Cells Involved in the Graft-versus-host Reaction <em>in vitro</em>.

The cell types involved in the cellular immune response were studied with the GVH in vitro as a test system. Comparison of the activities of cells of different lymphoid organs in the GVH in vitro showed the cells of peripheral lymph glands and thoracic duct to be the most active. Second in activity were the cells from peritoneal exudate, mesenterial lymph nodes and spleen. Weak activity was found in thymus and bone marrow cells, whereas cells from Peyer&#39;s patches showed no activity at all. Treatment of donor animals with ATS, cortisone or cyclophosphamide simultaneously with (acceptor-) transplantation antigen, resulted in spleen cells which were less active in the GVH in vitro. No such results were obtained after treatment of donor animals with dimethylbenzanthracene or cyclo- phosphamide without antigen. Fractionation of donor spleen cells on a bovine serum albumin density gradient resulted in an accumulation of activity in one of the high density fractions (D), whereas this was reduced in the low density fractions (C, B and A) and absent in the highest density fraction (E). Separation of thymus cells on a glass bead column coated with transplantation antigen resulted in augmented activity of the adherent cell fractions, while the effluent cells were less active than the original cells. Fractionation of cells on an uncoated column resulted in adherent and non-adherent cells which were both inactive in the GVH in vitro. [ABSTRACT FROM AUTHOR]