Figure 2.

Memory-like T cells have intermediate in vivo function in the absence of secondary lymphoid organs. Memory-like (naive_Rag2^−/−) and antigen-experienced memory (memory_Rag2^−/−) T cells were generated in Rag2^−/− hosts and adoptively transferred to splenectomized aly/aly heart transplant recipients. The naïve group received T cells harvested from naïve wt and 2C mice as described in Methods. (A) Phenotype of naive, naive_Rag2^−/−, and memory_Rag2^−/− allospecific T cells determined before adoptive transfer by four-color flow analysis after gating on the CD8⁺1B2⁺ (2C TCR-tg) cell population. Histograms shown are representative of 4–5 experiments. (B) Cardiac allograft survival in splenectomized aly/aly mice that received naïve (●, n = 4), naive_Rag2^−/− (■, n = 4), or memory_Rag2^−/− (○, n = 5) T cell populations. (C) Histological (hematoxylin/eosin, H&E) and immunohistochemical (CD3) analysis of cardiac allograft tissue harvested 100 days after transplantation in the naive and naive_Rag2^−/− group and on the day of rejection in the memory_Rag2^−/− group. (Magnification = ×200.)