Analyses of the anaphylactic and immune reactions by means of perfusion experiments with the isolated guinea-pig lungs show that we are here concerned with three essential factors:
Cellular hypersensitiveness, or the anaphylactic response of the hypersensitive fixed pulmonary tissues,
Humoral anaphylaxis, or the chemical response (anaphylotoxin formation) of the anaphylactic blood, and
Humoral immunity, or the inhibiting or protecting action of the immune blood.
In the 14-day anaphylactic guinea-pig, the fatal bronchial spasm is due, in part to fixed cellular hypersensitiveness, in part to humoral anaphylaxis.
In the 4-week anaphylactic guinea-pig, the fixed cellular hypersensitiveness is usually greater than that of the 14-day anaphylactic guinea-pig. The humoral reaction, however, is usually absent. The fatal bronchial spasm in the 4-week anaphylactic guinea-pig is usually due solely to fixed cellular hypersensitiveness.
The immune guinea-pig usually shows a fixed cellular hypersensitiveness greater than that of the 14-day anaphylactic guinea pig. A fatal bronchial spasm is prevented in the immune guinea-pig, however, by the inhibiting or protecting action of the immune blood.
The immune guinea-pig, therefore, shows a seemingly paradoxical phenomenon, the coexistence of a fixed cellular hypersensitiveness and a humoral immunity.
Presented before the Society of American Bacteriologists, New Haven, Conn., December 27, 1916, and before the American Society for Experimental Pathology, New York City, December 28, 1916.