Hans-Joachim Gabius

Bio: Hans-Joachim Gabius is an academic researcher from Ludwig Maximilian University of Munich. The author has contributed to research in topics: Galectin & Lectin. The author has an hindex of 85, co-authored 699 publications receiving 28085 citations. Previous affiliations of Hans-Joachim Gabius include Utrecht University & Tokyo University of Science.

Chemical biology of the sugar code.

Abstract: A high-density coding system is essential to allow cells to communicate efficiently and swiftly through complex surface interactions. All the structural requirements for forming a wide array of signals with a system of minimal size are met by oligomers of carbohydrates. These molecules surpass amino acids and nucleotides by far in information-storing capacity and serve as ligands in biorecognition processes for the transfer of information. The results of work aiming to reveal the intricate ways in which oligosaccharide determinants of cellular glycoconjugates interact with tissue lectins and thereby trigger multifarious cellular responses (e.g. in adhesion or growth regulation) are teaching amazing lessons about the range of finely tuned activities involved. The ability of enzymes to generate an enormous diversity of biochemical signals is matched by receptor proteins (lectins), which are equally elaborate. The multiformity of lectins ensures accurate signal decoding and transmission. The exquisite refinement of both sides of the protein-carbohydrate recognition system turns the structural complexity of glycans--a demanding but essentially mastered problem for analytical chemistry--into a biochemical virtue. The emerging medical importance of protein-carbohydrate recognition, for example in combating infection and the spread of tumors or in targeting drugs, also explains why this interaction system is no longer below industrial radarscopes. Our review sketches the concept of the sugar code, with a solid description of the historical background. We also place emphasis on a distinctive feature of the code, that is, the potential of a carbohydrate ligand to adopt various defined shapes, each with its own particular ligand properties (differential conformer selection). Proper consideration of the structure and shape of the ligand enables us to envision the chemical design of potent binding partners for a target (in lectin-mediated drug delivery) or ways to block lectins of medical importance (in infection, tumor spread, or inflammation).

Modulatory Potency of the β-Galactoside-specific Lectin from Mistletoe Extract (Iscador) on the Host Defense System in Vivo in Rabbits and Patients

Abstract: Proprietary extract of mistletoe (Iscador) that has federal approval for clinical application can exhibit immunomodulatory capacity. However, the nature of this responsible substance has still remained elusive. To validate the hypothesis that specific lectin-carbohydrate interactions at least participate in eliciting immunomodulation, the modulatory efficiency of the major β-galactoside-specific mistletoe lectin (ML I) from the clinically applied extract on selected immunological parameters was monitored “ in vivo ” in rabbits. Injections of nontoxic doses of the purified lectin or even only of its carbohydrate-binding subunit (0.25–1.0 ng/kg) into rabbits yielded significant increases in natural killer cytotoxicity, frequency of large granular lymphocytes, and phagocytic activity of granulocytes. In the clinically relevant situation, changes in these parameters were also determined in cancer patients after extract (Iscador) injection s.c. as well as i.v., emphasizing the potential relevance of the lectin. Comparative analyses of the changes in the selected parameters following injection of extract with normal lectin content as well as of extract, selectively depleted of lectin, into healthy volunteers corroborated this inference. Lectin depletion by affinity chromatography was highly specific and did not affect any other substance in the extract. Remarkably, contamination by endotoxin has been rigorously excluded in each applied specimen. These results encourage detailed elucidation of lectin action on various parts of the tumor defense system “ in vitro ” with the long range goal of achieving progress in the treatment of cancer through immunological strategies, exploring selective mediatory lectin-carbohydrate interactions.

Increased Secretion of Tumor Necrosis Factor α, Interleukin 1, and Interleukin 6 by Human Mononuclear Cells Exposed to β-Galactoside-specific Lectin from Clinically Applied Mistletoe Extract

Abstract: A β-galactoside-specific lectin from proprietary mistletoe extract, recently reported to exhibit immunomodulatory potency in vivo (T. Hajto, K. Hostanska, and H-J. Gabius, Cancer Res. 49: 4803–4808, 1989), induced increased secretion of tumor necrosis factor α, interleukin 1, and interleukin 6 in cultures of human peripheral blood mononuclear cells. The enhancement of secretion, determined independently by bioassays and enzyme-linked immunosorbent assay-based quantitation, was caused by selective protein-carbohydrate interaction, as revealed by the strict dependence on the presence of the carbohydrate-binding subunit of the lectin and the reduction of the effect of the lectin in the presence of the specific lectin-binding sugar as well as anti-lectin antibodies. Increased cytokine levels in serum of patients after injection of optimal lectin doses corroborated the in vitro results. Thus, these data provide an explanation for the increases in cellular parameters of the host defense system in vivo , which presents a further step toward their potentially beneficial clinical exploitation in standardized regimens.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Extracellular vesicles: exosomes, microvesicles, and friends.

Abstract: Cells release into the extracellular environment diverse types of membrane vesicles of endosomal and plasma membrane origin called exosomes and microvesicles, respectively. These extracellular vesicles (EVs) represent an important mode of intercellular communication by serving as vehicles for transfer between cells of membrane and cytosolic proteins, lipids, and RNA. Deficiencies in our knowledge of the molecular mechanisms for EV formation and lack of methods to interfere with the packaging of cargo or with vesicle release, however, still hamper identification of their physiological relevance in vivo. In this review, we focus on the characterization of EVs and on currently proposed mechanisms for their formation, targeting, and function.

Shedding light on the cell biology of extracellular vesicles.

Abstract: Extracellular vesicles are a heterogeneous group of cell-derived membranous structures comprising exosomes and microvesicles, which originate from the endosomal system or which are shed from the plasma membrane, respectively They are present in biological fluids and are involved in multiple physiological and pathological processes Extracellular vesicles are now considered as an additional mechanism for intercellular communication, allowing cells to exchange proteins, lipids and genetic material Knowledge of the cellular processes that govern extracellular vesicle biology is essential to shed light on the physiological and pathological functions of these vesicles as well as on clinical applications involving their use and/or analysis However, in this expanding field, much remains unknown regarding the origin, biogenesis, secretion, targeting and fate of these vesicles

Biogenesis, Secretion, and Intercellular Interactions of Exosomes and Other Extracellular Vesicles

Abstract: In the 1980s, exosomes were described as vesicles of endosomal origin secreted from reticulocytes. Interest increased around these extracellular vesicles, as they appeared to participate in several cellular processes. Exosomes bear proteins, lipids, and RNAs, mediating intercellular communication between different cell types in the body, and thus affecting normal and pathological conditions. Only recently, scientists acknowledged the difficulty of separating exosomes from other types of extracellular vesicles, which precludes a clear attribution of a particular function to the different types of secreted vesicles. To shed light into this complex but expanding field of science, this review focuses on the definition of exosomes and other secreted extracellular vesicles. Their biogenesis, their secretion, and their subsequent fate are discussed, as their functions rely on these important processes.

Biological properties of extracellular vesicles and their physiological functions

Abstract: In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system.