Inhibition of programmed cell death by constitutive expression of hbcl-2 in peripherally expanding T cells restores recall responses to HY-disparate skin grafts at suboptimal inocula but fails to restore primary responses.
(A) TXY/TCD mice were reconstituted with 1 × 106 primed LN cells constitutively expressing hbcl-2 (●, n = 9) 24 hours after placement of a male tail skin graft. This resulted in restoration of HY-disparate skin graft rejection when compared to mice receiving unprimed hbcl-2 transgenic inocula (▪, n = 6) or primed cells from nontransgenic littermate controls (♦, n = 9). Primed hbcl-2 transgenic inocula did not enhance graft rejection in thymus-bearing controls (▾, dashed line, n = 5) when compared to primed inocula from nontransgenic littermate controls (▴, dashed line, n = 5,P = .49). (B) Reconstitution of TXY/TCD mice with 1 × 106 naive hbcl-2 transgenic LN cells followed by sensitization with enriched male dendritic cells does not restore rejection of HY-disparate skin grafts placed 3 weeks after cell transfers (●, n = 5). Titration of the inocula to 10 × 106 (▪, n = 5) and 25 × 106(♦, n = 5) leads to HY-disparate graft rejection at a rate comparable to thymus-bearing controls (▴, dashed line, n = 5) analogous to nontransgenic inocula (Figure 2B).
