Sensitivity of Blood Cells to Allergens
Testing of Allergic Reactions in Vitro Individual Sensitivity of Blood Cells to Allergens with the Help of Dielectrophoresis
Tech Area / Field
- MED-DID/Diagnostics & Devices/Medicine
- BIO-CGM/Cytology, Genetics and Molecular Biology/Biotechnology
3 Approved without Funding
State Research Center of Virology and Biotechnology VECTOR, Russia, Novosibirsk reg., Koltsovo
- RAMS / Siberian Branch of Russian Academy of Medical Sciences / Institute of Clinical Immunology, Russia, Novosibirsk reg., Novosibirsk
- Bio-ID Diagnostics, Inc, USA, OH, Cleveland
Project summaryAllergic reactions to medications present a serious medical problem. True allergic reactions to medicaments occur with a frequency of 1:10.000. At the same time according to the data obtained by different authors the incidence of hypersensitivity to medications among the patients receiving a drug therapy in hospital conditions ranges from 7 to 15%. Among the drugs causing allergic reaction most frequently are first of all antibiotics of penicillin series having a в-lactam ring in their structure, sulfanilamide, nonsteroid antiphlogistic, and antispasmodic medications [1-5]. It should be noted that the problem of allergen diagnostics in vitro and determination of inpidual sensitivity of population is of great importance for production of antibiotics in industrial scale.
Diagnostic methods existing at present are directed to revealing a certain effector mechanism (IgE-depended or caused by Т-cells), or certain clinical effects of the reactions of immediate type (e.g., quick formation of blisters in the skin sample) or delayed type (in the form of postponed development of papulous eruption in the skin sample). Probably for this reason the skin samples and different laboratory methods (radioallergosorbent test, evaluation of allergen-induced activation of basophiles and production of inflammatory mediators by them) in spite of sufficiently high specificity (SP 83-93%) are characterized by relatively low sensitivity (SN at a level of 25-35%). In many cases only combined use of several tests allows the sensitivity of laboratory diagnostics of drug allergy to be improved up to 60-70%. The method of estimation of inpidual sensitivity to drugs by the test of blast transformation in vitro (SP 85%, SN 78%) is an exception, however the use of this method is limited by technical complexity and duration of the test performance [1-22].
Therefore development of simple, easy to use and high-sensitive methods for in vitro testing allergens is still an urgent problem.
The data accumulated in literature demonstrate that a single cell is a universal system high sensitive to the action of different external factors, which change the physical and chemical characteristics of a cell and thus affect its biological activity. The drug allergens are related to these factors [23-29]. It is commonly supposed at present that an antigen plays a role of the first signal on the cell membrane. Many processes of reconstruction resulting in formation of signal substances, mediators occur in membrane. In a sensibilized organism practically any blood cell (erythrocyte, neutrophile, basophile, eosinophile, monocyte and lymphocyte) is able at a certain level to respond to introduction of specific allergen by alteration of its physical and chemical characteristics with the help of different mechanisms that underlie the development of the I, II, and IV class allergic reactions [1-23]. That is why the method of dielectrophoresis is a promising approach to in vitro testing inpidual sensitivity to the allergens. The essence of the method is as follows. Cell suspension is exposed to non-uniform alternating electric field (NUAEF). Inpidual interaction of a single cell with electric field is accompanied by polarization. An induced dipole moment arises in the cell volume. The values of dipole moment and coefficient of polarization depend on amplitude-frequency characteristic of electric field as well as on the physical and chemical parameters of cell itself. The following effects are observed in NUAEF: translational motion of cells and their deposition on electrodes; orientation of cells along the electric field line; formation of the cell cooperation chains; cell deformation; rotation of single cells; cooperative revolution of cells relatively to each other.
Researches performed in SRC VB Vector in cooperation with the Institute of Clinical Immunology, Siberian Branch of Russian Academy of Medical Science have shown that the interaction of mononuclears with, for example, mitogen (concavalin A) alters considerably their physical, chemical and viscoelastic properties. The pattern of cell behavior in the NUAEF changes as early as at the first minutes of the interaction. It should be noted that the accumulated experimental data regarding this effect are scanty.
The complex pattern of the behavior of a single cell in NUAEF connected with its inpidual physical and chemical characteristics as well as the possible alterations in the cell characteristics resulting from its interaction with the drug allergens can be used as a basis for development of a new method for in vitro testing allergens and inpidual drug sensitivity determination using dielectrophoresis.
The aim of the project is to develop the real time method for in vitro testing of allergens on the basis of measurements of physical characteristic of cells in non-uniform alternating electric field.
The method that will be developed in the course of project pursuance will allow the material and time costs of testing allergens in vitro and determination of inpidual drug sensitivity to be decreased considerably. Thus the method will significantly facilitate the instrumental control of the patient treatment efficiency. Besides, according to our estimations the given method will be characterized by a high reliability of the diagnostics of drug allergy independently on the specificity of effector mechanisms realized through IgE antibodies or specific T cells, or clinical manifestation pattern in the form of hypersensitivity reactions of immediate or delayed type in each patient. Thus it can be supposed that the indicated method will be characterized by a high sensitivity and selectivity as well as simplicity in use. It will serve as a basis for a new line of technology connected with the development of high sensitive devices for allergen diagnostics. The above-formulated aim is supposed to be achieved by the efforts of 48 specialists of SRC VB “Vector” and Institute of Clinical Immunology, SB RAMS.
It is planned that after completion of the project the stage of application of its results in practice will be performed in cooperation with the company BIO-ID Diagnostics, Inc. (CAMP Manufacturing and Technology Complex 1768 E.25th Street, Cleveland, Ohio 44114, USA) and Institute of Clinical Immunology of SB RAMS.
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