The applicability of whole-cell hybridization for the identification of pathogenic bacteria in blood from septic patients was examined. Oligonucleotide probes, fluorescently labeled with fluorescein isothiocyanate, directed against the variable regions of the 16S rRNAs of the following bacterial species and/or genera were used: Streptococcus spp., Enterococcus faecalis, Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Escherichia coli, Pseudomonas aeruginosa, and the Enterobacteriaceae family. A probe specific for the rRNAs of almost all bacteria and its complementary, reversed counterpart was used as positive and negative control, respectively. The probes were used in conjunction with a fast and simple-to-use protocol for whole-cell hybridization. This protocol yields an identification after 25 to 45 min, depending on whether the bacterium is gram positive or gram negative. A total of 182 blood samples which tested positive in a blood culture machine were investigated. All probes except for the ones for S. aureusand the CoNS showed sensitivities and specificities of 1.000. It was concluded that whole-cell hybridization is well suited for the fast screening of septic blood containing streptococci and/or enterococci or gram-negative rods.

Virosomes are reconstituted viral envelopes which lack the genetic material but retain the cell entry and membrane fusion characteristics of the virus they are derived from. Thus, influenza virosomes are taken up by cells via receptor-mediated endocytosis, which directs the particles to the endosomal cell compartment. Subsequently, the virosomal membrane fuses with the endosomal membrane induced by the mildly acidic pH within the endosomes. This fusion process establishes continuity between the lumen of the virosome and the cell cytosol. Upon interaction of virosomes with antigen-presenting cells (APCs), protein antigens encapsulated within virosomes will be delivered to the cell cytosol, and thus, into the MHC class I presentation pathway. Indeed, virosome-mediated delivery of antigens in vivo results in efficient priming of a class I MHC-restricted cytotoxic T lymphocyte (CTL) response.