Publications by authors named "H Martin Vordermeier"

194 Publications

RNA-Seq Transcriptome Analysis of Peripheral Blood From Cattle Infected With Across an Experimental Time Course.

Front Vet Sci 2021 28;8:662002. Epub 2021 May 28.

Animal Genomics Laboratory, UCD School of Agriculture and Food Science, UCD College of Health and Agricultural Sciences, University College Dublin, Dublin, Ireland.

Bovine tuberculosis, caused by infection with members of the complex, particularly , is a major endemic disease affecting cattle populations worldwide, despite the implementation of stringent surveillance and control programs in many countries. The development of high-throughput functional genomics technologies, including RNA sequencing, has enabled detailed analysis of the host transcriptome to infection, particularly at the macrophage and peripheral blood level. In the present study, we have analysed the transcriptome of bovine whole peripheral blood samples collected at -1 week pre-infection and +1, +2, +6, +10, and +12 weeks post-infection time points. Differentially expressed genes were catalogued and evaluated at each post-infection time point relative to the -1 week pre-infection time point and used for the identification of putative candidate host transcriptional biomarkers for infection. Differentially expressed gene sets were also used for examination of cellular pathways associated with the host response to infection, construction of gene interaction networks enriched for host differentially expressed genes, and time-series analyses to identify functionally important groups of genes displaying similar patterns of expression across the infection time course. A notable outcome of these analyses was identification of a 19-gene transcriptional biosignature of infection consisting of genes increased in expression across the time course from +1 week to +12 weeks post-infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fvets.2021.662002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8193354PMC
May 2021

Interferon-γ Response of subsp. Infected Goats to Recombinant and Synthetic Mycobacterial Antigens.

Front Vet Sci 2021 26;8:645251. Epub 2021 Mar 26.

Animal and Plant Health Agency, Addlestone, United Kingdom.

Despite its potential for early diagnosis of subsp. (MAP) infection, the IFN-γ release assay is not used routinely, because of low specificity of the established crude antigen preparation Johnin (PPDj). Limited data are available assessing the potential of MAP-derived protein and lipopeptide antigens to replace PPDj in assays for goats, while cattle and sheep have been studied more extensively. Furthermore, MAP infection is claimed to interfere with the diagnosis of bovine tuberculosis when other crude antigen preparations (PPDb, PPDa) are applied. In this study, the diagnostic potential of MAP-derived recombinant protein antigens, synthetic MAP lipopentapeptides and of specific peptide cocktails was assessed compared to crude mycobacterial antigen preparations in experimentally infected goats. Goats were inoculated with MAP, or subsp. (MAH) as surrogate for environmental mycobacteria, non-exposed animals served as controls. Complex-specific antibody and PPDj-induced IFN-γ responses were monitored . Infection status was assessed by pathomorphological findings and bacteriological tissue culture at necropsy 1 year after inoculation. The IFN-γ response to 13 recombinant protein antigens of MAP, two synthetic MAP lipopentapeptides and three recombinant peptide cocktails of was investigated at three defined time points after infection. At necropsy, MAP or MAH infection was confirmed in all inoculated goats, no signs of infection were found in the controls. Antibody formation was first detected 3-6 weeks post infection (wpi) in MAH-inoculated and 11-14 wpi in the MAP-inoculated goats. Maximum PPDj-induced IFN-γ levels in MAH and MAP exposed animals were recorded 3-6 and 23-26 wpi, respectively. Positive responses continued with large individual variation. Antigens Map 0210c, Map 1693c, Map 2020, Map 3651cT(it), and Map 3651c stimulated increased whole blood IFN-γ levels in several MAP-inoculated goats compared to MAH inoculated and control animals. These IFN-γ levels correlated with the intensity of the PPDj-induced responses. The two synthetic lipopentapeptides and the other MAP-derived protein antigens had no discriminatory potential. Stimulation with peptide cocktails ESAT6-CFP10, Rv3020c, and Rv3615c did not elicit IFN-γ production. Further work is required to investigate if test sensitivity will increase when mixtures of the MAP-derived protein antigens are applied.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fvets.2021.645251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8034290PMC
March 2021

A molecularly defined skin test reagent for the diagnosis of bovine tuberculosis compatible with vaccination against Johne's Disease.

Sci Rep 2021 Feb 3;11(1):2929. Epub 2021 Feb 3.

Animal and Plant Health Agency, Bacteriology, Addlestone, UK.

Tuberculin Purified Protein Derivatives (PPDs) exhibit multiple limitations: they are crude extracts from mycobacterial cultures with largely unknown active components; their production depends on culture of mycobacteria requiring expensive BCL3 production facilities; and their potency depends on the technically demanding guinea pig assay. To overcome these limitations, we developed a molecularly defined tuberculin (MDT) by adding further antigens to our prototype reagent composed of ESAT-6, CFP-10 and Rv3615c (DIVA skin test, DST). In vitro screening using PBMC from infected and uninfected cattle shortlisted four antigens from a literature-based list of 18 to formulate the MDT. These four antigens plus the previously identified Rv3020c protein, produced as recombinant proteins or overlapping synthetic peptides, were formulated together with the three DST antigens into the MDT to test cattle experimentally and naturally infected with M. bovis, uninfected cattle and MAP vaccinated calves. We demonstrated significant increases in MDT-induced skin responses compared to DST in infected animals, whilst maintaining high specificity in unvaccinated or MAP vaccinated calves. Further, MDT can also be applied in in vitro blood-based interferon-gamma release assays. Thus, MDT promises to be a robust diagnostic skin and blood test reagent overcoming some of the limitations of PPDs and warrants full validation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-82434-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7859399PMC
February 2021

Genetic screening for the protective antigenic targets of BCG vaccination.

Tuberculosis (Edinb) 2020 09 1;124:101979. Epub 2020 Aug 1.

Department of Microbial Sciences, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK. Electronic address:

Bovine tuberculosis is an important animal health problem and the predominant cause of zoonotic tuberculosis worldwide. It results in serious economic burden due to losses in productivity and the cost of control programmes. Control could be greatly improved by the introduction of an efficacious cattle vaccine but the most likely candidate, BCG, has several limitations including variable efficacy. Augmentation of BCG with a subunit vaccine booster has been shown to increase protection but the selection of antigens has hitherto been left largely to serendipity. In the present study, we take a rational approach to identify the protective antigens of BCG, selecting a BCG transposon mutant library in naïve and BCG-vaccinated cattle. Ten mutants had increased relative survival in vaccinated compared to naïve cattle, consistent with loss of protective antigen targets making the mutants less visible to the BCG immune response. The immunogenicity of three putative protective antigens, BCG_0116, BCG_0205 (YrbE1B) and BCG_1448 (PPE20) was investigated using peptide pools and PBMCs from BCG vaccinated cattle. BCG vaccination induced PBMC to release elevated levels of IP10, IL-17a and IL-10 in response to all three antigens. Taken together, the data supports the further study of these antigens for use in subunit vaccines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tube.2020.101979DOI Listing
September 2020

Memory B cells and tuberculosis.

Vet Immunol Immunopathol 2020 Mar 2;221:110016. Epub 2020 Feb 2.

National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA, USA.

Immunological memory is a central feature of adaptive immunity. Memory B cells are generated upon stimulation with antigen presented by follicular dendritic cells in the peripheral lymphoid tissues. This process typically involves class-switch recombination and somatic hypermutation and it can be dependent or independent on germinal centers or T cell help. The mature B cell memory pool is generally characterized by remarkable heterogeneity of functionally and phenotypically distinct sub-populations supporting multi-layer immune plasticity. Memory B cells found in human patients infected with Mycobacterium tuberculosis include IgD+ CD27+ and IgM+ CD27+ subsets. In addition, expansion of atypical memory B cells characterized by the lack of CD27 expression and by inability to respond to antigen-induced re-activation is documented in human tuberculosis. These functionally impaired memory B cells are believed to have adverse effects on host immunity. Human and animal studies demonstrate recruitment of antigen-activated B cells to the infection sites and their presence in lung granulomas where proliferating B cells are organized into discrete clusters resembling germinal centers of secondary lymphoid organs. Cattle studies show development of IgM+, IgG+, and IgA+ memory B cells in M. bovis infection with the ability to rapidly differentiate into antibody-producing plasma cells upon antigen re-exposure. This review discusses recent advances in research on generation, re-activation, heterogeneity, and immunobiological functions of memory B cells in tuberculosis. The role of memory B cells in post-skin test recall antibody responses in bovine tuberculosis and implications for development of improved immunodiagnostics are also reviewed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.vetimm.2020.110016DOI Listing
March 2020