Ntained for up to 3-4 weeks.Human T Lineage Development In VitroFigure 3. Generation of CD3+ thymocytes. (A) CD7hiCD3hi and CD7 dim CD3 cells were detected at day 7. (B) By day 12 approximately 90 of all the cells generated were CD3+ thymocytes. (C) A matrix seeded with approximately 300 CD34+ cord blood derived progenitors generated about 2900 CD3+ cells after 14 days. At that time about 150 CD34+ progenitors were still present whereas no other cell types were detected. The image A is representative of three different experiments while images B and C show a single experiment.doi: 10.1371/journal.pone.0069572.gFlow Cytometry AnalysisCell suspensions were analyzed using different combinations of conjugated monoclonal antibodies (mAbs) and their corresponding isotype controls after pre-incubation for 10 minutes at 4oC with 10 of FcR blocking reagent (Miltenyi). All antibodies were obtained from BD Biosciences unless stated otherwise, and were used according to the manufacturer’s instructions. The following mAbs (clones) were used: CD1a (HI149), CD3 (UCHT1), CD4 (RPA-T4), CD45 (HI-30), CD8 (SK-1), CD7 (6B7), CD38 (HIT-2), CD10 (HI-10), HLA-DR (G46-6), CD11c (Biolegend 3.9), CD56 (Biolegend MEM-188), CD135-APC (Biolegend BV 10A4H2), CD45/ CD34 cocktail (Miltenyi MB4-6D6/AC136), CD20 (Miltenyi LT20), Analysis of flow cytometry samples was performed on a C6 Accuri instrument.Reverse transcriptase-polymerase chain reactionThe RNA was isolated using Trizol (Invitrogen) and total RNA (1 ) in 20 was transcribed into cDNA using the high capacity cDNA Reverse Transcription kit (Applied Biosystems). The cDNA product was mixed with QIAGEN SYBR Green Reagent and primers, and MedChemExpress ML 281 Real-time PCR performed using a CFX96 Bio-Rad real time PCR system (Bio-Rad). For the generation of standard curves, gene inserts were amplified using Green GoTaq Flexi DNA Polymerase (Promega), and the PCR product size controlled by 1.5 agarose gel electrophoresis. DNA concentration was measured with a spectrophotometer (Picodrop) and serial dilutions prepared starting from 1011 copies/ as calculated by using Avogadro’s formula. All cDNA samples were 50-14-6 site normalized to ribosomal protein subunit 29 (RPS-29) housekeeping gene signals [12]. Primers used were as follows (anneal temperature): Dll-Human T Lineage Development In VitroFigure 4. Most of generated cells are mature thymocytes by day12. . The presence of double positive CD4+CD8+ and either CD4+ or CD8+ single positive CD3+ thymocytes was evident by day 12 when only about 2 of total CD45+ cells still expressed CD34. The images are representative of three different experiments.doi: 10.1371/journal.pone.0069572.gforward 5′ CTGATGACCTCGCAACAGAA3′ reverse 5′ ATGCTGCTCATCACATCCAG3′ (60 ), Dll-4 forward 5’ACTGCCCTTCAATATTCACCT-3′ reverse 5′ GCTGGTTTGCTCATCCAATAA3′ (60 ), IL-7 forward 5′ TGAAACTGCAGTCGCGGCGT3′ reverse 5′ AACATGGTCTGCGGGAGGCG3′ (57 ), RPS-29 forward 5′ GCTGTACTGGAGCCACCCGC3′ reverse 5′ TCCTTCGCGTACTGACGGAAACAC3′ (55-60 ).10000 goat anti-rat IgG IRDye 800 (LI-COR) and normalized to -actin using 1:10000 mouse IgG2a isotype anti-human–actin (Sigma-Aldrich) plus 1:10000 goat anti-mouse IgG IRDye 680 (LI-COR).TREC analysisDNA was isolated from blood and newly generated CD3+ cells using Trizol reagent (Invitrogen) according to the manufacturer’s instructions and DJ signal join ype T-cell receptor excision circles (sj-TREC) were assayed. DNA (50 ng) was used in each RPS-29, sj-TREC PCR reactions in order to calculate T.Ntained for up to 3-4 weeks.Human T Lineage Development In VitroFigure 3. Generation of CD3+ thymocytes. (A) CD7hiCD3hi and CD7 dim CD3 cells were detected at day 7. (B) By day 12 approximately 90 of all the cells generated were CD3+ thymocytes. (C) A matrix seeded with approximately 300 CD34+ cord blood derived progenitors generated about 2900 CD3+ cells after 14 days. At that time about 150 CD34+ progenitors were still present whereas no other cell types were detected. The image A is representative of three different experiments while images B and C show a single experiment.doi: 10.1371/journal.pone.0069572.gFlow Cytometry AnalysisCell suspensions were analyzed using different combinations of conjugated monoclonal antibodies (mAbs) and their corresponding isotype controls after pre-incubation for 10 minutes at 4oC with 10 of FcR blocking reagent (Miltenyi). All antibodies were obtained from BD Biosciences unless stated otherwise, and were used according to the manufacturer’s instructions. The following mAbs (clones) were used: CD1a (HI149), CD3 (UCHT1), CD4 (RPA-T4), CD45 (HI-30), CD8 (SK-1), CD7 (6B7), CD38 (HIT-2), CD10 (HI-10), HLA-DR (G46-6), CD11c (Biolegend 3.9), CD56 (Biolegend MEM-188), CD135-APC (Biolegend BV 10A4H2), CD45/ CD34 cocktail (Miltenyi MB4-6D6/AC136), CD20 (Miltenyi LT20), Analysis of flow cytometry samples was performed on a C6 Accuri instrument.Reverse transcriptase-polymerase chain reactionThe RNA was isolated using Trizol (Invitrogen) and total RNA (1 ) in 20 was transcribed into cDNA using the high capacity cDNA Reverse Transcription kit (Applied Biosystems). The cDNA product was mixed with QIAGEN SYBR Green Reagent and primers, and Real-time PCR performed using a CFX96 Bio-Rad real time PCR system (Bio-Rad). For the generation of standard curves, gene inserts were amplified using Green GoTaq Flexi DNA Polymerase (Promega), and the PCR product size controlled by 1.5 agarose gel electrophoresis. DNA concentration was measured with a spectrophotometer (Picodrop) and serial dilutions prepared starting from 1011 copies/ as calculated by using Avogadro’s formula. All cDNA samples were normalized to ribosomal protein subunit 29 (RPS-29) housekeeping gene signals [12]. Primers used were as follows (anneal temperature): Dll-Human T Lineage Development In VitroFigure 4. Most of generated cells are mature thymocytes by day12. . The presence of double positive CD4+CD8+ and either CD4+ or CD8+ single positive CD3+ thymocytes was evident by day 12 when only about 2 of total CD45+ cells still expressed CD34. The images are representative of three different experiments.doi: 10.1371/journal.pone.0069572.gforward 5′ CTGATGACCTCGCAACAGAA3′ reverse 5′ ATGCTGCTCATCACATCCAG3′ (60 ), Dll-4 forward 5’ACTGCCCTTCAATATTCACCT-3′ reverse 5′ GCTGGTTTGCTCATCCAATAA3′ (60 ), IL-7 forward 5′ TGAAACTGCAGTCGCGGCGT3′ reverse 5′ AACATGGTCTGCGGGAGGCG3′ (57 ), RPS-29 forward 5′ GCTGTACTGGAGCCACCCGC3′ reverse 5′ TCCTTCGCGTACTGACGGAAACAC3′ (55-60 ).10000 goat anti-rat IgG IRDye 800 (LI-COR) and normalized to -actin using 1:10000 mouse IgG2a isotype anti-human–actin (Sigma-Aldrich) plus 1:10000 goat anti-mouse IgG IRDye 680 (LI-COR).TREC analysisDNA was isolated from blood and newly generated CD3+ cells using Trizol reagent (Invitrogen) according to the manufacturer’s instructions and DJ signal join ype T-cell receptor excision circles (sj-TREC) were assayed. DNA (50 ng) was used in each RPS-29, sj-TREC PCR reactions in order to calculate T.