Abstract
The manner in which developing animals achieve immunologic competence and the way that they initiate an active response to the very first antigenic challenges are currently of great theoretical interest in immunology. While the young of some mammalian species mature immunologically only after birth, in other species the developing fetus is able to mount active immunologic responses in utero, often at surprisingly early gestational ages (1). Moreover, the young animal does not attain full immunologic competence all at once. Rather, it appears to possess a finely controlled immunologic clock whereby competence to each antigen appears at a discrete and reproducible time during development, some capacities arising before and some after birth according to the species (2, 3). In this study we are concerned with whether, following the young animal's transition from immunologic nonreactivity to an ability to respond to the given antigen, there is any immaturity or restriction in this initial response.
Footnotes
This work was supported by United States Public Health Service Grant AI-06713 from the National Institutes of Health, an unrestricted gift from the Alcon Laboratories, Inc., and an Independent Order of Odd Fellows Research Professorship.
