THE FACTOR OF IMMUNIZATION IN THE RAT

Abstract

Using a popliteal lymph node weight assay the graft-versus-host activity of lymphocytes from donors immunized with allogeneic tissue has been assayed by comparison with that of lymphocytes from nonimmune donors. When the donors were immunized against weak histocompatibility antigens (non-AgB) the specific GVH activity of its lymphocytes was increased. This increase was greater if spleen cells rather than thoracic duct lymphocytes were the source of the donor cells used for assay. The increase in GVH activity was also greater if the standard immunization procedure of two successive skin allografts was followed by three boosting injections of allogeneic lymphoid cells.