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R E Mandrell

Publications and source records attributed to R E Mandrell.

At least 55 records · Page 3Linked to original sources
PubMed1989

Structure and heterogeneity of the oligosaccharides from the lipopolysaccharides of a pyocin-resistant Neisseria gonorrhoeae.

The compositions and partial structures of the oligosaccharides from the lipopolysaccharides (LPS) of a pyocin-resistant Neisseria gonorrhoeae (strain JW31R) have been determined by liquid secondary ion mass spectrometry (LSIMS), tandem mass spectrometry, and methylation analysis. Four major structures were identified with Mr 2123, 2000, 1961, and 1838, as well as seven species of lower abundance of Mr 1758-1272. The largest of the major oligosaccharides (Mr, 2122) consists of 3-deoxymanno-2-ketooctulosonic acid (KDO)-Hep2GalNAcGlcNAcGal4Glc2 (Hep, heptose) and phosphoethanolamine (PEA). The smaller oligosaccharides are truncated versions of this larger oligosaccharide. The oligosaccharides consist of a common triantennary structure containing KDO at the reducing terminus attached to a heptose disaccharide. A hexose (Hex)2-3 branch is attached to the heptose linked directly to KDO and a GalNAc-Hex3, GlcNAc, and PEA are separately attached to the second heptose. These oligosaccharides are the first structures to be determined for a gonococcal LPS and should further our understanding of the structural and antigenic diversity of these glycolipids.

Bacteriocins↗
PubMed1989

Neisseria lactamica and Neisseria meningitidis share lipooligosaccharide epitopes but lack common capsular and class 1, 2, and 3 protein epitopes.

Neisseria lactamica, a common human pharyngeal commensal, contributes to acquired immunity to Neisseria meningitidis. To define the surface antigens shared between these two species, we used monoclonal antibodies (MAbs) to study 35 N. lactamica strains isolated in various parts of the world for cross-reactivity with meningococcal capsules, outer membrane proteins, and lipooligosaccharides (LOS). No N. lactamica strain reacted significantly with MAbs specific for capsular group A, B, C, Y, or W, and we were unable to extract capsular polysaccharide from them. Only 2 of 33 strains reacted weakly with MAbs against class 2 serotype proteins P2b and P2c. None reacted with MAbs specific for meningococcal class 1 protein P1.2 or P1.16 or class 2/3 serotype protein P2a or P15. Most N. lactamica strains (30 of 35) bound one or more of seven LOS-specific MAbs. Two LOS epitopes, defined by MAbs O6B4 and 3F11, that are commonly found on pathogenic Neisseria species were found on 25 of 35 N. lactamica. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting showed that the LOS of N. lactamica are composed of multiple components that are physically and antigenically similar to the LOS of pathogenic Neisseria species. Among four other commensal neisserial species, only Neisseria cinerea shared LOS epitopes defined by MAbs O6B4 and 3F11. Previous studies have shown that pharyngeal colonization with N. lactamica induces bactericidal antibodies against the meningococcus. We postulate that shared N. lactamica and meningococcal LOS epitopes may play an important role in the development of natural immunity to the meningococcus.

Antibodies, Monoclonal↗
PubMed1989

Human immune response to meningococcal outer membrane protein epitopes after natural infection or vaccination.

Antibody levels in 41 sets of human acute- and convalescent-phase meningococcal sera were compared with those in 23 sets of human prevaccination and 2-week postvaccination sera. We used a modification of a solid-phase radioimmunoassay (SPRIA) technique to test each of the human serum samples as inhibitors of monoclonal antibodies (MAbs) that bind (HIMSPRIA) to the outer membrane complex from a 2a:P1.2:P5.1 strain. We used three murine MAbs specific for the 2a, P1.2, and P5.1 epitopes on meningococcal class 1, 2, and 5 proteins, respectively, to detect antibodies with similar specificities in human sera. Each of 40 available matching strains from patients were also screened with the three MAbs in a nitrocellulose spot blot assay. A total of 37 (92%) were positive for the 2a epitope, 36 (90%) were positive for the P1.2 epitope, and 16 (40%) were positive for the P5.1 epitope. Of 38 available convalescent-phase sera, 27 (71%) matched with these strains and had detectable inhibiting antibody for each of the MAb-defined protein epitopes of the infecting strain. Three convalescent-phase sera had no HIMSPRIA activity for MAb-defined epitopes that were present on the infecting strain; others had activity for one or two of the epitopes. The results were similar for pre- and postvaccination sera. The average level of HIMSPRIA activity for the P1.2 epitope was greater than fivefold higher in postvaccination sera compared with that in convalescent-phase sera. Sera with distinct patterns of HIMSPRIA activity also were tested by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis and showed a correlation between the HIMSPRIA activity for particular epitopes and the level of antibody binding to the immunoblotted proteins possessing those epitopes. A comparison of the HIMSPRIA and the bactericidal activity of selected postvaccination sera indicated a possible correlation between HIMSPRIA and bactericidal activity, but it also suggested the presence of bactericidal antibodies with specificities other than those defined by the MAbs.

Antibodies, Bacterial↗
PubMed1988

Lipooligosaccharides (LOS) of Neisseria gonorrhoeae and Neisseria meningitidis have components that are immunochemically similar to precursors of human blood group antigens. Carbohydrate sequence specificity of the mouse monoclonal antibodies that recognize crossreacting antigens on LOS and human erythrocytes.

We have used mouse mAbs, 3F11 and 06B4, that are specific for highly conserved epitopes of Neisseria gonorrhoeae lipooligosaccharides (LOS) to identify immunochemically similar structures on human erythrocytes. mAb 3F11 agglutinated erythrocytes from all randomly selected adult humans, while mAb 06B4 agglutinated only 80% of the same specimens. The antibodies had an activity with erythrocytes similar to human cold agglutinins in that agglutination occurred at 4 degrees C and decreased with increasing incubation temperature. Human infant erythrocytes were agglutinated less well, but enzymatic treatment of either infant or adult cells resulted in an increase in expression of the 3F11- and 06B4-defined epitopes. Both antibodies bound to a series of neutral glycosphingolipids from human erythrocytes and neutrophils that have a type 2 (Gal beta 1----4GlcNAc) or N-acetyllactosamine structure. Neither antibody bound to glycosphingolipids from human meconium, which have a type 1 (Gal beta 1----3GlcNAc) structure. The antibodies were unable to bind to N-acetyl-lactosamine glycosphingolipids with a nonreducing terminal sialic acid or a Gala1----3Gal disaccharide. Antibody binding also was blocked by the presence of fucose linked to the penultimate glucosamine residue of N-acetyllactosamine glycosphingolipids. Although both antibodies bound to linear and branched-chain N-acetyllactosamine glycosphingolipids, 3F11 had a higher affinity for branched structures than did 06B4. The activity of 3F11 with human adult and infant treated and untreated erythrocytes with N-acetyllactosamine glycosphingolipids, and with LOS was very similar, if not identical, in specificity to 1B2, an mAb prepared from mice inoculated with a linear N-acetyllactosamine glycosphingolipid.

Adult↗
PubMed1988

Electromorphic characterization and description of conserved epitopes of the lipooligosaccharides of group A Neisseria meningitidis.

We studied the lipooligosaccharides (LOS) of 28 group A Neisseria meningitidis of epidemiologically diverse origins to investigate whether each of the LOS serotypes found in serogroup A could be identified physically as well as antigenically. Using a dot blot assay with LOS-specific monoclonal antibodies (MAbs), we identified four epitopes that were serotype specific. The LOS from strains of each serotype were electromorphically and antigenically distinct when analyzed by silver-stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. The LOS of L8 strains contained a 3,600-Mr component that bound the L8 MAb. The LOS of L9 strains contained two major components of 4,500 and 4,200 Mr. They bound the L9 MAb to the larger component. The LOS of L10 strains had a single major component of 4,000 Mr that bound the L10 MAb. The LOS of L11 strains contained a major 3,600-Mr component that could not be distinguished from the 3,600-Mr LOS of L8 strains by SDS-PAGE but that bound the L11 MAb. LOS of group A strains contained a highly conserved epitope in addition to a serotype-specific epitope. This was identified by a MAb that bound to all the strains on dot-blots and to multiple LOS components of various Mrs on immunoblots. We conclude that the LOS which bear the L9, L10, and L11 determinants are physically distinct and can be identified by SDS-PAGE or MAb binding or both. L8 and L11 are both borne on a 3.6-kilodalton LOS and can only be distinguished serologically.

Antibodies, Bacterial↗
PubMed1988

Interaction between human natural anti-alpha-galactosyl immunoglobulin G and bacteria of the human flora.

Anti-alpha-galactosyl immunoglobulin G (anti-Gal) is a natural antibody present in unusually high amounts in human sera. It constitutes as much as 1% of circulating immunoglobulin G in humans and displays a distinct specificity for the carbohydrate epitope galactosyl alpha(1----3) galactosyl (Gal alpha 1----3Gal). Recently, it has been suggested by various investigators that anti-Gal may be related to some autoimmune phenomena, since marked elevation of its titer was found in sera of patients with autoimmune thyroid disorders, rheumatoid arthritis, glomerulonephritis, and Chagas' disease. In view of the ubiquitous presence of anti-Gal in high titers in humans, throughout life, we hypothesized that, analogous with synthesis of anti-blood group antibodies against bacterial antigens, bacteria within normal intestinal flora may provide constant antigenic stimulation for the synthesis of anti-Gal. This hypothesis would imply that anti-Gal may bind to a variety of bacterial strains of human flora. In the present study, the interaction between affinity chromatography-purified anti-Gal and various bacterial strains was studied. By the use of a direct immunostaining assay and an enzyme-linked immunosorbent assay, anti-Gal was found to interact with a variety of Escherichia coli, Klebsiella, and Salmonella strains, some of which were isolates from normal stool. Furthermore, the anti-Gal-binding sites in some strains were found to be present on the carbohydrate portion of bacterial lipopolysaccharides. It is thus suggested that Gal alpha 1----3Gal epitopes in the outer membranes of normal flora enterobacteria may provide a continuous source for antigenic stimulation. Since there is no immune tolerance to the Gal alpha 1----3Gal carbohydrate structure in humans, anti-Gal seems to be constantly produced in response to these enterobacteria. In addition, bacteria which express Gal alpha----3Gal epitopes and which may adhere to various cells mediated binding of anti-Gal to human cell lines. These findings raise the possibility that anti-Gal may damage normal human tissues via inflammatory processes facilitated by bacterial Gal alpha 1----3Gal epitopes.

Antigen-Antibody Reactions↗
PubMed1987

The immunochemistry of neisserial LOS.

The outer membrane glycolipids of Neisseria lack long polysaccharides and are properly termed lipooligosaccharides (LOS). A Neisseria strain makes from two to six LOS of Mr 3150-7100. Different species commonly make LOS of identical Mr and epitope content. Oligosaccharide (OS) differences account for physical heterogeneity. OS consist of a conserved triantenary basal oligosaccharide, two linear segments of (n) hexose residues that determine OS mass, and terminal sequences similar to those of glycosphyngolipids. Epitope expression is linked to physical heterogeneity and conditioned by the molecular environment of the outer membrane. Serotype epitopes are expressed on Mr-restricted LOS. LOS regulate complement activation onto the bacterial surface and, hence, immune lysis.

Antigens, Bacterial↗
PubMed1987

Phenotypic variation in epitope expression of the Neisseria gonorrhoeae lipooligosaccharide.

Gonococcal lipooligosaccharides (LOSs) are a series of antigenically complex heteropolymers. To investigate whether all members of clonally selected populations of Neisseria gonorrhoeae express antigenically similar LOS, we studied gonococcal strains 4505 and 220 with monoclonal antibodies 6B4 and 3F11 which have specificity for different oligosaccharide epitopes on the same or comigrating LOS unit(s) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Fluorescent-antibody and immunoelectron microscopy studies indicated that all members of the clonally selected populations were not homogenous for the epitopes these antibodies recognized. Fluorescence-activated cell sorting studies of 3F11-coated strain 220 indicated that the density of epitope expression was a function of time of growth. The population could be separated into two broad groups corresponding to organisms staining strongly or weakly for the 3F11 epitope, and the epitope density decreased during the late-log and stationary phases of growth. Sequentially staining organisms on Formvar grids with 6B4 and 3F11, followed by staining with either 5- or 15-nm colloidal gold spheres conjugated to goat anti-mouse immunoglobulin M demonstrated the following populations of cells among organisms derived from a single clone: organisms which stained for both 6B4 and 3F11 epitopes and organisms which stained for either 6B4 epitopes alone or 3F11 epitopes alone. Immunofluorescence microscopy studies with rhodamine and fluorescein goat anti-mouse immunoglobulin M conjugates sequentially staining organisms on Formvar grids with 3F11 and 6B4 also demonstrated these three populations. Analysis of LOS preparations made over the last 5 years indicated no change in serotype antigen concentration or in sodium dodecyl sulfate-polyacrylamide gel electrophoresis migration pattern. These studies indicate that while clonally selected strains of Neisseria gonorrhoeae undergo phenotypic variation at the epitope level, the impact of this variation on the total LOS of the population has little overall effect on its antigenic or physicochemical properties.

Antibodies, Monoclonal↗
PubMed1985

Elaboration of a 3.6-kilodalton lipooligosaccharide, antibody against which is absent from human sera, is associated with serum resistance of Neisseria gonorrhoeae.

Neisseria gonorrhoeae strains that resist lysis by normal human sera (NHS) do so, in part, because NHS contain immunoglobulin M (IgM) specific for lipooligosaccharide (LOS) antigens of serum-sensitive strains, but lack antibodies for LOS antigens that can serve as loci for immune lysis of serum-resistant (serr) strains. We used a monoclonal antibody (McAb), specific for an epitope within a 3.6-kilodalton (kDa) component of Neisseria meningitidis L8 LOS, that binds a 3.6-kDa gonococcal LOS component so that we could explore further serr gonococcal strains. The McAb bound to the LOS of 6 of 7 serr of strains but not to the LOS of 0 of 14 serum-sensitive and serum-intermediate gonococcal strains of diverse origin. We studied three serr strains further. Strain 7134 does not elaborate the 3.6-kDa LOS component and does not bind the McAb; strains WR220 and WR302 do elaborate the 3.6-kDa LOS component. The titer (log2) at which the McAb, diluted in NHS, lysed strain WR220 was 7.7; for WR302 it was 3.7, and for 7134 it was 0. Addition of McAb to NHS caused increased classical and alternative-pathway C3 deposition onto strain WR220, but only classical-pathway-activated C3 deposition onto strain WR302. The difference in lytic effectiveness of the McAb for the two strains, therefore, may result from differences in alternative-pathway augmentation of McAb-dependent classical-pathway activation on their surfaces. None of 40 randomly selected normal young adults had serum antibody that could compete with the McAb for binding to WR220 LOS in a solid-phase RIA. We conclude that the 3.6-kDa LOS component is commonly expressed by serr strains of N. gonorrhoeae and that antibody to it would be lytic if present in human serum, but that it is infrequently, if ever, present. As a result, strains elaborating this LOS are resistant to lysis by NHS.

Animals↗
PubMed1984

Use of a zwitterionic detergent for the restoration of the antibody-binding capacity of electroblotted meningococcal outer membrane proteins.

A method is described for the partial restoration of the antibody-binding capacity of meningococcal class 2 outer membrane proteins (40-42 K molecular weight) following denaturation (dissociation) in boiling sodium dodecyl sulfate (SDS). The method relies on the presence of 0.1-0.4% zwitterionic detergent in the electrode buffer during the electroblot transfer of proteins from SDS-polyacrylamide gels to nitrocellulose paper. Meningococcal class 2 proteins which had lost their earlier capacity to bind mouse monoclonal antibodies in the normal blot procedure after SDS-polyacrylamide gel electrophoresis, bound monoclonal antibodies following the addition of the zwitterionic detergent to the blot buffer. Human post-vaccination anti-class 2 protein antibodies reacted with serotype 2a class 2 protein in a similar manner. This simple modification to the electroblot procedure proved helpful in identifying mouse monoclonal antibodies and human antibodies specific for native meningococcal class 2 proteins.

Animals↗
PubMed1984

Monoclonal antibodies to serotype 2 and serotype 15 outer membrane proteins of Neisseria meningitidis and their use in serotyping.

A series of murine monoclonal antibodies to serotype 2 and serotype 15 strains of Neisseria meningitidis were produced which were specific for outer membrane proteins of classes 1, 2, 3, and 5. A panel of eight monoclonal antibodies that exhibited a high degree of serotype specificity when reacted with prototype strains of known serotype were selected for study. Each of the corresponding epitopes was localized on a specific outer membrane protein by means of immunoprecipitation, electroblotting, or both. The serotype 2a-, 2b-, and 2c-specific antibodies bound to the class 2 protein, the serotype 15-specific antibody bound to the class 3 protein, two antibodies (3-1-P1.2 and 3-1-P1.16) bound to class 1 proteins, and two antibodies (1-1-P5.1 and 3-1-P5.2) bound to class 5 proteins. Six of these monoclonal antibodies were used in a spot-blot procedure to survey 122 case isolates (groups B, C, Y, and W135) and 363 carrier isolates (all serogroups) for the presence of the 2a, 2b, 2c, 15, P1.2, and P1.16 epitopes. A total of 66% of the case isolates and 30% of the carrier isolates reacted with one or more of the monoclonal antibodies. The use of monoclonal antibodies for serotyping of meningococci appears to be feasible and easy and appears to have significant advantages over the use of polyclonal typing sera.

Antibodies, Bacterial↗
PubMed1983

Importance of complement source in bactericidal activity of human antibody and murine monoclonal antibody to meningococcal group B polysaccharide.

The bactericidal activity of human antibody and murine monoclonal antibody to meningococcal group B polysaccharide was investigated as a function of the complement source. The immunoglobulin M murine monoclonal antibody 2-2-B was shown by several different methods to be highly specific for meningococcal group B and Escherichia coli K1 capsular polysaccharides. It had strong bactericidal activity in conjunction with either rabbit or human complement, but gave a higher titer with rabbit complement. A strong prozone was observed in each case. Human postvaccination antibody to meningococcal group B polysaccharide was strongly bactericidal with rabbit complement, but had little or no bactericidal activity in conjunction with human complement. Antibodies in adult normal human sera that were bactericidal with rabbit complement were also found to be predominantly directed against the meningococcal group B capsular polysaccharide. Human antibodies that were bactericidal with human complement appeared to be primarily directed against noncapsular antigens.

Animals↗
PubMed1980

Type-specific antigens of group A Neisseria meningitidis: lipopolysaccharide and heat-modifiable outer membrane proteins.

The solid-phase radioimmunoassay inhibition method was used to analyze the noncapsular surface antigens of group A Neisseria meningitidis for type specificity. By use of antisera prepared against group A strains, three serologically distinct lipopolysaccharide antigens and five outer membrane protein antigens were identified among group A strains from a variety of geographical origins. Two of the lipopolysaccharide antigens were unique to group A strains while the third was similar to those on strains of other meningococcal serogroups. Fractionation of outer membrane proteins in the presence of 2% sodium deoxycholate followed by quantitative inhibition of the typing reactions with the subfractions revealed that the protein responsible for type specificity was not the principal outer membrane protein, but, most likely, the 31,000-dalton, heat-modifiable outer membrane protein. Thus, although group A strains may share a common principal outer membrane protein, typing is feasible using other surface antigens. In a survey of 82 group A strains, 93% were typable with respect to outer membrane proteins.

Animals↗
PubMed1979

Complex of meningococcal group B polysaccharide and type 2 outer membrane protein immunogenic in man.

A noncovalent complex of meningococcal group B polysaccharide and type 2 outer membrane protein has been characterized and its potential as a vaccine against group B meningococcal disease investigated. The polysaccharide component was found to have a partition coefficient, K(d), of 0.34 on Sepharose CL-4B in the presence of sodium deoxycholate. The protein consisted of four to five major proteins including the principal outer membrane protein. Hydrophobic binding between the protein and polysaccharide was demonstrated by gel filtration and isopycnic CsCl density gradient centrifugation and found to involve all of the proteins. After demonstrating safety and immunogenicity in animals, two lots of vaccine were tested in a total of eight volunteers. Two 120-mug doses were given subcutaneously at 0 and 5 wk. Mild local reactions occurred in all eight volunteers, but no systemic reactions were observed. 2 wk after the first dose, six of the volunteers had increased levels of bactericidal antibodies against both the group B polysaccharide and the outer membrane proteins. Antibody rises to the group B polysaccharide (mean 6-fold) were confirmed by passive hemagglutination assays and rises to the proteins (mean 10-fold) by a solid phase radioimmunoassay. The second dose resulted in little or no increase in antibody titers. Antibody titers declined over a period of 14 wk but mostly remained above preimmunization levels. Bactericidal antibodies with specificity for the group B polysaccharide were mostly of the immunoglobulin (Ig)M class, and were directed against a determinant associated only with high molecular weight polysaccharides. We conclude that both the group B polysaccharide and the outer membrane protein are immunogenic in man when presented as a complex and that the complex warrants further testing and development as a vaccine against group B meningococcal disease.

Adult↗
PubMed1978

Safety and immunogenicity of a Neisseria meningitidis type 2 protein vaccine in animals and humans.

Two Neisseria meningitidis vaccines consisting principally of outer membrane protein (lot 138I-0) or outer membrane protein plus group C polysaccharide (lot 138I-M1) were prepared from the group C type 2 strain 138I. Lipopolysaccharide and lipid were removed by gel filtration in the presence of sodium deoxycholate. The vaccines were found to be nontoxic and nonpyrogenic in animals. They provided active protection in mice against mucin-enhanced killing by group B type 2 meningococci and induced good titers of type-specific bactericidal and hemagglutinating antibodies in rabbits. In five volunteers the vaccines were well tolerated and induced significant increases in serum bactericidal activity against both group C and group B strains. Three of five volunteers had a two- to fourfold increase in antibodies to the outer membrane proteins, but these antibodies did not appear to have bactericidal activity. The bactericidal antibodies to both group B and group C strains were directed against the capsular polysaccharides.

Animals↗
PubMed1977

Lipopolysaccharide serotyping of Neisseria meningitidis by hemagglutination inhibition.

The method of hemagglutination inhibition was used to investigate the antigenic diversity of lipopolysaccharide (LPS) from Neisseria meningitidis and to develop a serotyping systems based on this antigen. The system uses outer membrane complex prepared by a simple extraction procedure to inhibit homologous hemagglutination reactions involving sheep erythrocytes sensitized with purified LPS and rabbit antiserum raised to whole meningococci. Antisera with specificity for eight different LPS determinants were used as typing sera to serotype a cross section of 67 meningococcal strains. Only two strains (both group A) were not typable with the eight sera, and most strains had more than one type. Comparison of LPS type and bactericidal serotype suggests that the LPS and protein serotypes are independent serological markers.

Antibodies, Bacterial↗