Kinetics of antigen-sensitive cells in the lymphoid organs of rats during allotransplantation reaction.

The kinetics of antigen-sensitive cells in the peripheral blood, spleens, regional lymph nodes, and thymuses of rats was investigated at different time intervals after immunization with allogeneic lymph node cells or after immunization with allogeneic skin or tumour grafts. The lytic effect of the immunizing antigen in vitro was estimated by the percentage of surviving cells after 24 h incubation with the specific antigen prepared from the lymph nodes of graft donors. The percentage of active lymphocytes in individual lymphoid organs of rats immunized with allogenic lymphocyte suspensions was determined by the nucleolar test. Regional lymph node enlargement was evaluated by determining lymph node relative weights and enlargement indices. An immunologically specific enlargement of the regional lymph nodes, increased numbers of ASC and increased percentage of active lymphocytes were seen as early as 24 h after immunization with allogeneic lymph node cells. At this time, the number of ASC in the peripheral blood was reduced and the percentage of active lymphocytes was low. After immunization with allogeneic skin and tumour grafts, ASC were detected first in the peripheral blood, then in the regional lymph nodes as late as 8 days after immunization, and after 10 days in the spleens.