Alteration of dealcylated lipopolysaccharide antagonistic properties by interaction with plasma factors.

The acyl poly(1,3)galactoside (APG) from Klebsiella pneumoniae is a bis-acylated lipopolysaccharide (LPS) devoid of ester-linked fatty acids. APG interacts with CD14 and CD11b/CD18 on monocytes. This study addressed the role of serum proteins in the binding and functional properties of APG as a candidate LPS antagonist. In the absence of serum, APG did not induce tumor necrosis factor alpha (TNF-alpha) synthesis by human mononuclear cells and dose-dependently inhibited their activation induced by different LPS. Conversely, in the presence of 5% autologous plasma, APG activated cells and did not antagonize LPS. Serum decreased APG but not LPS binding to monocytes. Binding competition experiments indicated that APG and LPS competed for the same receptors in serum-free conditions but bound to different receptors in the presence of plasma. The data indicate that serum-dependent LPS receptors do contribute to LPS activation of monocytes but do not recognize deacylated LPS analogues.

Influence of technetium-99m-labeling conditions on physico-chemical and related biological properties of an acylated poly-galactosidic macrophage targeting agent for inflammation imaging.

The potential of 99m-Tc-J001 for the investigation of inflammatory lesions via the targeting of recruited macrophages (M phi) has already been documented in several experimental models and in human diseases. To achieve a functional imaging of inflammation via M phi targeting, minimal labeled colloid content and high in vivo stability of 99mTc-J001 are essential. The actual specificity of such scintigraphy is closely dependent upon the radiolabeling of only the J001 molecules available for M phi targeting. To develop an appropriate radiopharmaceutical kit, optimization of the labeling conditions was achieved from a series of pilot formulations that were evaluated for radiolabeling efficiency and both in vitro and in vivo 99mTc-J001 stability. Colloids were characterized using autocorrelation spectroscopy and multiangle laser-light scattering, radioactive colloid content of the formulations being deduced from biodistribution studies. This work has made possible the definition of a formulation exhibiting a radiolabeling yield > 97.0%, associated with in vivo stability and minimal colloid formation, thus greatly enhancing the specificity of such macrophage scintigraphy.

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

Galectin-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.

Macrophage targeting with technetium-99m labelled J001 acylated poly-galactoside for scintigraphy of inflammation: optimization and assessment of imaging specificity in experimental arthritis.

J001, an acylated poly-(1,3)-galactoside purified from the membrane of Klebsiella pneumoniae, associates selectively with macrophages via the binding to CD11b and CD14 molecules. Inflammatory foci known to recruit macrophages could thus be imaged with technetium-99m labelled J001. This study aims to define the optimal scintigraphic protocol for 99mTc-J001 imaging and to evaluate the specificity of J001 scans. A dose range study was conducted in rabbits with immunological arthritis using six different specific activities ranging from 370 to 11840 MBq·mg-1 while the intravenously injected activity was constant (37 MBq) Radiochemical purity for each preparation was documented together with the in vivo stability of the 99mTc-J001 complex using exclusion-diffusion radioHPLC of serum collected 1 h after radiopharmaceutical administration. Scintigraphic images were recorded at 2, 3 and 4h and analysed using indexes calculated from regions of interest. Specificity of the macrophage imaging was assessed by comparison with scans obtained after administration of 99mTcO4(- )or 99mTc-albumin nanocolloids. A protocol of plasma transfusion was also used to inject 99mTc-J001 after complete removal of radioactive colloids likely to be generated during the labelling. For the higher specific activities (5920 and 11840 MBq.mg-1), radiochemical purity degradation and in vitro 99mTc transchelation were noted. To prevent transchelation and 99mTc bond hydrolysis likely to impair imaging specificity, 1480 MBq.mg-1 corresponding to 25microg injected J001 was found to be the optimal usable specific activity. Results obtained with the various tracers support the hypothesis that macrophage targeting is the main factor involved in the J001 imaging of arthritis.

201T1 and 99Tcm-J001X macrophage scintigraphy: two radionuclide imaging techniques for the surveillance of acute localized radiation over-exposures.

The therapeutic or surgical management of acute localized irradiation is very complicated due to the delayed occurrence of ionizing radiation effects. There is a great need for non-invasive imaging techniques to delineate healthy from exposed tissues. Such a technique should be of value considering that spread of damage can occur from apparently silent fibrotic foci. Of the scintigraphic procedures, 99Tcm first-pass scintigraphy has already been recommended by the International Atomic Energy Agency (IAEA) for the evaluation of irradiated tissues. In order to improve the scintigraphic surveillance of accidental over-exposures, the potentials of 201T1 and 99Tcm-J001X were evaluated on an experimental porcine model reproducing the late fibrotic effect encountered after localized irradiation. J001X, an acylated poly-(1,3)-galactoside of bacterial origin, was used for the functional imaging of the inflammatory reaction which took place after irradiation. This scintigraphy, based on targeting of activated macrophages recruited by lesions, was performed together with 201T1 scans for the assessment of blood perfusion and cellular metabolism. Our results demonstrate that these two radiopharmaceuticals provide reliable information for the management of accidental localized over-exposure, J001X allowing the assessment of the inflammatory reaction and 201T1-chloride being mainly useful for imaging the delayed onset of fibrosis.

Lymphoscintigraphy via the targeting of macrophages with 99mTc-J001X poly-galactoside in a model of pyogranulomas developed in sheep lymph nodes.

Lymphoscintigraphy usually involves labeled microparticles or colloids that distribute in the lymph flow. A new strategy for imaging pathological lymph nodes would be the targeting of macrophages recruited in these lesions. The potential for lymphoscintigraphy of the highly diffusible J001X acylated polygalactoside labeled with 99mTc was studied and compared to usual colloidal agents in a model of infectious granulomas developed in sheep. Scintigraphic and histological assessment of the specificity of targeting was performed using a MAb (OM1) raised against ovine macrophages taken as reference. This study has evidenced the ability of J001X specifically to image pathologic lymph nodes and more especially the second lymph node in the same chain with a significant scintigraphic contrast.

Acylation of the lipid A region of a Klebsiella pneumoniae LPS controls the alternative pathway activation of human complement.

Two mechanisms of direct activation of the complement system by LPS have been extensively documented: (i) activation of the alternative pathway (AP) by the polysaccharide region, and (ii) activation of the classical pathway (CP) by the lipid A region. Here we demonstrate that LPS from the Klebsiella pneumoniae I-145 strain activates the AP by a mechanism dependent on the acylation of the lipid A region. Cleavage of C3 by K. pneumoniae LPS in EGTA was blocked by polymyxin B. Two 34 kDa derivatives were prepared from a membrane extract of this K. pneumoniae strain: (i) an acyl-poly (1,3) galactoside containing two galactosamine-bound ester-linked and two amide-linked fatty acids (EFA-APG), and (ii) an acyl-poly (1,3) galactoside devoid of ester-linked fatty acids (APG). APG and EFA-APG share the structure of LPS molecules, with a long polysaccharidic chain, a core, and a lipid A region. The AP was activated by EFA-APG but not by APG nor by the isolated polygalactose chain GC-APG, indicating a critical role for ester-linked fatty acids in AP activation. Polymyxin B which binds to the lipid A region of LPS completely inhibited AP activation by EFA-APG. A small part of EFA-APG was shown to form aggregates in saline, but aggregation was not decreased by polymyxin B. Furthermore, APG formed aggregates of similar size although it was not able to activate AP. Therefore the role of lipid A acylation in triggering AP activation is not exclusively mediated by aggregation of the molecule. LPS from the rough strain of Salmonella minnesota (Sm Re LPS) directly activates the CP but not the AP. However, when mixed with the polygalactose chain GC-APG, Sm Re LPS activated the AP. The data demonstrate a cooperation between the lipid A region and the polysaccharidic chain in activation of the AP. Similar cooperation may occur with other LPS molecules.

Evaluation of possible interference of anti-inflammatory drugs upon scintigraphic imaging with macrophage targeting 99mTc-J001X: effects of methylprednisolone, dexamethasone, indomethacin and methotrexate.

J001X, an acylated poly-(1,3)-galactoside isolated from Klebsiella pneumoniae proteoglycan, has been developed to target cells from the monocyte-macrophage lineage. Recent experimental work and initial clinical trials have proved the potential of this molecule labeled with 99mTc for the scintigraphy of inflammatory foci. In a model of radiation-induced inflammation in pigs, the scintigraphic contrast was observed to be very sensitive to a single injection of methylprednisolone given 12 h before scintigraphy. The present study was undertaken to confirm this effect and to estimate the possible interference of various anti-inflammatory agents on the in vivo targeting of macrophages by J001X. Methylprednisolone, dexamethasone, indomethacin and methotrexate used at an immunosuppressive dose were tested to assess the possible risk of false-negative examinations in patients thus treated. Analysis of the results indicated that among the four drugs tested, only methylprednisolone at 0.5-1 mg/kg could interfere with J001X scintigraphy.

Binding to leukocytes and induction of TNF alpha production involve different sites within the lipid-A region of LPS-like molecules.

The induction of TNF alpha synthesis in whole blood culture assay and isolated peripheral blood mononuclear cells was investigated, using LPS from Klebsiella pneumoniae and two water-soluble 34 kDa derivatives designed as acylpolygalactoside (APG) and EFA-APG, an APG molecule bearing two additional ester-linked fatty acids. Both APG and EFA-APG bind to monocytes by specific ligand receptor interaction but only EFA-APG could induce TNF alpha synthesis. It is concluded that ester-linked fatty acids are not involved in LPS binding to the cell surface, but play a critical role in the triggering of cellular responses.

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.

Role of acyl residues in polyclonal murine B cell activation by acylpoly(1,3)galactosides from Klebsiella pneumoniae.

Several components of Klebsiella pneumoniae including a membrane proteoglycan (Kp-MPG) were reported to activate macrophages and to induce T-independent polyclonal activation of mouse B cells. Chemically defined derivatives of Kp-MPG were prepared and characterized, enabling us to approach the molecular substructures involved in the binding to lymphocytes and the activation of B cells. Five derivatives were characterized: (i) an acylpoly(1,3)galactoside containing ester-linked fatty acids (EFA-APG) which was obtained by mild alkaline hydrolysis, (ii) a polymer of EFA-APG (APG pol1), (iii) a preparation obtained by drastic alkaline hydrolysis and delipidation which removed the esterified fatty acids (APG), (iv) a polymer of the latter compound (APG pol2), and (v) an APG preparation submitted to mild acid hydrolysis which removed all fatty acids but left the galactose chain of APG (GC-APG) intact. The derivatives were studied for their capacity to bind to and to activate mouse splenocytes. Binding was investigated on BALB/c and C3H/HeJ splenocytes by indirect immunofluorescence using biotinylated F(ab')2 of anti-Kp-MPG antibodies and the streptavidin-phycoerythrin amplification system in flow cytometry and by competition of unlabeled APG with biotinylated APG. Activation was studied by measuring (i) [3H]thymidine incorporation into spleen cells from BALB/c, C3H/HeJ, nude (nu+/nu+) mouse strains, and purified B cells of BALB/c; (ii) immunoglobulin secretion in culture supernatants; and (iii) blastogenesis. The results demonstrate a specific uptake of EFA-APG and APG by T cells as well as by B cells and exclude a contribution of the polygalactose part of the APG molecule (GC-APG) to the binding to spleen lymphocytes. Unlike LPS from the same strain of K. pneumoniae, APG pol1 stimulated B cell activation in the LPS-resistant C3H/HeJ strain as well as in BALB/c mice. The compounds did not activate T cells and were T-independent B cell activators, stimulating nu+/nu+ spleen cells and inducing primarily IgM and IgG3 synthesis. Polymers were more potent activators than monomers and removal of ester-linked fatty acids completely abrogated B cell-activating properties. The monomer APG antagonized B cell activation by Kp-MPG, LPS from K. pneumoniae, and APG pol1. The data indicate that within the EFA-APG molecule, distinct substructures are required for binding and for triggering B cell response.

Scintigraphic potentials of J001X acylated poly-galactoside for imaging inflammatory lesions in pigs.

Although several approaches already exist for the imaging of inflammatory foci, new specific strategies providing functional data on the lesions are required to determine the extent of the disease and also to assess anti-inflammatory treatment. In our study, we investigated the scintigraphic potential of 99mTc-J001X, an agent developed for the targeting of macrophages. Due to its well documented and progressive evolution of lesions, a model of radiation-induced inflammation in pigs was chosen. Our results demonstrated the ability of J001X to provide images of inflammatory foci with a high contrast. The contribution of some specific and non-specific parameters possibly involved in the scintigraphic behavior of J001X is discussed.

Bacterial lysates and ribosomes as inducers of specific immune responses: a comparative study.

A bacterial lysate (OM-85 BV), a preparation of purified bacterial ribosomes (D53) and a placebo were tested for ability to induce the local appearance of specific antibody-containing cells. The three compounds were given orally to 90 children who required tonsillectomy. Surgery was carried out after 1 month of therapy. Frozen-cut sections of each tonsil were tested in indirect immunofluorescence. Cells containing antibodies directed to Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae or Klebsiella pneumoniae were enumerated. Lowest values were noted in the placebo group. Slightly higher numbers were observed after treatment with OM-85 BV, but significant increases were noted only for the elevated numbers of specific antibody-containing cells observed after D53 therapy. Bacterial ribosomal preparations thus contribute efficient induction of specific local immune responses in man.

Activation of human monocyte chemiluminescence response by acylpoly(1,3)galactosides derived from Klebsiella pneumoniae.

The stimulating activity of several preparations isolated from a membrane proteoglycan of a nonencapsulated smooth strain of Klebsiella pneumoniae (Kp-MPG) on the oxidative burst of human blood monocytes was assessed by luminol-enhanced chemiluminescence (CL). Five Kp derivatives were studied: a 34-kd acylpoly(1,3)galactoside (APG), obtained by drastic alkaline hydrolysis and purified by chromatography; an APG preparation subjected to acid hydrolysis that removed the core part and all fatty acids, leaving intact the galactose chain of APG (GC-APG); an APG preparation subjected to mild oxidation (ox APG); a preparation obtained by mild alkaline hydrolysis of Kp-MPG, containing additional ester-linked C14 and C16 fatty acids bound to the APG molecule (EFA-APG); and a polymer of the latter compound, APG pol. EFA-APG directly stimulated monocyte CL, whereas Kp-MPG, APG pol, and the whole bacterial cells had little or no activity. APG itself and ox APG induced a weaker response than EFA-APG. Polymyxin B sulfate completely inhibited the CL response to bacterial lipopolysaccharide (LPS) but not to EFA-APG. The stimulating action of EFA-APG on blood monocytes was dependent on the extracellular levels of both calcium and magnesium. Preincubation of monocytes with monoclonal antibody anti-Mac-1 directed against CD11b, the alpha chain of complement receptor type 3 (CR3; CD11b/CD18), strongly inhibited CL activation by EFA-APG and to a lesser extent CL activation by unopsonized zymosan and rough LPS. Altogether, these findings provide indirect evidence for the contribution of the CD11b/CD18 integrin in the functional interaction of EFA-APG with monocyte membranes. They demonstrate the role of fatty acids in the triggering of monocyte oxidative burst, while the polysaccharide chain itself does not contribute to induction of the CL response in this model. In keeping with the effects of EFA-APG and APG, we show that the monocyte CL response was triggered by bacterial LPS from the rough strain of Salmonella minnesota Re 595 and its lipid A, but not by LPS from smooth strains, again suggesting a critical role for the lipid moiety.

Binding of a membrane proteoglycan from Klebsiella pneumoniae and its derivatives to human leukocytes.

The binding of a membrane proteoglycan from a non-encapsulated strain of Klebsiella pneumoniae (Kp-MPG) and four derivatives thereof, to human leukocytes, was investigated by indirect immunofluorescence using biotinylated F(ab')2 fragments of anti-Kp-MPG antibodies and the streptavidin-phycoerythrin amplification system in flow cytometry. Four Kp-MPG derivatives were studied: 1/ an acylpoly(1,3)galactoside (APG), 2/ an APG preparation submitted to acid hydrolysis which removed all fatty acids, but left intact the galactose chain of APG (GC-APG), 3/ a preparation obtained by mild alkaline hydrolysis, containing additional ester-linked C14 and C16 fatty acids bound to the APG molecule (EFA-APG) and 4/ a polymer of the latter compound (APG pol). Kp-MPG, APG and EFA-APG were shown to bind exclusively to monocytes at the lowest concentrations (from 0.15 to 3 microM APG). At higher concentrations, these compounds interacted with polymorphonuclear leukocytes, and with lymphocyte subsets in the following decreasing order: B cells, NK cells, CD8+ and CD4+ lymphocytes. Neither APG pol or GC-APG nor K. pneumoniae smooth LPS showed significant binding to leukocytes. However Kp-LPS treated by drastic alkaline hydrolysis displayed binding properties similar to those of APG. Removal of the ester-linked C14 and C16 fatty acids from EFA-APG did not affect the binding of the molecule. The capacity of cells from the myelomonocytic lineage to bind Kp-MPG and APG was very low in phenotypically immature cell lines (HL60 and U937) as compared with monocytes or polymorphonuclear cells. Treatment of U937 cells with interferon-gamma up-regulated their APG binding capacity along with the expression of the integrin CD 11 b and the CD 14 molecule, whereas monocytes exposed to interferon-gamma showed an increased binding of APG associated with an elevated expression of the galactose specific lectin Mac-2. The data demonstrate a preferential binding of Kp-MPG and APG to cells of the monocyte/macrophage lineage. APG binding does not involve the poly (1,3) galactose chain and the ester-linked C14 and C16 fatty acids but requires the presence of the hydrophobic part of the molecule.

Scintigraphy with J001 macrophage targeting glycolipopeptide. A new approach for sarcoidosis imaging.

Scintigraphy with radiolabeled J001 as a ligand for macrophage targeting is a new approach for sarcoidosis imaging. J001 is a fully characterized acylated peptido-poly (1,3) galactoside isolated from Klebsiella membrane proteoglycans and able to bind electively recruited macrophages. Its physiochemical properties allow rapid absorption by the respiratory tract when this agent, labeled by 99m technetium, is administered as an aerosol. Images are obtained within 3 to 5 h after inhalation. In the present study, we determined the ability of J001 scintigraphy to localize areas of sarcoidosis involvement in 22 patients compared with gallium scanning in ten of them. Nineteen patients underwent bronchoalveolar lavage (BAL) and serum angiotensin-converting enzyme (ACE) assay. J001 scintigraphy was also performed on a control group of six patients with extrathoracic melanoma, in whom J001 scintigraphy was used to evaluate the cutaneous extent of the tumor and the lymph node involvement. In this control group, no fixation appeared in the thoracic area. In the sarcoidosis group, 18 positive results were observed. One stage 0 patient had a mediastinal fixation. Five of the six stage 1 patients had a fixation located in the mediastinum, the lungs, and the wrists. Five of the six stage 2 patients had positive foci located in the mediastinum or the lung areas and in the myocardium in one of them. Six of the nine stage 3 patients had positive J001 scintigraphy occurring in the lungs and/or the mediastinum. One patient had a fixation on the main bronchi. J001 scintigraphy and gallium scanning, performed in ten patients, were positive in seven of them. There were discrepancies between the BAL results and J001 scintigraphy, as well as between the ACE results and J001 scintigraphy. In conclusion, 99mTc-J001 scintigraphy appears to be a sensitive and rapid technique for the imaging of thoracic sarcoidosis at the three stages of the disease.

Binding of a bacterial acylpoly(1,3)galactoside to human blood leucocytes.

The binding of a 34-kDa (mol. wt.) acylpoly(1,3)galactoside (APG) extracted from a membrane proteoglycan of Klebsiella pneumoniae to human blood leucocytes was investigated. APG is made of a long poly(1,3)galactose chain, a core-like region and a lipid moiety which comprises two glucosamine residues bound to a phosphate group and two beta OH myristic acids. Fluoresceinated APG was shown to bind preferentially to monocytes and to a lesser extent to polymorphonuclear neutrophils, as determined by flow cytometry. Binding of fluoresceinated APG was inhibited by unlabelled APG; it was concentration dependent, but not saturable, with rapid kinetics. It occurred at +4 degrees C but was markedly increased at 37 degrees C. It involved trypsin-sensitive molecules on the membrane of monocytes. Neither the parent proteoglycan nor lipopolysaccharide from K. pneumoniae or Salmonella minnesota competed for APG binding. A minor non-specific binding to lymphocytes, occurring predominantly on B cells, was observed. Unlike that of lipopolysaccharide, the APG binding was not blocked by polymyxin B sulphate. Interaction between the galactose chain of APG and the galactose receptor does not account for the binding of APG to monocytes because the galactose receptor (Mac-2) is expressed at high density on activated macrophages but not on monocytes. Despite its strong binding to human blood monocytes, APG displayed a much weaker activity than K. pneumoniae membrane proteoglycan with respect to induction of monocyte cytokine synthesis. When administered as a Technetium 99 conjugate, APG was shown to label inflammatory foci in experimental animals, and its property as a marker of macrophages is currently being evaluated in clinical trials.

Monocyte cytokine secretion induced by chemically-defined derivatives of Klebsiella pneumoniae.

The capacity of a K. pneumoniae membrane proteoglycan (Kp-MPG) and four of its chemically defined derivatives to activate human monocytes was studied by measuring immunoreactive IL-1 beta, IL-6 and tumour necrosis factor-alpha (TNF-alpha) in culture supernatants. Monocyte culture supernatants were also tested for their comitogenic activity on concanavalin A-stimulated thymocytes and for their cytotoxic activity on the mouse fibroblastic L929 cell line. The four Kp-MPG derivatives were: (i) an acylpoly(1-3)galactoside (APG); (ii) an APG preparation submitted to acid hydrolysis which removed all fatty acids but left intact the galactose chain of APG (GC-APG); (iii) a preparation obtained by mild alkaline hydrolysis, containing additional ester-linked C14 and C16 fatty acids bound to the APG molecule (EFA-APG); and (iv) a polymer of the latter compound (APG pol). Kp-MPG induced the synthesis of IL-1 beta, IL-6 and TNF-alpha with dose-responses and kinetics similar to those of Salmonella minnesota lipopolysaccharide (Sm-Re-LPS). APG pol and EFA-APG induced the secretion of the three cytokines with lower potency than Kp-MPG or Sm-Re-LPS. APG did not trigger any detectable cytokine production and GC-APG induced only borderline and inconsistent responses. Our data demonstrate the critical role of ester-linked C14 and C16 fatty acids in the triggering of monocyte response to Kp-MPG derivatives.

Scintigraphy with J001X, a Klebsiella membrane glycolipid, for the early diagnosis of chronic berylliosis: results from an experimental model.

A glycolipid (J001X) isolated from the membrane proteoglycans of a non-pathogenic strain of Klebsiella pneumoniae was developed to bind selectively to macrophages. A scintigraphic technique could thus be developed and applied to an experimental model of lung berylliosis. Six baboons were injected intratracheally with a beryllium metal suspension. Three to 24 months later, they were submitted to both an anatomical and a functional respiratory evaluation. Two baboons were explored at the early stage of alveolitis and four baboons at a more advanced stage characterised by a granulomatous disorder. Scintigraphy was performed using J001X labelled with 99mtechnetium administered as an aerosol. In the six baboons, conventional imaging techniques (chest x ray film, computed tomography scan, gallium scintigraphy), failed to show either any lung abnormality or mediastinal lymph nodes consistent with beryllium disease. In the two recently contaminated baboons, J001X scintigraphy showed a well defined parenchymal fixation facing the contaminated lobe. In the four baboons who were at a more advanced stage of berylliosis, J001X fixation was always focused paratracheally without any significant involvement of the lung parenchyma. The subcarinal and laterotracheal lymph nodes seen at necropsy corresponded to J001X scintigraphic fixations. In conclusion, when compared with conventional techniques such as chest x ray film, computed tomography scan, magnetic resonance imaging, and gallium scintigraphy, J001X scintigraphy has proved its ability to detect occult lesions in experimental berylliosis in baboons. By comparison with gallium scintigraphy, scintigraphy with J001X appears to have superior sensitivity and can be performed in four hours.

Ribosomes as carriers for antigenic determinants of the surface of micro-organisms.

Over the past twenty-five years, many authors have reported evidence of the immunoprotective capacity of ribosomes isolated from bacteria, fungi and parasites. Since 1971 we have explored the protective capacity of ribosomes isolated from a large variety of micro-organisms responsible for human and animal diseases. Accurate biochemical characterization of ribosomes always reveals trace amounts of non-ribosomal components such as short polysaccharides strongly linked to ribosomal RNA after phenol extraction even under denaturing conditions. rRNA-antigen complexes have been purified from Klebsiella pneumoniae ribosomes inducing high level of protection against homologous experimental infection in mice. Monoclonal antibodies raised against ribosomes and then selected for their ability to confer passive immunity to mice have been used to study the mechanism of the protection induced by ribosomes and to characterize their "immunogenic principle". These investigations have clearly shown the presence on ribosomes of epitopes corresponding to antigens normally exposed on the membrane of the bacteria. In the original concept of "ribosomal immunotherapy" that we have developed, ribosomes can be considered as natural carriers for cell surface epitopes, presenting them to the immune system in a highly immunogenic configuration.