Biomedical subjects

D T Berman

Publications and source records attributed to D T Berman.

15 recordsLinked to original sources

PubMed1979

Enzyme-linked immunosorbent assay for bovine immunoglobulin subclass-specific response to Brucella abortus lipopolysaccharides.

An enzyme-linked immunosorbent assay was developed to follow the bovine response, by immunoglobulin class and subclass, to defined smooth and rough lipopolysaccharides (LPS) of Brucella abortus. Binding to smooth LPS of immunoglobulin G1 (IgG1) and IgG2 in sera from Brucella-infected animals was significantly greater than binding in sera from normal uninfected animals. Competition or steric blocking among IgM, IgG1, and IgG2 for binding sites on smooth LPS was shown to occur. Binding of IgM to Brucella smooth LPS with sera from uninfected animals was elevated above the assay control levels, and attempts to eliminate this nonspecific IgM binding were not successful. The same levels of nonspecific IgM binding were also seen with Brucella rough LPS, Escherichia coli LPS, and Pseudomonas solanacearum LPS. Sera from some, but not all, Brucella-infected animals showed elevated binding of IgG1 and IgM to both E. coli LPS and Brucella rough LPS as well as to Brucella smooth LPS. This was interpreted as specific antibody. Cross-reactions between B. abortus smooth or rough LPS and E. coli LPS could not be shown by immunodiffusion.

Animals↗

PubMed1979

Purification and characterization of smooth and rough lipopolysaccharides from Brucella abortus.

In an attempt to obtain pure and well characterized smooth lipopolysaccharide (S-LPS) and rough lipopolysaccharide (R-LPS), smooth and rough strains of Brucella abortus were extracted by two different modifications of the phenol-water method. S-LPS was obtained in the phenol phase, and R-LPS was obtained in the aqueous phase. Further purification was accomplished by treatment with enzymes, detergents, NaI as a chaotropic agent to separate non-covalently bound contaminants, and by gel filtration. The degree of purity of the molecules was determined by chemical and immunological analysis and by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. Lipid identification by gas-liquid chromatography showed seven major fatty acids. Palmitic acid accounts for about 50%, stearic acid accounts for about 10%, and hydroxylated fatty acids account for less than 5% of total fatty acids. 2-Keto-3-deoxyoctonate but not heptose was detected in the sugar analysis. Protein was found to be firmly bound to S-LPS but not to R-LPS.

Antigens, Bacterial↗

PubMed1979

Brucella abortus lipopolysaccharide is mitogenic for spleen cells of endotoxin-resistant C3H/HeJ mice.

Preparations of lipopolysaccharide (LPS) from rough and smooth strains of Brucella abortus were mitogenic for spleen cells of athymic nude mice, C3H/HeAU mice, and the endotoxin-resistant C3H/Hej mice. The mitogenic response induced by crude smooth-LPS (f5) was greater than that produced by purified smooth-LPS (f5p); however, the dose-response curves were similar for both preparations. The mitogenic activity of mouse spleen cells to both f5 and f5p was higher than that produced by stimulation with purified rough-LPS. The dose-response curves with rough-LPS were also qualitatively different from those produced with the preparations of smooth-LPS.

Animals↗

PubMed1978

Antibody response to antigens distinct from smooth lipopolysaccharide complex in Brucella infection.

The smooth lipopolysaccharide complex of the outer surface of smooth Brucella abortus cells is believed to be the antigenic component involved in serological tests routinely used for the diagnosis of brucellosis. Sera from cattle vaccinated or infected with B. abortus generally contain antibody directed toward the smooth lipopolysaccharide complex. The brucella organism contains a large number of other antigenically distinct components. The biological significance of some of these antigens has been demonstrated by showing that sera from infected cattle have precipitins to these components. These sera revealed up to seven distinct lines in immunoelectrophoresis with a protein-rich antigen mixture prepared from rough strain B. abortus 45/20, whereas sera from strain 19-vaccinated cattle did not reveal these lines at 4 or more months after vaccination. Monospecific antisera were prepared against six antigens in this mixture, and the purification of two of them by antibody affinity chromatography is described.

Animals↗

PubMed1978

Isolation of Erysipelothrix rhusiopathiae from tonsils of apparently normal swine by two methods.

Erysipelothrix rhusiopathiae was isolated from the tonsils of 62 of 63 (98%) apparently normal pigs, using 2 procedures: (1) enrichment culture at 5 C followed by mouse inoculation, and (2) Wood's technique. There was no significant difference (P less than or equal to 0.01) in the sensitivity of erysipelothrix detection between the 2 procedures. Each of the isolates selected for identification had morphologic and tinctorial properties consistent with E rhusiopathiae and was identified by direct immunofluorescence.

Animals↗

PubMed1976

Endotoxic activity of rough organisms of Brucella species.

A rough-specific antigen extracted from the rough species Brucella ovis and lipopolysaccharide extracted from smooth Brucella abortus demonstrated equivalent levels of activity in tests for mouse lethality and limulus lysate clotting activity. Acetone-extracted whole cells of B. ovis and of B. canis and of a rough mutant of B; abortus had the same toxicity for mice, but it was not possible to extract endotoxin from B. canis by the methods used.

Animals↗

PubMed1976

Studies of Brucella lipopolysaccharide.

Brucella endotoxin differs from other gramnegative endotoxins in that it is recovered in the phenol phase rather than the aqueous phase of the Westphal hot phenol water procedure. This was the first described from this laboratory by Redfearn (1960) with phenol-killed smooth B. abortus and B. melitensis and has since been confirmed by others. Preliminary extraction of brucella cells with acetone, as called for in the original Westphal procedure, was followed by Renoux et al. (1973) who reported that the aqueous phase lacked endotoxic activity and the phenol phase had very low toxicity. In order to test the hypothesis that prior acetone extraction removes lipid A, we have repeated the Redfearn procedure with acetone extracted cells and have confirmed that the major portion of the endotoxic activity resides in the phenol phase. Acetone treatment does not remove the lipid A believed to be responsible for mouse lethality as well as necrotizing activity in guinea pig and rabbit skin. Preparations of brucella endotoxin (lipopolysaccharide) contain varying amounts of polypeptide some of which is tightly bound. The dermal response of sensitized guinea pigs to brucella LPS was shown to be a combination of reactions comprising those due to (1) innate toxicity of lipid A, (2) antibody mediated reactions due to polysaccharide portion of the molecule and (3) delayed hypersensitivity due to polypeptide portion of the molecule.

Antigens, Bacterial↗

PubMed1976

The role of living vaccines in prophylaxis.

Although strain 19 vaccine has been widely recognized as the most effective vaccine for the control of bovine brucellosis, its use in the United States has declined in the last ten years. When the national level of infection was reduced to 1%, it was believed possible to move towards complete eradication of bovine brucellosis. The continued use of strain 19 vaccine was thought to interfere with the goal of complete eradication because: 1. persistence of serum agglutination titers in some animals caused confusion in the serological diagnosis, 2. occasional persistence of strain 19 infection in adult animals caused reactions in surveillance tests which required follow-up herd tests, 3. vaccination was reported to "mask" virulent infection in a herd by prolonging the incubation period. These perceived disadvantages of strain 19 are discussed in relation to the benefits derived from its use in infected areas. In the last ten years the number of calves vaccinated with strain 19 has steadily declined, whereas the national average of infected cattle has remained stationary. The level of infection in some areas has increased however. The date for complete eradication of bovine brucellosis in the United States has had to be postponed. A retrospective examination of the brucellosis eradication program shows that in general those states which vaccinated 40% or more of their eligible calves with strain 19 were able to eradicate brucellosis. States which still have a bovine brucellosis problem, in general, have never employed wide-scale vaccination. Other factors contributing to these differences in the progress of eradication will be discussed. The important role of strain 19 in the successful eradication of bovine brucellosis in some areas of the United States has been the reduction in the level of infection to the point where eradication was economically feasible.

Animals↗

PubMed1976

Multiplication of Staphylococci in vitro in normal and mastitic milk from vaccinated and nonvaccinated cows.

Mastitis was induced by injection of cell walls of Staphylococcus aureus into the mammary glands of normal cows and of cows which had been vaccinated parenterally with a staphylococcal bacterin in adjuvant. Multiplication of S aureus in normal milk and in mastitic milk from vaccinated and nonvaccinated cows was determined in constant volume cultures. Growth was significantly inhibited during the 1st 6 hours of incubation, regardless of the nature of the milk or the vaccination status of the cows. Growth was inhibited for 24 hours in normal milk, and the organisms grew exponentially in mastitic milk regardless of the vaccination status of the cows.

Animals↗

PubMed1975

Antibody-mediated and delayed-type hypersensitivity reactions to Brucella skin test antigens in guinea pigs.

Cutaneous hypersensitivity responses to brucella antigens of different composition were studied in guinea pigs sensitized by infection with smooth brucella or immunization with killed rough brucella in adjuvant. These animals had circulating antibodies to smooth lipopolysaccharide or protein antigens, respectively. Intradermal skin tests, active cutaneous anaphylaxis, passive cutaneous anaphylaxis, and immunodiffusion tests were performed. Delayed-type hypersensitivity reactions uncomplicated by accompanying antibody-mediated reactions were seen only in infected guinea pigs with protein antigen that was entirely free of lipopolysaccharide. In the adjuvant-immunized animals, the protein antigen evoked overlapping antibody-mediated and delayed-type reactions. Lipopolysaccharide and polysaccharide preparations contained varying amounts of protein components. In infected animals, reactions of these antigens were clearly antibody mediated, but participation of delayed-type hypersensitivity could not be excluded. In adjuvant-immunized animals, the antibody-mediated reaction to the lipopolysaccharide preparation was caused by its protein component.

Animals↗

PubMed1975

Leukocyte response of bovine mammary gland to injection of killed cells and cell walls of Staphylococcus aureus.

Injection of mammary glands of cows with heat-killed staphylococcal cells, staphylococcal cell walls, or distilled water induced leukocytosis. The magnitude of leukocytic response to staphylococcal antigens in cows of each treatment group depended on the extent of previous experience with staphylococcal cell materials. The 2nd intramammary injection produced greater reactions than did the 1st, and the 1st injection in cows previously parenterally vaccinated with killed cells in oil-water adjuvant produced responses comparable with those elicited by the 2nd intramammary injection in nonvaccinated cows. The implications that these changes have toward understanding the pathogenesis of, and immunity to, staphylococcal mastitis were discussed.

Animals↗

PubMed1975

Cell-mediated immune reactions in vitro to cell walls and peptidoglycan from Staphylococcus aureus.

Migration inhibition factor (MIF) was produced by peritoneal exudate (PE) cells from guinea pigs sensitized with heat-killed cells of Staphylococcus aureus cultured in vitro with staphylococcal cell walls or defined subunits of the cell walls. MIF activity was assayed by inhibition of migration of alveolar macrophages from lungs of normal guinea pigs. Specificity of inhibition was established using PE cells from tuberculin sensitive guinea pigs and tuberculin as appropriate controls. Staphylococcal cell walls, their peptidoglycan complex, and teichoic acid-peptidoglycan fragments stimulated MIF production by staphylococcus sensitive PE cells. Peptidoglycan fragments and teichoic acid were ineffective antigens.

Animals↗

PubMed1975

Cell-mediated immunity to cell wall antigens of Staphylococcus aureus in vitro. II. The production of chemotactic factor by guinea pig peritoneal exudate cells.

Peritoneal exudate cells from sensitized guinea pigs were incubated in culture with staphylococcal cell walls. Filtered supernatant fluids from the cultures were chemotactic for horse leukocytes. Maximum chemotactic activity was observed in supernatant fluids of cultures incubated 1.5 hours. Activity disappeared after 4.5 and 18 hours additional incubation.

Animals↗

PubMed1975

Preparation of monospecific antiserums against porcine immunoglobulins, using agarose-linked immunosorbents.

Immunoglobulins IgG, IgA, and IgM were isolated from porcine serum and milk, and antiserums against the 3 immunoglobulin classes were prepared. Monospecificity of the antiserums for the gamma-, alpha-, and mu-chains was obtained by absorbing them in agarose-linked immunosorbent columns. These immunosorbents were prepared by linking IgG or IgA-IgM to CNBr-activated agarose. Contaminating anti-alpha2-macroglobulin antibodies in the anti-IgA and anti-IgM serums were removed with agarose-linked fetal globulins.

Absorption↗

PubMed1975

Isolation of porcine secretory immunoglobulin A by affinity chromatography and determination of its component chains.

Porcine secretory immunoglobulin A (SIgA) was isolated in a single step from porcine milk whey by affinity chromatography, using antiporcine alpha-chain specific antibody linked to CNBr-activated agarose. The isolated SIgA contained no other proteins detectable by immunodiffusion of immunoelectrophoresis. After reduction and alkylation with dithiothreitol and iodoacetamide, the SIgA was chromatographed on gel equilibrated with 6.0 M urea and 1.0 M propionic acid. Polyacrylamide gel electrohoresis of the fractions eluted revealed the presence of light chain, alpha-chain secretory component, and J-chain.

Animals↗