Loss of anti-mycobacterial efficacy in mice over time following vaccination with Mycobacterium bovis bacillus Calmette-Guérin

Mycobacterium bovis bacillus Calmette-Guérin (BCG) is the most often used vaccine worldwide and sole vaccine against tuberculosis. BCG is protective against severe form of childhood tuberculosis but less or not protective to adult pulmonary tuberculosis. Therefore, improved vaccination strategies and development of new tuberculosis vaccines are urgent demands. For those purposes, appropriate animal models that reflect human are critically useful. However, in animal models, BCG vaccination protects well against subsequent challenge of Mycobacterium tuberculosis. In this study we evaluated the duration of protective efficacy of the BCG vaccination in mice over time and found that efficacy was diminished 40 weeks after vaccination. The aged mice older than 45 weeks are protected sufficiently after the vaccination with BCG, suggesting that loss of its efficacy is not dependent on the age of mice but rather depends on the period from vaccination. The loss of protection occurred in TH1 polarized STAT6 deficient mice despite the maintenance of interferon (IFN)-gamma production activity of lymph node cells and splenic CD4⁺ T cells against M. tuberculosis antigens. Our data suggest that the duration from vaccination may explain the variation in BCG efficacy against adult pulmonary tuberculosis.     

Lymphadenitis as a complication following vaccination with Bacillus Calmette-Guérin (BCG)

A healthy 14-months-old boy developed suppurative adenitis some weeks after Bacillus Calmette Guérin (BCG) vaccination. The tumour grew rapidly, showed fluctuation and eventually incision was needed. Culture of the abscess was negative. The diagnosis was: regional lymphadenitis after BCG vaccination. This suppurative lymphadenitis is a non-serious complication of BCG vaccination and has been reported in 0.1 to 4% of those vaccinated. As the BCG vaccination is given only to the at-risk population in the Netherlands, BCG complications are rare. Non-suppurative nodal swellings are considered a normal post-vaccination reaction and do not require treatment.     

Assessment of different formulations of oral Mycobacterium bovis Bacille Calmette-Guérin (BCG) vaccine in rodent models for immunogenicity and protection against aerosol challenge with M. bovis

Bovine tuberculosis (bTB) caused by infection with Mycobacterium bovis is causing considerable economic loss to farmers and Government in the United Kingdom as its incidence is increasing. Efforts to control bTB in the UK are hampered by the infection in Eurasian badgers (Meles meles) that represent a wildlife reservoir and source of recurrent M. bovis exposure to cattle. Vaccination of badgers with the human TB vaccine, M. bovis Bacille Calmette-Guérin (BCG), in oral bait represents a possible disease control tool and holds the best prospect for reaching badger populations over a wide geographical area. Using mouse and guinea pig models, we evaluated the immunogenicity and protective efficacy, respectively, of candidate badger oral vaccines based on formulation of BCG in lipid matrix, alginate beads, or a novel microcapsular hybrid of both lipid and alginate. Two different oral doses of BCG were evaluated in each formulation for their protective efficacy in guinea pigs, while a single dose was evaluated in mice. In mice, significant immune responses (based on lymphocyte proliferation and expression of IFN-gamma) were only seen with the lipid matrix and the lipid in alginate microcapsular formulation, corresponding to the isolation of viable BCG from alimentary tract lymph nodes. In guinea pigs, only BCG formulated in lipid matrix conferred protection to the spleen and lungs following aerosol route challenge with M. bovis. Protection was seen with delivery doses in the range 10(6)-10(7) CFU, although this was more consistent in the spleen at the higher dose. No protection in terms of organ CFU was seen with BCG administered in alginate beads or in lipid in alginate microcapsules, although 10(7) in the latter formulation conferred protection in terms of increasing body weight after challenge and a smaller lung to body weight ratio at necropsy. These results highlight the potential for lipid, rather than alginate, -based vaccine formulations as suitable delivery vehicles for an oral BCG vaccine in badgers.     

Bacillus Calmette-Guérin vaccination using a microneedle patch

Tuberculosis (TB) caused by Mycobacterium tuberculosis continues to be a leading cause of mortality among bacterial diseases, and the bacillus Calmette-Guérin (BCG) is the only licensed vaccine for human use against this disease. TB prevention and control would benefit from an improved method of BCG vaccination that simplifies logistics and eliminates dangers posed by hypodermic needles without compromising immunogenicity. Here, we report the design and engineering of a BCG-coated microneedle vaccine patch for a simple and improved intradermal delivery of the vaccine. The microneedle vaccine patch induced a robust cell-mediated immune response in both the lungs and the spleen of guinea pigs. The response was comparable to the traditional hypodermic needle based intradermal BCG vaccination and was characterized by a strong antigen specific lymphocyte proliferation and IFN-γ levels with high frequencies of CD4⁺IFN-γ⁺, CD4⁺TNF-α⁺ and CD4⁺IFN-γ⁺TNF-α⁺ T cells. The BCG-coated microneedle vaccine patch was highly immunogenic in guinea pigs and supports further exploration of this new technology as a simpler, safer, and compliant vaccination that could facilitate increased coverage, especially in developing countries that lack adequate healthcare infrastructure.     

Mucosal immunization with recombinant heparin-binding haemagglutinin adhesin suppresses extrapulmonary dissemination of Mycobacterium bovis bacillus Calmette-Guérin (BCG) in infected mice

It is generally accepted that cellular immunity plays a critical role in the protection against Mycobacterium tuberculosis, an intracellular pathogen. Recently, however, an increasing number of reports indicate the important contribution of humoral immunity against mycobacterial infection. Since M. tuberculosis establishes its primary lesion in the lung, induction of humoral immunity in the airway tract by mucosal immunization regime could provide protective immunity against tuberculosis. In this study, mycobacterial heparin-binding haemagglutinin adhesin (HBHA) was used as an immunization antigen because HBHA is an essential virulence factor required for the infection of lung epithelial cells and extrapulmonary dissemination of mycobacteria. The effects of intranasal immunization with a yeast-expressed recombinant (r) HBHA co-administered with a mucosal adjuvant cholera toxin (CT) on the induction of humoral and cellular immunity were examined, and its protective efficacy against pulmonary challenge infection with Mycobacterium bovis bacillus Calmette-Guérin (BCG) was evaluated. HBHA-specific antibodies were induced in serum and airway tract of immunized mice, which specifically recognized native HBHA expressed on M. bovis BCG. Th1-type immunity against mycobacterial antigens was also enhanced in the lung of immunized mice after pulmonary BCG infection. Furthermore, the immunization suppressed bacterial load in the spleen after pulmonary BCG infection. These results indicate that systemic and local humoral immunity induced by the HBHA-based mucosal vaccine impairs extrapulmonary dissemination, thus providing immune protection against mycobacterial infection.     

Bacille Calmette-Guérin (BCG) vaccination at birth and antibody responses to childhood vaccines. A randomised clinical trial

IntroductionBCG vaccination has been associated with beneficial non-specific effects on child health. Some immunological studies have reported heterologous effects of vaccines on antibody responses to heterologous vaccines. Within a randomised clinical trial of Bacille Calmette-Guérin (BCG) vaccination at birth, The Danish Calmette Study, we investigated the effect of BCG at birth on the antibody response to the three routine vaccines against DiTeKiPol/Act-Hib and Prevenar 13 in a subgroup of participants.MethodsWithin 7 days after birth, children were randomised 1:1 to BCG vaccination or to the control group (no intervention). After three routine vaccinations given at age 3, 5 and 12 months, antibodies against DiTeKiPol/Act-Hib and Prevenar 13 (Streptococcus pneumoniae serotype type 4, 6B, 9V, 14, 18C, 19F and 23F) were measured 4 weeks after the third vaccine dose.ResultsAmong the 300 included children (178 BCG; 122 controls), almost all children (>96%) had antibody responses above the protective levels. Overall BCG vaccination at birth did not affect the antibody level. When stratifying by ‘age at randomisation' we found a possible inducing effect of BCG on antibodies against B. pertussis and all pneumococcal serotypes, when BCG was given after the first day of life. Girls had significantly higher antibody levels for Haemophilus influenza type b and pneumococcus than boys.Conclusions and relevanceThree routine vaccinations with DiTeKiPol/Act-Hib and Prevenar 13 induced sero-protective levels in almost all children. No overall effect of neonatal BCG vaccination was observed.     

The influence of neonatal Bacille Calmette-Guérin (BCG) immunisation on heterologous vaccine responses in infants

IntroductionBacillus Calmette-Guérin vaccine (BCG), one of the most widely used vaccines, does not only provide protection against tuberculosis and other mycobacterial infections, but also has non-specific (heterologous) immunomodulatory effects. In participants in a randomised trial, we investigated the effect of neonatal BCG immunisation on antibody responses to routine infant vaccines given in the first year of life.MethodsAntibodies against antigens in the diphtheria, tetanus, pertussis, polio, Haemophilus influenzae type b (Hib), and the 13-valent pneumococcal conjugate vaccines were measured in 91 (45 BCG-vaccinated, 46 BCG-naïve) infants one month after, and in 310 (169 BCG-vaccinated, 141 BCG-naïve) infants seven months after immunisation at 6 weeks, 4 and 6 months of age. In addition, antibodies against meningococcus C, Hib, measles, mumps, and rubella were measured in 147 (78 BCG-vaccinated, 69 BCG-naïve) infants one month after immunisation at 12 months of age. The seroprotection rates for each vaccine and the geometric mean concentrations (GMC) of antibodies were compared in BCG-vaccinated and BCG-naïve infants.ResultsAt 7 months of age, seroprotection rates were high in both BCG-vaccinated and BCG-naïve infants. At 13 months of age, seroprotection rates were lower than at 7 months of age, particularly for pertussis and a number of pneumococcal antigens, with generally higher rates for the latter in BCG-vaccinated infants. Although not statistically significant, antibody responses in BCG-vaccinated infants were consistently higher against diphtheria, tetanus, and pneumococcal antigens at both 7 and 13 months of age, and against measles and mumps at 13 months of age, but were lower against Hib one month after immunisation at both 7 and 13 months of age.ConclusionThe immunomodulatory effect of BCG on antibody responses to heterologous vaccines adds to the evidence that BCG immunisation at birth has broad heterologous effects on the infant immune system.     

Management and outcome of Bacille Calmette-Guérin vaccine adverse reactions

BackgroundBacille Calmette-Guérin (BCG) vaccine is one of the most widely used vaccines globally. Management of local BCG complications (injection site reactions and suppurative or non-suppurative lymphadenitis) varies between clinicians, and the optimal approach remains uncertain.AimTo determine the clinical features, management and outcome of BCG complications at two large acute hospitals in London, United Kingdom.MethodsAll children presenting with complications of BCG vaccination between January 2008 and December 2013 were included in this observational study. Medical and electronic laboratory records were reviewed to determine clinical features, treatment and outcome.ResultsSixty children presented with adverse reactions. Two-thirds (65%) presented with BCG lymphadenitis, one-third (30%) presented with injection site complications and two children (3%) presented with both injection site reaction and lymphadenitis; only one child (2%) had disseminated BCG disease. The majority (88%) of children with injection site reactions were managed conservatively; overall, 95% showed complete resolution within 6 months. Among children with lymphadenitis, 46% were managed conservatively, whilst 54% had anti-tuberculous therapy and/or a procedure (aspiration mostly, or surgery); complete resolution was seen in 59% of cases.ConclusionsInjection site reactions and non-suppurative lymphadenitis were generally managed conservatively, with good outcomes. There was more variation in management and outcome of suppurative lymphadenitis and the optimal approach remains uncertain.     

Clinical features and outcomes of Bacille Calmette-Guérin (BCG)-induced diseases following neonatal BCG Tokyo-172 strain immunization

BackgroundBacille Calmette-Guérin (BCG) vaccination at birth may cause mild and benign local adverse effects (AE). More serious AE are rarely reported.ObjectiveTo describe clinical features and outcomes of BCG (Tokyo-172 strain)-induce diseases (BCG-ID) that required medical attention at a tertiary care center in Bangkok, Thailand.MethodWe retrospectively reviewed medical records from January 2007 to December 2016 that were selected by ICD-10 codes. The inclusion criteria were the patients under 3 years of age who developed lymphadenitis, osteitis, or disseminated infections of which BCG was a possible pathogen. Cases were classified into suspected (clinically compatible without laboratory confirmation), probable (suspected cases with M. tuberculosis complex identified), and confirmed BCG-ID (probable cases with molecular confirmation of M. bovis BCG strain).Results95 children were identified; 57 (60.0%) were male, and the median age at presenting symptom was 3.5 (range: 0.6–28.7) months. Of these, 25 (26.3%) were suspected, 49 (51.6%) were probable, and 21 (22.1%) were confirmed BCG-ID. Overall, 87 (92%) children had regional lymphadenitis corresponding to the BCG site, 5 (5%) had osteitis, and 3 (3%) had disseminated BCG. Of those with lymphadenitis, average size was 2.2 (range 0.7–5) cm. in diameter and 53% (46/87) had pulmonary involvement. Five children with immunodeficiency; three had disseminated BCG and two had lymphadenitis. Eight (9.2%) patients with lymphadenitis underwent needle aspiration; 57 (65.5%) had surgical excision. All children with BCG osteitis underwent surgical intervention in combination with anti-tuberculosis treatment. One patient with osteitis experienced long-term leg length discrepancy.ConclusionRegional lymphadenitis was the most common feature of BCG-ID requiring medical attention. That none of the BCG osteitis were immunocompromised hosts suggested the potential virulence of BCG in neonates. A systematic national surveillance and reporting system is needed to develop accurate estimates of population incidence and support development of effective vaccine policy.     

Mycobacterium ulcerans-specific immune response after immunisation with bacillus Calmette-Guérin (BCG) vaccine

BackgroundBacillus Calmette–Guérin (BCG) vaccine provides partial protection against Buruli ulcer caused by Mycobacterium ulcerans in epidemiological studies. This study aimed to quantify M. ulcerans-specific immune responses induced by BCG immunisation.MethodsIntracellular cytokine analysis of in-vitro experiments done 10 weeks after BCG immunisation in 130 Australian infants randomised to one of three BCG vaccine strains given either at birth (BCG-Denmark, BCG-Japan, or BCG-Russia) or at two months of age (BCG-Denmark).ResultsProportions of polyfunctional CD4⁺ T-cells were higher in M. ulcerans-stimulated compared to unstimulated control samples. These proportions were not influenced by the vaccine strain or timing of the immunisation. The M. ulcerans-specific immune responses showed similar patterns to those observed in M. tuberculosis-stimulated samples, although they were of lower magnitude.ConclusionsOur data show that BCG immunisation induces M. ulcerans-specific immune responses in infants, likely explaining the cross-protective effect observed in epidemiological studies. (ACTRN12608000227392)     

Prospects in Mycobacterium bovis Bacille Calmette et Guérin (BCG) vaccine diversity and delivery: Why does BCG fail to protect against tuberculosis?

Mycobacterium tuberculosis (M.tb) infection leads to active tuberculosis (TB), a disease that kills one human every 18 s. Current therapies available to combat TB include chemotherapy and the preventative vaccine Mycobacterium bovis Bacille Calmette et Guérin (BCG). Increased reporting of drug resistant M.tb strains worldwide indicates that drug development cannot be the primary mechanism for eradication. BCG vaccination has been used globally for protection against childhood and disseminated TB, however, its efficacy at protecting against pulmonary TB in adult and aging populations is highly variable. In this regard, the immune response generated by BCG vaccination is incapable of sterilizing the lung post M.tb infection as indicated by the large proportion of individuals with latent TB infection that have received BCG. Although many new TB vaccine candidates have entered the development pipeline, only a few have moved to human clinical trials; where they showed no efficacy and/or were withdrawn due to safety regulations. These trials highlight our limited understanding of protective immunity against the development of active TB. Here, we discuss current vaccination strategies and their impact on the generation and sustainability of protective immunity against TB.     

Effects of Mycobacterium bovis Calmette et Guérin (BCG) in oncotherapy: Bladder cancer and beyond

The Mycobacterium bovis Bacillus Calmette et Guérin (BCG) vaccine was generated in 1921 with the efforts of a team of investigators, Albert Calmette and Camille Guérin, dedicated to the determination to develop a vaccine against active tuberculosis (TB) disease. Since then, BCG vaccination is used globally for protection against childhood and disseminated TB; however, its efficacy at protecting against pulmonary TB in adult and aging populations is highly variable. Due to the BCG generated immunity, this vaccine later proved to have an antitumor activity; though the standing mechanisms behind are still unclear. Recent studies indicate that both innate and adaptive cell responses may play an important role in BCG eradication and prevention of bladder cancer. Thus, cells such as natural killer (NK) cells, macrophages, dendritic cells, neutrophils but also MHC-restricted CD4 and CD8 T cells and γδ T cells may play an important role and can be one the main effectors in BCG therapy. Here, we discuss the role of BCG therapy in bladder cancer and other cancers, including current strategies and their impact on the generation and sustainability of protective antitumor immunity against bladder cancer.     

Dietary glutamine supplementation increases the activity of peritoneal macrophages and hemopoiesis in early-weaned mice inoculated with Mycobacterium bovis bacillus Calmette-Guérin

Infants who are breast-fed have been shown to have a lower incidence of certain infectious diseases compared with formula-fed infants. Glutamine is one of the most abundant amino acids found in maternal milk and it is essential for the function of immune system cells such as macrophages. The purpose of this study was to investigate the effect of glutamine supplementation on the function of peritoneal macrophages and on hemopoiesis in early-weaned mice inoculated with Mycobacterium bovis bacillus Calmette-Guérin (BCG). Mice were weaned at 14 d of age and distributed to 2 groups and fed either a glutamine-free diet (n = 16) or a glutamine-supplemented diet (+Gln) (n = 16). Both diets were isonitrogenous (with addition of a mixture of nonessential amino acids) and isocaloric. At d 21, 2 subgroups of mice (n = 16) were intraperitoneally injected with BCG and all mice were killed at d 28. Plasma, muscle and liver glutamine concentrations and muscle glutamine synthetase activity were not affected by diet or inoculation with BCG. The +Gln diet led to increased leukocyte and lymphocyte counts in the peripheral blood (P < 0.05) and granulocyte and lymphocyte counts in the bone marrow and spleen (P < 0.05). The +Gln diet increased spreading and adhesion capacities, hydrogen peroxide, nitric oxide, and tumor necrosis factor-alpha (TNFalpha) syntheses and the phagocytic and fungicidal activity of peritoneal macrophages (P < 0.05). The interaction between the +Gln diet and BCG inoculation increased the area under the curve of interleukin (IL)-1beta and TNFalpha syntheses (P < 0.05). In conclusion, the intake of glutamine increases the function of peritoneal macrophages and hemopoiesis in early-weaned and BCG-inoculated mice. These data have important implications for the design of breast milk substitutes for human infants.     

Management of Bacillus Calmette-Guérin osteomyelitis/osteitis in immunocompetent children—A systematic review

BackgroundBacillus Calmette-Guérin (BCG) osteomyelitis/osteitis in immunocompetent children is a rare but serious complication of BCG immunization. Rationale for its treatment is unclear.MethodsDue to the rarity of this complication, no randomized control trials has ever been conducted to evaluate methods of intervention. As such, we searched the literature for any reported BCG vaccination-related osteomyelitis/osteitis among immunecompetent children published before April 15, 2014. We summarized the data from different affected regions of the body by recording the number of reported cases, while noting outcomes and their medical and/or surgical interventions.ResultsFrom 34 eligible studies gleaned from a screening of 804 articles, a total of 331 cases were enrolled. Involvement of the lower limbs was present in 55.6%, followed by the axial skeleton (26.0%), the upper limbs (15.4%), and multiple bones (3.0%). Of the 64 patients having records of detailed chemotherapy regimens, 45 patients (70%) received two or fewer drugs. Among the 80 patients with detailed surgical records, 50 (62.5%) received surgical procedures for diagnostic purposes. While there were uneventful outcomes for those receiving diagnostic procedures, 7 of the 30 (23.3%) patients receiving surgical interventions had major complications (p = 0.002, Fisher's exact test). The overall prognosis was good with a 97.6% cure rate. Nevertheless, eight patients (2.4%) suffered major complications.ConclusionsThe rationale for treatment of BCG osteomyelitis/osteitis in immunocompetent children is highly subjective. However, patients receiving diagnostic procedures instead of surgical interventions may avoid major complications. Because only a few of the publications had detailed treatment information, further studies are needed to identify proper treatments, while infant BCG vaccination is still in use.     

Immunogenicity of a recombinant Mycobacterium bovis bacille Calmette-Guèrin expressing malarial and tuberculosis epitopes

Recombinant Mycobacterium bovis bacille Calmette-Guèrin (rBCG) expressing the malarial epitopes F2R(II)EBA and (NANP)3 as well as two T cell epitopes of the M. tuberculosis ESAT-6 antigen, generated in favour of mycobacterium codon usage elicited specific immune response against these epitopes. Immunised Balb/c mice demonstrated an increase in almost all of the IgG subclasses against both malarial epitopes and enhanced splenocyte proliferative response against the malarial epitopes as well as selected peptides of ESAT-6. Furthermore, flow cytometric analyses showed elevated numbers of CD4+ lymphocytes expressing IFN-gamma and IL-2 against the ESAT-6 peptides, suggesting a specific Th1-mediated response. This study demonstrated that expressing malarial and TB epitopes in a single rBCG construct induced appropriate humoral and cellular immune response against immunogenic epitopes from both organisms.     

The effect of bacille Calmette-Guérin vaccination at birth on immune response in China

Bacille Calmette-Guérin (BCG) vaccine is still the most effective approach to prevent tuberculosis in childhood. In order to provide protection against severe forms of childhood tuberculosis, it is customary to give BCG vaccination at birth in China. Tuberculin skin testing after vaccination is usually used to evaluate the immunogenic activity and protective efficacy of the BCG. We report the results of a multi-site prospective cohort study to evaluate the immunological reactivity against BCG in four prefectural cities in China. A total of 59,022 newborn infants were vaccinated between January 2011 and March 2012, and follow-up data on 27,517 vaccinated infants were available for this study. Of these, 679 (2.5%) had PPD readings of 0–5 mm, 17,072 (62.0%) had PPD readings of 5–10 mm of induration, 8864 (32.2%) had readings of 10–15 mm, 815 (3.0%) had readings of 15–20 mm, and 87 (0.3%) had readings of >20 mm of induration. The size of PPD reaction varied significantly with the geographic location, gender, season of vaccination, and grade of hospital administering the BCG vaccine (P < 0.001). 97.8% of the infants with a BCG scar of >1 mm had a positive TST reaction. However, only 56.9% of infants without a BCG scar had a positive PPD reaction. Our results demonstrate that the BCG immunization among newborn infants in China induces satisfactory immune response. In addition, BCG scars provide a useful indicator of vaccination response in Chinese infants.     

Mycobacterium tuberculosis infection in First Nations preschool children in Alberta: implications for BCG (bacille Calmette-Guérin) vaccine withdrawal

BACKGROUND: On April 1, 2004, BCG (bacille Calmette-Guérin), a tuberculosis (TB) control vaccine, was discontinued in all but four high-risk communities in Alberta. To confirm the safety of vaccine withdrawal, and for future planning, the annual risk of infection (ARI) was determined in preschool First Nations children. METHODS: First Nations children born into reserve communities in Alberta between April 1, 1998 and March 31, 2004, and still living on reserve in 2004-2005, were identified. Health centre TB histories were validated by cross-referencing the birth cohort with the provincial TB Registry. Children that were not BCG vaccinated and not known to be tuberculin skin test (TST) positive underwent a TST. Birth cohort children were grouped as follows: (i) BCG vaccinated; (ii) BCG non-vaccinated, no TST; (iii) BCG non-vaccinated, TST; (iv) BCG vaccination status unknown. The ARI was calculated and the age and community characteristics of the groups were compared. RESULTS: There were 8447 children in the 6-year birth cohort, 4699 (55.6%) vaccinated, 2696 (31.9%) non-vaccinated, and 1052 (12.5%) whose vaccination status was unknown. Of the non-vaccinated children, 1921 (71.3%) were tested and only 2 were TST positive. No other TST positive, BCG non-vaccinated children were identified in the TB Registry cross-match. The prevalence of infection in 2004-2005 was 0.1% and the ARI was 0.03%. The community risk of TB exposure was comparable in tuberculin-tested and non-tested BCG non-vaccinated children. CONCLUSION: In low BCG-uptake First Nations communities in Alberta, the ARI is low and it is safe to withdraw BCG.