Transfer of immunity by transfer of bone marrow cells: a requirement for T lymphocytes and sensitivity to cyclophosphamide.

Thymectomized, lethally irradiated mice reconstituted with bone marrow cells (TIR mice) from normal donors succumbed after i.p. challenge with xenogeneic (rat) Yoshida ascites sarcoma (YAS) given 1 month after irradiation and reconstitution. YAS rejection and production of YAS-antibodies was induced in TIR mice by a single i.v. injection of normal syngeneic spleen cells given 1 day after the tumor. Purified splenic T lymphocytes also induced YAS rejection in TIR mice, but splenic B lymphocytes did not affect progressive tumor growth. Tumor was also rejected in TIR mice that had been reconstituted with bone marrow cells from YAS-immune donors. The sera of these TIR mice did not contain tumor antibodies between reconstitution and YAS challenge, but a high YAS-antibody titer was present after YAS challenge and rejection. Immunofluorescence did not reveal any dramatic differences in the spleen and bone marrow content of T and B lymphocytes of TIR mice reconstituted with cells from normal donors and those reconstituted with cells from the YAS-immunized donors. Transfer of YAS-resistance was abolished when the bone marrow cells from immunized donors were treated with Thy 1.2 antiserum and complement, or when bone marrow donors were injected with cyclophosphamide 1 day after immunization. Cyclophosphamide was also shown to induce strong and specific suppression of YAS-antibody production in normal mice.