Twenty-nine murine monoclonal antibodies (MAbs) were prepared against antigenic determinants in the core and lipid A regions of Escherichia coli and Salmonella minnesota lipopolysaccharide (LPS). At least eight distinct MAb specificities were identified. Epitopes recognized by MAbs bearing these specificities were localized in the hexose, heptose, and 2-keto-3-deoxy-D-manno-octulosonic acid regions of the core oligosaccharide and on lipid A. Two groups of MAbs exhibited multispecificity for similar but distinct core- and lipid A-related epitopes. Some core-reactive MAbs cross-reacted with corresponding E. coli and Salmonella rough mutant chemotypes; others were specific for E. coli J5 LPS. Lipid A-specific MAbs reacted with free lipid A from diverse sources. Few MAbs reacted with smooth LPS. Antibody cross-reactivity was restricted by inter- and intraspecies differences in covalent core structure and by epitope concealment by overlying O-side chain and core sugars. The putative cross-reactive and antiendotoxic properties of MAbs specific for the core-lipid A complex may be limited by the inability of such MAbs to recognize determinants on "native" LPS.

a b s t r a c t C-type natriuretic peptide (CNP) is a member of the small family of natriuretic peptides that also includes atrial natriuretic peptide (ANP) and brain, or B-type natriuretic peptide (BNP). Unlike them, it performs its major functions in an autocrine or paracrine manner. Those functions, mediated through binding to the membrane guanylyl cyclase natriuretic peptide receptor B (NPR-B), or by signaling through the non-enzyme natriuretic peptide receptor C (NPR-C), include the regulation of endochondral ossification, reproduction, nervous system development, and the maintenance of cardiovascular health. To date, the regulation of CNP gene expression has not received the attention that has been paid to regulation of the ANP and BNP genes. CNP expression in vitro is regulated by TGF-␤ and receptor tyrosine kinase growth factors in a cell/tissue-specific and sometimes species-specific manner. Expression of CNP in vivo is altered in diseased organs and tissues, including atherosclerotic vessels, and the myocardium of failing hearts. Analysis of the human CNP gene has led to the identification of a number of regulatory sites in the proximal promoter, including a GC-rich region approximately 50 base pairs downstream of the Tata box, and shown to be a binding site for several putative regulatory proteins, including transforming growth factor clone 22 domain 1 (TSC22D1) and a serine threonine kinase (STK16). The purpose of this review is to summarize the current literature on the regulation of CNP expression, emphasizing in particular the putative regulatory elements in the CNP gene and the potential DNA-binding proteins that associate with them.Published by Elsevier Inc.

In vitro and in vivo antibacterial and protective properties of murine monoclonal antibodies (MAbs) to Escherichia coli O111:B4 lipopolysaccharide (LPS) were evaluated in relation to antibody isotype and complement-fixing activity. Six O side chain-specific MAbs, including two IgMs and one of each IgG subclass, were analyzed for quantitative binding and C3 deposition on intact bacteria, complement-mediated bactericidal and opsonophagocytic activity, and protection against intraperitoneal infections in mice. Although C3 was deposited on bacteria in the presence of normal human serum (NHS) alone, LPS-specific MAbs increased C3 attachment in a dose-dependent manner. Bacterial killing occurred only in the presence of both antibody and complement NHS and required an intact alternative pathway. The efficiency of bacterial killing varied by antibody isotype (IgM greater than IgG2a greater than other IgG subclasses) and correlated with C3-fixing capacity. Opsonophagocytic activity of MAbs exhibited a similar isotype-related rank order. Likewise, IgM was more active than IgG, and IgG2a was superior to other IgG subclasses, in MAb-mediated protection against intraperitoneal infection. These data document the interdependent antibacterial and complement-fixing properties of LPS-reactive MAbs and the degree to which both activities are determined by antibody class and isotype.

AVL was identified in 19.5 % of OIF deployers and travel to northwest Iraq correlated with infection. Further studies are needed to inform risk for reactivation VL in U.S. veterans and to target additional blood safety and surveillance measures.

Sixteen murine monoclonal antibodies (MAbs) reactive with the O-side chain, core oligosaccharide, or lipid A of Escherichia coli O111:B4 and Salmonella minnesota lipopolysaccharide (LPS) were evaluated for binding activity against wild-type and rough mutant strains using a fluorescence-activated cell sorter (FACS) and fluorescein-conjugated antiimmunoglobulin probe. O-side-chain-reactive MAbs produced immunofluorescence against homologous, smooth strains up to 500-fold higher than controls. Many core- and lipid A-reactive MAbs exhibited limited reactivity with smooth bacteria. Some core- and lipid A-associated epitopes, however, were better recognized by MAbs on intact bacteria than on isolated LPS. FACS analysis of binding by the core-reactive MAb, J8-4C10, to E. coli O26:B6 smooth bacteria revealed staining and non-staining bacterial phenotypes that were sorted and stably expressed in subculture. FACS analysis thus documented differences in the whole-cell reactivity of MAbs specific for various LPS subcomponents, differences in MAb reactivity with isolated and cell-associated LPS, and spontaneous changes in the phenotypic expression of certain LPS-associated epitopes on intact bacteria.

Controversy exists regarding isotype-related differences in the antibacterial and protective properties of lipopolysaccharide (LPS)-specific antibodies of the immunoglobulin M (IgM) class and various IgG subclasses. To clarify this issue, a murine hybridoma secreting IgM monoclonal antibody (MAb) specific for the O polysaccharide of Pseudomonas aeruginosa serogroup O6 LPS was class switched, by sib selection, to produce an IgG3 MAb with identical specificity and variable region heavy and light chain nucleotide sequences. This IgG3-secreting cell line was further switched to the production of O-specific, variable region-identical IgG1, IgG2b, and IgG2a MAbs. Functional comparisons of these LPS-specific IgM and IgG MAb isotypes revealed similar LPS binding, opsonic, and protective activities. Relatively minor isotype-related differences in levels of efficiency of MAbmediated, complement-dependent opsonophagocytic killing (IgM > IgG2a > IgG3 > IgG2b > IgG1) were not associated with corresponding differences in in vivo functions. These findings, in conjunction with previously published data, support a cautious approach to generic conclusions regarding the immunotherapeutic superiority of LPS-specific antibodies belonging to either the IgM or IgG class or to a particular IgG subclass.

A murine monoclonal antibody (MAb) was prepared against Pseudomonas aeruginosa immunotype-1 (It-1) lipopolysaccharide (LPS). The MAb bound It-1 LPS in the enzyme-linked immunosorbent assay and in the immunodiffusion and immunoblotting assays, agglutinated and opsonized It-1 bacteria, and protected against challenge with live It-1 organisms in a murine burn infection model. All of these activities were immunotype specific. Correlation of the opsonic and protective properties of the MAb with its recognition site on the LPS O side chain confirmed that such immunotype-specific determinants are important targets for protective antibodies in Pseudomonas disease. The functional equivalence of this MAb and polyclonal antibodies from hyperimmune plasma underscores the therapeutic potential of single MAbs which recognize critical determinants in the LPS 0 side chain. 656 single MAbs directed toward appropriate epitopes on the exposed 0 side chain of Pselidomonas LPS and perhaps other LPSs.MATERIALS AND METHODS LPSs. P. aeruginosa It-1 LPS (Fisher-Devlin-Gnabasik system [12]), purified by hot phenol-water extraction (38) and gel filtration chromatography, was obtained from List Biological Laboratories, Campbell, Calif. Trichloroacetic acid-extracted LPSs from Fisher immunotypes 2 through 7 (15) were obtained from M. Fisher, Parke, Davis & Co., Detroit, Mich.Preparation of MAbs. Female BALB/c mice (Charles River Breeding Laboratories, Inc., Wilmington, Mass.) were immunized with four weekly intraperitoneal (i.p.) injections of 108 heat-killed P. aeruiginosa It-I organisms (obtained from M. Fisher, Parke, Davis). Four days after the final immunization, the spleens were removed aseptically and dissociated into a single-cell suspension. Approximately 5 x 107 spleen cells were fused with 5 x 107 non-immunoglobulin-producing Sp 2/0-Ag 14 myeloma cells (33) (American Type Culture Collection, Rockville, Md.; CRL 1581) by using 4,000-molecular-weight polyethylene glycol (50% [wt/vol] in water) as previously described (8). After fusion, the cells were washed and suspended in 80 ml of medium containing hypoxanthine, aminopterin, and thymidine. This mixture was dispensed in 100-[il portions into 96-well tissue culture plates (Costar, Cambridge, Mass.) previously seeded with 3 x 105 BALB/c spleen cells. The cultures were incubated in a 10% CO2 atmosphere at 37°C and fed with hypoxanthineand thymidine-containing medium on day 7. The supernatants from viable cultures were screened by enzyme-linked immunosorbent assay (ELISA) for antibody (see below) on days 14 and 21. Hybridomas from positive wells (i.e., optical density > 0.8) were cloned by limiting dilution in 96-well culture plates containing 3 x 105 splenic feeder cells per well. Positive clones were recloned three times, grown in large-scale culture in serum-free medium,

Lipopolysaccharide (LPS)-monocyte/macrophage interactions are central to the infected host's inflammatory response to gram-negative bacteria. Flow cytometry was used to analyze the regulation by LPS-specific monoclonal antibodies (MAbs) of fluorescein isothiocyanate-conjugated LPS uptake by human peripheral blood monocytes. The uptake of LPS was stimulated by fresh or heat-inactivated serum (NHS or delta NHS) or by LPS-binding protein and inhibited by alpha-LPS or alpha-CD14 (LPS receptor) MAbs. The inhibition of alpha-LPS uptake was offset in the presence of NHS by a simultaneous MAb-mediated increase in LPS uptake that was blocked by alpha-complement receptor 1. Monocyte tumor necrosis factor-alpha responses to LPS were augmented by NHS and delta NHS and inhibited by alpha-LPS MAbs. Thus, alpha-LPS MAbs down-regulate the proinflammatory uptake of LPS by human monocytes via membrane-bound CD14 while promoting complement-mediated opsonic uptake through membrane-associated CR1.