Patterns of in vitro sensitization of isolated smooth muscle tissues with precipitating antibody.

Anaphylactic sensitization of guinea pig ileum has been obtained by incubation of the isolated organ in a bath of Tyrode solution containing rabbit antibodies against hen egg albumin. The degree of sensitization has been estimated by the intensity of the contraction of the tissue after addition of the specific antigen. It has been found that the degree of sensitization is proportional to the concentration of antibody in the incubation mixture. A linear relationship has been encountered between the antibody concentration and the reciprocal of the square of the time of incubation, to obtain equal sensitization of the organ. Diminishing the temperature during the incubation considerably slows down the sensitization process. The value of the Q is about 2.5 in the region of 38° to 30°, and 1.6 between 30° and 10°. The sensitization process is not affected by the acidity of the medium, between 8.2 and 5.6, unless carbon dioxide is present, in which case the sensitization is diminished as the H is lowered. Non-specific rabbit gamma-globulin interferes with sensitization. When its concentration is 100-fold that of the antibody, sensitization does not take place. Repeated washing of an already passively sensitized organ does not impair its anaphylactic response. But desensitization can be achieved by incubation with non-specific rabbit gamma-globulin. Treatment with carbonic acid at H 5.8 during one hour significantly affects the anaphylactic condition.