Table I.

Generation of Bone Marrow Chimeras

Group	Donors 1	Donors 2	Recipients	Expected outcome
Experimental	TCRβ2/2 IFN-γ2/2	TCRδ2/2	IFN-γ2/2	γδ T cells cannot produce IFN-γ
Control	TCRβ2/2 IFN-γ1/1	TCRδ2/2	IFN-γ2/2	γδ T cells can produce IFN-γ

Bone marrow chimeras were prepared as described in Materials and Methods. Bone marrow cells from TCRδ^−/− mice (normal αβ T cells without γδ T cells) together with bone marrow cells either from TCRβ^−/− IFN-γ^−/− mice (γδ T cells lack the ability to produce IFN-γ) or from TCRβ^−/− IFN-γ^+/+ mice (γδ T cells can produce IFN-γ) in a 1:1 ratio were injected intravenously into irradiated IFN-γ^−/− mice (to eliminate any radio-resistant source of endogenous IFN-γ). All mice were on the B6 background and were age and sex matched. 12 wk after reconstitution, mice were injected with MCA or with B16 F0 melanoma cells.