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The earliest step in B lineage differentiation from common lymphoid progenitors is critically dependent upon interleukin 7.

Miller JP, Izon D, DeMuth W, Gerstein R, Bhandoola A, Allman D - J. Exp. Med. (2002)

Bottom Line: Using a stromal-free culture system, we show that interleukin (IL)-7 is sufficient to promote the in vitro differentiation of CLPs into B220(+) CD19(+) B lineage progenitors.Consistent with current models of early B cell development, surface expression of B220 was initiated before CD19 and was accompanied by the loss of T lineage potential.These findings challenge previous notions regarding the point in B cell development affected by the loss of IL-7R signaling and suggest that IL-7 plays a key and requisite role during the earliest phases of B cell development.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.

ABSTRACT
Little is known about the signals that promote early B lineage differentiation from common lymphoid progenitors (CLPs). Using a stromal-free culture system, we show that interleukin (IL)-7 is sufficient to promote the in vitro differentiation of CLPs into B220(+) CD19(+) B lineage progenitors. Consistent with current models of early B cell development, surface expression of B220 was initiated before CD19 and was accompanied by the loss of T lineage potential. To address whether IL-7 receptor (R) activity is essential for early B lineage development in vivo, we examined the frequencies of CLPs and downstream pre-pro- and pro-B cells in adult mice lacking either the alpha chain or the common gamma chain (gamma(c)) of the IL-7R. The data indicate that although gamma(c)(-/-) mice have normal frequencies of CLPs, both gamma(c)(-/-) and IL-7R(alpha)(-/-) mice lack detectable numbers of all downstream early B lineage precursors, including pre-pro-B cells. These findings challenge previous notions regarding the point in B cell development affected by the loss of IL-7R signaling and suggest that IL-7 plays a key and requisite role during the earliest phases of B cell development.

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Lack of AA4+ B220+ CD43+ pro-B cells in adults lacking components of the IL-7R. BM cells from 8-wk-old C57BL/6, μMT−/−, IL-7Rα+, and γc−/− mice were stained with FL-CD43 (S7), PE-CD19 (1D3), APC-Cy7-B220, APC-AA4, and BI–anti-CD24/HSA (30F1) revealed with SA-PE-TR. 200,000 events per tube were subsequently analyzed on a MoFlo® flow cytometer as described in Materials and Methods. Data are representative of four separate experiments. Numbers indicate the fraction of events among the parent population falling within the indicated gate and were consistent with three or more mice per group.
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fig3: Lack of AA4+ B220+ CD43+ pro-B cells in adults lacking components of the IL-7R. BM cells from 8-wk-old C57BL/6, μMT−/−, IL-7Rα+, and γc−/− mice were stained with FL-CD43 (S7), PE-CD19 (1D3), APC-Cy7-B220, APC-AA4, and BI–anti-CD24/HSA (30F1) revealed with SA-PE-TR. 200,000 events per tube were subsequently analyzed on a MoFlo® flow cytometer as described in Materials and Methods. Data are representative of four separate experiments. Numbers indicate the fraction of events among the parent population falling within the indicated gate and were consistent with three or more mice per group.

Mentions: As shown in Fig. 3 , B220+ CD43+ BM cells in adult C57BL/6 mice can be subdivided into both AA4+ CD19+ pro-B cells and a AA4− CD19+ population that was not detected in μMT−/− BM. Significantly, although B220+ CD43+ AA4+ CD19+ CD24/HSA+ pro-B cells were clearly apparent in the BM of C57BL/6 and μMT−/− adults, we could not detect these cells in either IL-7Rα−/− or γc−/− adults (Fig. 3), indicating an arrest in B cell development before the pro-B cell stage in IL-7R–deficient mice. Consistent with this interpretation, among these populations only cells derived from the AA4+ CD19+ population proliferated in IL-7–supplemented stromal cultures, and additional analyses demonstrated that the B220+ CD43+ CD19+ AA4− population (Fig. 3, upper right) expressed high levels of sIgM (unpublished data), and may therefore constitute recirculating CD43+B1 B cells (21). Furthermore, although we readily detected B cells in the spleens of IL-7Rα−/− and γc−/− adults, these cells expressed a sIgMhigh sIgDlow surface phenotype indicative of fetal-derived B1 B cells in accordance with the recent findings of Carvalho et al. (19; unpublished data). Finally, it should be noted that an AA4− CD19low population of unknown identity was detected in a subset of IL-7Rα−/− and γc−/− adults. Together, these data indicate that the loss of IL-7R activity leads to an arrest in B cell development before the development of pro-B cells.


The earliest step in B lineage differentiation from common lymphoid progenitors is critically dependent upon interleukin 7.

Miller JP, Izon D, DeMuth W, Gerstein R, Bhandoola A, Allman D - J. Exp. Med. (2002)

Lack of AA4+ B220+ CD43+ pro-B cells in adults lacking components of the IL-7R. BM cells from 8-wk-old C57BL/6, μMT−/−, IL-7Rα+, and γc−/− mice were stained with FL-CD43 (S7), PE-CD19 (1D3), APC-Cy7-B220, APC-AA4, and BI–anti-CD24/HSA (30F1) revealed with SA-PE-TR. 200,000 events per tube were subsequently analyzed on a MoFlo® flow cytometer as described in Materials and Methods. Data are representative of four separate experiments. Numbers indicate the fraction of events among the parent population falling within the indicated gate and were consistent with three or more mice per group.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2193997&req=5

fig3: Lack of AA4+ B220+ CD43+ pro-B cells in adults lacking components of the IL-7R. BM cells from 8-wk-old C57BL/6, μMT−/−, IL-7Rα+, and γc−/− mice were stained with FL-CD43 (S7), PE-CD19 (1D3), APC-Cy7-B220, APC-AA4, and BI–anti-CD24/HSA (30F1) revealed with SA-PE-TR. 200,000 events per tube were subsequently analyzed on a MoFlo® flow cytometer as described in Materials and Methods. Data are representative of four separate experiments. Numbers indicate the fraction of events among the parent population falling within the indicated gate and were consistent with three or more mice per group.
Mentions: As shown in Fig. 3 , B220+ CD43+ BM cells in adult C57BL/6 mice can be subdivided into both AA4+ CD19+ pro-B cells and a AA4− CD19+ population that was not detected in μMT−/− BM. Significantly, although B220+ CD43+ AA4+ CD19+ CD24/HSA+ pro-B cells were clearly apparent in the BM of C57BL/6 and μMT−/− adults, we could not detect these cells in either IL-7Rα−/− or γc−/− adults (Fig. 3), indicating an arrest in B cell development before the pro-B cell stage in IL-7R–deficient mice. Consistent with this interpretation, among these populations only cells derived from the AA4+ CD19+ population proliferated in IL-7–supplemented stromal cultures, and additional analyses demonstrated that the B220+ CD43+ CD19+ AA4− population (Fig. 3, upper right) expressed high levels of sIgM (unpublished data), and may therefore constitute recirculating CD43+B1 B cells (21). Furthermore, although we readily detected B cells in the spleens of IL-7Rα−/− and γc−/− adults, these cells expressed a sIgMhigh sIgDlow surface phenotype indicative of fetal-derived B1 B cells in accordance with the recent findings of Carvalho et al. (19; unpublished data). Finally, it should be noted that an AA4− CD19low population of unknown identity was detected in a subset of IL-7Rα−/− and γc−/− adults. Together, these data indicate that the loss of IL-7R activity leads to an arrest in B cell development before the development of pro-B cells.

Bottom Line: Using a stromal-free culture system, we show that interleukin (IL)-7 is sufficient to promote the in vitro differentiation of CLPs into B220(+) CD19(+) B lineage progenitors.Consistent with current models of early B cell development, surface expression of B220 was initiated before CD19 and was accompanied by the loss of T lineage potential.These findings challenge previous notions regarding the point in B cell development affected by the loss of IL-7R signaling and suggest that IL-7 plays a key and requisite role during the earliest phases of B cell development.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.

ABSTRACT
Little is known about the signals that promote early B lineage differentiation from common lymphoid progenitors (CLPs). Using a stromal-free culture system, we show that interleukin (IL)-7 is sufficient to promote the in vitro differentiation of CLPs into B220(+) CD19(+) B lineage progenitors. Consistent with current models of early B cell development, surface expression of B220 was initiated before CD19 and was accompanied by the loss of T lineage potential. To address whether IL-7 receptor (R) activity is essential for early B lineage development in vivo, we examined the frequencies of CLPs and downstream pre-pro- and pro-B cells in adult mice lacking either the alpha chain or the common gamma chain (gamma(c)) of the IL-7R. The data indicate that although gamma(c)(-/-) mice have normal frequencies of CLPs, both gamma(c)(-/-) and IL-7R(alpha)(-/-) mice lack detectable numbers of all downstream early B lineage precursors, including pre-pro-B cells. These findings challenge previous notions regarding the point in B cell development affected by the loss of IL-7R signaling and suggest that IL-7 plays a key and requisite role during the earliest phases of B cell development.

Show MeSH
Related in: MedlinePlus