Aim: To detect the existence of sjTRECs in TCR 23 Vbeta subfamilies in normal peripheral blood and cord blood, and to evaluate the recent thymic emigrants of naive T cells of different TCRbeta subfamilies.
Methods: Different amounts of DNA from samples (4 cases of thymocytes, 10 cases of cord blood and 10 cases of normal PBMCs) were amplified to estimate the frequency of 23 TCR Vbeta-Dbeta sjTRECs by using semi-nest PCR.
Results: At the same cellular concentration, the most frequency of Vbeta-Dbeta1 sjTRECs was found in thymocytes, the second was in cord blood, and the lowest was in peripheral blood. At 2x10(5), 5x10(4) and 1x10(4) cells level, sjTRECs of most Vbeta subfamilies could be detected in cord blood and peripheral blood, while sjTRECs of some Vbeta subfamilies could be detected at 1x10(3) cells level. The frequencies of Vbeta2-, Vbeta4-, Vbeta7-, Vbeta11- and Vbeta19-Dbeta1 sjTRECs and the number of detectable Vbeta subfamilies from normal PBMCs were obviously lower than those from cord blood.
Conclusion: The technique of semi-quantitive PCR to detect sjTRECs in 23 Vbeta subfamilies was successfully established. Naive T cells from different Vbeta subfamilies could be detected with different frequency.