Biomedical subjects

M S Bergdoll

Publications and source records attributed to M S Bergdoll.

At least 55 records · Page 3Linked to original sources

PubMed1986

Detection of staphylococcal enterotoxins by enzyme-linked immunosorbent assays and radioimmunoassays: comparison of monoclonal and polyclonal antibody systems.

Murine monoclonal antibodies reactive with at least one of the serological types of staphylococcal enterotoxin were examined for use in assay systems for the detection of enterotoxin at the level of 1.0 ng of enterotoxin per ml. An antibody sandwich enzyme-linked immunosorbent assay was devised for each toxin type by identifying an effective antibody pair. One antibody (the coating antibody) was coated onto a polystyrene plate and removed the enterotoxin from the test solution; the second antibody (the probing antibody) was conjugated to horseradish peroxidase and detected the captured toxin. Enterotoxins A and E could be detected in the same system by the use of cross-reacting monoclonal antibodies. All subtypes of enterotoxin C could be detected in one assay system. Two effective systems were described for each of types B and D. Each of these systems, when compared with the homologous enterotoxin-specific polyclonal rabbit antibody systems, was found to compare favorably. The monoclonal enzyme-linked immunosorbent assay systems for the detection of enterotoxins A and C2 were examined for a variety of food extracts; no abnormal interference could be detected from these extracts. The monoclonal antibody systems were also compared with the homologous enterotoxin-specific polyclonal serum for the detection of enterotoxin by the competitive radioimmunoassay (RIA). Single monoclonal antibodies generally did not perform as well in the RIA as did the homologous toxin-specific polyclonal serum. However, pools of monoclonal antibodies were prepared that approached the sensitivity and precision of the polyclonal system for the detection of each toxin by the RIA.

Animals↗

PubMed1986

Involvement of coagulase-negative staphylococci in toxic shock syndrome.

Coagulase-negative staphylococci that produce toxic shock syndrome toxin 1 (TSST-1) or a staphylococcal enterotoxin or both were isolated from various sources. Coagulase-negative strains that produce TSST-1 alone or with enterotoxin A were the only staphylococci isolated from seven patients with toxic shock syndrome. Two other toxic shock syndrome patients had coagulase-positive staphylococci also, but only the coagulase-negative strains produced TSST-1. Coagulase-positive and coagulase-negative strains that produced TSST-1 were isolated from two other toxic shock syndrome patients. In addition, coagulase-negative staphylococci that produced toxins were isolated from patients with other staphylococcal infections and from food implicated in a case of food poisoning.

Bacterial Toxins↗

PubMed1986

Latex agglutination test for staphylococcal toxic shock syndrome toxin 1.

A reversed passive latex agglutination method, in which latex particles were sensitized with specific anti-toxic shock syndrome toxin-1 (TSST-1) immunoglobulin, was found to be a simple and sensitive method for the detection of TSST-1 production by Staphylococcus aureus strains. The minimum amount of TSST-1 detectable was approximately 1.0 ng/ml. Of 41 S. aureus isolates from toxic shock syndrome patients and controls, 23 were positive for TSST-1 production, whereas only 20 strains were positive for TSST-1 production by an Ouchterlony immunodiffusion method. The reversed passive latex agglutination method was used to examine S. aureus strains isolated in Japan from staphylococcal infections, feces from healthy individuals, food from poisoning outbreaks, and market food.

Bacterial Toxins↗

PubMed1986

Involvement of staphylococcal enterotoxins in nonmenstrual toxic shock syndrome.

Adequate evidence is available to show that the major toxin responsible for toxic shock syndrome (TSS) is TSS toxin 1 (TSST-1). More than 90% of the staphylococcal strains isolated from TSS patients produce this toxin. However, approximately 60% of these strains produce one or more of the staphylococcal enterotoxins, with a number of them producing only enterotoxin, primarily enterotoxin B. Of 55 staphylococcal strains isolated from nonmenstrual cases, 46 produced TSST-1; 42 produced one of the enterotoxins, including 8 that produced only enterotoxin B. The fact that the enterotoxins can produce in monkeys many signs and symptoms similar to those observed in TSS in humans implicates them as the cause of some cases of TSS.

Adolescent↗

PubMed1986

Antibodies to staphylococcal enterotoxins and toxic shock syndrome toxin 1 in sera of patients and healthy people in Rio de Janeiro, Brazil.

Sera from 33 persons with staphylococcal infections and from 37 healthy persons were surveyed for the presence of antibody to staphylococcal enterotoxins A, B, C, D, and E and toxic shock syndrome toxin 1. Thirty-one (93.9%) of the patients and 35 (94.6%) of the control group had antibodies to one or more of the enterotoxins. The numbers of patients with antibody to the enterotoxins were as follows: A, 8; B, 9; C, 7; D, 17; E, 21; and toxic shock syndrome toxin 1, 11. The numbers of healthy individuals with antibody to the enterotoxins were as follows: A, 6; B, 12; C, 8; D, 27; E, 21; and toxic shock syndrome toxin 1, 9.

Antitoxins↗

PubMed1986

Production of human and murine interleukin-2 by toxic shock syndrome toxin-1.

Toxic shock syndrome toxin-1 (TSST-1), isolated from Staphylococcus aureus strains associated with toxic shock syndrome (TSS), is known as a potent mitogen and interleukin-1 inducer. The potential of TSST-1 as an interleukin-2 (IL-2) inducer was tested on human peripheral blood lymphocytes (HPBL) and murine spleen lymphocytes (MSL). These cells were incubated with TSST-1 and the supernatants analysed for IL-2 production. Preincubation of IL-2-dependent indicator cells (IC) with a monoclonal antibody specific for murine IL-2 receptors inhibited their proliferation by supernatants of TSST-1-treated MSL, thus strongly suggesting that they contain IL-2. The concentrations of TSST-1 required for HPBL or MSL to produce IL-2 ranged between 10(-1) and 10(-4) micrograms/ml. The amount of IL-2 units/ml varied little from one experiment to another. In contrast, IL-2 production by PHA-stimulated HPBL or Con A-stimulated MSL showed great variability and dependence on mitogen concentration. T-cell depleted MSL exposed to TSST-1 produced less IL-2. Experiments with germ-free mice and TSST-1-primed mice demonstrated that IL-2 production is not related to TSST-1 antigenicity.

Adult↗

PubMed1985

Development of serum antibody to toxic shock toxin among individuals with toxic shock syndrome in Wisconsin.

The presence of Staphylococcus aureus producing toxic shock toxin (TST) and the absence of antibody to TST (anti-TST) in acute-phase sera are markers for toxic shock syndrome (TSS). We used radioimmunoassay methods to examine 133 acute-phase and 277 convalescent-phase serum specimens from 181 patients with TSS for anti-TST. Among confirmed menstrual cases, nine (9.5%) of 95 patients had demonstrable anti-TST in acute-phase sera obtained during the first seven days of illness; patients with probable or non-menstrual TSS had a higher prevalence of anti-TST in acute-phase sera. Five (33.3%) of 15 individuals with confirmed menstrual TSS developed anti-TST as early as seven to nine days after TSS onset; 32 (62.7%) of 51 patients had demonstrable anti-TST in sera obtained more than one year after their episode of TSS. This study demonstrates a gradual rate and low magnitude of development of anti-TST after TSS and supports the diagnostic usefulness of measuring anti-TST levels in sera from patients suspected of having TSS.

Acute Disease↗

PubMed1985

Fibronectin enhances transfection of Staphylococcus aureus.

The factor in normal sera primarily responsible for the enhancement of transfection (and transformation) of Staphylococcus aureus was identified as fibronectin. Serum samples which were depleted of fibronectin by affinity chromatography showed a marked decrease in enhancing activity. Fibronectin isolated from sera of several animal species demonstrated enhancing activity.

Animals↗

PubMed1985

Spontaneous occurrence of Staphylococcus aureus mutants with different pigmentation and ability to produce toxic shock syndrome toxin 1.

Spontaneous mutants that have pigmentation different than that of their parents were isolated from three Staphylococcus aureus strains associated with toxic shock syndrome. These mutants produced toxic shock syndrome toxin 1 in amounts varying from less than 0.05 to greater than 25 times that produced by the parents. The occurrence of nonpigmented variants may be overlooked if only one isolate from a patient with toxic shock syndrome is selected for analysis.

Bacterial Toxins↗

PubMed1985

Toxic shock syndrome--the role of the toxin.

From isolates of Staphylococcus aureus derived from patients suffering from toxic shock syndrome a toxin was identified by tests in monkeys and was found to be distinct from the enterotoxin responsible for staphylococcal food poisoning. When purified, this TSS toxin (TSST-1) was characterised and used to generate antibodies in rabbits. Only a small proportion of routine staphylococcal isolates produce TSST-1, though it is clear that this toxin has existed for some years. At the same time, TSST-1 producing staphylococci have been isolated in every continent, yet very few cases of toxic shock syndrome have been recognised in developing countries. Using the purified TSST-1, human sera have been examined for the presence of antibodies. Patients with the disease had either no antibodies, or low titres.

Animals↗

PubMed1984

Analysis of the mitogenic effects of toxic shock toxin on human peripheral blood mononuclear cells in vitro.

It has been shown previously that the staphylococcal enterotoxins A and B are T-cell mitogens and also cause inhibition of murine plaque-forming cells generated in vitro. Similarly, toxic shock toxin, a 24,000-MW protein produced by toxic shock-associated strains of Staphylococcus aureus, is mitogenic and inhibits the generation of both murine and rabbit plaque-forming cells. In this study, an analysis of the T-cell response to toxic shock toxin was performed. Human peripheral blood mononuclear cells responded to toxic shock toxin over a broad dosage range (1 ng/ml to 5 micrograms/ml) with maximum proliferation at day 4 (96 hr) of culture. Heat treatment (100 degrees C for 60 min) of toxic shock toxin attenuated its mitogenic effects by only a small amount, and this attenuation could be reversed with increasing concentration of the toxin. By cytofluorography, both untreated and toxic shock toxin-treated small lymphocytes manifested normal percentages of OKT3+, OKT11+, OKT4+, OKT8+, HLA/DR+, and Leu-7+ cells. However, toxic shock toxin-induced blasts were 99% OKT11+ and expressed the receptor for interleukin 2 (89%-100% TAC+). Approximately 85% of the blasts were OKT4+, and 25% of the blasts were OKT8+. Proliferation of purified, double-rosetted T cells was enhanced monotonically by the addition of irradiated "non-T" cells. Irradiated, monocyte-enriched non-T cells were 2.5 times more potent than unfractionated non-T cells in producing quantitatively similar proliferation by toxic shock toxin-stimulated, autologous T cells. In addition, preincubation of non-T cells for 24 hr with toxic shock toxin, followed by extensive washing and irradiation, induced substantial proliferation by unexposed, autologous T cells. These data show that toxic shock toxin is mitogenic for T cells and requires accessory cells for maximal activity. Further, this substance appears to induce both a subset of OKT4+ (Class II MHC-restricted) and OKT8+ (Class I MHC-restricted) blasts.

Antigen-Presenting Cells↗

PubMed1984

Staphylococcal enterotoxin A gene is associated with a variable genetic element.

The genetic determinant of Staphylococcus aureus enterotoxin A (SEA) has been cloned in pBR322 in Escherichia coli and found to be expressed and secreted into the periplasmic space in that organism. The SEA gene (entA) is within a 2.5-kilobase-pair HindIII fragment that is part of a discrete genetic element 8-12 kilobase pairs in length. This entA element has a standard chromosomal location [between the purine (pur) and isoleucine-valine (ilv) markers] in most S. aureus strains. In some strains it is unlinked to pur-ilv. However, its internal structure is conserved at different locations. Some naturally occurring SEA-nonproducer (EntA-) strains lack the entire entA element, and one instance of its spontaneous loss is reported. Other naturally occurring strains have EntA- structural variants of the element at the same pur-ilv location at which the intact element is most commonly found. Some of these strains are EntA-, others are EntA+; the latter have a second, unlinked copy of the element containing their functional entA gene. These results suggest that entA is associated with a structurally unstable, possibly mobile, discrete genetic element.

DNA Restriction Enzymes↗

PubMed1984

Spread of a toxic-shock syndrome-associated strain of Staphylococcus aureus and measurement of antibodies to staphylococcal enterotoxin F.

A gentamicin-resistant isolate of Staphylococcus aureus producing staphylococcal enterotoxin F (SEF) was isolated from a burn unit nurse during three episodes of toxic-shock syndrome (TSS). The nurse's reciprocal titer of antibodies to SEF was less than or equal to 5 during the three episodes, and when the titer rose to 1,000 no further relapses occurred despite continued colonization. The unusual antibiotic susceptibility pattern of the organism enabled demonstration of its spread. During four months, 12 (41%) of 29 burn unit patients, three other burn unit nurses, and a household contact of the nurse with TSS became colonized. None, including two patients whose initial reciprocal titers were less than or equal to 5, developed TSS. This experience illustrates significant cross-transmission of a TSS-associated strain and a temporal association of antibodies to SEF with cessation of recurrences of TSS. Additional factors must explain why other individuals lacking antibodies to SEF did not develop TSS.

Adult↗

PubMed1984

Study of staphylococcal toxic shock syndrome toxin in human epithelial cell culture.

Staphylococcal toxic shock syndrome toxin (TST) inhibited growth of normal human epithelial (Chang) cells in culture, increasing the generation time 28% and 64% at concentrations of 4 X 10(-7)M and 8 X 10(-7)M, respectively. Fluorescence and electron microscopy of the cells treated with TST revealed the location of TST in the coated pits, specialized areas of the cell membrane known to contain high-affinity receptors for other polypeptide ligands. TST was labeled with 125I without detectable damage to the molecule and was shown to bind specifically to epithelial cells. A 100-fold excess of unlabeled TST inhibited binding of 125I-labeled toxin to the cells. Binding data indicated 10(4) receptor sites per cell for TST and a dissociation constant of 4 X 10(-9)M. Specific high-affinity binding of 125I-labeled TST to epithelial cells and the location of receptor sites in coated pits implies a possibility that the toxin is internalized by receptor-mediated endocytosis.

Animals↗

PubMed1984

Isolation and some properties of an enterotoxin produced by Bacillus cereus.

Extracellular proteins produced by Bacillus cereus B-4ac were separated by chromatography on Amberlite CG-400, QAE-Sephadex, Sephadex G-75, and hydroxylapatite. A fraction, containing three detectable antigens, obtained from chromatography on hydroxylapatite caused fluid accumulation in ligated rabbit ileal loops, was dermonecrotic to rabbit skin, was cytotoxic to cultured cells, and was lethal to mice after intravenous injection. Two other fractions obtained from chromatography on hydroxylapatite showed essentially no toxic activity when tested individually. Each nontoxic fraction contained two of the three proteins present in the toxic material. When the two nontoxic fractions were combined, activity in all of the biological assays was observed. Antiserum against either of the nontoxic fractions neutralized the dermonecrotic response of the combined material. These results suggest that all of these biological activities probably are due to a single entity and that more than one component probably comprise the toxic entity.

Animals↗

PubMed1984

Effects of staphylococcal enterotoxin A on the rat gastrointestinal tract.

Staphylococcal enterotoxin A (SEA) was administered orally (15 micrograms) to two groups of rats. A marked immune reaction was evoked in the stomach and proximal small intestine of the first group. The second group of rats was used to study the absorptive fate and sites of action of orally administered SEA, utilizing immunoperoxidase staining. After oral dosing of the second group of rats. SEA-related immunoperoxidase staining was confined to: (i) neutrophils and macrophages, principally in the duodenum, and (ii) glomerular neutrophils and cells of the proximal convoluted tubules. Peroxidase staining of the kidney was noted within 15 min of exposure, indicating that SEA or some major postabsorption antigenic product can promptly pass through an intact gastrointestinal mucous membrane and become renally localized. Intestinal and renal detoxification and removal was indicated by an absence of detectable antigen in rats 180 min postexposure. Neuronal binding of SEA in the gastrointestinal tract was not demonstrable.

Animals↗

PubMed1984

Monoclonal antibodies to staphylococcal enterotoxins B and C: cross-reactivity and localization of epitopes on tryptic fragments.

Murine monoclonal antibodies reactive with staphylococcal enterotoxins B (SEB) and C1 (SEC1) were isolated by hybridoma techniques. Of the nine antibodies, three reacted only with SEB, two reacted with SEB and SEC1, three reacted with all subtypes of SEC, and one reacted only with SEC2 and SEC3. All of the antibodies reacted with protein blotted onto nitrocellulose from electrophoresis gels which corresponded to the enterotoxin band. Fragments of SEB and SEC1 were generated by limited digestion of the toxin with trypsin. With the immunoblot technique, four of the five antibodies reactive with SEB reacted with the tryptic fragment of molecular weight 17,000, and the five antibodies reactive with SEC1 reacted with the tryptic fragment of molecular weight 14,000.

Animals↗

PubMed1984

Staphylococcal toxic shock toxin specifically binds to cultured human epithelial cells and is rapidly internalized.

Staphylococcal toxic shock syndrome toxin (TST) was labeled with 125I under mild conditions without apparent destruction of the molecule. [125I]TST bound specifically to human epithelial (Chang) cells in culture; the binding was inhibited by a 100-fold excess of unlabeled toxin. Scatchard analysis of the binding data indicated about 10(4) receptor sites per cell and a dissociation constant (Kd) of 4 X 10(-9) M. When cells pretreated with TST at 4 degrees C were swiftly transferred to 37 degrees C, the amount of surface-bound toxin rapidly declined, as determined by release of noninternalized label from the cell surface. Half-time (t1/2) of internalization was about 1.5 min. Ultrastructural studies showed that toxin labeled with ferritin-conjugated antibodies entered the cytoplasm via coated pits forming coated vesicles in the first 2 min of incubation at 37 degrees C. The coated vesicles coalesced with transport vesicles that are ultrastructurally unlike receptosomes. Thus, the unusual ultrastructural pattern of this internalization suggests that TST is initially internalized by receptor-mediated endocytosis and then enters an alternate pathway involving translocation in special transport vesicles, perhaps to other cells.

Bacterial Toxins↗