Synergism between Thymocytes and Lymph Node Cells in the Graft-Versus-Host Response. Effect of Cortisone Treatment of the Thymus Cell Donor

Abstract

Combinations of thymic cells from 1-month-old and lymph node cells from 6-month-old C57BL mice were tested for their capacity to give a synergistic effect in the graft-versus-host reaction (G-v-H) when injected into young A/Sn × C57BL F₁-hybrids. No clear synergism was observed between normal thymic cells and lymph node cells.

Two days after cortisone treatment of the thymus cell donors the cell number in the thymus had dropped to 5% of its original value and the relative G-v-H reactivity exhibited a 15-fold increase. There was no evidence, however, of an enrichment of cells capable of amplifying the G-v-H reaction. On day 12 after steroid treatment the G-v-H reactivity of the organ had decreased, but there was a marked tendency of the cell population to act synergistically with lymph node cells. After another 8 days the thymus cell population had regained its G-v-H reactivity and diminished its “amplifying” capacity. The transformation of amplifying cells into G-v-H reactive cells is a possible explanation of this phenomenon.