TABLE 6.

Effect of TCRβ transgene on irradiation-induced thymic lymphomagenesis in SCID mice^a

Strain	Irradiation	Cellularity (10−6)	No. with thymic lymphoma/total
TCRβ-SCID	−	4.3 ± 3.9	0/7
SCID	+	122.5 ± 67.0	4/6
TCRβ-SCID	+	5.8 ± 3.0	0/12

^aEffect of a TCRβ transgene on radiation-induced thymic lymphomagenesis in SCID mice. TCRβ-SCID mice and their nontransgenic SCID littermates were irradiated with 100 cGy within 48 h after birth or were left untreated and evaluated at 16 to 24 weeks of age for the presence of thymic lymphoma. All irradiated TCRβ-SCID mice appeared to be healthy and showed no evidence of lymphoma at the time of sacrifice. In contrast, their irradiated nontransgenic littermates developed thymic lymphoma, as evidenced by invasive thymic masses that compromised respiration.