Project description:Bordetella pertussis is the etiological agent of whooping cough, a bacterial infection of especially children, which may be fatal without treatment. In frame of studies to investigate putative effects of vaccination on host-pathogen interaction and clonal distribution of strains, in addition to Corynebacterium diphtheriae and Clostridium tetani toxoid vaccines, also whole-cell and acellular pertussis vaccines were analyzed by mass spectrometry.
Project description:Murine lung gene expression responses to primary and secondary infection with Bordetella pertussis. Data were compared to other parameters such as flow cytometry and multiplex immunoassays.
Project description:Since the introduction of new generation pertussis vaccines, resurgence of pertussis is observed in many developed countries. Former whole-cell pertussis vaccines (wP) are able to protect against disease and transmission but have been replaced in several industrialized countries because of their reactogenicity and adverse effects. Current acellular pertussis vaccines (aP), made of purified proteins of Bordetella pertussis, are efficient at preventing disease but fail to induce long-term protection from infection. While the systemic and mucosal T cell immunity induced by the two types of vaccines has been well described, much less is known concerning B cell responses. Taking advantage of an inducible AID-Cre-EYFP fate-mapping mouse model, we sorted and analyzed by scRNAseq the transcriptomic profiles of memory B cells after a combination of prime:boost with the two classes of vaccines. B220+EYFP+GL7-PNA- memory B cells from the draining lymph nodes (dLNs) of tamoxifen-fed mice were FACS sorted 7 weeks after boost, alongside with B220+EYFP+GL7+PNA+ germinal center (GC) B cells and B220+GL7-PNA-EYFP-IgD+ naive B cells as a control population for the unsupervised clustering analysis. Single-cell mRNA sequencing was performed according to an adapted version of the SORT-seq protocol (Muraro et al., 2016, PMID: 27693023, with primers described in van den Brink et al. 2017), with cDNA libraries generation, sequencing and reads alignment performed at Single Cell Discoveries (Utrecht, Netherlands).
Project description:Pertussis is a highly contagious, acute respiratory disease in humans caused by the Gram-negative pathogen Bordetella pertussis. Pertussis has resurged in the face of intensive vaccination and this has coincided with the emergence of strains carrying a particular allele for the pertussis toxin promoter, ptxP3, which is associated with higher levels of pertussis toxin (Ptx) production. Within 10 to 20 years, ptxP3 strains have nearly completely replaced the previously dominant ptxP1 strains resulting in a worldwide selective sweep. In order to identify B. pertussis genes associated with the selective sweep, we compared the expression of genes in ptxP1 and ptxP3 strains that are under control of the Bordetella master virulence regulatory locus (bvgASR). The BvgAS proteins comprise a two component sensory transduction system which is regulated by temperature, nicotinic acid and sulfate. By increasing the sulfate concentration, it is possible to change the phase of B. pertussis from virulent to avirulent. Until recently, the only distinctive phenotype of ptxP3 strains was a higher Ptx production. Here we identify additional phenotypic differences between ptxP1 and ptxP3 strains which may have contributed to its global spread by comparing global transcriptional responses under sulfate-modulating conditions. We show that ptxP3 strains are less sensitive to sulfate-mediated gene suppression, resulting in an increased production of the vaccine antigens pertactin (Prn) and Ptx and a number of other virulence genes, including a type III secretion toxin, Vag8, a protein involved in complement resistance, and lpxE involved in lipid A modification. Furthermore, enhanced expression of the vaccine antigens Ptx and Prn by ptxP3 strains was confirmed at the protein level. Identification of genes differentially expressed between ptxP1 and ptxP3 strains may elucidate how B. pertussis has adapted to vaccination and allow the improvement of pertussis vaccines by identifying novel vaccine candidates.
