

Immunological screening of a genomic M. bovis BCG library expressed in M. smegmatis and identification of the M. bovis BCG analog of ClpB.

This work describes the screening of a M. bovis BCG cosmid library in M. smegmatis with a hyperimmune rabbit anti-BCG serum. Cross-reactive antibodies interfere with the detection of BCG specific antigens in M. smegmatis culture filtrates. We, therefore, screened parallel western blots with serum adsorbed with a M. smegmatis cell lysate and unadsorbed serum. Comparison of the western blots allowed distinction between BCG specific and cross-reactive M. smegmatis antigens. Thirty-one cosmids expressed BCG specific antigens. One of them, a hitherto undescribed 100 kDa antigen was subcloned, sequenced and expressed in E. coli. It shows a high degree of homology to ClpB, a member of the Clp family of proteases and was immunologically reactive with the rabbit hyperimmune serum against M. bovis BCG. A positive signal was also obtained with sera of patients with tuberculosis. This antigen is a previously unrecognized target of the human immune response to mycobacteria.

Animals↗

Expression of foreign genes in Mycobacterium bovis BCG strains using different promoters reveals instability of the hsp60 promoter for expression of foreign genes in Mycobacterium bovis BCG strains.

SETTING: Optimization of BCG as a vehicle for live recombinant vaccines requires improved strategies for stable antigen expression. OBJECTIVES: To investigate the effects of various combinations of post-translational signals and promoters on expression and stability in different BCG strains. DESIGN: Plasmids were constructed using mycobacterial promoters (hsp60, 19-kDa antigen, 85A antigen--from the Mycobacterium tuberculosis complex--and the 18-kDa antigen from Mycobacterium leprae) and post-translation signals (85A antigen secretion and 19-kDa antigen acylation signals), coupled with reporter genes. RESULTS: The 19-kDa acylation signal had little effect on expression, while the 85A secretion signal enhanced markedly the levels of cell-associated product. Inclusion of the hsp60 promoter caused plasmid instability; various deletions affecting the promoter region occurred during or soon after transformation, but not during subsequent growth of the transformants, nor with other promoters. BCG Moreau appeared to be more susceptible to deletions than other BCG strains. CONCLUSIONS: The 85A signal may prove useful in optimizing gene expression in BCG, irrespective of secretion of the product. Deletions associated with the hsp60 promoter may be due to a transient lethal induction of the hsp60 promoter associated with electroporation. With intact plasmid there was no marked difference in expression between BCG strains.

Animals↗

Antigenic analysis between BCG and tumor cells by BCG-monoclonal antibodies.

Antigenic relation between Mycobacterium bovis strain BCG and experimental animal tumor cells was analyzed with BCG monoclonal antibodies (BCG-MoAbs). Four BCG-MoAbs of 602, 603, 609, and 612 were successfully established and applied for the antigenic analysis of Meth A, RL male 1, colon tumor 26 of mouse, and line 10 of guinea pig tumor. MoAb 602 showed broad reactivity against all types of tumor cells. BCG antigen(s) was clearly recognized as small granules on the tumor cell surface under the fluorescence microscope, indicating that the animal tumor cells shared the common antigen(s) with BCG.

Animals↗

[Immune response against BCG 65 kDa protein antigen in bladder cancer with BCG instillation therapy. Analyses carried out with the gene of this protein to develop a monoclonal antibody].

The BCG 65 kDa protein is part of the 60 kDa heat-shock protein (hsp) family. It is clear that hsp has a huge homology among mammalian and bacterial cells. In our study, we have observed the relevance of this protein in the anti-tumor response. Antibody production against the BCG 65 kDa protein was determined by solid phase ELISA using the sera of 51 bladder cancer patients who have undergone BCG instillation therapy. The BCG 65 kDa protein was made by E. coli transfected with pTB12 (plasmid DNA) which encodes this protein. It was clearly observed that the level of serum antibody titer to this protein was raised by the above instillation therapy. In order to investigate the role of this protein in anti-tumor response, we developed monoclonal antibodies against BCG 65 kDa protein. Four monoclonal antibodies were developed (B-20, B-97, B-108, B-167). We also estimated the epitope defined by each monoclonal antibody by using the truncated protein which was produced by E. coli transfected with the deletion mutants of pTB12. At this stage, we proceeded with observation of the cross epitope between mammalian cancer cells and BCG after using these monoclonal antibodies. There is no cross epitope defined by B-20, B-97 and B-167 in mammalian cells. However, the epitope defined by B-108 exists in normal tissue as well as in bladder cancer cells.

Administration, Intravesical↗

[Suppression of parasitemia in rodent filariasis (Litomosoides carinii) by immunization with BCG and microfilaria. I. Intracutaneous inoculation of BCG].

After intracutaneous inoculation of BCG and challenge by subcutaneous injection of infective larvae of Litomosoides carinii, the parasitaemia of the filarial infection in cotton rats remains significantly lower when BCG and larvae are applied in the region of the same popliteal and ileal lymph nodes. However, when the infective larvae are directed to other regional lymph nodes (Ln cubitales and axillares), the depression of microfilaraemia is missed. The worm load (recovery rate) and the expulsion of microfilariae by the adult worms are not influenced by the BCG inoculation. Obviously BCG stimulates the lymphatic tissue unspecifically, and the infective larvae produce the first antigen contact, which is boostered by the microfilariae at the onset of patency. When the intracutaneous BCG inoculation is combined with specific antigen stimulation by simultaneous injection of blood microfilariae in the region of the same lymph nodes, the microfilaraemia of the challenge infection disappears completely or remains extremely low.

Animals↗

Possible mechanism of the preventive effect of BCG against diabetes mellitus in NOD mouse. II. Suppression of pathogenesis by macrophage transfer from BCG-vaccinated mice.

Our previous reports showed that a single injection of live BCG, one of the biological response modifiers, prevents insulitis and overt diabetes in NOD mice and that the suppression could be due to the generation of some type of suppressor cells in the BCG-treated mice. Furthermore, a more recent study has revealed that macrophages suppressive against a variety of lymphocyte functions can be induced by BCG, which suggests that these macrophages are involved in the suppression of the pathogenesis. To obtain valid evidence for this speculation, the effects of transfer of macrophage and T-cell fractions on the pathogenesis were examined in the present study. Transfer of macrophage-enriched spleen cell fraction harvested from the BCG-treated females to young females abolished the occurrence of spontaneous diabetes up to the age of 25 to 30 weeks. Also, macrophage transfer prevented the progress of insulitis. In contrast, transfer of a T-cell-enriched fraction did not suppress insulitis and overt diabetes. From these results, it could be concluded that the suppression of the autoimmune pathogenesis of diabetes by BCG is due to the generation of suppressor macrophages.

Animals↗

Initial high-grade T1 urothelial cell carcinoma: feasibility and prognostic significance of lamina propria invasion microstaging (T1a/b/c) in BCG-treated and BCG-non-treated patients.

OBJECTIVES: This study aimed to determine the prognostic value of depth of lamina propria invasion in initial high-grade T1 bladder tumors. Secondary aims were to evaluate the prognostic significance of concomitant carcinoma in situ (CIS) and the impact of bacillus Calmette-Guérin (BCG) treatment as well as to assess the feasibility of microstaging by pathologists in a community setting. PATIENTS AND METHODS: Ninety-seven tumors were available for study and were substaged according to invasion superficial to, into or beyond the muscularis mucosae (MM) (T1a, T1b, T1c). Outcomes were compared by chi-square analysis. Recurrence-free and progression-free survival estimates were obtained by Kaplan-Meier analysis. BCG treatment impact and prognostic significance of CIS were also evaluated (Cox regression). RESULTS: T1 subclassification was possible in 87% (85/97) of cases: 38 (39.1%) T1a, 10 (10.3%) T1b, and 37 (38.1%) T1c; in 12 patients (12.4%) substaging was not possible. Mean age was 66.4 years and mean follow-up was 53 months. Recurrence rates were similar for all groups. By contrast, the progression rate for deep lamina propria-invasive tumors, i.e. T1b and T1c, was 34% (16/47) in comparison to 8% (3/38) for T1a (p=0.016). Progression-free intervals were significantly different in patients with (T1b, T1c) or without (T1a) deep lamina propria involvement (p=0.003), regardless of BCG treatment (p=0.02). BCG-treated patients (67 cases) showed a slight trend towards a better outcome, but differences were not significant. CIS was associated with more than 50% of cases that progressed. On multivariate analysis, depth of invasion and CIS remained two independent prognostic factors, increasing the hazards ratio of progression to 4.47 and 3.19 respectively. CONCLUSIONS: The depth of invasion in the TURB specimens is an independent prognostic factor for T1 bladder cancer even in BCG-treated patients. Associated CIS significantly increases the risk of progression in these patients. The percentage of cases that can be substaged according to the depth of lamina propria involvement increases over time with the collaboration between urologists and pathologists. Consequently, we support that routine pathological assessment of the level of MM invasion in patients with stage T1 bladder cancer should be included in the histopathological report.

Adjuvants, Immunologic↗

Genetic diversity of clinical Mycobacterium bovis BCG isolates from an immunocompromised patient with BCG infection.

BACKGROUND: The Bacillus Calmette-Guérin (BCG) vaccine is widely administered to prevent severe tuberculosis but can cause serious adverse events, including disseminated BCGosis, in immunocompromised individuals. However, studies investigating the in vivo genetic adaptation and microevolution of this live-attenuated vaccine during prolonged infection remain limited. METHODS: Two clinical Mycobacterium bovis BCG isolates (BCG01 and BCG02) and a lot-matched vaccine strain (VAC) underwent whole-genome sequencing. Phenotypic drug susceptibility testing was performed on the clinical isolates. Genomic relatedness was assessed using SNP-distance clustering and maximum-likelihood phylogeny against global reference strains. Comparative variant analysis was performed to identify mutations specific to BCG01 and BCG02 relative to VAC, and genotypic drug resistance was assessed using TB-Profiler. RESULTS: Phylogenomic analyses and SNP distance confirmed that both clinical isolates were derived from the BCG Tokyo 172 vaccine strain. BCG02 exhibited twice the mutational burden of BCG01, acquiring mutations in genes associated with cell wall biosynthesis (mas, ppsA), regulatory adaptation (pknK, dnaA), and surface antigens (pecA, PE/PPE). Crucially, whereas BCG01 remained susceptible to first-line drugs, BCG02 acquired a canonical rpoB Ser450Leu mutation (100% frequency) and a heteroresistant inhA Ile194Thr mutation (13% frequency), resulting in multidrug-resistant (MDR) BCGosis. CONCLUSION: Although structurally stable, the BCG Tokyo 172 vaccine strain can undergo rapid, clinically significant microevolution and clonal selection within immunocompromised hosts. The in vivo acquisition of multidrug resistance underscores the critical need for pre-vaccination immune screening and comprehensive laboratory monitoring of BCG-associated adverse events.

BCGosis↗

BCG-induced increase in interferon-gamma response to mycobacterial antigens and efficacy of BCG vaccination in Malawi and the UK: two randomised controlled studies.

BACKGROUND: The efficacy of BCG vaccines against pulmonary tuberculosis varies between populations, showing no protection in Malawi but 50-80% protection in the UK. To investigate the mechanism underlying these differences, randomised controlled studies were set up to measure vaccine-induced immune responsiveness to mycobacterial antigens in both populations. METHODS: 483 adolescents and young adults in Malawi and 180 adolescents in the UK were tested for interferon-gamma (IFN-gamma) response to M tuberculosis purified protein derivative (PPD) in a whole blood assay, and for delayed type hypersensitivity (DTH) skin test response to tuberculin PPD, before and 1 year after receiving BCG (Glaxo 1077) vaccination or placebo or no vaccine. FINDINGS: The percentages of the randomised individuals who showed IFN-gamma and DTH responses were higher in Malawi than in the UK pre-vaccination-ie, 61% (331/546) versus 22% (47/213) for IFN-gamma and 46% (236/517) versus 13% (27/211) for DTH. IFN-gamma responses increased more in the UK than in Malawi, with 83% (101/122) and 78% (251/321) respectively of the vaccinated groups responding, with similar distributions in the two populations 1 year post-vaccination. The DTH response increased following vaccination in both locations, but to a greater extent in the UK than Malawi. The IFN-gamma and DTH responses were strongly associated, except among vaccinees in Malawi. INTERPRETATION: The magnitude of the BCG-attributable increase in IFN-gamma responsiveness to M tuberculosis PPD, from before to 1 year post-vaccination, correlates better with the known levels of protection induced by immunisation with BCG than does the absolute value of the IFN-gamma or DTH response after vaccination. It is likely that differential sensitisation due to exposure to environmental mycobacteria is the most important determinant of the observed differences in protection by BCG between populations.

Adolescent↗

Effect of BCG on alloimmune cell-mediated cytotoxicity in (C57BL/6Jfemale x A/Jmale)F1 mice. I. Effect of different BCG treatments on cytotoxicity mediated by T-cells and macrophages.

The effect of BCG on the development of cell-mediated cytotoxicity (CMC) in the spleens of allogeneic tumor-bearing female (C57BL/6Jfemale x A/Jmale)F1 mice was studied. BCG-treated tumor-bearing animals elicited a stronger CMC response than did the untreated tumor-bearing animals. Furthermore, the degree of activation was dependent on the time, route of injection, and dose of BCG. Therefore, if the BCG was administered at suboptimal conditions, a less marked stimulation of the CMC resulted. A combination of a high BCG dose given iv 12 days before implant of P815 tumor cells and a low, second dose given at the time of implant produced the most marked activation of the CMC response. By the use of in vitro technique, the specific CMC was mediated mostly by T-cells, with macrophages making a less significant contribution.

Animals↗

Failure of the Mycobacterium bovis BCG vaccine: some species of environmental mycobacteria block multiplication of BCG and induction of protective immunity to tuberculosis.

The efficacy of Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccine against pulmonary tuberculosis (TB) varies enormously in different populations. The prevailing hypothesis attributes this variation to interactions between the vaccine and mycobacteria common in the environment, but the precise mechanism has so far not been clarified. Our study demonstrates that prior exposure to live environmental mycobacteria can result in a broad immune response that is recalled rapidly after BCG vaccination and controls the multiplication of the vaccine. In these sensitized mice, BCG elicits only a transient immune response with a low frequency of mycobacterium-specific cells and no protective immunity against TB. In contrast, the efficacy of TB subunit vaccines was unaffected by prior exposure to environmental mycobacteria. Six different isolates from soil and sputum samples from Karonga district in Northern Malawi (a region in which BCG vaccination has no effect against pulmonary TB) were investigated in the mouse model, and two strains of the Mycobacterium avium complex were found to block BCG activity completely.

Acyltransferases↗

Granulomatous hepatitis caused by Bacillus Calmette-Guerin (BCG) infection after BCG bladder instillation.

BACKGROUND: Bladder instillations with Bacillus Calmette-Guerin (BCG) are commonly used as immunotherapy for bladder carcinoma. Sometimes patients experience serious systemic side effects, such as sepsis or pneumonitis. Granulomatous hepatitis is a rare serious side effect, which has been considered a hypersensitivity reaction to BCG. PATIENT: The first case of granulomatous hepatitis after BCG bladder instillation in which mycobacteria were identified by staining techniques and mycobacterial DNA was detected in liver tissue using the polymerase chain reaction is reported. CONCLUSION: The granulomatous hepatitis was caused by BCG infection of the liver after haematogenous dissemination of BCG, rather than hypersensitivity.

Administration, Intravesical↗