Heterotopic transplantation of syngeneic lymphoid tissues in mice. The ability of graft repopulation cells to enhance cell-mediated immunity as measured in the lymphocyte-induced angiogenesis assay.

Fragments of murine spleen and Peyer's patches were transplanted under the kidney capsule of syngeneic recipients. The ability of graft-repopulating cells to enhance cell-mediated immunity was tested in a lymphocyte-induced angiogenesis assay. The ability to evoke angiogenesis expressed by cells isolated from 10-day-old grafts of both tissues was significantly lower than that of cells isolated from organs in situ and was restored to control levels in both types of grafts 30 days after transplantation. Cells of Peyer's patch grafts showed weaker ability to induce angiogenesis than cells of spleen grafts regardless of the graft's age. Cells isolated from Peyer's patches in situ also showed weaker angiogenesis-inducing ability compared with normal spleen cells. Hence the results suggest that the repopulation of lymphoid tissue graft is specifically influenced by the graft's microenvironment.