Figure 5.

Primary and secondary proliferative responses by AND TCR⁺ RAG^−/− T cells are greater in the absence of CTLA-4. (A) Naive AND TCR⁺ RAG^−/− CTLA-4-deficient and littermate control lymph node T cells were isolated and stimulated (2 × 10⁴ cell per well) with irradiated I-E^k-transfected L cells (2 × 10⁴ cell per well) and pigeon or moth cytochrome c (PCC_88–104 and MCC_93–103, respectively). (B) Secondary response. AND TCR⁺ RAG^−/− T cells from CTLA-4^−/− and littermate control animals were expanded in vitro as described in Methods and Materials. The cells were collected, ficolled, and restimulated with PCC_88–104 or MCC_93–103 as described above. These are representative data of at least three experiments.