<sec><title>Objectives</title><p>To circumvent the limitations of the current golden standard method, colony-forming unit (CFU) assay, for viability of Bacille Calmette–Guérin (BCG) vaccines, we developed a new method to rapidly and accurately determine the potency of BCG vaccines.</p></sec><sec><title>Methods</title><p>Based on flow cytometry (FACS) and fluorescein diacetate (FDA) as the most appropriate fluorescent staining reagent, 17 lots of BCG vaccines for percutaneous administration and 5 lots of BCG vaccines for intradermal administration were analyzed in this study. The percentage of viable cells measured by flow cytometry along with the total number of organisms in BCG vaccines, as determined on a cell counter, was used to quantify the number of viable cells.</p></sec><sec><title>Results</title><p>Pearson correlation coefficients of FACS and CFU assays for percutaneous and intradermal BCG vaccines were 0.6962 and 0.7428, respectively, indicating a high correlation. The coefficient of variation value of the FACS assay was less than 7%, which was 11 times lower than that of the CFU assay.</p></sec><sec><title>Conclusion</title><p>This study contributes to the evaluation of new potency test method for FACS-based determination of viable cells in BCG vaccines. Accordingly, quality control of BCG vaccines can be significantly improved.</p></sec>
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Objectives
Bacillus Calmette-Guérin (BCG) vaccination has proven to be efficient in immunologically naïve infants; however, it has not been investigated that maternal natural exposure to <i>Mycobacterium</i> and/or BCG vaccine could influence the characteristics of immune responses to BCG in newborns. In this study, we analyzed whether the maternal immune status to <i>M tuberculosis </i>(<i>M tb</i>) can affect neonatal immunity to BCG using a mouse model. Methods
Neonates were obtained from mice that were previously exposed to live BCG, to live <i>M avium</i>, or to heat-killed <i>M tb</i> H37Rv, and from naïve control mothers. One week after birth, the neonates were divided into two subgroups: one group immunized with live BCG via the subcutaneous route and the other group of neonates sham-treated. Interferon-gamma (IFNγ) secretion in response to <i>in vitro </i>stimulation with heat-killed BCG or purified protein derivative (PPD) was examined. Protection against <i>M tb</i> infection was evaluated by challenging mice nasally with live <i>M tb</i> H37Rv followed by counting colonies from spleen and lung homogenates. Results
BCG-immunized neonates showed increased IFNγ secretion in response to heat-killed BCG or PPD. All mice in BCG-immunized neonates subgroups showed reduced bacterial burden (colony forming unit) in the lungs when compared with control naive neonate mice. However, no statistically significant difference was observed when comparing BCG-immunized mice born from mothers previously exposed to <i>M avium</i> or immunized with either heat-killed H37Rv or live BCG and mice born from naïve mothers. Conclusion
The maternal immune status to <i>M tb</i> does not appear to impact on the immunogenicity of BCG vaccine in their progeny in our experimental conditions
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Adverse reactions to the Bacillus Calmette–Guérin (BCG) vaccine in new-born infants—an evaluation of the Danish strain 1331 SSI in a randomized clinical trial Thomas Nørrelykke Nissen, Nina Marie Birk, Jesper Kjærgaard, Lisbeth Marianne Thøstesen, Gitte Thybo Pihl, Thomas Hoffmann, Dorthe Lisbeth Jeppesen, Poul-Erik Kofoed, Gorm Greisen, Christine Stabell Benn, Peter Aaby, Ole Pryds, Lone Graff Stensballe Vaccine.2016; 34(22): 2477. CrossRef
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