What Makes You Feel Sick After Inflammation? Predictors of Acute and Persisting Physical Sickness Symptoms Induced by Experimental Endotoxemia

We aimed to identify statistical predictor variables of lipopolysaccharide (LPS)-induced physical sickness symptoms during the acute and late inflammatory phases using multivariate regression analyses. Data from N = 128 healthy volunteers who received i.v. LPS injection (0.4 or 0.8 ng/kg) or placebo were pooled for analyses. Physical sickness symptoms experienced during the acute (0-6h postinjection) and late (6-24h postinjection) phases were assessed with the validated General-Assessment-of-Side-Effects (GASE) questionnaire. LPS-treated subjects reported significantly more physical sickness symptoms. Physical symptoms during the acute phase were associated with LPS-induced mood impairments and interleukin (IL)-6 increases, explaining 28.5% of variance in GASE scores. During late phase, LPS-induced increases in cortisol and IL-6 plasma concentrations and baseline depression were significant predictor variables, explaining 38.5% of variance. In patients with recurrent or chronic inflammatory states, these factors may act as risk factors ultimately contributing to an exacerbation of sickness symptoms, and should be considered as potential targets for therapeutic strategies.

MPLA shows attenuated pro-inflammatory properties and diminished capacity to activate mast cells in comparison with LPS

BACKGROUND

Monophosphoryl lipid A (MPLA), a nontoxic TLR4 ligand derived from lipopolysaccharide (LPS), is used clinically as an adjuvant in cancer, hepatitis, and malaria vaccines and in allergen-specific immunotherapy. Nevertheless, its cell-activating effects have not been analyzed in a comprehensive direct comparison including a wide range of different immune cells. Therefore, the objective of this study was the side-by-side comparison of the immune-modulating properties of MPLA and LPS on different immune cells.

METHODS

Immune-activating properties of MPLA and LPS were compared in human monocytes and mast cells (MCs), a mouse endotoxin shock model (ESM), and mouse bone marrow (BM)-derived myeloid dendritic cells (mDCs), T cells (TCs), B cells, and MCs.

RESULTS

In a mouse in vivo ESM and a human ex vivo monocyte activation test (MAT), MPLA induced the same cytokine secretion pattern as LPS (ESM: IL-6, IL-12, TNF-α; MAT: IL-1β, IL-6, TNF-α), albeit at lower levels. Mouse mDCs and ex vivo isolated B cells stimulated with MPLA required a higher threshold to induce TRIF-dependent cytokine secretion (IL-1β, IL-6, IL-10, and TNF-α) than did LPS-stimulated cells. In mDC:DO11.10 CD4 TC cocultures, stimulation with MPLA, but not with LPS, resulted in enhanced OVA-specific IL-4 and IL-5 secretion from DO11.10 CD4 TCs. Unexpectedly, in both human and mouse MCs, MPLA, unlike LPS, did not elicit secretion of pro-inflammatory cytokines.

CONCLUSIONS

Compared to LPS, MPLA induced a qualitatively similar, but less potent pro-inflammatory immune response, but was unable to activate human or mouse MCs.

[Current concept for the microbiological safety of cell-based medicinal products]

Ensuring microbiological safety in advanced-therapy medicinal products is still a big challenge for manufacturers. There are fundamental problems, especially in cell-based medicinal products, regarding sterility of source materials, short shelf-life of final products, and the selection of suitable microbiological methods. Different from classical medicinal products, there is the need to evaluate a large number of possible risks and to calculate the risk-benefit balance. Depending on the source material, the presence of micro-organisms with specific growth requirements has to be considered. They cannot be detected by conventional testing methods, but may replicate after the application of the preparation in the recipient. Mycoplasmas are the primary representatives of these contaminants and specific testing procedures are required. Additionally, depending on the source and processing of the biological material, specific testing methods for mycobacteria and other contaminants should be included. Alternative microbiological methods (e.g. NAT, flow cytometry) should be applied in order to reduce the time to detection and to provide reliable results before application of a preparation, but should be also assessed for their possible use for the detection of conventionally undetectable micro-organisms.

Bacterial safety of cell-based therapeutic preparations, focusing on haematopoietic progenitor cells

Bacterial safety of cellular preparations, especially haematopoietic progenitor cells (HPCs), as well as advanced therapy medicinal products (ATMPs) derived from stem cells of various origins, present a challenge for physicians, manufacturers and regulators. The article describes the background and practical issues in this area and illustrates why sterility of these products cannot currently be guaranteed. Advantages and limitations of approaches both for classical sterility testing and for microbiological control using automated culture systems are discussed. The review considers novel approaches for growth-based rapid microbiological control with high sensitivity and faster availability of results, as well as new methods for rapid bacterial detection in cellular preparations enabling meaningful information about product contamination within one to two hours. Generally, however, these direct rapid methods are less sensitive and have greater sampling error compared with the growth-based methods. Opportunities for pyrogen testing of cell therapeutics are also discussed. There is an urgent need for development of novel principles and methods applicable to bacterial safety of cellular therapeutics. We also need a major shift in approach from the traditional view of sterility evaluation (identify anything and everything) to a new thinking about how to find what is clinically relevant within the time frame available for the special clinical circumstances in which these products are used. The review concludes with recommendations for optimization of microbiological control of cellular preparations, focusing on HPCs.

[Problems in microbial safety of advanced therapy medicinal products. Squaring the circle]

Today, sterility of parenteral drugs is practically guaranteed. Well-defined procedures in the pharmaceutical industry enable effective protection against contamination by bacteria and fungi. In contrast, problems regarding microbial safety of advanced therapy medicinal products (ATMPs), especially of cell therapeutics, are at best only partially solved. The latter should be understood as a challenge for manufacturers, regulators, and physicians. Many of the manufacturing principles mentioned above are not applicable in production of cell therapeutics. Sterility of source materials cannot be guaranteed and the hitherto known procedures for sterilization are, as a rule, not feasible. Thus, the sterility of the final product cannot be guaranteed. Considering the extremely short shelf life of many cell therapeutics, sometimes only a few hours, the results from established methods for sterility testing are often available too late. Furthermore, the sterility of a test sample does not indicate sterility of the whole product. In most cases, conventional methods for pyrogen testing are not applicable for ATMPs. This paper demonstrates relevant limitations regarding microbial safety and pyrogenicity. Possibilities to overcome these problems are discussed and some novel solutions are proposed.

Lipopolysaccharide and ceramide docking to CD14 provokes ligand-specific receptor clustering in rafts

The glycosylphosphatidylinositol-anchored receptor CD14 plays a major role in the inflammatory response of monocytes to lipopolysaccharide. Here, we describe that ceramide, a constituent of atherogenic lipoproteins, binds to CD14 and induces clustering of CD14 to co-receptors in rafts. In resting cells, CD14 was associated with CD55, the Fcgamma-receptors CD32 and CD64 and the pentaspan CD47. Ceramide further recruited the complement receptor 3 (CD11b/CD18) and CD36 into proximity of CD14. Lipopolysaccharide, in addition, induced co-clustering with Toll-like receptor 4, Fcgamma-RIIIa (CD16a) and the tetraspanin CD81 while CD47 was dissociated. The different receptor complexes may be linked to ligand-specific cellular responses initiated by CD14.

Toll-like receptor-2 mediates Treponema glycolipid and lipoteichoic acid-induced NF-kappaB translocation

Recently Toll-like receptors (TLRs) have been found to be involved in cellular activation by microbial products, including lipopolysaccharide, lipoproteins, and peptidoglycan. Although for these ligands the specific transmembrane signal transducers TLR-4, TLR-2, or TLR-2 and -6 have now been identified, the molecular basis of recognition of lipoteichoic acids (LTAs) and related glycolipids has not been completely understood. In order to determine the role of TLRs in immune cell activation by these stimuli, experiments involving TLR-2-negative cell lines, TLR-expression plasmids, macrophages from TLR-4-deficient C3H/HeJ-mice, and inhibitory TLR-4/MD-2 antibodies were performed. Glycolipids from Treponema maltophilum and Treponema brennaborense, as well as highly purified LTAs from Staphylococcus aureus and Bacillus subtilis exhibited TLR-2 dependence in nuclear factor kappaB activation and cytokine induction; however, T. brennaborense additionally appeared to signal via TLR-4. Fractionation of the T. brennaborense glycolipids by hydrophobic interaction chromatography and subsequent cell stimulation experiments revealed two peaks of activity, one exhibiting TLR-2-, and a second TLR-4-dependence. Furthermore, we show involvement of the signaling molecules MyD88 and NIK in cell stimulation by LTAs and glycolipids by dominant negative overexpression experiments. In summary, the results presented here indicate that TLR-2 is the main receptor for Treponema glycolipid and LTA-mediated inflammatory response.

Structures in Bacillus subtilis are recognized by CD14 in a lipopolysaccharide binding protein-dependent reaction

The CD14 molecule expressed on monocytes and macrophages is a high-affinity receptor for bacterial lipopolysaccharide (LPS) and hence an important component of the innate immune system. LPS binding protein (LBP) is required to facilitate the binding of LPS to CD14 in vitro and is necessary for the induction of an inflammatory response to LPS in vivo. Here we show that CD14 and LBP can also bind to lipoteichoic acid from the gram-positive bacterium Bacillus subtilis. Although CD14 does not interact with intact B. subtilis organisms, a brief exposure of the bacteria to serum converts them into a form which can bind to CD14 in an LBP-dependent reaction. When serum-pretreated B. subtilis organisms are incubated with the myelomonocytic cell line U937, which expresses CD14, the bacteria are rapidly phagocytosed. The phagocytosis is strictly dependent both on LBP and on CD14. These in vitro results suggest that LBP plays a role in the innate response not only to gram-negative but also to gram-positive infections.

Ubiquitin and ubiquitination in cells from the marine sponge Geodia cydonium

Marine sponges, e.g. Geodia cydonium, have been intensively used to investigate the biochemical and molecular biological basis of cell-cell- and cell-matrix adhesion. It has been shown that a family of galactose-specific lectins, which are present in the extracellular space of G. cydonium, is a main component involved in cell-matrix adhesion in the sponge system. In the present study it is outlined that the purified 16-kDa lectin-1 binds to a 67-kDa membrane-associated protein. This lectin-binding protein undergoes mono- and diubiquitination after incubation of dissociated sponge cells with the homologous aggregation factor (AF), a molecule involved in cell-cell adhesion. The gene coding for polyubiquitin was characterized and found to be composed of three tandem repeat building blocks. Northern analysis indicated the presence of only one type of ubiquitin-specific mRNA (1.65 kb). The level of this transcript increased by 10-fold after incubation of the dissociated cells with AF for 8 h; in contrast, lectin-1 caused only a small effect on the steady-state level of ubiquitin mRNA. These data indicate that the expression of the polyubiquitin gene is directly or indirectly regulated by the AF and suggest that ubiquitination might be a process which controls the function of the membrane-associated lectin-binding protein during matrix-cell adhesion.