Abstract
Lymph node fragments taken from rabbits previously immunized by a single footpad injection of both rat serum albumin and diphtheria toxoid were exposed to a secondary stimulus with either of these two antigens in vitro. The resulting secondary response was followed in tissue culture for a month. A difference was established in the antibody responses to rat albumin and diphtheria toxoid. Anti-diphtheria antibody formation was found to be more sensitive to hydrocortisone and less dependent on the presence of serum in the medium.