Kimishige Ishizaka

Biological Activities of Aggregated Gamma Globulin I. Skin Reactive and Complement-Fixing Properties of Heat Denatured Gamma Globulin.

Summary 1. Aggregated human gamma globulin, obtained by heating, gave immediate skin reactions in normal guinea pigs and inactivated complement, whereas aggregated bovine gamma globulin did not have either activity. 2. Aggregated human gamma globulin and antigen-antibody complexes are comparable on weight basis with respect to skin reactivity and complement inactivation. 3. Divalent cation(s) are required for inactivation of complement by aggregated HGG. Inactivation of C3 by aggregated HGG is markedly dependent upon temperature. 4. A tentative hypothesis concerning the mechanism of complement fixation by antigen-antibody reaction is presented.

Molecular Mimicry Between Insulin and Retroviral Antigen p73: Development of Cross-Reactive Autoantibodies in Sera of NOD and C57BL/KsJ db/db Mice

Enzyme-linked immunosorbent assay (ELISA) was used to study temporal development of murine autoantibodies against insulin and both type C and intracisternal type A retroviral antigens. The nonobese diabetic (NOD) mouse, a model for autoimmune, insulin-dependent diabetes, was compared with a related, but diabetes-resistant, strain, nonobese normal (NON). Similarly, C57BL/KsJ db/db mice (insulin-resistant model of insulin-dependent diabetes and obesity) were compared with diabetes-resistant C57BL/6 db/db mice. NOD mice developed much higher autoantibody titers than did NON mice. Whereas type C autoantibodies in NOD developed to peak titer shortly after mice were weaned, autoantibodies against insulin and p73 (group-specific antigen of the intracisternal type A particle) did not develop until shortly before, or concomitant with, the development of hyperglycemia. Two NOD mice not developing hyperglycemia during the 40-wk study period were distinguished from the mice developing diabetes by a delayed onset of insulin (but not p73) autoantibodies. Our findings suggest that in NOD mice, the appearance of insulin and p73 autoantibodies signifies that extensive underlying necrosis of β-cells occurred. C57BL/KsJ db/db mice (with extensive β-cell necrosis and early hyperglycemia) developed much higher autoantibody titers to insulin and p73 than did the diabetes-resistant C57BL/6 db/db mice. However, the presence of autoantibodies in normoglycemic C57BL/KsJ +/db controls demonstrated that elevated autoantibody titers alone were insufficient to produce diabetes in this model. Absorption studies indicated that autoantibodies against p73 recognized a common epitope on insulin and IgE-binding factor. The potential significance of this molecular mimicry is discussed.

Immunoglobulin E (IgE)

Publisher Summary This chapter provides an overview of immunoglobulin E (IgE). IgE is the least component of the immunoglobulin family in humans and experimental animals. The concentration of the immunoglobulin in normal human serum is in the order of 100 to 200 ng/ml. However, IgE antibodies have unique biologic activities. The antibodies sensitize mast cells and basophils of homologous species, and the reactions of antigen to cell-bound IgE antibodies induce the release of a variety of mediators, which cause allergic symptoms. Purification of monoclonal IgE is further described. Many investigators tried to purify polyclonal IgE from the serum of atopic patients, serum of rats infected with the nematode, Nippostrongylus brasiliensis and ascitic fluids of mice immunized with an appropriate antigen. Although they succeeded to enrich IgE and to identify the protein, polyclonal IgE has never been purified. So far, only monoclonal IgE is purified from the serum of E myeloma patients, ascites of rats bearing IgE-producing immunocytoma and ascites of mice bearing IgE producing hybridomas. The chapter further explains purification of mouse monoclonal IgE by antigen-coated affinity column.

IgE-Binding Factors

Gene cloning of rodent IgE-binding factors was accomplished, using messenger RN A of a rat T cell hybridoma, 23B6, which produce IgE-suppressive factor. Transfection of cos 7 monkey kidney cells with

Regulation of the IgE Antibody Response

The IgE synthesis is regulated by T cell derived IgE-binding factors in an isotype-specific manner. The IgE-potentiating and IgE-suppressive factors may share common structural genes; therefore, a common polypeptide chain and their biologic activities are determined by posttranslational glycosylation processes. Under the physiological conditions, the carbohydrate moieties in the IgE-binding factors formed by a subset of T cells are determined by the ratio between two T cell factors, i.e., glycosylation-enhancing factors and glycosylation-inhibiting factors (GIF), in their environment. GIF is an immunosuppressive lymphokine. Repeated injections of this lymphokine into antigen-primed mice facilitated the generation of antigen-specific suppressor T cells and suppressed both IgE and IgG antibody responses. This effect of GIF was reproduced in vitro. Activation of antigen-specific T cells by antigen-pulsed macrophages, followed by propagation of the antigen-activated T cells by interleukin 2 in the presence of GIF resulted in the generation of suppressor T cells which produced antigen-specific GIF upon antigenic stimulation. Some of the T cell hybridomas constructed from the antigen-specific suppressor T cells formed antigen-specific GIF upon antigenic stimulation. The antigen-specific GIF formed by the T cell hybridoma share several common properties with antigen-specific suppressive factor and suppressed the antibody response of syngeneic mice in a carrier-specific manner. The results obtained with mouse lymphocytes suggest a maneuver to suppress the IgE antibody formation to an allergen in atopic patients.

Immunochemical studies of dextran coupled ragweed pollen allergen, antigen E

Abstract The major allergen of ragweed pollen antigen E has been coupled to periodate oxidized dextrans, followed with sodium borohydride reduction to stabilize the linkages. Two products having molecular weights of about 100,000 and 140,000 were prepared, and the molar ratio of dextran to antigen E in both products was the same in the range of 2–5. The antigenic and the allergenic activities of the products were on a molar basis about seven to eight fold less than those of antigen E. On dextranase digestion of the products, their biological activities were restored. The products were immunogenic in rabbits to stimulate the formation of antibodies reacting with antigen E and with dextran.

Treatment of ragweed hay fever with urea-denatured antigen E

Urea-denatured antigen E (UDE) has lost the major determinants of antigen E (AgE), eliciting neither IgE nor IgG antibodies to native AgE in mice. UDE, however, stimulates T cells so that repeated injections result in specific but partial suppression of ongoing IgE responses to native AgE. An attempt was made to apply this property to the treatment of 10 ragweed-allergic human volunteers by repeated subcutaneous injections of UDE over about 18 mo. Local and systemic allergic reactions limited the dose to 4 to 75 microgram UDE per injection. Little or no antibody response to AgE was induced. Five patients had increased basophil sensitivity to UDE after 4 mo of injections. Five of eight patients who completed the study had evidence of suppression of IgE responses by exhibiting a 20% or less increase of IgE antibodies to ragweed on natural seasonal exposure. Three patients still exhibited this evidence at the next season of exposure 10 mo after the last injection. The two patients who received the lowest doses had greater than usual seasonal rises of IgE antibodies. There was no clinical evidence of improvement of hay fever symptoms. The results indicate that the immunologic properties of UDE in humans are similar to those in mice. The clinical applicability of these properties remains doubtful.

The Identification and Significance of Gamma E

The experiments leading to the establishment of IgE as a distinct immunoglobulin class to which belong the antibodies implicated in atopic allergy are described. Research into the properties of the new immunoglobulin class has elucidated the mechanisms involved in histamine release and clarified the structure of the gamma E globulin molecule. The author also speculates on the role IgE may play against infection.

Regulation of IgE Biosynthesis

A biologic cell product that in an experimental system completely and and specifically suppresses the IgE response! This is one of the intriguing findings that give rise to optimism that the growing understanding of mechanisms that regulate normal IgE responses will, in the not-too-distant future, provide rational and effective therapy for the prevention and management of atopic diseases.

Role of Glycosylation Inhibiting Factor (GIF), a Phospholipase Inhibitory Protein, in the Generation of Antigen-Specific Suppressor T Cells

Previous experiments on the isotype-specific regulation of the IgE antibody response revealed T cell factors which have affinity for IgE and either enhance or suppress the IgE response (1). The major differences between the IgE-potentiating factors (PF) and IgE-suppressive factors (SF) are carbohydrate moieties in the molecules. The IgE-potentiating factors bind to lentil lectin and Con A, suggesting that the factors contain N-linked, mannose-rich oligosaccharide. In contrast, IgE-suppressive factors have no affinity for these lectins but bound to peanut agglutinin (2). Recent experiments in collaboration with Drs. Moore and Martens in DNAX Institute of Molecular Biology indicate that IgE-PF and IgE-SF share a common structural gene (3). Transfection of COS 7 monkey kidney cells with the cDNA clone 8.3, which encodes the rodent IgE-binding factor (4) resulted in the formation of IgE-PF, whereas the transfection of the same cells with the same cDNA clone in the presence of tunicamycin resulted in the formation of IgE-SF.