Pierre Grabar

Méthode immuno-électrophorétique d'analyse de mélanges de substances antigéniques

Resume On effectue dabord une electrophorese du produit a etudier dans un gel de gelose a 1.5–2% dans un tampon veronal de λ 2 = 0.05 et aved une chute de potentiel de 3–4 V/cm dans le gel. On fait ensuite diffuser des immunserums precipitants perpendiculairement a laxe de migration electrophoretique. Chaque constituant du melange etudie donne une bande de precipitation specifique independante, ce qui permet de le distinguer grâce a sa specificite immunologique et de le definir par sa mobilite electrophoretique relative. Les details techniques sont decrits et les possibilites de la methode sont discutes.

Autoantibodies and the physiological role of immunoglobulins

In this article Pierre Grabar returns to the proposal he first made 30 years ago that alloreactive and autoreactive antibodies represent a physiological system for disposing of the products of metabolism and catabolism.

Hypothesis. Auto-antibodies and immunological theories: An analytical review

Abstract Auto-antibodies can exist in small amounts in normal organisms and appear in quantity after tissue destruction or alteration by exogeneous agents. Assuming that the immunological phenomena originally are not a “defence mechanism” but rather a physiological system of handling metabolic and catabolic substances, the appearance of auto-Ab is a normal process. “Self” constituents are normally degraded by autolytic enzymes, but in cases of massive destruction of tissues, these enzymes can be inhibited by substrate excess. Cells capable of synthetizing auto-Abs which exist normally are then activated and auto-Abs appear; they facilitate phagocytosis. The same mechanism acts for “not self” substances if undegraded by existing enzymes. Tolerogens, resulting from degradation, can block the receptors on immunocompetent cells. Possibly, they may differ from immunogens in possessing only one determinant group susceptible to do it. Experimental data are cited supporting the “transporteurs” theory proposed years ago by the author.

The use of immunochemical methods in studies on proteins.

Publisher Summary The chapter discusses the use of immunochemical methods in studies on proteins. The main value of immunochemical methods is that they are specific and sensitive. It is also known that the specificity of the antigen–antibody reaction is because of the spatial configuration of some chemical groupings in the antigen molecule. The chapter explores the main advantages of the immunoelectrophoretic analysis:(1) its simplicity, (2) the possibility of analyzing very complex mixtures, (3) each of the components can be defined or identified by its electrophoretic mobility. The advantages as well as the limitations of immunochemical methods are because of the use of a specific reagent, the antibody. The chapter deals with the aspects of this problem, which have a direct connection with the use of antibodies as reagents in the precipitin reactions. Because these reagents are formed in animals receiving injections of antigens, the main problem is the way to provoke the formation of precipitating antibodies in a conveniently chosen animal at a maximal concentration. A very large spectrum of biochemical research problems can be approached by the use of immunochemical methods. For simplification, the problems are classified arbitrarily into three groups: static or descriptive biochemistry, alterations or modifications of proteins, and structural problems.

SELF AND " NOT-SELF " IN IMMUNOLOGY

Abstract If, instead of the classical assumption that immunological phenomena are based on defence mechanisms, it is assumed that they are derived from the physiological system of nutrition and involve the transport of catabolic and metabolic substances, and the cleaning up of residual products, this same mechanism can be envisaged as acting as a defence against foreign substances. No further complicated ad-hoc hypotheses are then required to explain immunological phenomena such as recognition of self , autoantibody formation, and, possibly, tolerance.

Immunologische spezifität von lactatdehydrogenase isozymen dreiner säugetier-organismen

Abstract 1. 1. Lactate dehydrogenase ( l -lactate: NAD oxidoreductase, EC 1.1.1.27) isozymes from pig, beef and man have been compared by analyzing their immunological properties. The investigations were carried out mainly by means of agar precipitation techniques—immunoelectrophoretic analysis and double diffusion—in combination with a very sensitive lactate dehydrogenase (both containing mainly isozyme I and some isozyme II and III), isozyme V from pig skeletal muscle and a mixture of the five isozymes from human brain. 2. 2. As we reported previously 22 the isozyme I and V from pig possess different antigentic structures, as shown by a clear cut reaction of non identity in double diffusion and by absorption experiments. The failure of anti-isozyme V from pig skeletal muscle to react with isozyme I now confirms this statement. 3. In addition, a variation of immunoelectrophoretic analysis permitted us to provide evidence for the different antigenic structures of the human isozymes I and V even though we disposed only of mixtures of human isozymes. 4. The isozymes I and II from beef and from man show in immunoelectrophoretic analysis a reaction of partial identity. The isozymes I, II, and III from pig as well as II, III, and IV from man seem to be in close relation to each other. 5. All these results are in good agreement with the concept of Markert that mammalian lactate dehydrogenase molecules are composed of 4 sub-units “A” and “B”, isozyme I being the BBBB-, isozyme V the AAAA-form. 6. 3. The cross reactions of lactate dehydrogenase isozymes from pig, beef, and man were studied in detail. It is shown that the cross reactions follow very closely the concept of Markert , “heart-type” cross reacting with “heart-type”, and ‘muscle-type” with “muscle-type”. 7. Absorption experiments with pure isozymes I or V and subsequent analysis of the remaining cross reactions in the respective supernatants (experiments soon to be published in detail 12,23 ) confirm this results. 8. The advantage of the reported cross reactions for clinical research is stressed.

Étude de la gliadine et de la glutenine après réduction ou oxydation

Abstract The following conclusions can be drawn from the results obtained in this study. 1. 1. Cleavage of S-S bridges of gliadin and glutenin induces modifications in the number of electrophoretically observed constituents and in their mobilities, but not in their molecular dimensions. 2. 2. Gliadin is composed of at least two sub-fractions with molecular weights of 60 000 and 20 000, respectively. The antigenic structure of these sub-fractions is identical and they contain proteins with a single peptide chain. 3. 3. Cleavage of disulfide bonds destroys the antigenic reactivity of gliadin, at least in its capacity to form insoluble complexes with antibodies. 4. 4. Glutenin is not a simple polymer of gliadin formed by S-S bridges. It is composed of at least two sub-fractions, one of which has a molecular weight of 60 000 and the other greater than 100 000. 5. 5. The cleavage of S-S bridges destroys the original antigenic structure of glutenin, which is identical to that of gliadin, but a new antigenic structure appears, which is different from the original one. This new antigenic structure is located on the sub-fraction of the reduced glutenin possesing a molecular weight of 60 000.

A new technique for direct detection of glycoproteins and polysaccharides after electrophoresis or immunoelectrophoresis in agar gel

Abstract A technique for the detection of glycoproteins and polysaccharides after electrophoresis or immunoelectrophoresis in agar gels is described. The method is based on the formation of aldehyde-aryl hydrazones from the carbohydrates oxidized by periodic acid. The aldehyde-aryl hydrazones are subsequently converted to a formazan derivative by coupling with a diazonium salt.

The “globulines-transporteurs” theory and auto-sensitization

Abstract Many years ago, the author suggested that the plasma proteins, now called immunoglobulins, were not necessarily a particular “defense mechanism” but a physiological system of “transporteurs” of catabolic and metabolic products, these last corresponding to the “not self” antigens. In recent years, the existence of normal auto-antibodies and their frequent appearance in various conditions (particularly when an abundant destruction of tissue occurs) have been amply demonstrated. In contrast to other theories of the mechanism of recognition of self antigens, the author considers that in normal conditions these components are degraded by autolytic enzymes: therefore no activation of the corresponding immuno-competent cells take place. In cases of massive destruction of tissues or cells the enzyme activity is inhibited by the excess of substrate and the non-degraded auto-antigens induce the formation of auto-antibodies by the corresponding cells, which persist normally in the organism. Therefore, there is no need to imagine a particular mechanism for the actual synthesis of antibodies for self antigens. The possible role of enzyme degradation in immunological unresponsiveness is discussed. As auto-antibodies are specific “transporteurs” of catabolic products, their existence represents an additional argument for the original proposal.

Action des ultrasons sur une oxydase

Resume Les ultrasons (frequence 960 Kc/sec; intensite 76 watts) inactivent tres rapidement des solutions aqueuses de polyphenoloxydase de Agricus campestris purifiee, en presence dair. Contrairement a ce qui se passe dans de nombreux autres cas, lhydrogene ne protege pas, mais ralentit seulement cette inactivation, qui est probablement due a lactivite chimique des U.S. Cet exemple montre que lextraction denzymes de cellulas a laide des U.S. peut etre accompagnee eventuellement de leur complete inactivation.