Study of ribosomal vaccine against experimental Staphylococcal skin infection in rabbit

Il s’agit d'un vaccin constitué d’une partie d'ARN ribosomal de Sta phylococcus (souche humaine de St. aureus, St. epidermidis) et d’une partie et demie environ de protéoglycanes membranal res de Klebsiella {Kl. pneumoniae, biotype a, non pathogène). La vaccination par voie sous-cutanée, deux fois à 15 jours d'intervalle, à la dose de 12,5 mcg (ARNr + protéoglycanes) protège le lapin contre une infection expérimentale, pratiquée 3 semaines après la dernière vaccina tion, par voie intradermique avec une souche pathogène de St. aureus isolée chez le lapin. La protection est appréciée par la réduction (76 %) et par la diminution de la nécrose de la surface réagissante cutanée en comparaison des témoins. La nature de la protection est ensuite discutée ainsi que le mécanisme général d’action des vaccins ribosomaux.The vaccine is composed of one part of Staphylococcus ribosomal RNA (human strains of St. aureus, St. epidermidis) and approximately of one part and half of Klebsiella glycoproteins membranes (Kl. pneumoniae, biotype a, apathogen). 12,5 meg of the vaccine (rRNA + glycoproteins membranes) are injected subcutaneously to each rabbit at 15 days-intervals. The challenge is performed three weeks later, after the second vaccination, by the intra- dermal injection of live pathogen Staphylococcus aureus strain isolated from rabbit. The protection is appreciated by the reduction (76 %) of the surface area of the lesions and by the diminution of the necrosis in comparison with the controls. The nature of the protection is discussed and the general mechanism activity of the ribosomal vaccines

The animal lectin galectin-3 interacts with bacterial lipopolysaccharides via two independent sites.

International audienceGalectin-3 is a beta-galactoside binding protein expressed by activated macrophages, epithelial cells, and certain other cell types. Galectin-3 has a C-terminal carbohydrate binding domain, an N-terminal part consisting of a proline- and glycine-rich repetitive domain, and a small N-terminal domain. Two independent LPS binding sites on galectin-3 were demonstrated by binding of biotinylated LPS to immobilized recombinant galectin-3. One appears to be the carbohydrate binding site in the C-terminal domain that confers binding of LPS from Klebsiella pneumoniae that has a beta-galactoside-containing polysaccharide chain. This binding is best demonstrated using galectin-3 immunocaptured by a mAb to the N-terminal part (M3/38) and is inhibited by lactose. In contrast, Salmonella minnesota R7 LPS (Rd mutant), which is devoid of beta-galactosides, appears to bind to a site within the N-terminal part of galectin-3. This interaction is best demonstrated using galectin-3 directly immobilized in wells, and it is inhibited by the Ab M3/38, but not by lactose. Binding inhibition by polymyxin B and the profile of inhibition by a panel of LPSs with different amounts of the inner and outer cores present indicate that this second binding site recognizes the lipid A/inner core region of LPSs

Le ciblage des macrophages : un nouveau concept pour l'imagerie des ganglions lymphatiques pathologiques

National audienc

Study of ribosomal vaccine against experimental Staphylococcal skin infection in rabbit

Il s’agit d'un vaccin constitué d’une partie d'ARN ribosomal de Sta phylococcus (souche humaine de St. aureus, St. epidermidis) et d’une partie et demie environ de protéoglycanes membranal res de Klebsiella {Kl. pneumoniae, biotype a, non pathogène). La vaccination par voie sous-cutanée, deux fois à 15 jours d'intervalle, à la dose de 12,5 mcg (ARNr + protéoglycanes) protège le lapin contre une infection expérimentale, pratiquée 3 semaines après la dernière vaccina tion, par voie intradermique avec une souche pathogène de St. aureus isolée chez le lapin. La protection est appréciée par la réduction (76 %) et par la diminution de la nécrose de la surface réagissante cutanée en comparaison des témoins. La nature de la protection est ensuite discutée ainsi que le mécanisme général d’action des vaccins ribosomaux.The vaccine is composed of one part of Staphylococcus ribosomal RNA (human strains of St. aureus, St. epidermidis) and approximately of one part and half of Klebsiella glycoproteins membranes (Kl. pneumoniae, biotype a, apathogen). 12,5 meg of the vaccine (rRNA + glycoproteins membranes) are injected subcutaneously to each rabbit at 15 days-intervals. The challenge is performed three weeks later, after the second vaccination, by the intra- dermal injection of live pathogen Staphylococcus aureus strain isolated from rabbit. The protection is appreciated by the reduction (76 %) of the surface area of the lesions and by the diminution of the necrosis in comparison with the controls. The nature of the protection is discussed and the general mechanism activity of the ribosomal vaccines

Le ciblage des macrophages : un nouveau concept pour l'imagerie des ganglions lymphatiques pathologiques

National audienc

CD14 and CD11b mediate serum-independent binding to human monocytes of an acylpolygalactoside isolated from Klebsiella pneumoniae.

A water-soluble acylpolygalactosyl (APG) of 34 kDa was obtained from the Klebsiella pneumoniae membrane by alkaline hydrolysis and delipidation. APG comprises a poly(1,3)galactose chain, a core, and a lipid moiety made of a glucosamine disaccharide with two N-linked beta OH-myristates. The monocyte binding sites for APG were investigated by flow cytometry. Biotin-labelled APG (Biot-APG) bound to monocytes at 4 degrees C in the absence of serum, calcium, and magnesium. The binding was dose dependent, saturable, and displaced by unlabelled APG. Neither the polysaccharide chain present in APG-related molecules nor the PPi group or additional ester-linked myristates and palmitates were required for APG binding. The role of CD11b and CD14 was demonstrated by competitive inhibition with monoclonal antibodies and by the uptake of APG by these solubilized proteins. APG was rapidly internalized into monocytes at 37 degrees C while CD14 and CD11b/CD18 molecules were partially down-modulated. Lipopolysaccharides (LPS) from the same K. pneumoniae strain and from Escherichia coli and Salmonella minnesota partially competed for Biot-APG binding in the absence but not in the presence of serum. When altered by alkaline hydrolysis, those LPS became strong competitors for APG binding. It was concluded that alkaline hydrolysis of the K. pneumoniae membrane yielded molecules structurally related to LPS which bind to LPS membrane receptors in the absence of serum

In vitro cell activating properties of the composite ribosomal vaccine D53

D53 (RibomuntyR) is a composite vaccine made of immunogenic ribosomes from 4 bacterial species (Klebsiella pneumoniae, Haemophilus influenzae, Streptococcus pyogenes and Streptococcus pneumoniae) associated with a membrane proteoglycan from a non encapsulated strain of Klebsiella pneumoniae. D53 is a potent inducer of interleukin-1 production by mouse BALB/c spleen cells as shown by the C3H/HeJ thymocyte co-stimulation assay. Furthermore D53 triggers DNA synthesis by mouse spleen cells and induces the maturation of B lymphocytes into immunoglobulin secreting cells. Polyclonal B cell activation by D53 was readily achieved in the C3H/HeJ strain which is deficient in its response to E. coli lipopolysaccharide. The proliferative response to D53 was abrogated by removal of B cells from the spleen cell suspension, but it was not altered after depletion of T cells or adherent cells. D53 induced polyclonal B cell activation of spleen cells from athymic nude mice and from CBA/N mice. Each component of D53 induced polyclona B cell activation except ribosomes from Streptococcus pneumoniae. Each triggered Interleukin-1 synthesis except ribosomes from Klebsiella penumoniae. These in vitro properties may account for some of the in vivo immunostimulating properties of this composite vaccine