The Mycobacterium bovis Bacille Calmette-Guérin (BCG) vaccine is given to >120 million infants each year worldwide. Most studies investigating the immune response to BCG have focused on adaptive ...immunity. However the importance of TCR-gamma/delta (γδ) T cells and NK cells in the mycobacterial-specific immune response is of increasing interest.
Participants in four age-groups were BCG-immunized. Ten weeks later, in vitro BCG-stimulated blood was analyzed for NK and T cell markers, and intracellular IFNgamma (IFNγ) by flow cytometry. Total functional IFNγ response was calculated using integrated median fluorescence intensity (iMFI).
In infants and children, CD4 and CD4-CD8- (double-negative (DN)) T cells were the main IFNγ-expressing cells representing 43-56% and 27-37% of total CD3+ IFNγ+ T cells respectively. The iMFI was higher in DN T cells compared to CD4 T cells in all age groups, with the greatest differences seen in infants immunized at birth (p=0.002) or 2 months of age (p<0.0001). When NK cells were included in the analysis, they accounted for the majority of total IFNγ-expressing cells and, together with DN Vδ2 γδ T cells, had the highest iMFI in infants immunized at birth or 2 months of age.
In addition to CD4 T cells, NK cells and DN T cells, including Vδ2 γδ T cells, are the key populations producing IFNγ in response to BCG immunization in infants and children. This suggests that innate immunity and unconventional T cells play a greater role in the mycobacterial immune response than previously recognized and should be considered in the design and assessment of novel tuberculosis vaccines.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Current immunodiagnostic tests for tuberculosis (TB), including the tuberculin skin test and IFN-γ release assay (IGRA), have significant limitations, which include their inability to distinguish ...between latent TB infection (LTBI) and active TB, a distinction critical for clinical management.
To identify mycobacteria-specific cytokine biomarkers that characterize TB infection, determine their diagnostic performance characteristics, and establish whether these biomarkers can distinguish between LTBI and active TB.
A total of 149 children investigated for TB infection were recruited; all participants underwent a tuberculin skin test and QuantiFERON-TB Gold assay. In parallel, whole-blood assays using early secretory antigenic target-6, culture filtrate protein-10, and PPD as stimulatory antigens were undertaken, and cytokine responses were determined by xMAP multiplex assays.
IFN-γ, interferon-inducible protein-10 (IP-10), tumor necrosis factor (TNF)-α, IL-1ra, IL-2, IL-13, and MIP-1β (macrophage inflammatory protein-1β) responses were significantly higher in LTBI and active TB cases than in TB-uninfected individuals, irrespective of the stimulant. Receiver operating characteristic analyses showed that IP-10, TNF-α, and IL-2 responses achieved high sensitivity and specificity for the distinction between TB-uninfected and TB-infected individuals. TNF-α, IL-1ra, and IL-10 responses had the greatest ability to distinguish between LTBI and active TB cases; the combinations of TNF-α/IL-1ra and TNF-α/IL-10 achieved correct classification of 95.5% and 100% of cases, respectively.
We identified several mycobacteria-specific cytokine biomarkers with the potential to be exploited for immunodiagnosis. Incorporation of these biomarkers into future immunodiagnostic assays for TB could result in substantial gains in sensitivity and allow the distinction between LTBI and active TB based on a blood test alone.
Current immune-based TB tests, including the tuberculin skin test (TST) and interferon-gamma release assays (IGRA), have significant limitations, including the inability to distinguish between latent ...TB infection (LTBI) and active TB. Few biomarkers with the potential to discriminate between these two infection states have been identified.
To determine whether functional profiling of mycobacteria-specific T cells can distinguish between TB-infected and -uninfected children, and simultaneously discriminate between LTBI and active TB.
One hundred and forty-nine children with suspected active TB or risk factors for LTBI were recruited at the Royal Children's Hospital Melbourne. Whole-blood stimulation assays, using ESAT-6, CFP-10, PPD, and heat-killed
as stimulants, were done, followed by intracellular cytokine staining and flow cytometric analysis.
Eighty-two participants in the well-defined diagnostic categories 'uninfected individuals' (asymptomatic, TST 0 mm / IGRA-;
= 61), LTBI (asymptomatic, TST ≥10 mm / IGRA+, normal chest radiograph;
= 15), or active TB microbiologically-confirmed (
= 3) or fulfilling stringent criteria (
= 3) were included in the final analysis. The proportions of mycobacteria-specific single-positive TNF-α+ and double-positive IFN-γ+/TNF-α+ CD4+ T cells were significantly higher in participants with active TB than in those with LTBI and uninfected individuals. Additionally, the frequency of IL-17-expressing CD4+ T cells, predominately with single-positive IL-17+ and double-positive IL-2+/IL-17+ phenotypes, was higher in participants with active TB than in the other two groups.
The frequencies and functional profiles of mycobacteria-specific CD4+ T cells differ significantly both between TB-infected and TB-uninfected children, and between LTBI and active TB. Although confirmation in further studies will be required, these findings indicate that functional profiling of mycobacteria-specific CD4+ T cells could potentially be exploited for novel immune-based TB assays that enable the distinction between infection states based on a blood sample alone.
BCG vaccine is one of the most commonly-administered vaccines worldwide. Studies suggest the protective efficacy of BCG against TB is better for children than for adults. One potential explanation is ...that BCG induces a better protective immune response in children. Twenty six children and adults were immunised with BCG. The proportion of Th1-cytokine-producing mycobacterial-specific T cells, and the concentrations of secreted cytokines, were measured before and 10 weeks after BCG immunisation. A significant increase in the proportion of mycobacterial-specific cytokine-producing T cells was observed in both age groups. After BCG immunisation, children and adults had comparable proportions of mycobacterial-specific polyfunctional CD4 T cells when measured relative to the total number of CD4 T cells. However, relative to the subset of Th-1-cytokine-producing CD4 T cells, the proportion of polyfunctional cells was greater in children. Concentrations of secreted cytokines were comparable in children and adults. These findings suggest that the mycobacterial-specific cell-mediated immune response induced by BCG immunisation in children and adults is similar. The implication of a shift to a more polyfunctional immune response within the Th1-cytokine-producing CD4 T cells in children is uncertain as this aspect of the immune response has not been assessed as a potential correlate of protection against TB.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Biosimilar medicines have shown similarity with the originator biologic and offer a similar clinical outcome generally at a lower cost. This paper identifies benefits of off-patent biologics and ...biosimilars, and illustrates these benefits with empirical data from Europe. We provide a narrative review of published literature on values and benefits of biosimilars in Europe. The results describe cost savings as the key driver stemming from the lower price of biosimilars, than that of originator products, and from price competition between biosimilar(s), originator, and next-generation products. Cost savings may then translate into a number of other associated benefits. The lower price of biosimilars and similar effectiveness to the originator biologics improve cost effectiveness, implying that reimbursement can be granted or extended to other patient groups, or that the biologic therapy can be moved to an earlier line of treatment. Cost savings from biosimilars can be used to increase patient access to therapy or to increase the number of healthcare professionals. Finally, competition between off-patent biologics and biosimilars may stimulate an innovation in the formulation and development of next-generation biologics. Our paper illustrates that the benefit of off-patent biologics and biosimilars is not restricted to cost savings, but that these medicines may contribute to an expansion of medical treatment options for patients, hence concomitantly contributing to the long-term sustainability of the healthcare system. This review provides a broader view for clinical and economic decision makers and healthcare professionals on the added benefits of off-patent biologics and their use in clinical practice.
We have isolated a cDNA from human placenta, which, when expressed heterologously in mammalian cells, mediates the transport of the water-soluble vitamin thiamine. The cDNA codes for a protein of 497 ...amino acids containing 12 putative transmembrane domains. Northern blot analysis indicates that this transporter is widely expressed in human tissues. When expressed in HeLa cells, the cDNA induces the transport of thiamine (Kt= 2.5 ± 0.6 μm) in a Na+-independent manner. The cDNA-mediated transport of thiamine is stimulated by an outwardly directed H+ gradient. Substrate specificity assays indicate that the transporter is specific to thiamine. Even though thiamine is an organic cation, the cDNA-induced thiamine transport is not inhibited by other organic cations. Similarly, thiamine is not a substrate for the known members of mammalian organic cation transporter family. The thiamine transporter gene, located on human chromosome 1q24, consists of 6 exons and is most likely the gene defective in the metabolic disorder, thiamine-responsive megaloblastic anemia. At the level of amino acid sequence, the thiamine transporter is most closely related to the reduced-folate transporter and thus represents the second member of the folate transporter family.
Scar formation following bacillus Calmette-Guérin (BCG) vaccination has been associated with lower all-cause mortality; the relation between scar and mycobacteria-specific protection against ...tuberculosis is debated.
To evaluate the association between BCG skin reaction and mycobacteria-specific immune responses.
A
analysis was done among 214 infants in Australia randomized to vaccination with one of three BCG vaccine strains (BCG-Denmark, BCG-Japan, or BCG-Russia) given at birth or BCG-Denmark given at 2 months of age.
BCG skin reaction size and characteristics 10 weeks after vaccination were related to the
mycobacteria-specific immune responses measured in stimulated whole blood. The size and characteristics of the skin reaction correlated positively with
immune responses, even after adjusting for BCG vaccine strain and age at vaccination. Specifically, the reaction size and characteristics correlated with the proportion of mycobacteria-specific polyfunctional CD4
T cells after stimulation with BCG and PPD and, to a lesser extent, after stimulation with
or
. A similar correlation was observed with concentrations of IFN-γ, IL-2, tumor necrosis factor, and IL-13 in the supernatant after stimulation with BCG, PPD, and
and to some degree for the proportions of mycobacteria-specific polyfunctional CD8
T cells and CD107
cytotoxic cells.
BCG skin reaction correlated with the magnitude of mycobacteria-specific T-cell responses. As T-cell responses play a key role in defense against mycobacteria, the relationship between BCG scar formation and protection against tuberculosis should be revisited. This may also extend to the need for BCG revaccination in scar-negative individuals.Clinical trial registered with www.australianclinicaltrials.gov.au/clinical-trial-registries (ACTRN12608000227392).
Approximately 100 million doses of bacille Calmette-Guérin (BCG) vaccine are given each year to protect against tuberculosis (TB). More than 20 genetically distinct BCG vaccine strains are in use ...worldwide. Previous studies suggest that BCG vaccine strain influences the immune response and protection against TB. Current data on which BCG vaccine strain induces the optimal immune response in humans are insufficient.
To compare the immune response to three different BCG vaccine strains given to infants at birth.
Newborn infants in a tertiary women's hospital were immunized at birth with one of three BCG vaccine strains. A stratified randomization according to the mother's region of birth was used.
The presence of mycobacterial-specific polyfunctional CD4 T cells measured by flow cytometry 10 weeks after immunization. Of the 209 infants immunized, data from 164 infants were included in the final analysis (BCG-Denmark, n = 54; BCG-Japan, n = 54; BCG-Russia, n = 57). The proportion of polyfunctional CD4 T cells was significantly higher in infants immunized with BCG-Denmark (0.013%) or BCG-Japan (0.016%) than with BCG-Russia (0.007%) (P = 0.018 and P = 0.003, respectively). Infants immunized with BCG-Japan had higher concentrations of secreted Th1 cytokines; infants immunized with BCG-Denmark had higher proportions of CD107-expressing cytotoxic CD4 T cells.
There are significant differences in the immune response induced by different BCG vaccine strains in newborn infants. Immunization with BCG-Denmark or BCG-Japan induced higher frequencies of mycobacterial-specific polyfunctional and cytotoxic T cells and higher concentrations of Th1 cytokines. These findings have potentially important implications for global antituberculosis immunization policies and future tuberculosis vaccine trials.
•Infant BCG immunisation induces M. ulcerans-specific immune responses.•M. ulcerans- and M. tuberculosis-specific immune responses are qualitatively similar.•Magnitude of M. ulcerans-specific immune ...responses was not influenced by BCG strain.•These in-vitro findings support the protective effect observed epidemiologically.
Bacillus 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.
Intracellular 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).
Proportions 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.
Our data show that BCG immunisation induces M. ulcerans-specific immune responses in infants, likely explaining the cross-protective effect observed in epidemiological studies. (ACTRN12608000227392)
The aqueous biphasic system (ABS) involving sodium malonateapolyethylene glycol (PEG) phases has been applied for the first time for separation of no-carrier-added 183Re (T1/2=70 d) from I--particle ...irradiated bulk tantalum target. The various ABS conditions were applied for investigating the separation by varying pH, temperature, PEG-molecular weight, concentration of salt. The extraction pattern was hardly affected by change in pH and the molecular weight of PEG. One step separation of nca 183Re from Ta was achieved at the optimal conditions of (i) 50% (w/w) PEG-4000a2 M sodium malonate, 40 degree C and (ii) 50% (w/w) PEG-4000a3 M sodium malonate, room temperature (27 degree C).
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