In vitro lymphocyte transformation in the development of experimental allergic thyroiditis

In vitro lymphocyte transformation to homologous thyroid antigen has been studied in cultures of lymph node cells obtained from 97 guinea pigs at weekly intervals after a single injection of homologous thyroid extract in complete Freund's adjuvant, using a method for measurement of 3-H-thymidine incorporation. Lymph node cell cultures from animals 1 week after sensitization showed a significant increase in thymidine incorporation after the addition of antigen. Two weeks after sensitization the stimulation was maximal, and then a lower but significant response continued during the next 5 weeks. There was no correlation between lymphocyte transformation and the level of circulating antibodies throughout the post-sensitization period examined. The early lymphocyte transformation contrasted with the later development of macrophage migration inhibitory factor activity.