RECONFIRMATION OF INDIRECT INDUCTION OF RADIOGENIC LYMPHOMAS USING THYMECTOMIZED, IRRADIATED B-10 MICE GRAFTED WITH NEONATAL THYMUSES FROM THY-1 CONGENIC DONORS
An experiment was conducted to reexamine earlier observations that lymphomas could develop from lymphocytes present in nonirradiated thymuses grafted into thymectomized, fractionally (170 R, 4 doses) irradiated mice by using B10.Thy 1 congenic donor-host combinations. The results indicated that: 37 of 91 thymectomized, fractionally irradiated B10.Thy 1.2 mice which were grafted s.c. with 7 day old thymuses from B10.Thy 1.1 donor mice had developed frank lymphomas between 90 and 270 days after thymus grafting; 28 of 37 lymphomas developed in this group were typed individually with respect to Thy 1 alloantigens by the cytoxicity assay using monoclonal anti-Thy 1.1 (T-11-D7) and anti-Thy 1.2 (F7D5) antibodies plus complement. Twenty-one thymic lymphomas (75%) had originated from lymphocytes of the nonirradiated thymus grafts and 5 tumors (17.9%) from cells of the irradiated hosts; 2 thymic lymphomas (7.1%) manifested no Thy 1 antigens; lymphoma cells originated from both nonirradiated thymus grafts and irradiated hosts possessed chromosome abnormalities, which were mainly numerical changes of some chromosomes or polyploidizations.