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Identification of a committed T cell precursor population in adult human peripheral blood.

Bruno L, Res P, Dessing M, Cella M, Spits H - J. Exp. Med. (1997)

Bottom Line: At a molecular level, they express the pre-T cell receptor alpha (pT alpha) gene, CD3-gamma, CD-delta and CD-epsilon, and RAG-1 recombination enzyme and have initiated rearrangements in the T cell receptor (TCR)-beta locus (D-J).Moreover, low levels of CD3 epsilon protein, but not of TCR-beta chain, can be detected in their cytoplasm.Our results suggest that CD4+CD3- cells identified in peripheral blood are different from CD3-CD4+CD8- thymocytes and may contain precursors of an extrathymic T cell differentiation pathway.

View Article: PubMed Central - PubMed

Affiliation: Basel Institute for Immunology, Switzerland.

ABSTRACT
Here, we report data concerning the discovery in adult human peripheral blood of a precursor cell population able to differentiate into CD4+CD3+ alpha beta + mature T cells. These cells, which represent 0.1-0.5% of total peripheral blood mononuclear cells (PBMC), express substantial levels of CD4, but lack CD3 surface expression. At a molecular level, they express the pre-T cell receptor alpha (pT alpha) gene, CD3-gamma, CD-delta and CD-epsilon, and RAG-1 recombination enzyme and have initiated rearrangements in the T cell receptor (TCR)-beta locus (D-J). Moreover, low levels of CD3 epsilon protein, but not of TCR-beta chain, can be detected in their cytoplasm. Our results suggest that CD4+CD3- cells identified in peripheral blood are different from CD3-CD4+CD8- thymocytes and may contain precursors of an extrathymic T cell differentiation pathway.

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CD3low to CD3high  T cells can be generated from the  CD2+ fraction of CD4+CD3−  CD14− PB cell population. (A)  FACS® profile of cultured CD2+,  CD4+CD3−CD14− cells after  10 d of growth in IL-2, IL-7,  PHA in the presence of allogeneic irradiated feeder cells. Double staining with CD4–PE and  CD3–FITC is shown. (B) FACS®  profiles of some representative  clones obtained by limiting dilution of CD4+CD3−CD14− sorted  cells. Culture conditions used were  the same as described above for  bulk cultures. Double staining  with CD4–PE and CD3–FITC  is shown.
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Figure 8: CD3low to CD3high T cells can be generated from the CD2+ fraction of CD4+CD3− CD14− PB cell population. (A) FACS® profile of cultured CD2+, CD4+CD3−CD14− cells after 10 d of growth in IL-2, IL-7, PHA in the presence of allogeneic irradiated feeder cells. Double staining with CD4–PE and CD3–FITC is shown. (B) FACS® profiles of some representative clones obtained by limiting dilution of CD4+CD3−CD14− sorted cells. Culture conditions used were the same as described above for bulk cultures. Double staining with CD4–PE and CD3–FITC is shown.

Mentions: As the CD2− and CD2+ fractions were differentially enriched in pTα-expressing cells, we asked whether either population could give rise to mature T cells when cultured in the presence of irradiated feeder cells, IL-2, IL-7, and PHA. CD3−CD4+CD8− thymocytes are completely unable to grow under these conditions (Spits, H., unpublished data). However, when 1 × 105 sorted potential precursor cells were cultured under these conditions, we observed that, while CD2+ cells developed into either CD4+CD3+ resembling mature T cells or CD4+CD3− cells (Fig. 8 A), CD2− cells were not able to expand. CD4+CD3− cells developing from the CD2+ fraction were found to have CD3 and TCR-β proteins in the cytoplasm and, after restimulation, gradually acquired CD3 surface expression (data not shown). pTα expression was not present in both CD4+ CD3+ and CD4+CD3− phenotypes obtained (data not shown).


Identification of a committed T cell precursor population in adult human peripheral blood.

Bruno L, Res P, Dessing M, Cella M, Spits H - J. Exp. Med. (1997)

CD3low to CD3high  T cells can be generated from the  CD2+ fraction of CD4+CD3−  CD14− PB cell population. (A)  FACS® profile of cultured CD2+,  CD4+CD3−CD14− cells after  10 d of growth in IL-2, IL-7,  PHA in the presence of allogeneic irradiated feeder cells. Double staining with CD4–PE and  CD3–FITC is shown. (B) FACS®  profiles of some representative  clones obtained by limiting dilution of CD4+CD3−CD14− sorted  cells. Culture conditions used were  the same as described above for  bulk cultures. Double staining  with CD4–PE and CD3–FITC  is shown.
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Related In: Results  -  Collection

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Figure 8: CD3low to CD3high T cells can be generated from the CD2+ fraction of CD4+CD3− CD14− PB cell population. (A) FACS® profile of cultured CD2+, CD4+CD3−CD14− cells after 10 d of growth in IL-2, IL-7, PHA in the presence of allogeneic irradiated feeder cells. Double staining with CD4–PE and CD3–FITC is shown. (B) FACS® profiles of some representative clones obtained by limiting dilution of CD4+CD3−CD14− sorted cells. Culture conditions used were the same as described above for bulk cultures. Double staining with CD4–PE and CD3–FITC is shown.
Mentions: As the CD2− and CD2+ fractions were differentially enriched in pTα-expressing cells, we asked whether either population could give rise to mature T cells when cultured in the presence of irradiated feeder cells, IL-2, IL-7, and PHA. CD3−CD4+CD8− thymocytes are completely unable to grow under these conditions (Spits, H., unpublished data). However, when 1 × 105 sorted potential precursor cells were cultured under these conditions, we observed that, while CD2+ cells developed into either CD4+CD3+ resembling mature T cells or CD4+CD3− cells (Fig. 8 A), CD2− cells were not able to expand. CD4+CD3− cells developing from the CD2+ fraction were found to have CD3 and TCR-β proteins in the cytoplasm and, after restimulation, gradually acquired CD3 surface expression (data not shown). pTα expression was not present in both CD4+ CD3+ and CD4+CD3− phenotypes obtained (data not shown).

Bottom Line: At a molecular level, they express the pre-T cell receptor alpha (pT alpha) gene, CD3-gamma, CD-delta and CD-epsilon, and RAG-1 recombination enzyme and have initiated rearrangements in the T cell receptor (TCR)-beta locus (D-J).Moreover, low levels of CD3 epsilon protein, but not of TCR-beta chain, can be detected in their cytoplasm.Our results suggest that CD4+CD3- cells identified in peripheral blood are different from CD3-CD4+CD8- thymocytes and may contain precursors of an extrathymic T cell differentiation pathway.

View Article: PubMed Central - PubMed

Affiliation: Basel Institute for Immunology, Switzerland.

ABSTRACT
Here, we report data concerning the discovery in adult human peripheral blood of a precursor cell population able to differentiate into CD4+CD3+ alpha beta + mature T cells. These cells, which represent 0.1-0.5% of total peripheral blood mononuclear cells (PBMC), express substantial levels of CD4, but lack CD3 surface expression. At a molecular level, they express the pre-T cell receptor alpha (pT alpha) gene, CD3-gamma, CD-delta and CD-epsilon, and RAG-1 recombination enzyme and have initiated rearrangements in the T cell receptor (TCR)-beta locus (D-J). Moreover, low levels of CD3 epsilon protein, but not of TCR-beta chain, can be detected in their cytoplasm. Our results suggest that CD4+CD3- cells identified in peripheral blood are different from CD3-CD4+CD8- thymocytes and may contain precursors of an extrathymic T cell differentiation pathway.

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