The differentiation or maturation potential of human thymocyte precursors has been studied by using a population of CD3/TCR-, CD4-, CD8- ("triple negative") thymocytes isolated by negative selection (TCR, T-cell receptor). This cell population, however, also contained 30-50% previously undescribed cells expressing very low levels of CD3/TCRγδ (CD3/TCRγδlow; ≈60% of which expressed the variable region gene Vδ1). Correspondingly, TCR γ and TCR δ gene rearrangements (predominantly Vδ1/joining region Jδ1) and full-length TCR γ and TCR δ transcripts (but only immature TCR β and no TCR α mRNAs) were found. These cells mobilized Ca2+ in response to ligation of CD3 but not following ligation of TCRγδ. When cultured in the presence of interleukin 7 or interleukin 2, these thymocytes gave rise to 30-60% CD3/TCRγδmedium and high cells (60-70% expressing Vδ1) seen as discrete populations. Thus, the proportion and Vδ phenotype of in vitro generated CD3/TCRγδ cells closely resembled those of CD3/TCRγδlow cells in freshly isolated "thymocyte precursor" preparations. Small numbers of TCRαβ+ cells also appeared. It is thus uncertain whether maturation, differentiation, or both account for the appearance of mature CD3/TCR+ thymocytes, although the former appears most likely.
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 1990|
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