Strain-Dependent Variation inMycobacterium bovisBCG-Induced Human T-Cell Activation and Gamma Interferon Production In Vitro

Abstract

Three commonly used Mycobacterium bovis BCG vaccine strains elicited different magnitudes of T-cell activation and gamma interferon production in vitro in healthy BCG-vaccinated individuals. Glaxo 1077 exhibited the greatest stimulatory capacity, followed by Pasteur 1173 and then Danish 1331. These differences may affect in vitro stimulation and vaccination-induced immunogenicity.Mycobacterium bovis bacillus Calmette-Guérin (BCG) is the only vaccine currently available to prevent tuberculosis. It is administered to over 100 million people per year (25), although its efficacy against pulmonary TB worldwide is variable (11). M. bovis BCG is an attenuated form of M. bovis obtained by 13 years of serial passage in vitro, following which it was found to provide protective immunity to challenge with virulent M. tuberculosis (3). M. bovis BCG was maintained by a process of serial passage for 40 years before methods for stable long-term storage became available, and this culminated in a family of approximately 13 daughter strains which are collectively known today by the generic term BCG. These strains have been shown to differ genetically (2,5,6,22) Despite the numerous differences previously found among BCG strains, and despite BCG stimulation being routinely used to study mycobacterium-specific immune responses, Tcell responses elicited by different BCG strains have not been compared in human cultures and were therefore investigated in this study.The BCG vaccine strains Danish 1331, Pasteur 1173, and Glaxo 1077 were grown in liquid cultures of Middlebrook 7H9 medium (Difco) supplemented with 10% Bacto Middlebrook ADC (Scientific Laboratory Supplies) and 0.025% Tween 80 (Difco), quantified by growth on Middlebrook 7H10 agar plates for 3 weeks, and kept frozen at Ϫ80°C for long-term storage. All three strain preparations were found to be 90 to 95% viable, as determined by fluorescein diacetate/ethidium bromide labeling. Peripheral blood mononuclear cells (PBMC) were isolated by density gradient centrifugation from seven healthy BCG-vaccinated donors, at least five of whom were likely to have been vaccinated with Glaxo 1077, and were cultured for 6 days either in the absence of antigenic stimulation or in the presence of one of the live M. bovis BCG strains titrated between 0.01 and 1 CFU per PBMC: if monocytes are estimated to constitute 10% of total PBMC, this is the equivalent of multiplicity of infection (MOI) ratios (M. bovis BCG bacilli to monocytes) of 0

Different Transcriptional Profiles of Human Monocyte-Derived Dendritic Cells Infected with Distinct Strains ofMycobacterium tuberculosisandMycobacterium bovisBacillus Calmette-Guérin

“…The goal of the present study was to determine whether the strains divergences may influence their relative immunogenicity [12, 13], virulence [14, 15], and viability [16], factors that must be considered for the design and improvement of a vaccine against TB.…”

T cells in mycobacterial infection and disease

“…There are many strains of BCG in use and these differ in immunogenicity [47]. Further BCG differs from Mtb in that it lacks RD-1 and absence of RD-1 alters induction of cells specific for antigens dependent upon RD-1 [48,49].…”

Approaches to Tuberculosis Mucosal Vaccine Development Using Nanoparticles and Microparticles: A Review

“…Although initially administrated by oral route, the BCG vaccine is currently administrated as a single intradermal injection, given at or soon after birth. 45 Current BCG vaccine efficiently protects children against the early manifestations of TB. In newborns the protective effect of BCG vaccine against TB compared with that in unvaccinated children is estimated at 74% (95% confidence interval [CI] 62%-83%) and 64% (95% CI 30%-82%) for meningitis, and up to 78% (95% CI 58%-88%) for disseminated disease.…”