scholarly journals Immunogenicity of Mycobacterium tuberculosis Antigens in Mycobacterium bovis BCG-Vaccinated and M. bovis-Infected Cattle

2006 ◽  
Vol 74 (8) ◽  
pp. 4566-4572 ◽  
Author(s):  
A. S. Mustafa ◽  
Y. A. Skeiky ◽  
R. Al-Attiyah ◽  
M. R. Alderson ◽  
R. G. Hewinson ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Bovis ◽  
Infected Cattle ◽  
Subunit Vaccines ◽  
Vaccine Candidates ◽  
Future Evaluation ◽  
Research Challenge ◽  
Interferon Responses ◽  
Recombinant Bcg

ABSTRACT The development of novel vaccine strategies supplementing Mycobacterium bovis BCG (BCG) constitutes an urgent research challenge. To identify potential subunit vaccine candidates, we have tested a series of eight recently identified Mycobacterium tuberculosis antigens in M. bovis-infected and BCG-vaccinated cattle. These antigens were characterized on the basis of their ability to induce in vitro gamma interferon responses in infected or BCG-vaccinated calves. We were able to establish a hierarchy of these antigens based on how frequently they were recognized in both groups of animals. In particular, we were able to prioritize frequently recognized proteins like Rv0287, Rv1174, and Rv1196 for future evaluation as subunit vaccines to be used in BCG-protein heterologous prime-boost vaccination scenarios. In addition, the antigen most dominantly recognized in M. bovis-infected cattle in this study, Rv3616c, was significantly less frequently recognized by BCG vaccinees and could be a target to improve BCG, for example, by increasing its secretion, in a recombinant BCG vaccine.

scholarly journals Stable Expression of Lentiviral Antigens by Quality-Controlled Recombinant Mycobacterium bovis BCG Vectors

2015 ◽  
Vol 22 (7) ◽  
pp. 726-741 ◽  
Author(s):  
Bryan E. Hart ◽  
Rose Asrican ◽  
So-Yon Lim ◽  
Jaimie D. Sixsmith ◽  
Regy Lukose ◽  
...  
Keyword(s):  
Mycobacterium Bovis ◽  
Antigen Expression ◽  
Full Length ◽  
Content Type ◽  
Immunodeficiency Virus ◽  
Vaccine Stability ◽  
Hiv Gp120 ◽  
Recombinant Bcg

ABSTRACTThe well-established safety profile of the tuberculosis vaccine strain,Mycobacterium bovisbacille Calmette-Guérin (BCG), makes it an attractive vehicle for heterologous expression of antigens from clinically relevant pathogens. However, successful generation of recombinant BCG strains possessing consistent insert expression has encountered challenges in stability. Here, we describe a method for the development of large recombinant BCG accession lots which stably express the lentiviral antigens, human immunodeficiency virus (HIV) gp120 and simian immunodeficiency virus (SIV) Gag, using selectable leucine auxotrophic complementation. Successful establishment of vaccine stability stems from stringent quality control criteria which not only screen for highly stable complemented BCG ΔleuCDtransformants but also thoroughly characterize postproduction quality. These parameters include consistent production of correctly sized antigen, retention of sequence-pure plasmid DNA, freeze-thaw recovery, enumeration of CFU, and assessment of cellular aggregates. Importantly, these quality assurance procedures were indicative of overall vaccine stability, were predictive for successful antigen expression in subsequent passaging bothin vitroandin vivo, and correlated with induction of immune responses in murine models. This study has yielded a quality-controlled BCG ΔleuCDvaccine expressing HIV gp120 that retained stable full-length expression after 1024-fold amplificationin vitroand following 60 days of growth in mice. A second vaccine lot expressed full-length SIV Gag for >1068-fold amplificationin vitroand induced potent antigen-specific T cell populations in vaccinated mice. Production of large, well-defined recombinant BCG ΔleuCDlots can allow confidence that vaccine materials for immunogenicity and protection studies are not negatively affected by instability or differences between freshly grown production batches.

scholarly journals Generation of Attenuated Mycobacterium bovis Strains by Signature-Tagged Mutagenesis for Discovery of Novel Vaccine Candidates

2005 ◽  
Vol 73 (4) ◽  
pp. 2379-2386 ◽  
Author(s):  
Desmond M. Collins ◽  
Bronwyn Skou ◽  
Stefan White ◽  
Shalome Bassett ◽  
Lauren Collins ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Bovis ◽  
Guinea Pigs ◽  
Essential Role ◽  
Immunoblot Analysis ◽  
Infection Model ◽  
Vaccine Candidates ◽  
Mouse Infection Model ◽  
Potential Vaccine

ABSTRACT Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex, has a particularly wide host range and causes tuberculosis in most mammals, including humans. A signature tag mutagenesis approach, which employed illegitimate recombination and infection of guinea pigs, was applied to M. bovis to discover genes important for virulence and to find potential vaccine candidates. Fifteen attenuated mutants were identified, four of which produced no lesions when inoculated separately into guinea pigs. One of these four mutants had nine deleted genes including mmpL4 and sigK and, in guinea pigs with aerosol challenge, provided protection against tuberculosis at least equal to that of M. bovis BCG. Seven mutants had mutations near the esxA (esat-6) locus, and immunoblot analysis of these confirmed the essential role of other genes at this locus in the secretion of EsxA (ESAT-6) and EsxB (CFP10). Mutations in the eight other attenuated mutants were widely spread through the chromosome and included pks1, which is naturally inactivated in clinical strains of M. tuberculosis. Many genes identified were different from those found by signature tag mutagenesis of M. tuberculosis by use of a mouse infection model and illustrate how the use of different approaches enables identification of a wider range of attenuating mutants.

scholarly journals Tuberculosis Vaccine Types and Timings

2014 ◽  
Vol 22 (3) ◽  
pp. 249-257 ◽  
Author(s):  
Ian M. Orme
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Bovis ◽  
Bacterial Pathogen ◽  
Content Type ◽  
Vaccine Candidates ◽  
Emergency Situations ◽  
Prophylactic Vaccines ◽  
New Vaccines

ABSTRACTTraditionally, the design of new vaccines directed againstMycobacterium tuberculosis, the most successful bacterial pathogen on the planet, has focused on prophylactic candidates that would be given to individuals while they are still young. It is becoming more apparent, however, that there are several types of vaccine candidates now under development that could be used under various conditions. Thus, in addition to prophylactic vaccines, such as recombinantMycobacterium bovisBCG or BCG-boosting vaccines, other applications include vaccines that could prevent infection, vaccines that could be given in emergency situations as postexposure vaccines, vaccines that could be used to facilitate chemotherapy, and vaccines that could be used to reduce or prevent relapse and reactivation disease. These approaches are discussed here, including the type of immunity we are trying to specifically target, as well as the limitations of these approaches.

Modification transmissible induite in vitro chez Mycobacterium tuberculosis et Mycobacterium bovis

1979 ◽  
Vol 25 (4) ◽  
pp. 462-474 ◽  
Author(s):  
P. Lafont ◽  
J. Lafont
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Bovis ◽  
Concanavalin A ◽  
Active Material ◽  
Biologically Active

A biologically active material (fraction "S") is isolated from cultures of scotochromogenic mycobacteria, Mycobacterium tuberculosis, or Mycobacterium bovis by disrupting the cells, sedimentation through 2.2 M sucrose, and ultrafiltration. The fraction "S" induces the modification of tubercle bacilli into non acid-fast bacteria forming smooth colonies on nutritive glycerol agar within 24–36 h of incubation. Three new phenotypes are thus obtained; two proved to be stable upon subculturing.Frequently the phenomenon occurs with a very large part of the Koch's bacillus population exposed to the inducing agent effect. It can be reproduced with crude preparations of DNA obtained from the fraction "S." It is inhibited by concanavalin A. The observed modification does not correspond to a transfer of characteristics of the inducing agent from the donor mycobacteria; furthermore it can be manifested even in the strain used for the preparation of the fraction "S."

scholarly journals Lack of Immune Responses to Mycobacterium tuberculosis DosR Regulon Proteins following Mycobacterium bovis BCG Vaccination

2007 ◽  
Vol 75 (7) ◽  
pp. 3523-3530 ◽  
Author(s):  
May Young Lin ◽  
Annemieke Geluk ◽  
Steven G. Smith ◽  
Amanda L. Stewart ◽  
Annemieke H. Friggen ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Immune Responses ◽  
Mycobacterium Bovis ◽  
Protective Efficacy ◽  
Transcriptional Profiling ◽  
In Silico Analysis ◽  
Dna Encoding ◽  
Bcg Vaccination ◽  
Dosr Regulon

ABSTRACT Mycobacterium bovis BCG is widely used as a vaccine against tuberculosis (TB), despite its variable protective efficacy. Relatively little is known about the immune response profiles following BCG vaccination in relation to protection against TB. Here we tested whether BCG vaccination results in immune responses to DosR (Rv3133c) regulon-encoded proteins. These so-called TB latency antigens are targeted by the immune system during persistent Mycobacterium tuberculosis infection and have been associated with immunity against latent M. tuberculosis infection. In silico analysis of the DosR regulon in BCG and M. tuberculosis showed at least 97% amino acid sequence homology, with 41 out of 48 genes being identical. Transcriptional profiling of 14 different BCG strains, under hypoxia and nitric oxide exposure in vitro, revealed a functional DosR regulon similar to that observed in M. tuberculosis. Next, we assessed human immune responses to a series of immunodominant TB latency antigens and found that BCG vaccination fails to induce significant responses to latency antigens. Similar results were obtained with BCG-vaccinated BALB/c mice. In contrast, responses to latency antigens were observed in individuals with suspected exposure to TB (as indicated by positive gamma interferon responses to TB-specific antigens ESAT-6 and CFP-10) and in mice vaccinated with plasmid DNA encoding selected latency antigens. Since immune responses to TB latency antigens have been associated with control of latent M. tuberculosis infection, our findings support the development of vaccination strategies incorporating DosR regulon antigens to complement and improve the current BCG vaccine.

scholarly journals Cell-free glycoengineering of the recombinant SARS-CoV-2 spike glycoprotein

2021 ◽  
Author(s):  
Johannes Ruhnau ◽  
Valerian Grote ◽  
Mariana Juarez-Osorio ◽  
Dunja Bruder ◽  
Erdmann Rapp ◽  
...  
Keyword(s):  
Expression System ◽  
Protein Glycosylation ◽  
Spike Glycoprotein ◽  
Complex Type ◽  
One Pot ◽  
Subunit Vaccines ◽  
Vaccine Candidates ◽  
Wide Range ◽  
The Impact

AbstractThe baculovirus-insect cell expression system is readily utilized to produce viral glycoproteins for research as well as for subunit vaccines and vaccine candidates, for instance against SARS-CoV-2 infections. However, the glycoforms of recombinant proteins derived from this expression system are inherently different from mammalian cell-derived glycoforms with mainly complex-type N-glycans attached, and the impact of these differences in protein glycosylation on the immunogenicity is severely underinvestigated. This applies also to the SARS-CoV-2 spike glycoprotein, which is the antigen target of all licensed vaccines and vaccine candidates including virus like particles and subunit vaccines that are variants of the spike protein. Here, we expressed the transmembrane-deleted human β-1,2 N-acetlyglucosamintransferases I and II (MGAT1∆TM and MGAT2∆TM) and the β-1,4-galactosyltransferase (GalT∆TM) in E. coli to in-vitro remodel the N-glycans of a recombinant SARS-CoV-2 spike glycoprotein derived from insect cells. In a cell-free sequential one-pot reaction, fucosylated and afucosylated paucimannose-type N-glycans were converted to complex-type galactosylated N-glycans. In the future, this in-vitro glycoengineering approach can be used to efficiently generate a wide range of N-glycans on antigens considered as vaccine candidates for animal trials and preclinical testing to better characterize the impact of N-glycosylation on immunity and to improve the efficacy of protein subunit vaccines.

scholarly journals Adjuvants and Antigen-Delivery Systems for Subunit Vaccines against Tuberculosis

Vaccines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 972
Author(s):  
Abu Salim Mustafa
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Immune Responses ◽  
Pulmonary Disease ◽  
Delivery Systems ◽  
Antigen Delivery ◽  
Special Issue ◽  
Subunit Vaccines ◽  
Recombinant Bcg ◽  
New Vaccines ◽  
Antigen Delivery Systems

The only licensed vaccine against tuberculosis is BCG. However, BCG has failed to provide consistent protection against tuberculosis, especially pulmonary disease in adults. Furthermore, the use of BCG is contraindicated in immunocompromised subjects. The research towards the development of new vaccines against TB includes the use of Mycobacterium tuberculosis antigens as subunit vaccines. Such vaccines may be used either alone or in the prime-boost model in BCG-vaccinated people. However, the antigens for subunit vaccines require adjuvants and/or delivery systems to induce appropriate and protective immune responses against tuberculosis and other diseases. Articles published in this Special Issue have studied the pathogenesis of BCG in children and the use of BCG and recombinant BCG as potential vaccines against asthma. Furthermore, the use of different adjuvants and delivery systems in inducing the protective immune responses after immunization with subunit vaccines has been described.

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