Characterization of the T cell receptor repertoire of neonatal T cells by RT-PCR and single strand conformation polymorphism analysis

We have analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR ) the individual non-germ line configurations of the T cell receptor (TCR) V beta chains expressed by T cells from eight individual cord blood specime ns. cDNA from each cord blood was amplified using a common primer coupled w ith a primer specific for each of 22 variable elements of the V beta chain family and the amplified fragments were separated under high resolution con ditions. With cDNA from adult blood las a control), all of the TCR chains w ere amplified as a smear consistent with the extensive polyclonality of adu lt T cells. In contrast, a heterogeneous pattern of amplification was obser ved with cDNAs from cord blood: only 26.7 +/- 21.9% of the 22 V beta chains analyzed were amplified as a smear, The majority of them were amplified as a discrete number of bands (up to 10) tin 68.2 +/- 18.7% of samples) and s ome of them as a single fragment (4.0 +/- 7.8%). Only one of the eight samp les analyzed expressed the majority (72.7%) of its V beta chains as a smear ? consistent with an adult-like TCR repertoire. In conclusion, cord blood e xpressed, on average, a less complex TCR repertoire than adult blood.