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Biomedical subjects

R Germanier

Publications and source records attributed to R Germanier.

At least 37 records · Page 2Linked to original sources
PubMed1985

Protection against fatal Pseudomonas aeruginosa sepsis by immunization with smooth and rough lipopolysaccharides.

The protective capacity of various native and mutant lipopolysaccharide antigens against fatal Pseudomonas aeruginosa burn wound sepsis was evaluated. Immunization with O-polysaccharide-deficient lipopolysaccharides derived from Escherichia coli J5 or Salmonella typhi Ty 21a afforded substantial protection against only one of five Pseudomonas aeruginosa challenge strains of various serotypes. Immunization with both lipopolysaccharide antigens evoked antibody of the immunoglobulin G class which recognized lipopolysaccharide isolated from the challenge strain against which protection was noted. This was not seen for the remaining four challenge strains. Attempts to demonstrate cross-serotype protection using O-antigen-deficient and core-deficient Pseudomonas aeruginosa lipopolysaccharide antigens was, for the most part, unsuccessful. In contrast, high levels of protection against all six serotypes of challenge strains were seen following immunization with homologous lipopolysaccharide.

Animals↗
PubMed1985

Safety and immunogenicity of Klebsiella pneumoniae K1 capsular polysaccharide vaccine in humans.

The safety and immunogenicity of two Klebsiella pneumoniae K1 capsular polysaccharide (CPS) vaccines were evaluated in humans. Trace quantities of lipopolysaccharide present in vaccine preparations were detoxified by treatment of K1 CPS in a 95% ethanol-0.1 N NaOH solution. This procedure greatly reduced the pyrogenicity of K1 CPS but did not markedly alter its antigenicity, molecular size, or immunogenicity for animals. Volunteers received either 25 or 50 micrograms of untreated or NaOH-treated K1 CPS vaccine subcutaneously. Systemic reactions on primary vaccination were infrequent with both vaccine preparations. However, the frequency and severity of local reactions were substantially reduced after immunization with NaOH-treated vaccine as compared with untreated K1 CPS. All vaccinees responded with a fourfold or greater rise in IgG and IgM titers. IgG antibody to K1 CPS isolated from immune sera was highly effective in preventing fatal experimental burn wound sepsis due to K. pneumoniae K1 in mice.

Adolescent↗
PubMed1985

Purification and vaccine potential of Klebsiella capsular polysaccharides.

Capsular polysaccharide (CPS) from 18 Klebsiella strains of different capsular types was isolated and characterized. Purified CPSs were composed primarily of carbohydrate with trace quantities of protein, nucleic acids, and lipopolysaccharide. All CPSs were of a high molecular weight, possessing a Kd of 0.01 to 0.11 as determined by gel filtration over Sepharose CL-4B. Low levels of lipopolysaccharide present in all preparations were responsible for the highly pyrogenic nature of one-half of the CPS preparations. Treatment of capsular material with dilute NaOH in 95% ethanol markedly reduced the pyrogenicity of all preparations and had a negligible effect on their molecular weight. The immunogenicity of the various native CPSs for mice varied considerably from serotype to serotype, but all evoked an anticapsular immunoglobulin G response. Five of 18 NaOH-treated polysaccharides were significantly (P less than 0.05) less immunogenic than their native counterparts. Human immunoglobulin G prepared from volunteers immunized with either native or NaOH-treated KP1-0 capsular polysaccharide was equally effective at preventing experimental fatal Klebsiella pneumoniae burn wound sepsis in mice.

Animals↗
PubMed1985

Bordetella pertussis filamentous hemagglutinin gene: molecular cloning of a potential coding sequence.

We have constructed an expression library of Bordetella pertussis DNA sequences, cloned in Escherichia coli. Random DNA fragments were inserted into the beta-galactosidase gene of bacteriophage lambda gt11 and plaques were screened with antibodies directed against filamentous hemagglutinin. The antigen-positive clone obtained expressed B. pertussis sequences as polypeptides fused to beta-galactosidase. The fusion polypeptides reacted both with antibodies to beta-galactosidase and with antibodies to filamentous hemagglutinin. The positive clone contains B. pertussis DNA sequences as determined by specific hybridization to Bordetella DNA.

Base Sequence↗
PubMed1984

Prevention of fatal experimental burn-wound sepsis due to Klebsiella pneumoniae KP1-O by immunization with homologous capsular polysaccharide.

The immunogenicity and protective capacity of highly purified Klebsiella pneumoniae KP1-O capsular polysaccharide was evaluated. Polysaccharide antigen from K. pneumoniae KP1-O was isolated, purified, and characterized. The final preparation consisted primarily of carbohydrate and was of high molecular weight (greater than or equal to 5 X 10(6]. The polysaccharide antigen was found to be immunogenic in mice in a dose-dependent fashion, as determined by ELISA. Prior immunization of mice with low doses of K. pneumoniae KP1-O polysaccharide provided highly significant protection (P less than .01) against fatal burn wound sepsis with the homologous strain. The level of protection correlated with IgG ELISA titers and was dependent upon prevention of bacteremia following challenge.

Animals↗
PubMed1984

Experimental Klebsiella pneumoniae burn wound sepsis: role of capsular polysaccharide.

The role of Klebsiella pneumoniae capsular polysaccharide in relation to virulence in a murine burn wound sepsis model was investigated. Burn trauma markedly predisposed mice to lethal K. pneumoniae sepsis. A highly encapsulated variant (KP1-O) derived from K. pneumoniae KP1 was found to be extremely virulent for burned mice (50% lethal dose less than 10 organisms), whereas another variant (KP1-T), which possessed a much smaller capsule, was comparatively nonvirulent (50% lethal dose greater than 10(6) organisms). Production of large quantities of capsular material by KP1-O allowed for its rapid growth in vivo and persistence in the blood and liver. These traits were not demonstrated by KP1-T, which was effectively cleared after challenge.

Animals↗
PubMed1984

Protection against fatal Pseudomonas aeruginosa burn wound sepsis by immunization with lipopolysaccharide and high-molecular-weight polysaccharide.

A murine burn wound model was employed to evaluate the relative efficacy of purified Pseudomonas aeruginosa lipopolysaccharide (LPS) and high-molecular-weight polysaccharide as protective immunogens. LPS was found to be both highly immunogenic and protective. As little as three 0.001-microgram doses elicited good immunoglobulin M and G titers and increased the mean lethal dose more than 1,000-fold. The level of protection against a live challenge correlated with antibody titers and was found to be serotype specific. An immunizing regimen which evoked only an immunoglobulin M response was still found to offer substantial protection. Immunization with a high-molecular-weight polysaccharide was also found to be protective. However, approximately 1,000-fold more high-molecular-weight polysaccharide, as compared with LPS, was needed to protect mice to an equivalent degree. Immunization with LPS was found to promote bacterial clearance and prevent establishment of bacteremia. A multivalent LPS vaccine conferred high levels of protection (110- to 53,000-fold) against eight different challenge strains of various serotypes.

Animals↗
PubMed1984

Role of lipopolysaccharide in virulence of Pseudomonas aeruginosa.

The role of lipopolysaccharide (LPS) in the virulence of Pseudomonas aeruginosa was studied. The virulence of several P. aeruginosa strains for burned mice was found to be directly related to the dispersion of LPS into either the phenol or the water phase after extraction. Virulence decreased as the proportion of LPS recovered from the phenol phase increased. No similar correlation was observed when several other strain characteristics were investigated. This phenomenon was studied in greater detail by using the "smooth"-specific phage E79 to select mutants altered in LPS structure. One such mutant, PA220-R2, was extensively characterized. LPS isolated from PA220-R2 was found to be completely deficient in high-molecular-weight polysaccharide material. This alteration rendered the strain serum sensitive and dramatically changed the reaction with O-specific typing sera and sensitivity to typing phages. However, motility, toxin A and elastase production, and 22 metabolic functions remained unchanged. PA220-R2 was found to be comparatively nonvirulent, with a 50% lethal dose more than 1,000-fold higher than that of its parent for burned mice. This was due to the inability of PA220-R2 to establish an infection in burned skin.

Animals↗
PubMed1984

Protection against fatal Klebsiella pneumoniae burn wound sepsis by passive transfer of anticapsular polysaccharide.

Klebsiella pneumoniae KP1-0 capsular polysaccharide (PS) was isolated from culture supernatants by coprecipitation with N-cetyl-N,N,N-trimethylammonium bromide. PS was composed primarily of carbohydrate and contained less than 1% (wt/wt) protein and nucleic acids. The protective capacity of passively transferred anti-PS was evaluated in a murine burn wound sepsis model. Anti-PS antibody was found to offer high levels of protection (P less than or equal to 0.02) against a low challenge dose of K. pneumoniae KP1-0. The 50% lethal dose for mice which received anti-PS antibody was increased from 10- to 40-fold over that for mice which received normal rabbit serum. Anti-PS antibody was found to be most effective at reducing mortality when administered before the challenge. In experiments designed to monitor the course of the infection, anti-PS was found to both delay the onset of bacteremia and reduce bacterial counts in the blood. Optimal protection against fatal burn wound sepsis was obtained by the use of a combined antibiotic and passive antibody therapy regimen.

Animals↗
PubMed1984

Oral vaccination against enteric bacterial infections: an overview.

The present situation and the future prospects for the use of oral vaccines against the major enteric diseases typhoid fever, shigellosis and cholera are discussed in this paper. No significant protection could be demonstrated for oral inactivated whole-cell vaccines. In contrast, an oral live vaccine based on the attenuated Salmonella typhi strain Ty 21a was highly efficacious in volunteer challenge studies and in a controlled field trial. Two attenuated strains are presently being tested in volunteer studies as candidate vaccines against shigellosis; one uses S. typhi Ty 21a and the other Escherichia coli K-12 as the carrier for shigella antigens. Experimental challenge studies in volunteers showed that recovery from clinical cholera confers solid and long-lasting protection. The goal of present research is to develop a vaccine that mimics the events of clinical cholera without causing disease.

Administration, Oral↗
PubMed1983

Simple model for the study of Pseudomonas aeruginosa infections in leukopenic mice.

A simple, reproducible model of fatal Pseudomonas aeruginosa sepsis in mice during immunosuppression was developed. Mice were rendered leukopenic (less than or equal to 800 leukocytes per mm3 of blood) for a period of 5 days by multiple injections of cyclophosphamide. Mice were challenged at the onset of leukopenia by instilling the bacteria onto a 0.5-mm incision made into the back. The mean lethal dose (LD50) for P. aeruginosa PA220 and M-2 was less than 20 bacteria. The mean time to death for these strains ranged from 46 to 59 h. Leukopenic mice were comparatively resistant when challenged with Klebsiella pneumoniae (LD50 = 1.5 x 10(6)) or Staphylococcus aureus (LD50 greater than 10(6)). Infection with P. aeruginosa was characterized by rapid bacterial multiplication in the skin at the site of infection, producing ecthyma gangrenosum. Bacteremia and colonization of the liver were pronounced 21 h postinfection. This model should prove to be a useful tool for studying the pathogenesis of P. aeruginosa infections under immunosuppressed conditions.

Animals↗
PubMed1983

Protection against Pseudomonas aeruginosa infection in a murine burn wound sepsis model by passive transfer of antitoxin A, antielastase, and antilipopolysaccharide.

The protective capacity of passively transferred immunoglobulin G (IgG) fractions from antitoxin (AT-IgG), antielastase (AE-IgG), and antilipopolysaccharide (ALPS-IgG) against Pseudomonas aeruginosa infection was evaluated in a murine burn wound sepsis model. Complete protection was afforded by homologous ALPS-IgG against intermediate challenge doses (10 50% lethal doses) of P. aeruginosa PA220, whereas AT-IgG and AE-IgG offered no significant protection (P less than 0.5). The simultaneous transfer of AT-IgG or AE-IgG with ALPS-IgG gave no additional protection above that seen with ALPS-IgG alone. The transfer of ALPS-IgG did not dramatically alter bacterial multiplication in the skin at the site of infection. However, bacteremia and infection of the liver were prevented. In parallel experiments, AT-IgG or AE-IgG did not significantly alter either the course of the infection or the number of bacteria seen in the blood, liver, or skin when compared with controls. ALPS-IgG administered 24 h before infection, at the time of infection, or 4 h postinfection provided complete protection. Even when ALPS-IgG was transferred at a time when the infection was well established locally in the skin (8 h postinfection), highly significant protection (P greater than 0.999) was obtained. Protection afforded by ALPS-IgG was serotype specific. These results indicate that antibody to lipopolysaccharide is of critical importance for protection against P. aeruginosa challenge in a relevant animal model.

ADP Ribose Transferases↗
PubMed1983

Passive protection against Pseudomonas aeruginosa infection in an experimental leukopenic mouse model.

An experimental leukopenic mouse model was used to evaluate the protective capacities of immunoglobulin G (IgG) fractions directed against toxin A (AT-IgG), elastase (AE-IgG), and lipopolysaccharide (ALPS-IgG) against fatal Pseudomonas aeruginosa infection. Statistically significant protection, as measured by long-term survival, was observed only when mice were treated with serotype-specific ALPS-IgG. The mean lethal dose for P. aeruginosa could be increased by as much as 6,600-fold for mice given ALPS-IgG as compared to mice which received only normal rabbit IgG. ALPS-IgG afforded high levels of protection, even when administered up to 6 h postchallenge. Experiments designed to monitor the growth and spread of a locally administered challenge showed that ALPS-IgG prevented bacteremia and organ colonization, which were pronounced in control animals. The effectiveness of combined antibiotic and immune therapy was tested. Gentamicin alone or in combination with AT-IgG or AE-IgG provided no detectable protection. However, its use with ALPS-IgG afforded substantially higher levels of protection than ALPS-IgG alone.

Animals↗
PubMed1983

Procholeragenoid: a safe and effective antigen for oral immunization against experimental cholera.

The immunogenicity and safety of procholeragenoid, a minimally toxic, heat-induced aggregate of cholera toxin (CT), were studied in enterically immunized rats and dogs. Although 99% less toxic than CT, procholeragenoid was only slightly less efficient in causing jejunal anti-CT responses in rats; in contrast, choleragenoid, the nontoxic B subunit pentamer of CT, was much less effective. The immunogenicity of procholeragenoid was due almost entirely to its large-molecular-weight components (MW = 10(6) to 10(7)) and was markedly reduced by preincubation with GM1 ganglioside or treatment with Formalin to eliminate residual toxicity. These findings suggest that molecular aggregation, binding to GM1 receptors on cell membranes, and stimulation of cellular adenylate cyclase each contributed to the effectiveness of procholeragenoid as a mucosal immunogen. In dogs, oral immunization with five 500-micrograms doses of procholeragenoid evoked vigorous anti-CT responses in jejunal mucosa without causing significant diarrhea. When subsequently challenged with virulent Vibrio cholerae, immunized dogs showed 83% protection against the development of severe or lethal diarrhea compared with non-immunized controls. These results confirm a protective role for mucosal antitoxin in experimental cholera and show that procholeragenoid is both safe and effective as an oral immunogen. Procholeragenoid, combined with other antigens of V. cholerae, may constitute a simple, safe, and effective oral vaccine for cholera.

Administration, Oral↗