Biomedical subjects

G B Pier

Publications and source records attributed to G B Pier.

At least 109 records · Page 6Linked to original sources

PubMed1988

Purified capsular polysaccharide-induced immunity to Staphylococcus aureus infection.

In this study, we determined that immunization with capsular polysaccharide from Staphylococcus aureus could protect mice against nonlethal infections induced by encapsulated staphylococci. We immunized mice with either formalin-killed bacteria or purified capsular polysaccharide (PCP) and challenged them with one of three related S. aureus strains that varied in capsule size. Quantitative cultures of blood and kidney from the animals were performed to evaluate protection. Immunization with whole bacteria protected mice against infection with the homologous strain. Mice immunized with PCP were protected when challenged intravenously with either a highly encapsulated S. aureus strain or a microencapsulated mutant but not with an unencapsulated mutant. Protection correlated with capsular antibody levels in the immunized animals. Immunity to staphylococcal infection could be passively transferred to naive animals by using immune serum. These experiments suggest that the S. aureus capsular polysaccharide merits further study as a potential vaccine candidate for preventing staphylococcal infection.

Animals↗

PubMed1988

Toxoid of Pseudomonas aeruginosa exotoxin A generated by deletion of an active-site residue.

Glutamic acid-553 of Pseudomonas aeruginosa exotoxin A (ETA), identified previously as an active-site residue, was deleted by oligonucleotide-directed mutagenesis of the cloned toxin gene in Escherichia coli. The purified mutant toxin was stable, fully immunoreactive, and capable of blocking toxin receptors. ADP-ribosyltransferase and cytotoxic activities were at least 10(6)-fold lower than those of wild-type ETA, and injection of mice with 50 micrograms (equivalent to 400 lethal doses of ETA) produced no ill effects. The mutant toxin elicited high levels of neutralizing anti-ETA antibodies in mice, which protected against a challenge with 100 micrograms of authentic ETA (greater than 600 lethal doses). The mutant protein has the attributes of a toxoid and may be useful as a component of vaccines for individuals at risk for infection by P. aeruginosa.

ADP Ribose Transferases↗

PubMed1988

X-linked immunodeficient mice as a model for testing the protective efficacy of monoclonal antibodies against Pseudomonas aeruginosa.

(DBA/N[female] X CBA/2[male])F1 males have been reported to be deficient in producing antibodies against a number of antigens, including carbohydrates (I. Scher, Adv. Immunol. 35:1-71, 1982). We show that F1 male mice, in contrast to females, made less lipopolysaccharide (LPS)-specific antibodies after immunization with heat-inactivated Pseudomonas aeruginosa and had significantly less naturally occurring LPS-specific antibodies. Furthermore, neutropenic males were 50 to 1,000 times more sensitive to challenge with representative isolates belonging to the seven Fisher immunotypes. Administration to neutropenic F1 males of a human monoclonal antibody specific for the O carbohydrates of P. aeruginosa immunotype 2 LPS or administration of serum from rabbits immunized with heat-inactivated P. aeruginosa immunotype 1 raised the level of resistance to bacterial challenge close to that of females. The results show that the X-linked immunodeficient mouse is an excellent model with which to test the protective efficacy of P. aeruginosa-specific monoclonal antibodies.

Animals↗

PubMed1988

Respiratory-mucin inhibition of the opsonophagocytic killing of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a frequent respiratory tract colonizer in diseases in which mucociliary clearance is defective. The most striking of these is cystic fibrosis. The reasons for this organism's ability to colonize the respiratory tract and to persist there are not fully understood. Earlier studies showed that P. aeruginosa adheres preferentially to tracheobronchial mucin when compared with enterobacteria. We reasoned that if adherence to respiratory mucin protected P. aeruginosa from opsonophagocytic killing, then the ability of this organism to chronically colonize the respiratory tract could be partially explained. Using an opsonophagocytic killing assay with human polymorphonuclear leukocytes, we found that respiratory mucin protected six strains of P. aeruginosa from opsonophagocytic killing but did not protect poorly adhering strains of Escherichia coli, Staphylococcus aureus, or group B streptococci. Incubating P. aeruginosa with the mucin prior to addition to the opsonic assay inhibited phagocytic killing, whereas incubation of polymorphonuclear leukocytes with mucin did not, suggesting that inhibition was not due to an effect of mucin on leukocytes per se but was a consequence of bacterial adherence to mucin. Further studies indicated no decrease in the binding of either antibody or complement component C3 to the bacterial surface in the presence of mucin. This suggests that phagocytic inhibition may be due to a defect in uptake or destruction of mucin-coated bacteria by the leukocytes. Thus, the adherence of P. aeruginosa to respiratory mucin potentially contributes to its persistence in the respiratory tract by interfering with host immune responses.

Adult↗

PubMed1987

Opsonophagocytic killing antibody to Pseudomonas aeruginosa mucoid exopolysaccharide in older noncolonized patients with cystic fibrosis.

The principal cause of morbidity and mortality in cystic fibrosis is persistent respiratory colonization with mucoid strains of Pseudomonas aeruginosa. To investigate possible mechanisms of resistance to this organism, we studied serum from 16 older (greater than or equal to 12 years) patients not colonized with mucoid P. aeruginosa, 11 older (greater than or equal to 14 years) colonized patients, 10 younger (less than or equal to 11 years) noncolonized patients, and 20 healthy adults. The samples from the older patients not colonized with mucoid P. aeruginosa contained antibody specific to the mucoid-exopolysaccharide antigen, which could mediate bacterial killing in conjunction with complement and white cells (titers of 4 to 80). These opsonophagocytic killing antibodies were not detected in samples from the 20 normal controls (P less than 0.0001 vs. noncolonized older patients) or 9 of 10 younger (less than or equal to 11 years) noncolonized patients (P = 0.0072 vs. noncolonized older patients). Although the patients with chronic colonization had higher titers of serum opsonophagocytic killing antibody than did the older noncolonized patients (P = 0.0005), these antibodies were not specific to the mucoid-exopolysaccharide antigen. We conclude that there is an association between mucoid-exopolysaccharide-specific opsonophagocytic killing antibody and a lack of detectable P. aeruginosa colonization in a subset of older, relatively healthy patients with cystic fibrosis.

Adolescent↗

PubMed1987

In vitro T cell-mediated killing of Pseudomonas aeruginosa. V. Generation of bactericidal T cells in nonresponder mice.

We have previously reported that BALB/c mice immunized with 10 micrograms of a Pseudomonas aeruginosa polysaccharide antigen (PS) and 100 micrograms vinblastine sulfate develop T cell-mediated protective immunity, but fail to generate an antibody response. Vinblastine functions in this system to remove a suppressor cell that normally inhibits expression of this form of immunity after PS immunization. T cells from CB.20 mice immunized with the 10 micrograms of PS and 100 micrograms vinblastine fail to kill P. aeruginosa in vitro. These mice are allotype congenic with BALB/c mice, differing at loci closely linked to the IgH-1 locus. Immunization of CB.20 mice with 10 micrograms PS and 100 micrograms vinblastine results in the appearance of T cells which suppress in vitro bactericidal activity of BALB/c T cells. In the current study we found that T cell-mediated bactericidal activity can be generated in CB.20 mice by increasing the dose of vinblastine given at the time of PS immunization. The phenotype of the CB.20 bactericidal T cell generated by high dose vinblastine is identical to that of the BALB/c bactericidal T cell, and the CB.20 bactericidal T cell can adoptively transfer protective immunity to granulocytopenic mice. After immunization of BALB/c and CB.20 mice with PS alone, approximately one log fewer CB.20 T cells than BALB/c T cells are required to suppress bacterial killing in vitro. Furthermore, the number of CB.20 T cells required to suppress in vitro bacterial killing is directly correlated with the dose of vinblastine administered at the time of immunization. Increasing the immunizing dose of PS overcomes suppressor activity and allows the generation of bactericidal T cells in BALB/c mice without a requirement for vinblastine. CB.20 mice fail to generate bactericidal T cells after immunization with high doses of PS. These results indicate that CB.20 and BALB/c mice both possess the full repertoire of T cells required to express bactericidal T cell activity and that the differences in their responses reflect only quantitative differences in suppressor cell activity.

Animals↗

PubMed1987

[Pseudomonas aeruginosa immunoglobulin in experimental pneumonia].

A guinea pig model of experimental Pseudomonas aeruginosa pneumonia was used to evaluate factors affecting the efficacy of passive immune therapy with Psomaglobin N, a hyperimmune P. aeruginosa globulin. Animals treated 2 h after infection with a single intravenous infusion of Psomaglobin N, 500 mg/kg, demonstrated 33% survival. Lower dosages were less effective and no survivors occurred among albumin-treated controls. Treatment with Psomaglobin N was effective if given 2 h or 8 h after infection but not if delayed until 24 h after infection. Animals rendered neutropenic with cyclophosphamide did not survive if treated with Psomaglobin N alone. However, when Psomaglobin N was added to tobramycin treatment, a significant increase in survival occurred (86%) as compared to that observed with tobramycin alone (43%) (p less than 0.05). We conclude that Psomaglobin N may offer a useful therapeutic option in management of P. aeruginosa pneumonia.

Animals↗

PubMed1987

Virulence studies, in mice, of transposon-induced mutants of Staphylococcus aureus differing in capsule size.

We used three related strains of Staphylococcus aureus to determine whether capsule size influenced bacterial virulence. Strain SA1 mucoid elaborated a large capsule demonstrable by transmission electron microscopy (TEM). Nonmucoid isolates were derived from strain SA1 mucoid by Tn551 insertional mutagenesis. By TEM, strain JL24 produced a "microcapsule," whereas strain JL25 was unencapsulated. Strain SA1 mucoid had a 50% lethal dose for mice greater than 3,000-fold lower than that of strains JL24 and JL25. Quantitative cultures of blood and kidney from animals challenged intravenously revealed that strain SA1 mucoid was cleared less readily from the bloodstream and kidneys than the nonmucoid mutants. In an in vitro assay, only strain SA1 mucoid demonstrated antibody-dependent, complement-mediated opsonophagocytosis by human leukocytes. Strains JL24 and JL25 were opsonized for phagocytosis by complement alone. Thus a highly encapsulated strain of S. aureus was more virulent in mice than two related nonmucoid strains. The microencapsulated mutant was not more virulent than the unencapsulated mutant.

Abscess↗

PubMed1987

Pseudomonas aeruginosa adhesins for tracheobronchial mucin.

Mucins of the tracheobronchial tree are preferential sites for adherence and colonization by Pseudomonas aeruginosa. They possess specific receptors for this organism that have amino sugars as their principal constituents. Since mucins probably reflect the receptors on the cellular surfaces, we hypothesized that the bacterial adhesins previously shown to mediate the binding of P. aeruginosa to cells would also mediate bacterial binding to mucins. We therefore tested the roles of the exopolysaccharide from mucoid strains of P. aeruginosa and pili from nonmucoid strains to see whether they are indeed the adhesins for mucins. Using a microtiter plate assay of adherence to mucins, we demonstrated that the mucoid exopolysaccharide bound to mucins and enhanced the adherence of mucoid strains to this substance. Antibodies raised against the exopolysaccharide from a single mucoid strain inhibited the adherence of all mucoid strains tested. Purified pili from nonmucoid strains inhibited the binding of nonmucoid strains but not of mucoid strains. Inhibition of adherence by antibody to pili was quite specific, antibody being able to inhibit only the binding of the homologous nonmucoid strain. These data support our previous observations with tracheal cells, confirming the similarity of the adhesins for respiratory tract cells and the mucins which cover them.

Adhesins, Bacterial↗

PubMed1987

A rabbit model of toxic shock syndrome that uses a constant, subcutaneous infusion of toxic shock syndrome toxin 1.

We have developed a rabbit model of toxic shock syndrome that uses a subcutaneous infusion pump to administer toxic shock syndrome toxin 1 (TSST-1). A dose of 150 micrograms, infused at a constant rate over a period of 7 days, resulted in a characteristic illness highlighted by fever, conjunctival hyperemia, cachexia, and lethargy. The illness was uniformly fatal, with a mean interval until death of 3.2 +/- 0.4 days. Serial determinations of serum chemistries confirmed the multisystem nature of this illness. Rabbits developed profound hypocalcemia, with levels falling from 15.5 +/- 0.2 to 7.6 +/- 0.4 mg/dl under the influence of TSST-1. Blood urea nitrogen and creatinine rose dramatically, in the setting of oliguria or anuria. Serum glutamicpyruvic transaminase was the most reliable indicator of hepatic dysfunction, with the mean rising from 48 U/liter before administration of TSST-1 to 546 U/liter among rabbits surviving 2 days of the infusion. Creatine phosphokinase also rose dramatically in 10 of 16 rabbits. Rabbits demonstrated relative neutrophilia and lymphopenia as well as an increase in the partial thromboplastin time. Histopathologic examination demonstrated disease of multiple organs, particularly the liver, spleen, and lymph nodes, all of which demonstrated inflammation, thrombosis, hemorrhage, and erythrophagocytosis. The concurrent administration of prednisolone with TSST-1 prevented death in four of four rabbits and greatly lessened the morbidity. Rabbits were not protected from morbidity or mortality by the concurrent administration of polymyxin B. We believe that a constant, subcutaneous infusion of TSST-1 in rabbits provides a reproducible model for studying the pathogenesis of TSS.

Adrenal Cortex Hormones↗

PubMed1987

Chemical characterization and immunogenicity of capsular polysaccharide isolated from mucoid Staphylococcus aureus.

In this study we report the isolation and purification of the capsular polysaccharide elaborated by Staphylococcus aureus SA1 mucoid. The capsule was isolated from bacterial extracts and culture supernatants by a series of ethanol precipitations and enzyme digestions, followed by ion-exchange chromatography. Teichoic acid contamination was eliminated by oxidation with sodium metaperiodate, and the final product eluted in the void volume of a Sephacryl S-300 column. The purified capsular polysaccharide was analyzed by gas-liquid chromatography-mass spectroscopy, 13C and 1H nuclear magnetic resonance, amino acid analysis, immunelectrophoresis, and numerous biochemical assays. The major constituents of the capsule were 2-acetamido-2-deoxy-alpha-galacturonic acid (4-O linked), 2-acetamido-2-deoxy-alpha-fucose (3-O linked), and taurine. The polysaccharide also contained O-acetyl groups which were removed by mild alkaline hydrolysis. Serologically and biochemically, the capsule from strain SA1 mucoid appeared very similar to that produced by strain M. Purified capsular polysaccharide was immunogenic in both rabbits and mice. The optimal immunizing dose in mice was 0.1 microgram of purified capsular polysaccharide administered intraperitoneally. SA1 mucoid resisted opsonophagocytic killing by human leukocytes and complement. However, antibodies raised to the purified capsular polysaccharide neutralized the antiphagocytic effect of the capsule.

Animals↗

PubMed1987

An immunohistological evaluation of Pseudomonas aeruginosa pulmonary infection in two patients with cystic fibrosis.

Pseudomonas aeruginosa is the principal pulmonary pathogen in patients with cystic fibrosis. All attempts to date to prevent or eradicate P. aeruginosa infections in these patients have been unsuccessful. Vaccination against P. aeruginosa has been proposed as a preventive strategy but it has not been adequately evaluated. The purpose of this study was to determine whether P. aeruginosa, present in the lungs of patients with cystic fibrosis, express surface antigens similar to those grown in vitro; this issue is of critical importance when choosing bacterial products as vaccine candidates. Lung sections from two patients who died of the pulmonary complications of cystic fibrosis were studied. Bacteria, both in lung sections and isolated from the lung sections and grown in vitro, reacted strongly with polyclonal and monoclonal antibodies against P. aeruginosa mucoid exopolysaccharide and outer membrane proteins F and H2; this suggested that these antigens are surface exposed in vivo. It was also found that bacteria in both lung sections were associated in situ with IgG, IgA, and C3 but not with IgM or C4.

Antibodies, Bacterial↗

PubMed1986

In vitro T cell-mediated killing of Pseudomonas aeruginosa. IV. Nonresponsiveness in polysaccharide-immunized BALB/c mice is attributable to vinblastine-sensitive suppressor T cells.

We reported previously that BALB/c mice immunized with a polysaccharide (PS) antigen isolated from immunotype 1 Pseudomonas aeruginosa and vinblastine sulfate develop T cell-mediated protective immunity, despite their failure to produce specific antibody. In vitro, Lyt-1-,2+, I-J+ T cells from vinblastine- and PS-immunized mice kill P. aeruginosa by secretion of a bactericidal lymphokine. BALB/c mice immunized with PS alone generate neither protective antibodies nor a protective T cell response. The current studies indicate that T cells from mice immunized with PS alone significantly suppress the bactericidal activity of T cells from mice immunized with vinblastine and PS. The suppressor T cells are of the same Lyt-1-,2+, I-J+ phenotype as the bactericidal T cells. Suppression is mediated by a soluble product of these suppressor T cells which both inhibits T cell proliferation and interferes with the production or release of the bactericidal lymphokine. Cyclophosphamide, used in other systems to remove suppressor T cells, fails to enhance bacterial killing and does not inhibit suppressor cell activity. These studies indicate that immunization with PS elicits responses in two functionally distinct subgroups of Lyt-1-,2+, I-J+ T cells, and that these cells are distinguishable by their sensitivity to vinblastine sulfate.

Animals↗

PubMed1986

Induction of interleukin-1 by strains of Staphylococcus aureus from patients with nonmenstrual toxic shock syndrome.

We studied the induction of human interleukin-1 (IL-1) production in strains of Staphylococcus aureus isolated from patients with nonmenstrual toxic shock syndrome (TSS). Of the 20 TSS-associated strains studied, 11 produced and nine did not produce TSS toxin-1 (TSST-1). Human monocytes were incubated with dilute staphylococcal supernatants, and IL-1 production was measured in a lymphocyte-activating factor assay. All 20 TSS-associated strains were potent inducers of IL-1, in comparison with none of 10 vaginal isolates of S. aureus from healthy women. TSST-1-positive strains were more potent than TSST-1-negative strains. Nine TSST-1-negative TSS-associated strains were compared with 14 strains of S. aureus from other clinical settings and were found to be significantly more potent inducers of IL-1 (P less than .01). Eight of these nine TSS-associated strains produced at least one staphylococcal enterotoxin. Stimulation of monocytes by products of S. aureus may play a role in the pathogenesis of TSS.

Bacterial Toxins↗

PubMed1986

Functionally active monoclonal antibody that recognizes an epitope on the O side chain of Pseudomonas aeruginosa immunotype-1 lipopolysaccharide.

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 O side chain.

Animals↗

PubMed1986

Polyclonal and monoclonal antibody therapy for experimental Pseudomonas aeruginosa pneumonia.

A human immunoglobulin G preparation, enriched in antibodies to lipopolysaccharide (LPS) Pseudomonas aeruginosa antigens (PA-IGIV) and murine monoclonal antibodies (MAb) to P. aeruginosa Fisher immunotype-1 (IT-1) LPS antigen and outer membrane protein F (porin), were evaluated for therapeutic efficacy in a guinea pig model of P. aeruginosa pneumonia. The concentration of antibodies to IT-1 LPS was 7.6 micrograms/ml in PA-IGIV and 478 micrograms/ml in the IT-1 MAb preparation. No antibody to IT-1 was detected in MAb to porin. For study, animals were infected by intratracheal instillation of IT-1 P. aeruginosa and then treated 2 h later with intravenous infusions of PA-IGIV, IT-1 MAb, or porin MAb. Control groups received intravenous albumin, and routinely died from pneumonia. Both PA-IGIV (500 mg/kg) and IT-1 MAb (greater than or equal to 2.5 mg/kg) treatment resulted in increased survival (P less than 0.01 to 0.001), and also improved intrapulmonary killing of bacteria. Porin MAb failed to protect from fatal pneumonia. IT-1 MAb treatment produced more survivals than did PA-IGIV treatment but only at dosages of MAb resulting in serum antibody concentrations greater than those achieved with PA-IGIV. PA-IGIV and IT-1 MAb demonstrated in vitro and in vivo (posttreatment guinea pig serum) opsonophagocytic activity for the IT-1 challenge strain. However, the polyclonal preparation required complement, whereas the MAb did not. We conclude that passive immunization with polyclonal hyperimmune P. aeruginosa globulin or with MAb to LPS antigens may be useful in the treatment of acute P. aeruginosa pneumonia. The relative efficacies of such preparations may be limited, however, by their type-specific LPS antibody concentrations.

Absorption↗

PubMed1986

Polysaccharide surface antigens expressed by nonmucoid isolates of Pseudomonas aeruginosa from cystic fibrosis patients.

We tested nonmucoid Pseudomonas aeruginosa isolates obtained from cystic fibrosis (CF) patients for the expression of lipopolysaccharide (LPS) serotype antigens, serum sensitivity, and production of mucoid exopolysaccharide (MEP). When all nonmucoid isolates were compared with a set of random mucoid isolates, 20 of 52 (38%) nonmucoid isolates were typable and serum resistant, compared with 13 of 51 (24%) mucoid isolates (P = 0.16 by chi-square analysis). However, nonmucoid strains from CF patients colonized only with nonmucoid strains were more frequently typable and serum resistant (67%) than were nonmucoid isolates from patients cocolonized with mucoid strains (31%) (P = 0.012, Fisher exact test). An inhibition enzyme-linked immunosorbent assay done with bacterial extracts, a direct-whole-cell enzyme-linked immunosorbent assay done with affinity-purified antibody to MEP, and immune electron microscopy all demonstrated production of MEP by all nonmucoid P. aeruginosa isolates tested, including nonmucoid revertants of mucoid strains. No other bacterial species tested positive in these assays. These findings suggest that MEP is produced by all P. aeruginosa isolates obtained from CF patients, that the initial colonizing nonmucoid strains produce a smooth LPS, and that once LPS-rough, mucoid strains appear in the sputum, the predominant LPS phenotype is rough regardless of colony morphology.

Antigens, Bacterial↗

PubMed1986

Structural analysis and immunogenicity of Pseudomonas aeruginosa immunotype 2 high molecular weight polysaccharide.

We analyzed high molecular weight polysaccharide (PS) from the Fisher immunotype 2 (IT-2) strain of Pseudomonas aeruginosa for molecular composition and structure, then determined its immunogenicity in healthy adults. The PS was composed of 2-acetamido-2,6-dideoxygalactose (N-acetyl fucosamine) and glucose in a molar ratio of 2:1. Structural analysis by carbon-13 and proton nuclear magnetic resonance confirmed that the high molecular weight PS was structurally identical to that of the O-specific side chain of the lipopolysaccharide. PS differed from this material in molecular size. Immunization of 19 adult volunteers with doses of 50-100 micrograms of PS resulted in significant rises (P less than 0.04-P less than 0.0001) in binding antibody levels and killing antibody titers 2 and 4 wk postimmunization. The only reaction to the vaccine was localized tenderness at the immunization site. Analysis of the immunoglobulin isotype response to the vaccine showed a rise in specific serum IgG and IgA antibodies. Heterologous responses to other P. aeruginosa PS antigens were not seen. The antibody levels attained by vaccination were comparable with those in acute-phase serum samples of patients who survived sepsis with IT-2 P. aeruginosa and were significantly higher (P less than 0.03) than specific antibody levels in bacteremic patients who died. These results confirm that PS is a high molecular weight, immunogenic form of the P. aeruginosa IT-2 serotype antigen, eliciting levels of type-specific antibody comparable with those seen among patients surviving an episode of P. aeruginosa sepsis.

Adult↗