Characterization of brucella skin-test antigens.

ceived very little attention apart from attempts to prepare reagents of varying grades of antigenic purity. Once these reagents have been available, they have usually been applied with some degree of parochial interest for the detection of one more sign of a Brucella infection. As the limitations of the test itself were clarified, and as serologic diagnosis improved, there was little motivation clinically to bring either knowledge of the antigens concerned, or the potential of the test itself to probe more deeply into the pathogenesis of the infectious disease, up to the level of development and use attained by the tuberculin test. Many interesting problems such as differentiation among bacterial species in the infection in nature might be aided by an effective and highly purified reagent from Brucella. Further knowledge of the possible spectrum of antigens capable of inducing the hypersensitivity could be of help in understanding the course of the infectious process, especially in the light of such phenomena as "L-forms" in vivo, the existence of lysogeny and its consequences in vivo, and the biologic roles of the various immunoglobulins in their regular sequence of appearance in the course of the infection. For these basic