Evidence for T cell receptor-HLA class II molecule interaction in the response to superantigenic bacterial toxins

The staphylococcal enterotoxins and related microbial T cell mitogens stimulate T cells by cross-linking variable parts of the T cell receptor (TcR) with MHC class II molecules on accessory or target cells. In this report we describe that a given combination of T cell, accessory cell (AC) and toxin can be non-stimulatory. However, the same T cell can respond to the same toxin on another AC and the same AC can present the same toxin to another T cell. This indicates that in the complex formed between TcR, toxin and class II molecule an interaction between TcR and class II molecule takes place.     

The influence of certain drugs on the response of smooth muscle to direct electrical stimulation

Summary Neither the absence of KCl from Tyrode's solution or the presence of 2·10^–7 adrenalin or 1·10^–5 atropine altered the response of the smooth muscle of a section of guinea pigtaenia coli to direct electrical stimulation. The response was depressed by 26, 39, 42, 43, 63, and 86% through the action of 4·10^–5 spasmolytin, 1·10^–4 dimedrol, 2·10^–4 promedol, 4·10^–5 dibazol, 4·10^–5 papaverine, and by 2.5·10^–5 2,4-dinitrophenol respectively. From published reports and our own results the explanation of the spasmolytic effects of adrenalin and atropine in smooth muscle appears to be that they act by an alteration of the condition of polarization of the smooth muscle fiber membranes, whereas papaverine appears to act both on the cell membrane and on the biochemical reaction of smooth muscle.(Presented by Active Member AMN SSSR V. V. Zakusov) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 54, No. 12, pp. 57–60, December, 1962     

Laboratory preparation of plasticware to support cell culture

Summary Many plastics, including polystyrene and poly(ethylene terephthalate), are unsuitable for cell culture applications as formed because they do not support cell growth. Although cells may attach to these materials, the attached cells typically round up and detach or die after a short time. However, plastics can be made to support normal cell attachment and growth through surface modification by glow discharge processes that produce ionized gas species which react with the surface of the plastic. This article describes radiofrequency glow discharge (RFGD) modification of plastics in the presence of organic vapors such as acetone, methanol and ethylene oxide. These treatments render laboratory plastics amenable to in vitro cell culture. Successful modification is a function of RFGD reaction parameters (position within the reactor, discharge power, system pressure, flow rate, and reaction time), and can be confirmed by electron spectroscopy for chemical analysis (ESCA). Identification by high resolution ESCA of functional groups introduced onto the surface by the RFGD process can be used to correlate cell growth with surface chemistry. A brief discussion of other processes thought to be used for preparation of commercial tissue culture ware is also provided.     

The role of the inflammasome in cellular responses to toxins and bacterial effectors

Invading pathogens are recognized by mammalian cells through dedicated receptors found either at the cell surface or in the cytoplasm. These receptors, like the trans-membrane Toll-like Receptors (TLR) or the cytosolic Nod-like Receptors (NLR), initiate innate immunity after recognition of molecular patterns found in bacteria or viruses, such as LPS, flagellin, or double-stranded RNA. Recognition of molecules produced only by a specific pathogen, such as a viral envelop protein or a bacterial adhesin does not appear to occur. Bacterial protein toxins, however, might compose an intermediate class. Considering the diversity of toxins in terms of structure, it is unlikely that cells respond to them via specific molecular recognition. It rather appears that different classes of toxins trigger cellular changes that are sensed by the cells as danger signals, such as changes in cellular ion composition after membrane perforation by pore-forming toxins or type III secretion systems. The signaling pathways triggered through toxin-induced cell alterations will likely play a role in modulating host responses to virulent bacteria. We will here describe the few studied cases in which detection of the toxin by the host cell was addressed. The review will include not only toxins but also bacteria effectors secreted by the bacterium in to the host cell cytoplasm.     

The influence of some antidepressant drugs on the nuclear volume of rat cingular cortex cells in culture

The changes in the volume of cell nuclei of the rat cingular cortex were investigated in culture after incubation with some antidepressant drugs. Two-week incubation of the cingular cortex culture with both tricyclic (desipramine, imipramine, amitryptyline) and non-tricyclic (mianserin) antidepressants in concentration of 3 X 10(-6) M resulted in a decrease of the volume of the cell nuclei. Because the size of the nucleus is regarded as a criterion of the cell metabolic activity, our results may point to a diminished activity of metabolic processes of the cells.     

The levator auris longus muscle of the mouse: a convenient preparation for studies of short- and long-term presynaptic effects of drugs or toxins

We describe here the levator auris longus muscle of the mouse as a convenient neuromuscular preparation for the in vitro study of presynaptic effects of drugs and toxins applied in vivo in young or adult mice. The good visibility of its motor axons and terminals using Nomarski optics allows accurate electrophysiological studies of presynaptic signals. In addition, the levator auris longus muscle is sufficiently thin to be stained as a whole mount preparation. Preliminary results indicate that some correlation can be established between changes in time course of the presynaptic signal and the morphology of motor endings after poisoning the levator auris longus muscle with botulinum type A toxin.     

Macrophage responses to bacterial toxins: a balance between activation and suppression

Toxins secreted by bacteria can impact the host in a number of different ways. In some infections, toxins play a crucial and central role in pathogenesis (i.e., anthrax), while in other bacterial infections, the role of toxins is less understood. The cholesterol-dependent cytolysins (CDCs), of which streptolysin O is a prototype, are a class of pore-forming toxins produced by many gram-positive bacteria and have only been studied in a few experimental infection models. Our laboratory has demonstrated that CDCs have effects on macrophages that are both pro- and anti-inflammatory. Here, we review evidence that CDCs promote inflammation by driving secretion of IL-1β and HMGB-1 from macrophages in a NLRP3-dependent manner, while also causing shedding of membrane microvesicles from cells that can interact with macrophages and inhibit TNF-α release. CDCs thus impact macrophage function in ways that may be both beneficial and detrimental to the host.     

The preparation of ultrathin films for use as cell culture substrates

Summary Ultrathin films of various biocompatible materials have been used as cell culture substrates. These materials include metals and ceramics and are deposited as clean, sterile, transparent, adhesive coatings. This paper describes the method of sputter coating as a means to deposit these films and discusses the unique properties associated with these culture surfaces.     

The mechanism of protracted collapse in young animals due to the action of bacterial toxins

Summary The reactions of young puppies (ages from 1 to 18 days) and of the older ones (ages from 1.5 to 3 months) to the action of lethal doses of staphylococcus and the dysentery toxins were analyzed on the basis of EEG, EKG respiration frequency and body temperature studies. In three month puppies a rapidly developing (within 5–8 minutes) collapse is followed by death. This collapse is characterized by an almost simultaneous disappearance of the EEG rhythms, respiratory center activity and that of the heart, as well as by an insignificant reduction of the body temperature (by 2–3°C). In case of young puppies death is preceded by prolonged collapse (lasting several hours). In young animals the latter is characterized by a gradual decrease of the body temperature to the environment level with the electric activity of the brain cortex disappearing 3–5 hours previous to the death of the animal. When the body temperature is prevented from dropping, the period of protracted collapse is decreased sharply. The above observations lead to the following explanation of this fact: in a protracted collapse of young puppies the liminal (critical) temperature at which the animal dies is decreased as a result, of alteration of the nervous centers by bacterial toxins.Presented by Active Member AMN SSSR V. N. Chemigovskii     

The influence of body size on the ventilatory response to hypercapnia

The slope of ventilatory response to hypercapnia at rest was determined in 77 healthy male students by means of the CO2 rebreathing method. It was found that the hypercapnic ventilatory response slope (S) was significantly lower in the lean group with BMI (body mass index) below 19 than that in the normal group, while there were no significant correlation between S and body weight or height. These results indicate that sensitivity of hypercapnia in the lean subjects differed from that of normal and overweight subjects.     

Studies of bronchial secretion. The influence of inflammatory response and bacterial infection

Bronchial secretions obtained during bronchoscopic examination of 60 children suffering from respiratory tract infections were studied for the concentration of immunoglobulins, anti-proteolytic factors, lactoferrin, and lysozyme. Eleven children having bronchial asthma without a history of chronic or recurrent infections of the respiratory tract were designated as a control. The results were analysed in relation to clinical diagnosis (chronic bronchitis, bronchitis, bronchiectasis) or to the local status of bronchial mucosa at the time of bronchoscopy (no inflammation, inflammation, inflammation with documented bacterial infection). The statistical analysis of the results revealed a decrease of lactoferrin and locally produced IgA in the group of children suffering from bronchitis and chronic bronchitis. Samples infected with Haemophilus species had significantly higher concentration of lactoferrin than any other group. Similarly, albumin in this group was higher than in the other group except that other bacteria were present. Samples infected with Haemophilus also had increased concentrations of S-IgA, IgG, and anti-proteolytic factors when compared with the group without local inflammation.     

Uncovered: the family relationship of a T-cell-membrane protein and bacterial toxins

Mono-ADP-ribosylation was originally discovered as the mechanism by which diphtheria toxin inactivates protein synthesis. It is now apparent that higher organisms use analogous mechanisms to regulate endogenous metabolism. Here, the relationship between bacterial toxins and vertebrate mono-ADP ribosyltransferases is explored.