Supporting this hypothesis, two other T cell repertoires, with a very high frequency of naive precursor, also exhibit a strong bias in TRAV12-2 usage, with a major role of the CDR1 loop: the T cell repertoire specific for the HTLV-1/A2 dominant epitope, (24) and for Yellow fever/A2 dominant one (23). Here, TRAV1-2 is linked to viral infectious disease.