Numerical expansion of tumor antigen-specific T cells using KT64/BBL aAPC. (a) Melanoma TIL that had been outgrown in for 4 weeks in IL-2 expand rapidly using KT64/BBL aAPC loaded with anti-CD3/28 in the presence of IL-2 (100 IU/mL). Day 9 expansion results for representative samples (TIL-A and TIL-B) are shown. (b) MART-1 peptide-specific CD8+ T cells are detectable in pre- and post-expansion TILs via flow cytometry using MART-1:27L-35 peptide/HLA-A*0201 tetramers. TILs were stained for viability, CD3, CD8 and MART-1:27L-35 peptide/HLA-A0201 tetramers. Viable CD3+ T cell gating was performed. (c) aAPC expanded melanoma TILs retain HLA-restricted tumor reactivity in a standard co-culture and cytokine detection assay. 105 aAPC-expanded TILs were co-cultured with 105 624 (A2+ MART-1+) or 938 (A2- MART-1+) melanoma cells, or OVCAR5 (A2+ MART-1-) or SKOV3 (A2- MART-1-) ovarian cancer cells. After overnight culture, supernatants were measured for secreted IFN-g.