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PubMed1991

Lectins from Triticum vulgaris and Limax flavus are universal antagonists of botulinum neurotoxin and tetanus toxin.

Lectins from Anguilla anguilla, Artocarpus integrifolia, Canavalia ensiformis, Datora stramonium, Glycine max, Limax flavus, Ricinus communis and Triticum vulgaris were tested for their abilities to antagonize the binding of botulinum neurotoxin and tetanus toxin to rat brain membranes and to antagonize the ability of these toxins to block neuromuscular transmission in mouse phrenic nerve-hemidiaphragm preparations. Lectins from Limax flavus and Triticum vulgaris, both of which have affinity for sialic acid, were antagonists of the various serotypes of botulinum neurotoxin and tetanus toxin. When tested against the high affinity binding site for botulinum neurotoxin type B, the lectin from Limax flavus had a Ki of 3.1 x 10(-7) M and the lectin from Triticum vulgaris had a Ki of 3.75 x 10(-7) M. When tested against the high affinity binding site for tetanus toxin, the lectins from Limax flavus and Triticum vulgaris had Ki values of 1.5 x 10(-7) and 1 x 10(-6) M, respectively. In all cases the lectins behaved as competitive antagonists. In reverse experiments, neither botulinum toxin nor tetanus toxin was a very effective antagonist of lectin binding to brain membranes. Studies on isolated neuromuscular preparations showed that the lectin from Triticum vulgaris did not affect transmission at concentrations of 10(-6) to 10(-3) M, but at a concentration of 3 x 10(-5) M the lectin produced highly statistically significant antagonism of the neuromuscular blocking properties of botulinum neurotoxin types A, B, C, D, E and F as well as tetanus toxin. The lectin did not antagonize beta-bungarotoxin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

The interaction between aminoquinolines and presynaptically acting neurotoxins.

Chloroquine and hydroxychloroquine block neuromuscular transmission in isolated tissues from mouse, rat, guinea pig and chick. Blockade is associated with depressed muscle responses to potassium and abolished muscle responses to nicotinic cholinergic agonists. Within certain time and concentration limits, the blocking effects of chloroquine and hydroxychloroquine are reversible. Both drugs antagonize the onset of paralysis caused by botulinum neurotoxin types A and B, but neither drug antagonizes tetanus toxin or beta-bungarotoxin. The ability of chloroquine and hydroxychloroquine to antagonize botulinum toxin is not due to blockade of nicotinic cholinergic receptors. At concentrations that produce neuromuscular blockade, d-tubocurarine does not antagonize botulinum toxin types A and B. Chloroquine causes botulinum toxin to remain at an antitoxin sensitive site. These data could mean that chloroquine acts at the cell membrane to inhibit toxin binding or internalization, or that it acts in the cell interior to inhibit lysosomal processing of toxin. Whatever its action, chloroquine is the most effective antagonist of botulinum toxin yet described.

Aminoquinolines↗
PubMed1983

[Bacterial antibodies and isoagglutinins in intravenous immunoglobulin preparations].

Various lots of intravenous immunoglobulins for passive immunization should contain almost the same, broad, antibody profile and provoke very low frequencies of untoward reactions. From 1976-1982 a study was undertaken to measure the level of antibodies directed against tetanustoxin, diphtheriatoxin, streptolysin O, staphylolysin, and salmonella in up to 82 lots. It is interesting to note that the measured level of antibodies in intravenous immunoglobulins varied only slightly as well qualitatively as quantitatively with one exception: an immunoglobulin of placental origin. The amount of tetanusantitoxin in the majority of lots of that preparation was ten-fold lower than that of the other immunoglobulins. Intravenous immunoglobulins contain generally 3-6 IE/ml antistaphylolysin, 600-1200 IE/ml antistreptolysin O, 10-20 IE/ml tetanusantitoxin, and 1-2 IE/ml diphtheriaantitoxin. Antibodies to salmonella could not be demonstrated. Some of the lots exhibited isoagglutinins up to a dilution of 1 : 4.

Agglutinins↗
PubMed1985

Animal studies of toxic shock syndrome.

Toxic shock syndrome (TSS) was first described in 1978 and since that year over 2990 cases have been reported to the Communicable Disease Center. The estimated case-fatality rate is 5.6%. The disease is characterized by fever, hypotension, rash, desquamation, and involvement of at least three other organ systems. Approximately 85% of the cases are menstrually related and tampon use has been identified as a risk factor. The remaining 15% of the cases occur in both sexes and are not specifically related to age or geographic location. In all cases where sought there is evidence for infection by Staphylococcus aureus. Nearly all S. aureus isolates are phage type 52/29 and elaborate a unique exotoxin (toxic shock toxin). This review explores both the successful and unsuccessful attempts to induce toxic shock or a TSS-like syndrome in animals other than man. The review identifies the baboon as an animal model of TSS and discusses the clinical and pathologic sequellae, in this species, after exposure to purified toxic shock toxin.

Animals↗
PubMed1964

THE ROLE OF TEMPERATE BACTERIOPHAGE IN THE PRODUCTION OF ERYTHROGENIC TOXIN BY GROUP A STREPTOCOCCI.

Non-lysogenic, non-toxinogenic Group A streptococci when infected by temperate bacteriophages isolated from known scarlatinal toxin-producing strains acquire the capacity to form erythrogenic toxin. This toxin causes a characteristic erythematous reaction in the skin of rabbits and is readily neutralizable by standard scarlatinal antitoxins. The production of toxin appears to be related to the synthesis of mature phage particles since ultraviolet enhancement of phage production results in a concomitant increase in toxin titer. In contrast, there is no increase in the production of another extracellular product, deoxyribonuclease, by these lysogenized streptococci. Furthermore, cellular disruption studies indicate that the toxin probably does not exist in a preformed state within the cell. Double diffusion reactions in agar indicate that a newly formed protein appears in the lysogenic culture filtrate and is absent in the non-lysogenic filtrates.

Animals↗
PubMed1987

Protection against cholera toxin after oral immunization is thymus-dependent and associated with intestinal production of neutralizing IgA antitoxin.

We studied whether gut mucosal IgA antitoxin production as well as the acquired protection against cholera toxin (CT) after oral immunization with CT are both thymus-dependent immune manifestations. In contrast to normal BALB/c mice, nude, athymic mice did not respond to oral immunizations with CT with either IgA antitoxin-producing cells (SFC) in the lamina propria or protection against challenge with CT in ligated intestinal loops. However, when nude mice were first reconstituted by grafting of syngeneic thymus glands, both IgA antitoxin SFC in the lamina propria and protection were stimulated by oral immunizations with CT and the response were of similar magnitude to those of normal mice after immunizations. During in vitro culture, isolated lamina propria lymphocytes from immunized but not from control mice concomitantly and proportionally produced IgA antitoxin and CT-neutralizing activity. We conclude that intestinal antitoxin formation and protection against toxin challenge after oral immunization with CT are both critically thymus-dependent and therefore likely to be under T-cell control.

Animals↗
PubMed1957

The assay of diphtheria toxin.

A precise assay of diphtheria toxin is described, based on the linear relationship between the diameter of the skin reaction to, and logarithm of the dose of, toxin. It eliminates the need for preliminary titrations, is economical, provides information about the slope of the log-dose response lines and, therefore, of the validity of the assay, and yields limits of error of potency from the internal evidence of the assay.A study has been made of the effects of avidity, combining power, toxicity and buffering on the assay of diphtheria toxins against the International Standards for both Diphtheria Antitoxin and Schick-Test Toxin.All the toxins assayed against the standard toxin, whatever their other properties might be, gave log-dose response lines of similar slope provided that they were diluted in buffered physiological saline. The assays were therefore valid.These experiments were repeated concurrently in non-immune and in actively immunized guinea-pigs, and comparable figures for potency obtained in both groups. The result was not significantly affected by the avidity or combining power of the toxin.However, non-avid toxins gave low values in Schick units when assayed, by the Römer & Sames technique, in terms of the International Standard for Diphtheria Antitoxin. The problem of the ultimate standard and the implications of these findings are discussed.

Biological Assay↗
PubMed2003

Characterization of the interactions within the mazEF addiction module of Escherichia coli.

In bacteria, programmed cell death is mediated through the unique genetic system called "addiction module," which consists of a pair of genes encoding a stable toxin and an unstable antitoxin. The mazEF system is known as an addiction module located on the Escherichia coli chromosome. MazF is a stable toxin, and MazE is a labile antitoxin interacting with MazF to form a complex. MazE and the MazE-MazF complex can bind to the mazEF promoter region to regulate the mazEF expression. Here we show that the binding of purified (His)6MazE to the mazEF promoter DNA was enhanced by MazF. The site-directed mutations at the conserved amino acid residues in MazE N-terminal region (K7A, R8A, S12A, and R16A) disrupted the DNA binding ability of both (His)6MazE and the MazE-MazF-(His)6 complex, suggesting that MazE binds to the mazEF promoter DNA through the N-terminal domain. The ratio of MazE to MazF(His)6 in the MazE-MazF(His)6 complex is about 1:2. Because both MazE and MazF-(His)6 exist as dimers by themselves, the MazE-MazF-(His)6 complex (76.9 kDa) is predicted to consist of one MazE dimer and two MazF(His)6 dimers. The interaction between MazE and MazF was also characterized with the yeast two-hybrid system. It was found that the region from residues 38 to 75 of MazE was required for its binding to MazF. Site-directed mutagenesis at this region revealed that Leu55 and Leu58 play an important role in the MazE-MazF complex formation but not in MazE binding to the mazEF promoter DNA. The present results demonstrate that MazE is composed of two domains, the N-terminal DNA-binding domain and the C-terminal domain interacting with MazF.

Amino Acid Sequence↗