The histidine kinase PdhS controls cell cycle progression of the pathogenic alphaproteobacterium Brucella abortus.

Bacterial differentiation is often associated with the asymmetric localization of regulatory proteins, such as histidine kinases. PdhS is an essential and polarly localized histidine kinase in the pathogenic alphaproteobacterium Brucella abortus. After cell division, PdhS is asymmetrically segregated between the two sibling cells, highlighting a differentiation event.

Identification and characterization of in vivo attenuated mutants of Brucella melitensis.

Brucella melitensis 16M is a Gram-negative alpha2-proteobacterium responsible for abortion in goats and for Malta fever in humans. This facultative intracellular pathogen invades into and survives within both professional and non-professional phagocytes. Signature-tagged mutagenesis (STM) was used to identify genes required for the in vivo pathogenesis of Brucella.

Quantitative assessment by flow cytometry of T-lymphocytes producing antigen-specific gamma-interferon in Brucella immune cattle.

Peripheral blood mononuclear cells (PBMC) isolated from cattle infected with Brucella secreted gamma-interferon (IFN-gamma) after antigen-specific stimulation with Brucellergene, which is a mixture of cytoplasmic proteins of rough Brucella melitensis B115. Following the depletion of the monocyte-macrophages from the PBMC, the enriched lymphocyte populations stimulated with Brucellergene did not produce IFN-gamma. Two-colour immunofluorescence staining of intracellular IFN-gamma and bovine cell surface molecules identified the cells producing IFN-gamma among the PBMC stimulated with Brucellergene.

Immunological response of mice to the bovine respiratory syncytial virus fusion glycoprotein expressed in recombinant baculovirus infected insect cells.

Bovine respiratory syncytial virus (BRSV) is a major cause of respiratory disease in calves. The BRSV genome encodes two major glycoproteins, G and F, which are the major targets for the host antibody response. We have expressed the F glycoprotein in insect cells (Sf9) using a recombinant baculovirus vector.

CD5+ B cells from bovine leukemia virus infected cows are activated cycling cells responsive to interleukin 2.

Most of the B cells from bovine leukemia virus (BLV) infected cows in persistent lymphocytosis (PL) were known to express the CD5 T-cell marker but it was not known whether this peculiar membrane phenotype relates to an activation state. It was demonstrated that these B cells were also flagged by two other membrane markers normally borne by cells belonging to the myeloid lineage (namely CD11b and CD11c). Moreover, cell cycle analysis illustrated that a significant percentage of these B cells (greater than 15%) left their resting (G0/G1) status and progressed through the cell cycle.