Controversies in BCG immunization

Parthasarathy, A

doi:10.1007/bf02723163

Cited by 2 publications

(2 citation statements)

References 4 publications

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“…Although the efficacy of BCG in preventing active TB in adults has been challenged, it saves millions of lives by preventing severe, disseminated extra-pulmonary TB, including miliary and meningitis TB in young children (Parthasarathy, 2003). As the genome sequences of M.tb and M. bovis show over 99.95 % identity, and the pathological changes caused by M. bovis in cattle are also similar to those of human TB, M. bovis and its isogenic attenuated strain BCG are ideal model strains for studying M.tb pathogenesis and immunity.…”

Section: Introductionmentioning

confidence: 99%

Mycobacterium bovis and BCG induce different patterns of cytokine and chemokine production in dendritic cells and differentiation patterns in CD4+ T cells

Zhang

Luo

et al. 2013

Microbiology

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Mycobacterium tuberculosis can infect dendritic cells (DCs), but the molecular mechanism by which these cells contribute to tuberculosis pathogenesis is largely unclear. Using Mycobacterium bovis and the attenuated strain M. bovis BCG as model strains, we analysed cytokine and chemokine secretion in murine DCs infected with M. bovis and BCG at 6, 12 and 24 h post-infection. BCG enhanced production of MCP-1, RANTES, IL-12, TNF-a and IL-6 in DCs, while M. bovis promoted secretion of IL-1b, IL-10 and IL-23. Heat-killed BCG and M. bovis both stimulated cytokine production, but at significantly lower concentrations than corresponding live bacteria. Quantitative RT-PCR and Western blotting indicated that NF-kB regulates production of most cytokines and chemokines. After DCs were infected for 24 h, the culture was used to activate naïve CD4 + T cells. A combination of the supernatant and activated DCs infected with M. bovis gave high expression of foxp3 and IL-10, directing differentiation of naïve CD4 + T cells into regulatory T cells (CD4 + CD25 + Foxp3 + ) more effectively than BCG. Furthermore, M. bovis-infected DC cultures induced CD4 + T cells to express significantly higher levels of IL-17, a Th17-type cytokine, while BCG-infected DC cultures stimulated an apparently higher production of IFN-c, a Th1-type cytokine. In addition, the mycobacteria did not exert a direct effect on the differentiation of CD4 + T cells. These differential cytokine profiles in DCs and CD4 + T cells, and the resultant development of CD4 + T subsets, may be related to the pathogenesis of tuberculosis.

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Section: Introductionmentioning

confidence: 99%

Mycobacterium bovis and BCG induce different patterns of cytokine and chemokine production in dendritic cells and differentiation patterns in CD4+ T cells

Zhang

Luo

et al. 2013

Microbiology

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“…These results agree with the reported BCG vaccine efficacy in protection against pulmonary TB, ranging 50-80 %. 22 A previous study by on 148 scar negative-BCG vaccinated-UK adolescents, showed increased in-vitro INF-γ production at 3 months (87 % responders) and 12 months (74 % responders) after BCG vaccination with the Danish strain. 23 In their study, INF-γ levels increased by 12.4 folds and 7.5 folds at 3 and 12 months respectively in comparison to non-vaccinated controls, with gradual reduction of response till 14 years post-vaccination.…”

Section: Discussionmentioning

confidence: 88%

Assessment of BCG vaccine immune response in a sample of Egyptian infants

Reda

Mohamed

Fouad

et al. 2021

Egypt J Pediatr Allergy Immunol

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Background:In Egypt, tuberculosis (TB) is considered the third most important public health problem after schistosomiasis and hepatitis C. We sought to investigate the immune response induced by the currently used Bacillus Calmette-Guerin (BCG) vaccine in a sample of Egyptian infants . Methods:A cross sectional study comprising 25 healthy BCG vaccinated infants, 14-24 months old was carried out. They were 15 boys and 10 girls. These infants were subjected to clinical and laboratory evaluation including blood counts, tuberculin intradermal test and in-vitro assessment of T cell response to purified protein derivative (PPD) and phytohemagglutinin (PHA) stimulation with measurement of IFN-γ in the supernatant of cultured mononuclear cells using the AssayMax Human interferon-gamma (IFN-γ) ELISA Kit (Assaypro), USA. Results: Among enrolled infants, 76 % had BCG scar and 28% had positive tuberculin test. IFN γ levels after PPD stimulation (median (IQR): 0.13 (0.09-0.44) ng/ml) and after PHA stimulation (median (IQR): 1 (0.99-1) ng/ml) were significantly higher than basal levels (median (IQR): 0.08 (0.05-0.22) ng/ml), p= 0.001. Only five infants (20 %) had failed IFN γ response after PPD stimulation and these infants showed also lower PHA stimulated p=0.03), in comparison to those with PPD stimulated IFN γ response. BCG scar positive and negative groups were comparable in their immunological parameters. Infants with positive tuberculin test results (n=7) showed significantly higher IFN γ levels after PPD stimulation in comparison to the negative tuberculin group (n=18) (z=-2.09, p= 0.036). Conclusion: In this small cohort, it appears that the current BCG vaccination in Egypt results in an acceptable level of immune response. Absent BCG scar does not indicate failed immunization. Further longitudinal studies on a large number of infants are recommended to estimate the real clinical protection conferred by the currently used vaccine .

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Controversies in BCG immunization

Cited by 2 publications

References 4 publications

Mycobacterium bovis and BCG induce different patterns of cytokine and chemokine production in dendritic cells and differentiation patterns in CD4+ T cells

Mycobacterium bovis and BCG induce different patterns of cytokine and chemokine production in dendritic cells and differentiation patterns in CD4+ T cells

Assessment of BCG vaccine immune response in a sample of Egyptian infants

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