EXPANDED CD4(-CELL CLONES IN ELDERLY HUMANS() AND CD8(+) T)

The diversity of the human TCR repertoire in aging has been studied by examining the profiles of complementarity-determining region 3 (CDR3) sizes expressed by the BV families, The TCRBV CDR3 profile, which sho ws size heterogeneity in young adult humans, is significantly restrict ed in aged humans, Clonal T cell expansions were identified using a PC R-based approach, in one or more BV families from all 14 healthy perso ns over the age of 65 that we studied, CD4(+) T cell expansions were i dentified in 8 of 11 donors and CD8(+) T cell expansions in 7 of 10 do nors, These clonal expansions were stable during a 2-year period, Inte restingly, more than half of the aged persons had clonal expansions wi thin the BV3, -14, -16, and -23 families, Although there was no homolo gy among the eight CDR3 sequences identified in clonal T cells from 8 aged persons, selective pressure on the expanded T cell clones was sug gested by the fact that the BV families used by the T cell clones were not proportional to the number of genes in the different BV families.