Maturation or differentiation of human thymocyte precursors in vitro?
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/TCR gamma delta (CD3/TCR gamma delta low; approximately 60% of which expressed the variable region gene V delta 1). Correspondingly, TCR gamma and TCR delta gene rearrangements (predominantly V delta 1/joining region J delta 1) and full-length TCR gamma and TCR delta transcripts (but only immature TCR beta and no TCR alpha mRNAs) were found. These cells mobilized Ca2+ in response to ligation of CD3 but not following ligation of TCR gamma delta. When cultured in the presence of interleukin 7 or interleukin 2, these thymocytes gave rise to 30-60% CD3/TCR gamma delta medium and high cells (60-70% expressing V delta 1) seen as discrete populations. Thus, the proportion and V delta phenotype of in vitro generated CD3/TCR gamma delta cells closely resembled those of CD3/TCR gamma delta low cells in freshly isolated "thymocyte precursor" preparations. Small numbers of TCR alpha beta + 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.
Groh
V
V
Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, MA 02138.
Fabbi
M
M
Strominger
J L
JL
D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000032:analysis; D015139:Blotting, Southern; D002454:Cell Differentiation; D002460:Cell Line; D002648:Child; D015329:Gene Rearrangement, T-Lymphocyte; D006801:Humans; D066298:In Vitro Techniques; D008212:Lymphocyte Depletion; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000032:analysis / Q000235:genetics; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D011948:Receptors, Antigen, T-Cell