Clonal T cell expansions within the CD4
To examine the nature of the skewed BV gene segment usage, the TCR repertoire of CD4+ CD28+ and CD4− CD28− T cells were analyzed by BV-BC-specific PCR of TCR sequences and subsequent size fractionation. Results for four BV-BC combinations from three individuals are shown. The CD4+ CD28+ population always showed a Gaussian distribution of band intensities, suggesting polyclonality. In contrast, dominant bands emerged in the CD4+ CD28− T cells. Clonality was confirmed by sequencing (Table 2). Of the 21 expanded BV elements (Table 1), 17 harbored one or more T cell clones.