Danysz phenomenon


[Jean Danysz, Polish-born Fr. pathologist, 1860-1928]
A phenomenon that illustrates the reversibility of precipitation of antibody and antigen complexes. When a specified amount of diphtheria toxin is added all at once to an antitoxin serum, the mixture is nontoxic; but when the same quantity of toxin is added in portions at about 30-min intervals, the mixture is toxic.