In vivo detection and partial characterization of effector and suppressor cell populations in spleens of @entity19 with large metastatic XXXX .

@entity1492 @entity19 @entity5 @entity3
The MC-2 @entity1492 , which is a transplantable @entity5 syngeneic for BALB/c @entity19 , metastasizes to lymph nodes draining subcutaneous inoculation sites, and also to the lungs. T cell-mediated immunity was detected in Winn assays using spleens from excision immunized @entity19 . T cell-mediated anti- @entity5 immunity was also detected in spleens from @entity19 with small @entity5 but disappeared as the @entity5 burden increased. Protective immune spleen cell activity in the Winn assay was inhibited by prior addition of spleen cells from @entity19 with large @entity5 , causing increased @entity5 incidence. Splenic metastases occasionally occurred in the MC-2 model, but were not demonstrable by bioassay in any of the experiments detecting splenic suppressor cell activity. In vivo protective activity was restored to advanced-stage @entity5 -bearer spleens by whole-body ionizing irradiation (0.5 and 2.5 Gy) of donor @entity19 15 h before sampling. Spleen cells from @entity19 with small @entity5 remained protective after 1.5, 2.5 and 4.0 Gy of irradiation in vivo. These results are consistent with the properties of radiosensitive suppressor T cells. In contrast to reports in other @entity5 models, suppressor cells were not detected until late in the course of MC-2 development. This is surprising in view of the aggressively metastatic nature of MC-2. It is postulated that modulation of the anti- @entity5 immune response by the suppressor cells is associated with @entity3 in this @entity5 model. The late appearance of both suppressor cells and metastatic cells in the spleen may reflect similar processes occurring earlier in regional lymph nodes.
