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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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Detection of partial (D–J) rearrangements of the TCR-β locus. (A) At DNA level. Genomic DNA was isolated from sorted  CD4+CD3−CD14−, CD4+CD3+, CD14+, and total PBMC and amplified by PCR using TBF1 and TBR1 primers to detect Dβ1–Jβ1 rearrangements. Normal PBMC and monocytes (CD14+) were used as positive and negative controls, respectively. PCR products were blotted and  hybridized with TBR3 probe. PCR products, ranging from 200 to 3,000  bp, and the Jβ segment used are indicated. GL, germline. (B) At RNA  level. Total RNA was first isolated from sorted CD4+CD3−CD14−,  CD14+, and from total PBMC and, subsequently, RT–PCR using TBF1  and Cβ primer set was performed. PCR products were blotted and  probed with a Cβ-specific primer.
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Figure 2: Detection of partial (D–J) rearrangements of the TCR-β locus. (A) At DNA level. Genomic DNA was isolated from sorted CD4+CD3−CD14−, CD4+CD3+, CD14+, and total PBMC and amplified by PCR using TBF1 and TBR1 primers to detect Dβ1–Jβ1 rearrangements. Normal PBMC and monocytes (CD14+) were used as positive and negative controls, respectively. PCR products were blotted and hybridized with TBR3 probe. PCR products, ranging from 200 to 3,000 bp, and the Jβ segment used are indicated. GL, germline. (B) At RNA level. Total RNA was first isolated from sorted CD4+CD3−CD14−, CD14+, and from total PBMC and, subsequently, RT–PCR using TBF1 and Cβ primer set was performed. PCR products were blotted and probed with a Cβ-specific primer.

Mentions: Several DJβ rearrangements (DJβ1.3, DJβ1.5, and DJβ1.6) could be demonstrated in genomic DNA from CD4+CD3− CD14− progenitors, in addition to a dominant germline band (GL) (Fig. 2 A). As expected, monocytes (CD14+) were characterized by the presence of an amplification product only in germline configuration, while in mature T cells (CD4+CD3+) and total PBMC all the different DJβ rearrangements were present. As expected, a band corresponding to germline gene configuration also could be detected in PBMC because of the presence of non-T populations. This result suggests the presence of T cell lineage committed cells within the pTα+ CD4+CD3− population.


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)

Detection of partial (D–J) rearrangements of the TCR-β locus. (A) At DNA level. Genomic DNA was isolated from sorted  CD4+CD3−CD14−, CD4+CD3+, CD14+, and total PBMC and amplified by PCR using TBF1 and TBR1 primers to detect Dβ1–Jβ1 rearrangements. Normal PBMC and monocytes (CD14+) were used as positive and negative controls, respectively. PCR products were blotted and  hybridized with TBR3 probe. PCR products, ranging from 200 to 3,000  bp, and the Jβ segment used are indicated. GL, germline. (B) At RNA  level. Total RNA was first isolated from sorted CD4+CD3−CD14−,  CD14+, and from total PBMC and, subsequently, RT–PCR using TBF1  and Cβ primer set was performed. PCR products were blotted and  probed with a Cβ-specific primer.
© Copyright Policy
Related In: Results  -  Collection

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Figure 2: Detection of partial (D–J) rearrangements of the TCR-β locus. (A) At DNA level. Genomic DNA was isolated from sorted CD4+CD3−CD14−, CD4+CD3+, CD14+, and total PBMC and amplified by PCR using TBF1 and TBR1 primers to detect Dβ1–Jβ1 rearrangements. Normal PBMC and monocytes (CD14+) were used as positive and negative controls, respectively. PCR products were blotted and hybridized with TBR3 probe. PCR products, ranging from 200 to 3,000 bp, and the Jβ segment used are indicated. GL, germline. (B) At RNA level. Total RNA was first isolated from sorted CD4+CD3−CD14−, CD14+, and from total PBMC and, subsequently, RT–PCR using TBF1 and Cβ primer set was performed. PCR products were blotted and probed with a Cβ-specific primer.
Mentions: Several DJβ rearrangements (DJβ1.3, DJβ1.5, and DJβ1.6) could be demonstrated in genomic DNA from CD4+CD3− CD14− progenitors, in addition to a dominant germline band (GL) (Fig. 2 A). As expected, monocytes (CD14+) were characterized by the presence of an amplification product only in germline configuration, while in mature T cells (CD4+CD3+) and total PBMC all the different DJβ rearrangements were present. As expected, a band corresponding to germline gene configuration also could be detected in PBMC because of the presence of non-T populations. This result suggests the presence of T cell lineage committed cells within the pTα+ CD4+CD3− population.

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.

Show MeSH