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Biomedical subjects

D L Kasper

Publications and source records attributed to D L Kasper.

At least 199 records · Page 11Linked to original sources
PubMed1977

Immunological investigation of infants with septicemia or meningitis due to group B Streptococcus.

Purified polysaccharide from type III group B Streptococcus contains both a type III-specific determinant and another determinant that is common to strains of serotypes other than type III. The polysaccharide contains sialic acid, galactose, heptose, glucose, glucosamine, and mannose. Serum antibody to this antigen was measured by means of a radioactive antigen-binding assay. Sera from 36 (67.9%) of 53 women with healthy newoborns contained antibody, a prevalence significantly different from that in sera from 15 women (13.3%) whose neonates developed septicemia or meningitis due to type III group B Streptococcus. Complete concordance for presence or absence of anticapsular antibody in sera from 14 women at delivery and in their neonates' cord sera was demonstrated; this concordance indicates transplacental transfer of antibody. Sera from each of four adults with invasive infection who were studied during convalescence contained antibody to the capsular polysaccharide of type III group B Streptococcus. In contrast, antibody was absent from 10 infants who had recovered from bacteremia, septicemia, and/or meningitis due to type III group B Streptococcus.

Antibodies, Bacterial↗
PubMed1977

Quantitative determination of antibody to capsular polysaccharide in infection with type III strains of group B Streptococcus.

The development of antibody in response to invasive infection with type III strains of group B Streptococcus was studied in sera from 31 infants and 4 adults by means of a quantitative radioactive antigen-binding assay. Low concentrations of antibody were consistently found in the acute sera of patients who developed clinical illness. Although adults with puerperal sepsis and infants with bone or joint infection uniformly demonstrated significant rises in serum antibody concentration after recovery, much lower levels of antibody were detected in convalescent sera from infants recovering from meningitis or sepsis. The median antibody concentration in sera from 43 parturients with type III strains of group B Streptococcus isolated from vaginal cultures whose neonates failed to develop symptomatic disease was significantly greater than that in sera from 29 mothers of infants with invasive, type III, group B streptococcal infection. Study of paired maternal and cord sera demonstrated a significant correlation between the antibody concentration in a mother's serum and that in her neonate.

Adolescent↗
PubMed1977

Characterization of gonococcal antigens responsible for induction of bactericidal antibody in disseminated infection.

The role of gonococcal antigens in serum bactericidal activity was determined for an isolate of Neisseria gonorrhoeae from a patient with disseminated gonococcal infection (DGI). Gonococcal outer membranes were purified by differential ultracentrifugation of sheared organisms treated with EDTA. The membranes were solubilized in an endotoxin-disaggregating buffer, and the proteins were separated from the endotoxin by molecular sieve chromatography. Chemical characterization of the endotoxin from the DGI strain revealed the presence of heptose (7.8% of carbohydrate composition) and 2-keto-3-deoxyoctonate (6.1%, wt/wt) in concentrations similar to rough endotoxins of gram-negative enteric bacteria. Dermal Schwartzman reactions were positive for this endotoxin (4 mug) and the corresponding outer membrane (139 mug), but negative for the protein fraction (>500 mug). The patient's whole serum or the IgG fraction, each with complement, reduced the number of the infecting organisms by greater than 1 log(10) in a bactericidal assay. Outer membrane and its protein and endotoxin fractions (0.8-500 mug) from the DGI strain were separately preincubated with the patient's convalescent serum and specific inhibition of bactericidal activity occurred with the endotoxin fraction (25 mug) and the outer membrane (100 mug); the protein (500 mug) exhibited no inhibition. Similar results were obtained by inhibiting the bactericidal activity of rabbit antiserum, prepared by intravenous inoculation of an isolate from a patient with pelvic inflammatory disease, with antigen purified from that strain. That this was specific immune inhibition and not anticomplementary activity was shown by the failure of these antigens to inhibit other complement-dependent bactericidal systems.

Adult↗
PubMed1977

Bacteroides fragilis subspecies in clinical isolates.

Isolates of Bacteroides fragilis from 83 infected patients were collected during 2 years. Of 103 isolates, 68% were subspecies fragilis. This was the single most common subspecies isolated from blood (12/17), intra-abdominal (11/28), wound (17/20), perirectal (11/16), pelvic (6/10), and other (8/11) sites. Sixteen patients had B. fragilis isolated in pure culture. Of these, 9/12 blood cultures and 4/4 cultures from other sites were ss. fragilis. The recent observation that ss. fragilis organisms are encapsulated whereas the other subspecies are generally unencapsulated was supported by indirect fluorescent antibody studies using antibodies prepared to the capsular material of ss. fragilis. All 33 strains of ss. fragilis and none of 13 strains of other subspecies were positive. The predominance of ss. fragilis in clinical isolates compared to its relative infrequency in normal fecal flora and its predominance in pure cultures, especially of blood, indicate that this is the most virulent of B. fragilis subspecies. This virulence may be related to encapsulation.

Abdominal Injuries↗
PubMed1977

Colonization with group B streptococci in girls under 16 years of age.

Cultures from the vagina, pharynx, and anal canal of 100 healthy girls, 2 months through 15 years of age, were examined for the presence of group B streptococci. Of the 100 participants, 20% were colonized at one or more of these three sites. Pharyngeal colonization was detected in 15% of the girls under 11 years of age and in 5% of those over 11 years of age. Colonization at anogenital sites were observed in 19% of participants under 3 years of age, in 25% of those 11 years of age and older, and in only 4% of those between the ages of 3 and 10 years (P less than .025). The concentration of serum antibody directed against the polysaccharide capsular antigen isolated from type III, group B Streptococcus appeared, in part, to be related to increasing age.

Adolescent↗
PubMed1977

Antigenic specificity of opsonophagocytic antibodies in rabbit anti-sera to group B streptococci.

An opsonophagocytic assay has been developed which requires human polymorphonuclear leukocytes, immune serum, and complement for optimal killing of Group B streptococci. Only with all three of these components was killing of greater than 1.0 log10 of the initial inoculum achieved, using rabbit antisera directed to homologous strains of each of the five known serotypes of Group B streptococci. Titers of specific antisera which opsonized the strains and resulted in greater than 1 log 10 reduction of colony-forming units, ranged from 1:100 (serotype Ib) to 1:3200 (serotype Ia). Cross-reactions between serotype-specific sera and heterologous strains were seen in certain instances. Type Ic strain and serotype Ic antiserum demonstrated cross-reactions with types Ia and Ib which were explainable by known shared antigens among these types. The only other cross-reaction which resulted in greater than 1 log 10 reduction in colony-forming units was when unabsorbed antiserum to strain Ia was used to opsonize a strain of serotype III. Opsonization of 10 serotype III strains was demonstrated with a single type III antiserum. Killing of nine of these strains required polymorphonuclear leukocytes, complement, and antiserum, but one strain, D136C, the reference strain, could be killed (greater than 1 log 10 reduction in colony-forming units) without either complement or specific antiserum. Inhibition studies were performed utilizing large m.w. polysaccharide antigens extracted from each serotype. These antigens inhibited opsonization of homologous strains by homologous antisera with 50% inhibition points ranging between 0.5 and 4 mug.

Animals↗
PubMed1976

Correlation of maternal antibody deficiency with susceptibility to neonatal group B streptococcal infection.

We investigated the role of maternal antibody in neonatal Group B streptococcal infection with a radioactive antigen-binding assay employing a purified polysaccharide antigen with both Type III and Group B determinants. Serums from seven women who gave birth to infants who had invasive Group B streptococcal infection with Type III strains were all deficient in antibody. In contrast, serums from 22 of 29 pregnant Type III vaginal carriers whose infants were healthy contained antibody with a prevalence significantly different from that in women delivering infants with Type III disease (P less than 0.01). Three healthy neonates born to women with antibody in serums had demonstrable antibody in umbilical-cord serum. These data suggest that transplacental transfer of maternal antibody protects infants from invasive Group B streptococcal infection with Type III strains.

Animals↗
PubMed1976

Immunochemical characterization of the "native" type III polysaccharide of group B Streptococcus.

The type III polysaccharide of -roup B Streptococcus has been isolated and purified by a method that employs washing of intact cells at neutral pH. That the polysaccharide prepared by this procedure is the "native" type III antigen is suggested by its molecular size in excess of 10(6) daltons, its degradation by acid and heat treatment to a fragment with immunologic characteristics of the classical HCl antigen, and its type-specific serologic activity. The type III polysaccharide in native form contains sialic acid, galactose, glucose, glucosamine, heptose, and mannose. It is acidic in nature, is resistant to neuramindiase degradation, contains no O-acetyl groups, and does not share antigenic determinants with capsular type K1 antigen of Escherichia coli or Group B polysaccharide antigen of Neiserria meningitidis.

Epitopes↗
PubMed1976

The polysaccharide capsule of Bacteroides fragilis subspecies fragilis: immunochemical and morphologic definition.

A large-molecular-weight capsular polysaccharide was isolated from strains of Bacteroides fragilis subspecies fragilis. By means of electron microscopy and staining with ruthenium red, the thick polysaccharide capsule was also visualized. With use of a radioactive antigen-binding assay, antibody to this capsular polysaccharide was demonstrated in antisera prepared in rabbits to each of eight strains of B. fragilis fragilis. Antibody of similar specificity was not found in antisera prepared to Bacteroides melaninogenicus or to strains of Bacteroides fragilis subspecies vulgatus and Bacteroides fragilis subspecies distasonis; such antibody was found in antisera to only one of two strains of Bacteroides fragilis subspecies thetaiotaomicron. The radioactive antigen-binding assay is a sensitive test for the detection of antibody to capsular polysaccharide. This polysaccharide antigen may form the basis of a serogrouping system for B. fragilis.

Antigen-Antibody Complex↗
PubMed1976

Chemical and biological characterization of the lipopolysaccharide of Bacteroides fragilis subspecies fragilis.

Bacterial lipopolysaccharides extracted from Bacteroides fragilis subspecies fragilis lacked 2-keto-3-deoxyoctonate and heptose, sugars which make up part of the inner core of most bacterial endotoxins. Over 98% of the lipid portion of this material could be removed easily with chloroform-methanol and alcohol, a finding which indicates a loose association between the polysaccharide and lipid moieties. The lipopolysaccharides caused gelation of limulus lysate at a concentration significantly higher than that for the endotoxin of Salmonella typhi. None of the extracts was lethal in 10-day-old chick embryos at doses of greater than 200 mug per egg, whereas the endotoxin of Neisseria meningitidis was lethal at a dose of 1.2 mug per egg. The local Shwartzman reaction could not be induced by levels of B. fragilis endotoxin of up to 1,000 mug per rabbit, whereas a (control) endotoxin of S. typhi induced this phenomenon at a level of 3 mug per rabbit. Intact oxygen-killed B. fragilis failed to provoke the local Shwartzman reaction at doses of 2,500 mug. These results indicate that B. fragilis has a lipopolysaccharide different from that of most gram-negative bacteria. Although it retains some of the chemical and biologic properties of classical endotoxin, it seems to lack others. This observation may have significant clinical implications.

Animals↗
PubMed1976

Microcapsule of type III strains of group B Streptococcus: production and morphology.

The yield of purified type III polysaccharide of group B Streptococcus was significantly improved by modification of the growth medium. Culture of organisms in standard Todd-Hewitt broth resulted in acid accumulation during the exponential phase of growth and poor yield of type III polysaccharide when extracted from cells by washing with neutral buffer solution. By increasing the buffering capacity of the broth medium, acid accumulation was prevented, and the number of viable cells was increased at the stationary phase of growth. Further, by increasing the concentration of glucose in the buffered medium, the yield of type III polysaccharide was increased two to three times. Electron microscopic investigations of cells grown in the modified broth medium demonstrated a thicker microcapsule than was found in organisms grown in standard broth.

Cell Wall↗
PubMed1976

Identification of sialic acid in polysaccharide antigens in group B Streptococcus.

By means of paper chromatographic techniques with purified, sialic acid-containing, bacterial antigen standards, sialic acid, as well as galactose and glucosamine, have been identified as components of each type-specific antigen of group B Streptococcus. Rhamnose was not detected in the group B antigen isolated by the classical HCl and heat extraction method.

Antigens, Bacterial↗
PubMed1975

Immunochemical characterization of the outer membrane complex of Bacteroides fragilis subspecies fragilis.

The outer membrane of gram-negative bacteria is immunologically the most important structure of the cell because of its accessibility to host defense mechanisms. By electron micrographic studies, it has been shown that Bacteroides fragilis has a cell envelope typical of gram-negative bacteria. The outer memberane of this envelope was found to consist of protein, two polysaccharides bound to lipid in various degrees, and loosely bound lipid. The protein component of the outer membrane had a distinct pattern when studied by polyacrylamide gel electrophoresis. Similar peptide band pattern were seen in all strains of Bacteroides fragilis subspecies fragilis studied, but this pattern was distinct from the pattern found in the outer membranes of other subspecies. The carbohydrates and the protein components were both associated with subspecies-specific immunoprecipitins. We propose that this antigenic complex represents the outer membrane of B. fragilis in its native state and that the immunologically important antigens of this organism are associated with this complex.

Antigens, Bacterial↗
PubMed1972

Isolation and characterization of a native cell wall complex from Neisseria meningitidis.

A cell wall complex has been isolated by gentle methods from both the medium supernatant fluid and whole organisms of Neissieria meningitidis cultures. The two types of preparations have been shown to be essentially identical on the basis of chemical composition, electron microscopy, and polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE). Four major components were identified in the complex: group-specific polysaccharide (4 to 10%), protein (45 to 65%), lipopolysaccharide (10 to 25%), and lipid (15 to 30%). The whole complex was found to be immunogenic in rabbits and to elicit production of antibody directed against the protein, the group-specific polysaccharide, and the lipopolysaccharide components. The isolated protein component was also found to be immunogenic in rabbits and to elicit production of serotype-specific antibody. The protein component was found to produce a band pattern in SDS-PAGE that is simple, reproducible, and strain dependent. The lipopolysaccharide component was found to have chemical and biological properties characteristic of bacterial endotoxin. We propose that this complex is representative of the outer trilaminar membrane of the meningococcal cell envelope in its native state.

Animals↗