Celiac disease IgA modulates vascular permeability in vitro through the activity of transglutaminase 2 and RhoA

Celiac disease is characterized by the presence of specific autoantibodies targeted against transglutaminase 2 (TG2) in untreated patients’ serum and at their production site in the small-bowel mucosa below the basement membrane and around the blood vessels. As these autoantibodies have biological activity in vitro, such as inhibition of angiogenesis, we studied if they might also modulate the endothelial barrier function. Our results show that celiac disease patient autoantibodies increase endothelial permeability for macromolecules, and enhance the binding of lymphocytes to the endothelium and their transendothelial migration when compared to control antibodies in an endothelial cell-based in vitro model. We also demonstrate that these effects are mediated by increased activities of TG2 and RhoA. Since the small bowel mucosal endothelium serves as a “gatekeeper” in inflammatory processes, the disease-specific autoantibodies targeted against TG2 could thus contribute to the pathogenic cascade of celiac disease by increasing blood vessel permeability.     

Immunogenicity of fatty acid anilides in rabbits and the pathogenesis of the Spanish toxic oil syndrome

Fatty acid anilides, the major xenobiotic found in the cooking oils responsible for the Spanish toxic oil syndrome, are immunogenic for rabbits as ascertained by a skin test reaction, the characterization of specific antibodies against anilides and the immunofluorescent detection of 'anilide dependent antigens' in tissue slices from treated animals.     

Nitrothiophenes with schistosomicidal activity

Summary A series of nitrothiophene compounds, with activity against Schistosoma mansoni in mice, is described and shown to be more effective than the corresponding nitrofurans.     

Comparative evaluation of 7 helminth antigens in the enzyme-linked immunosorbent assay (E.L.I.S.A.).

112 sera from Europeans with parasitologically proven helminthiasis were tested in the enzyme-linked immunosorbent assay (E.L.I.S.A.) against 6 crude extracts of various helminths (2 of adult worms: Dipetalonema viteae, Fasciola hepatica; 3 of eggs: Ascaris suum, Toxocara canis, Schistosoma mansoni; and of Echinococcus granulosus scolices) and against bovine hydatid fluid. Each serum was tested simultaneously at a fixed dilution of 1:160 against all antigens. Extensive cross-reactions were observed, leading to the conclusion that non-purified helminth antigens, even in combination, are of limited value for reliable serodiagnosis in E.L.I.S.A.     

Schistosoma mansoni: a chemoattractive factor released by males and its receptor in females

Chemoattraction between developing (23- to 28-day-old) and adult (10- to 12-week-old) Schistosoma mansoni males and females has been described previously. We report here on in vitro attraction of mature worms to released products of worms of the opposite sex. In the absence of a stimulus worms migrated randomly and did not show any preference in their orientation. Males were not significantly attracted to released products of females. Females exhibited greatest attraction to released products of males, and some attraction to the lipid fraction of released products of males. The aqueous fraction of male-released products slightly repelled females. Prior exposure to released products of males rendered females unresponsive to subsequent exposure, suggesting receptor saturation. These findings have important potential implications for the control of schistosomiasis by intercepting attraction and mating between males and females.     

Polyreactive antibodies in adaptive immune responses to viruses

B cells express immunoglobulins on their surface where they serve as antigen receptors. When secreted as antibodies, the same molecules are key elements of the humoral immune response against pathogens such as viruses. Although most antibodies are restricted to binding a specific antigen, some are polyreactive and have the ability to bind to several different ligands, usually with low affinity. Highly polyreactive antibodies are removed from the repertoire during B-cell development by physiologic tolerance mechanisms including deletion and receptor editing. However, a low level of antibody polyreactivity is tolerated and can confer additional binding properties to pathogen-specific antibodies. For example, high-affinity human antibodies to HIV are frequently polyreactive. Here we review the evidence suggesting that in the case of some pathogens like HIV, polyreactivity may confer a selective advantage to pathogen-specific antibodies.     

Cell proliferation, carcinogenesis and diverse mechanisms of telomerase regulation

Replication of linear genomes is incomplete and leaves terminal gaps. Solutions to this 'end replication' problem can be traced back to the prebiotic RNA world: 'fossils' of the presumptive archetypes of telomere structure and of the telomerase enzyme are retained in the terminal structures of some RNA viruses. Telomerase expression in mammals is ubiquitous in embryonic tissues but downregulated in somatic tissues of adults. Exceptions are regenerative tissues and, notably, tumor cells. Telomerase activation is controlled by cellular proliferation, and it is an early step in the development of many tumors. In contrast to mammals, indeterminately growing multicellular organisms, such as fish and crustaceae, maintain telomerase competence in all somatic tissues. In human tumor diagnostics, detection of proliferation markers with monoclonal antibodies is well established, and in this review, the significance of additional telomerase assays is evaluated. Telomerase inhibitors are attractive goals for application in tumor therapy, and telomerase knockout mice have proven that telomere erosion limits the lifespan of cells in vivo. In contrast, telomerase stimulation can be used to expand the potential of cellular proliferation in vitro, with possible applications for transplantation of in vitro expanded human cells, for immortalizing primary human cells as improved tissue models and for the isolation of otherwise intractable products, such as genuine human monoclonal antibodies.     

Liposomes as immunological carriers for the preparation of antimannosyl antibodies

Summary Antiserum was raised against an aminophenyl derivative of D-mannose grafted on to a liposomal surface. As characterized by immunodiffucion, quantitative precipitation and hapten inhibition, the antiserum was found to contain mannose specific antibodies in addition to antibodies against the aromatic phenyl group. Acknowledgment. We would like to thank Mr S. Kumar Roy for his excellen technical assistance.     

Liposomes as immunological carriers for the preparation of antimannosyl antibodies

Antiserum was raised against an aminophenyl derivative of D-mannose grafted on to a liposomal surface. As characterized by immunodiffusion, quantitative precipitation and hapten inhibition, the antiserum was found to contain mannose specific antibodies in addition to antibodies against the aromatic phenyl group.     

Alzheimer’s disease: the impact of age-related changes in reproductive hormones

Two classes of ovarian steroids, estrogens and progestins, are potent in protecting neurons against acute toxic events as well as chronic neurodegeneration. Herein we review the evidence for neuroprotection by both classes of steroids, provide plausible mechanisms for these potent neuroprotective activities and indicate the need for further clinical trials of both estrogens and progestins in protection against acute and chronic conditions that cause neuronal death. Estrogens at concentrations ranging from physiological to pharmacological are neuroprotective in a variety of in vitro and in vivo models of cerebral ischemia and brain trauma as well as in reducing key neuropathologies of Alzheimers disease. While the mechanisms of this potent neuroprotection are currently unresolved, a mitochondrial mechanism is involved. Progestins have been recently shown to activate many of the signaling pathways used by estrogens to neuroprotect, and progestins have been shown to protect against neuronal loss in vitro and in vivo in a variety of models of acute insult. Collectively, results of these animal and tissue culture models suggest that the loss of both estrogens and progestins at the menopause makes the brain more vulnerable to acute insults and chronic neurodegenerative diseases. Further clinical assessment of appropriate regimens of estrogens, progestins and their combination are supported by these data.     

Immunogenicity of fatty acid anilides in rabbits and the pathogenesis of the Spanish toxic oil syndrome

Summary Fatty acid anilides, the major xenobiotic found in the cooking oils responsible for the Spanish toxic oil syndrome, are immunogenic for rabbits as ascertained by a skin test reaction, the characterization of specific antibodies against anilides and the immunofluorescent detection of anilide dependent antigens in tissue slices from treated animals.Acknowledgments. This work was supported by a grant from the Fondo de Investigaciones Sanitarias to the C.S.I.C. Programme on Toxic Oil Syndrome. We are indebted to Dr M. Studt and Dr E. Fernández-Alvarez, from the National Center for Organic Chemistry, C.S.I.C., for kindly providing the synthetic fatty acid anilides. We also wish to thank Prof. C. Gitler for helpful discussion.     

Production of antibodies to amanitins as the basis for their radioimmunoassay.

The production of antibodies against amanitins is described. By means of these antibodies, a radioimmunoassay was developed which allows detection of as little as 0.5 ng of amanitins in 1 ml of serum. By this method, the clearance of alpha-amanitin from the blood of poisoned mice was measured.     

The neurosecretory system of the octopus vena cava: A neurohemal organ

Summary Endings of about two million small neurones form a voluminous neuropil inside the vena cava of cephalopods, in direct contact with the blood. These nerve endings are filled with masses of typical neurosecretory granules. By immunocytochemistry we could distinguish three different populations of secretory endings in the vena cava neuropil ofOctopus vulgaris: 1) a population of endings which were immunoreactive with antibodies against the pentapeptide proctolin; 2) a population with oxytocin/vasopressin- and neurophysin-like immunoreactivity; 3) a population immunoreactive with antibodies which were raised against the molluscan cardioexcitatory peptide Phe-Met-Arg-Phe-amide, against -melanotropin, and against atriopeptin. Extracts of the octopus vena cava stimulated amplitude and frequency of the isolated octopus heart preparation. Similar effects were exerted by peptides with the C-terminal structure-Arg-Phe-amide. Recently, we could isolate and identify in vena cava extracts four peptides; Phe-Met-Arg-Phe-amide, Phe-Leu-Arg-Phe-amide, Ala-Phe-Leu-Arg-Phe-amide and Thr-Phe-Leu-Arg-Phe-amide. Other peptides have not yet been identified. The fact that the peptides against which the immunoreactive antibodies were raised affected, in different organisms, blood volume, blood pressure, renal function and heart contraction suggests that one of the main functions of the neurosecretory system of the vena cava is a hormonal control of circulation.     

Observation of Schistosoma mansoni by scanning electron microscopy]

The integumental surface of adult Schistosoma mansoni was studied by scanning electron microscopy (SEM) at 220 to 10,000 magnifications. SEM shows certain basic features such as spines in the oral sucker and the acetabulum which may facilitate rasping and attachment of the parasite to stay in the bloodstream of the definitive host. It seems likely that SEM visualization will be a means for differentiation some species of the genus Schistosoma.     

Development and characterization of small bispecific albumin-binding domains with high affinity for ErbB3

Affinity proteins based on small scaffolds are currently emerging as alternatives to antibodies for therapy. Similarly to antibodies, they can be engineered to have high affinity for specific proteins. A potential problem with small proteins and peptides is their short in vivo circulation time, which might limit the therapeutic efficacy. To circumvent this issue, we have engineered bispecificity into an albumin-binding domain (ABD) derived from streptococcal Protein G. The inherent albumin binding was preserved while the opposite side of the molecule was randomized for selection of high-affinity binders. Here we present novel ABD variants with the ability to bind to the epidermal growth factor receptor 3 (ErbB3). Isolated candidates were shown to have an extraordinary thermal stability and affinity for ErbB3 in the nanomolar range. Importantly, they were also shown to retain their affinity to albumin, hence demonstrating that the intended strategy to engineer bispecific single-domain proteins against a tumor-associated receptor was successful. Moreover, competition assays revealed that the new binders could block the natural ligand Neuregulin-1 from binding to ErbB3, indicating a potential anti-proliferative effect. These new binders thus represent promising candidates for further development into ErbB3-signaling inhibitors, where the albumin interaction could result in prolonged in vivo half-life.     

Immunological observations following vasectomy

Summary Lymphocytotoxic antibodies (LCA) against panels of normal lymphocytes and leukemic B-cells were demonstrated in vasectomized men. Since vasectomy is known to induce antibody formation to spermatozoa, the demonstration of these lymphocytotoxic antibodies may be related to antigenic constitutents of spermatozoa such as HLA or B-cell alloantigens. Long term follow-up is needed to clarify the clinical significance of these antibodies.     

Immunological observations following vasectomy.

Lymphocytotoxic antibodies (LCA) against panels of normal lymphocytes and leukemic B-cells were demonstrated in vasectomized men. Since vasectomy is known to induce antibody formation to spermatozoa, the demonstration of these lymphocytotoxic antibodies may be related to antigenic constituents of spermatozoa such as HLA or B-cell alloantigens. Long term follow-up is needed to clarify the clinical significance of these antibodies.     

Antiproliferative effects of 4',5'-unsaturated adenine nucleosides on leukemia L1210 cells in vitro

Several 4',5'-unsaturated adenine nucleosides were shown to have antiproliferative activity against L1210 leukemia cells in vitro. The active nucleosides were cytotoxic to the L1210 cells as demonstrated by Trypan Blue uptake. The cytotoxicity was not induced by alterations in the ribonucleoside and deoxyribonucleoside triphosphate levels of the L1210 cells.     

Immunochemical similarities among the hemolymph juvenile hormone binding proteins of moths

The hemolymph from various species of moths was analyzed for cross-reactivity with a panel of six monoclonal antibodies made against the hemolymph juvenile hormone binding protein ofManduca sexta. With the exception of one antibody, the immunoreactivity was limited to the sphingid family. One monoclonal antibody cross-reacted with a number of lepidopteran species; however, families such as Noctuidae and Pyralidae, known to have high affinity, low molecular weight juvenile hormone binding proteins, did not cross-react. Immunological cross-reactivity withManduca sexta juvenile hormone binding protein in several primitive moth families supports the current model of phylogenetic relationships in the order Lepidoptera.     

Production and detection of antibody against estradiol receptor in the calf uterus. Interaction with the estrogen receptor from the hen oviduct]

The antibodies against estrogen receptor were obtained after injecting Rabbits with a cytoplasmic receptor fraction isolated from Calf uterus. The estrogen receptor was partially proteolysed by the action of trypsin and subsequently purified by affinity chromatography (purification 4,000 to 10,000 fold, to a purity of 5-20%). The affinity of the antibody for the proteolysed receptor is KD approximately 1 nM and serum titres have reached values of approximately 50 nM. The values remained constant after the third injection. Preliminary results indicate that the antibody has approximately the same affinity for "native" cytoplasmic estrogen receptor from Calf uterus, as well as for the "trypsinized" forms of estrogen receptor isolated from Calf uterine cytosol and Hen oviduct nuclei.