SummaryWe identified the stress-induced ClpP of Listeria monocytogenes and demonstrated its crucial role in intracellular survival of this pathogen. ClpP is a 21.6 kDa protein belonging to a family of proteases highly conserved in prokaryotes and eukaryotes. A clpP-deleted mutant enabled us to demonstrate that ClpP is involved in proteolysis and is required for growth under stress conditions. Intramacrophage survival of this mutant was strongly restricted, thus resulting in loss of virulence for the mouse. The activity of listeriolysin O, a major virulence factor implicated in bacterial escape from phagosomes of macrophages, was much reduced in the clpP mutant under stress conditions. Direct evidence for the role of ClpP in the intracellular parasitism was obtained by showing that virulence and haemolytic activity were fully restored by complementation of the mutant. These results suggest that ClpP is involved in the rapid adaptive response of intracellular pathogens during the infectious process.

No abstract

No abstract

We describe the expression and consistent production of a first target-specific recombinant human polyclonal antibody. An anti-Rhesus D recombinant polyclonal antibody, Sym001, comprised of 25 unique human IgG1 antibodies, was produced by the novel Sympress expression technology. This strategy is based on site-specific integration of antibody genes in CHO cells, using the FRT/Flp-In recombinase system. This allows integration of the expression construct at the same genomic site in the host cells, thereby reducing genomic position effects. Different bioreactor batches of Sym001 displayed highly consistent manufacturing yield, antibody composition, binding potency, and functional activity. The results demonstrate that diverse recombinant human polyclonal antibody compositions can be reproducibly generated under conditions directly applicable to industrial manufacturing settings and present a first recombinant polyclonal antibody which could be used for treatment of hemolytic disease of the newborn and/or idiopathic thrombocytopenic purpura.