Two autologous melanomahyphen;specific and MHChyphen;restricted human T cell clones with identical intrahyphen;tumour reactivity do not share the same TCR Valpha; and Vbeta; gene families

摘要

Among tumour infiltrating lymphocytes (TIL) of a melanoma patient, A CD8+, WT31+CTL clone (8B3) had been previously isolated which exhibited specific and MHC-restricted lytic activity against the autologous tumour. To molecularly characterize T cell receptor (TCR) alpha; and beta; transcripts of clone 8B3, sequence analysis of several cDNA isolates was carried out. Such analysis indicated that the functional alpha; and beta; chain of 8B3 are composed of Valpha;2.1/Jalpha;/Calpha; and Vbeta;8.2/Dbeta;/ Jbeta;1.2/Cbeta;1 gene segments. Eleven additional melanoma-reactive T cell clones from the same patient (one MHC-restricted and 10 MHC-unrestricted) were analysed for usage of the 8B3 Valpha;2 and Vbeta;8 gene segments by Northern blot hybridization. Neither the Valpha;2 nor the Vbeta;8 segments were used by 8D9, the second MHC-restricted melanoma-specific TIL clone that displayed intra-tumour reactivity identical to that of 8B3 recognizing only 4 out of 25 melanoma clones isolated from the same metastases. No Vbeta;8 expression was found among the MHC-unrestricted T cell clones and all but two (found in duplicate as 4C4 and 4A6) were also negative for Valpha;2 expression. Southern blot analysis revealed different TCR beta; chain rearrangements in most MHC-unrestricted T cell clones providing evidence of their independent derivation. Taken together these findings show that TCR of clone 8B3 is unique in composition and not shared by MHC-unrestricted melanoma-reactive T cell clones. The different set of Valpha; and Vbeta; families used by clone 8D9 further indicates that the TCR usage in the specific and MHC-restricted response to melanoma can be polyclonal.