IgG2 Antibodies Block IgE Antibody-Induced Asthma in Guinea Pigs

Abstract

In order to examine the blocking activity of IgG2 antibodies to guinea pig for IgE antibodies-induced guinea pig asthma, experiments were carried out as follows. Guinea pigs were passively sensitized intravenously with guinea pig serum containing IgE antibodies to ovalbumin (OA). 8 days after sensitization, IgG2 purified from guinea pigs hyperimmunized with OA was intravenously injected. One hour later, the guinea pigs were challenged by inhalation of OA solution. Asthma attacks were not observed in the guinea pigs, whereas the attacks were observed in guinea pigs passively sensitized with the IgE antibodies but injected IgG2 fraction from normal guinea pigs 1 h before inhalation. These observations suggested that IgG antibodies that increased after immunotherapy might block asthma caused by inhalation of allergens in humans.

Experimental Asthma in Guinea Pigs Sensitized with Mites <i>(Dermatophagoides farinae)</i>

“…The result might show an importance of human IgG antibodies for protecting asthmatic responses to anti gens. This result was coincident with our previous re sult that asthma attacks of guinea pigs passively sensi tized with IgE antibodies to ovalbumin were com pletely inhibited by prior intravenous injection of IgG2 antibodies to that antigen [2], This is also con sistent with the results of clinical studies that the ratio of IgE/IgG antibodies had a relation to the efficacy of immunotherapy with ragweed [7], In guinea pigs, IgGl as well as IgE antibodies have the characteristics to sensitize autologous and homol ogous tissues. As the rate of asthma attack upon the challenge with mite antigen was higher in group 10, and this group had a higher ratio of IgE-/IgG2-, IgE-/IgGl -antibodies and a lower ratio of IgGl-/-IgG2-antibodies, it might be possible that the asthma attack upon the challenge was mainly due to IgE an tibodies in our experiments.…”

“…Immunization for raising IgE antibodies in guinea pigs was performed similarly as previously described [2], 0.2 ml of the solution containing 1, 10, 100 or 1,000 pg of protein was mixed with 4 mg aluminium hydroxide gel in 0.8 ml saline, and intraperitoneally injected to each guinea pig of approximately 300 g. Each group consisted of 10-20 animals (1 pg; n = 15; 10 pg; n = 20; 100 pg; n = 10, 1,000 pg; n = 10). Twenty-six days after the first immunization, 250 m g/kgof cyclophosphamide was intraperi toneally injected.…”

Inhibition of Allergen-Induced Bronchoconstriction in Sensitized Guinea Pigs by Orally Administered Allergen

“…Although there are some reports that IgG2 anti body is able to block IgGl-and IgE-induced asthma [15], this could possibly not be the mechanism in volved in this experimental model, considering the fact that antibody measurements before and after al lergen administration failed to show any change in IgG2 antibody level. IgE antibodies titrated by 8 days passive cutaneous anaphylaxis, and IgGl and IgG2 antibodies measured by ELISA were comparable in the sera obtained from animals before and after CME treatment.…”

Inhibition of Endogenous Leukotriene-Mediated Lung Anaphylaxis in Guinea Pigs by a Novel Receptor Antagonist ONO-1078

“…Guinea pig sera containing IgE antibodies to ovalbumin (anti-OA GP serum) were prepared by the method described by Graziano et al [6] with some modifications [7,8]. Characteristics of gui nea pig anti-OA IgE were examined by passive cutaneous anaphy laxis (PCA).…”

“…The pulmonary function of the guinea pigs was estimated ac cording to Mead's method with some modification as previously described [7,8]. The merit of this method is that respiratory resis tance and respiratory flow pattern can be measured in unanesthe tized guinea pigs.…”