Selective detection of humoral antibodies in bronchial asthma using fluorescent antibody technique.

In patients with asthma, various types of antibodies can be differentiated according to their chemical nature and biological activity. For example, electrophoresis shows that reagin is in the y-1A fraction and blocking antibody in the 72-fraction. The former participates in anaphylaxis, and the latter suppresses anaphylaxis. Although they both combine with antigen, their mechanisni of combining may differ somewhat. On the basis of these characteristics, a new plan for the selective detection of these antibodies was outlined and is described in this report. Sensitized erythrocytes can be used for thc purpose of giving form to soluble allergens and of concentrating the allergens on a cell surface or at cell boundaries. These sensitized erythrocytes presumably become surrounded by antibody when they come into contact with the serum of an asthmatic patient, and the antigenantibody complexes should be visible when the fluorescent antibody technique is eniploycd with the use of labelled anti-human 7-globulin. It was hypothesized that with the use of fluorescent anti-human 7-1A globulin reagins could be detected specifically, and with the use of fluorescent antihuman y2-globulin, blocking antibody. The first step was to show that asthma antibodies can be demonstrated on sensitized erythrocytes with fluorescent antibody technique. Procedure Antigen: Commercial housc dust extract was used mainly. Sensitized erythrocytes: Human erythrocytes of blood type were used. A medium containing tannic acid or bidiazotized benzidine (BDB) was used to sensitize the erythrocytes by Boyden'sl and by Stavitsky's2 methods as previously described. Antigen-antibody reaction on smear preparations: Sensitized erythrocytes were resuspended in 0.2% bovine serum albumin saline solution, and smeared on thin glass slides. After quick drying in front of an electric fan, smears were fixed in absolute alcohol at -70°C, then covered with a patient's serum, sealed with a cover glass to prevent drying. The preparation was left in a moist chamber at 0 5°C for several hours. After prolonged and careful washing, the preparation was fixed again in absolute alcohol at -70°C.