Role of repetitive antigen patterns for induction of antibodies against antibodies.

Antibody responses against antibodies, such as rheumatoid factors, are found in several immunopathological diseases and may play a role in disease pathogenesis. Experience shows that they are usually difficult to induce experimentally. Antibodies specific for immunoglobulin constant regions (anti-allotypic) or for variable regions (anti-idiotypic) have been investigated in animal models; the latter have even been postulated to regulate antibody and T cell responses via network-like interactions. Why and how such anti-antibodies are induced during autoimmune diseases, has remained largely unclear. Because repetitively arranged epitopes in a paracrystalline structure of a viral envelope cross-link B cell receptors efficiently to induce a prompt T-independent IgM response, this study used immune complexes containing viruses or bacteria to evaluate the role of antigen pattern for induction of anti-antibody responses. We present evidence that antibodies bound to strictly ordered, but not to irregularly arranged, antigens dramatically enhance induction of anti-antibodies, already after a single immunization and without using adjuvants. The results indicate a novel link between anti-antibody responses and infectious agents, and suggest a similar role for repetitive self-antigens such as DNA or collagen involved in chronic immunopathological diseases.

Interleukin-6 is produced by bone and modulated by parathyroid hormone.

Interleukin-6 (IL-6) is a cellular regulatory molecule, the diverse functions of which relate to cells both within and outside the immune system. In this report we demonstrated that bone tissue, specifically osteoblasts, produce interleukin-6 and that this function can be modulated by the osteotrophic hormone parathyroid hormone (PTH). Given that the complex process of bone remodeling is now thought to be regulated not only by systemic hormones but also by locally produced factors, the existence of a parathyroid hormone-stimulated production of interleukin-6 by osteoblasts may have important physiological significance.

Monoclonal antibody to endotoxin attenuates hemorrhage-induced lung injury and mortality in rats.

OBJECTIVES: To determine the possible role of enteric bacteria-derived endotoxin in the pathogenesis of the lung injury and mortality in rats following hemorrhagic shock and resuscitation. DESIGN: Prospective, randomized study. SETTING: Animal laboratory of an institute for research traumatology. SUBJECTS: Male Sprague-Dawley rats, weighing 450 to 480 g. INTERVENTIONS: Anesthetized rats were subjected to a prolonged hemorrhagic shock (mean arterial pressure of 30 to 35 mm Hg for 180 mins) followed by resuscitation. A murine monoclonal antibody to lipopolysaccharide from Escherichia coli and Salmonella, WN1 222-5, was administered at a total dose of 5 mg/kg i.v., starting at the onset of shock (WN1 group). The control group was treated similarly to the WN1 group but received saline at the same volume as WN1 222-5. MEASUREMENTS AND MAIN RESULTS: The 48-hr mortality rate was significantly reduced by WN1 222-5 treatment (28.6% in the treatment group vs. 78.6% in the control group; p = .0169). The characteristic lung injury in this model was significantly reduced in the WN1 group, as assessed by microscopic histopathologic examination increase in lung wet weight (7.60 +/- 0.47 g/kg in the control group vs. 5.14 +/- 0.31 g/kg in the WN1 group; p = .0002), and pulmonary neutrophilic infiltration (myeloperoxidase activity: 1835 +/- 567 mU/g wet weight in the control group vs. 891 +/- 212 mU/g wet weight in the WN1 group). CONCLUSIONS: These data suggest that a) endotoxin derived from enteric bacteria might play an important role in the pathogenesis of lung injury; and b) antiendotoxin agents, such as WN1 222-5, appear to protect against endogenous bacterial endotoxin-related disorders in severe hemorrhagic shock in rats.

SAR of 4-hydroxypiperidine and hydroxyalkyl substituted heterocycles as novel p38 map kinase inhibitors.

The 4-hydroxypiperidine substituent was found to confer high p38 selectivity devoid of COX-1 affinity, when attached to a series of pyridinyl substituted heterocycles. Pyridinyloxazole 11 showed a promising in vivo profile with bioavailability of 64% and ED50 in rat collagen induced arthritis of 10 mg/kg po bid. In contrast to pyridinylimidazoles such as SB 203580, 11 did not inhibit human cytochrome P450 isoenzymes.

A broadly cross-protective monoclonal antibody binding to Escherichia coli and Salmonella lipopolysaccharides.

During the last decade, episodes of sepsis have increased and Escherichia coli has remained the most frequent clinical isolate. Lipopolysaccharides (LPS; endotoxin) are the major toxic and antigenic components of gram-negative bacteria and qualify as targets for therapeutic interventions. Molecules that neutralize the toxic effects of LPS are actively investigated. In this paper, we describe a murine monoclonal antibody (MAb; WN1 222-5), broadly cross-reactive and cross-protective for smooth (S)-form and rough (R)-form LPS. As shown in enzyme-linked immunosorbent assay and the passive hemolysis assay, WN1 222-5 binds to the five known E. coli core chemotypes, to Salmonella core, and to S-form LPS having these core structures. In immunoblots, it is shown to react with both the nonsubstituted core LPS and with LPS carrying O-side chains, indicating the exposure of the epitope in both S-form and R-form LPS. This MAb of the immunoglobulin G2a class is not lipid A reactive but binds to E. coli J5, an RcP+ mutant which carries an inner core structure common to many members of the family Enterobacteriaceae. Phosphate groups present in the inner core contribute to the epitope but are not essential for the binding of WN1 222-5 to complete core LPS. Cross-reactivity for clinical bacterial isolates is broad. WN1 222-5 binds to all E. coli clinical isolates tested so far (79 blood isolates, 80 urinary isolates, and 21 fecal isolates) and to some Citrobacter, Enterobacter, and Klebsiella isolates. This pattern of reactivity indicates that its binding epitope is widespread among members of the Enterobacteriaceae. WN1 222-5 exhibits biologically relevant activities. In vitro, it inhibits the Limulus amoebocyte lysate assay activity of S-form and R-form LPS in a dose-dependent manner and it neutralizes the LPS-induced release of clinically relevant monokines (interleukin 6 and tumor necrosis factor). In vivo, WN1 222-5 blocks endotoxin-induced pyrogenicity in rabbits and lethality in galactosamine-sensitized mice. The discovery of WN1 222-5 settles the long-lasting controversy over the existence of anti-core LPS MAbs with both cross-reactive and cross-protective activity, opening new possibilities for the immunotherapy of sepsis caused by gram-negative bacteria.