鈴木 昌彦

Heterogeneity of V-alpha-1+ and V-beta-10+ TCR alpha-beta-chains, which are predominantly used in anti-FBL-3 CTL clones established in vitro, was investigated at a nucleotide level in FBL-3 tumor-infiltrating lymphocytes (TIL) in vivo. The majority (90%) of V-beta-10+ beta-chains dominated in TIL used homogeneous V-beta-10D-beta-2.1 sequences identical to that used in the T cell clones with cytotoxic functions. The homogeneous TCR beta-chain expression was dominant and found to be about 10% of the total TCR beta-chains in the TIL population, which was a > 300- to 900-fold increase than in the regional lymph nodes. This is in good agreement with the in vitro data showing that about 11% CTL clones used the homogeneous V-beta-10D-beta-2.1+ beta-chain. However, the J-beta segment does not seem to contribute greatly to the recognition and selection of this TCR because some of homogeneous VD+ beta-chains were associated with J-beta segments other than J-beta-2.7 of the CTL clones. The frequency of the V-alpha-1J-alpha-112-2+ alpha-chain expression of the CTL type was much less (3- to 80-fold increase compared to that of lymph node) and also varied in sample materials, indicating the lower contribution of the alpha-chain for the oligoclonality of the TCR. The results were also confirmed by quantitative PCR and RNase protection assays. This suggests that the dominant expression of the homogeneous TCR beta-chain is due to the expansion of the particular anti-FBL-3 CTL in the tumor in situ. Also, the TCR beta-chain, especially the V-beta-D-beta region, rather than alpha-chain is more important for the recognition and selection of the anti-FBL-3 TIL with cytotoxic functions.