HSC

CMP

CommonLymphoidProgenitor

proB preB B

CD4-CD8-

CD4+

GMP

MEP

CD8+

Thymus

Common Myeloid Progenitor

HematopoieticStem Cell

Granulocyte Macrophage

Erythrocyte Megakaryocyte

CD4+ CD8+

immature

Hematopoiesis

IgM IgD

CLP

Thymopoiesis

Thymus

TN3

HSC

44+25- 4+8+

44-25-44+25+

44-25+

4+

8+

TN4TN2

TN1

Myeloid ErythroidCMP

Common Myeloid Progenitor

CD3-CD4-CD8-

(TN, 3-5%)

CD4+CD8+

CD4+CD8+

Common Lymphoid Progenitor

CLP

HSC

CMP

CommonLymphoidProgenitor

proB preB B

CD4-CD8-

CD4+

GMP

MEP

CD8+

Thymus

Common Myeloid Progenitor

HematopoieticStem Cell

Granulocyte Macrophage

Erythrocyte Megakaryocyte

CD4+ CD8+

immature

Hematopoiesis

IgM IgD

CLP

PROPERTIES OF PLURIPOTENTIAL HEMATOPOIETIC STEM CELLS

Self-Renewal

Differentiation

Dick, J. 2003. Nature 423:231-232

HSC Self-Renewal and Differentiation

Weissman, I.L. 2000. Science 287:1442-1446

Phenotypic Characteristics of HSC

CD

127

Lin

CD

117

Lin- CD127-

PHSC 0.08 %

1.0 %

Sca-1

FACS Profile of HSC

Dorshkind, K. 1990. Annu. Rev. Immunol. 8:111-137.

HSC

CMP

CommonLymphoidProgenitor

proB preB B

CD4-CD8-

CD4+

GMP

MEP

CD8+

Thymus

Common Myeloid Progenitor

HematopoieticStem Cell

Granulocyte Macrophage

Erythrocyte Megakaryocyte

CD4+ CD8+

immature

Hematopoiesis

IgM IgD

CLP

Specification versus Commitment

Akashi et al. 2000. Nature. 404:193-197.

Expression of Transcription Factors During Hematopoiesis

Busslinger, M. 2000. Curr. Opinion Immunol. 12:151-158.

Expression of Pax5 is Required for B Lymphopoiesis

Where Should Branchpoints Be Drawn?

HSC

CMP

CommonLymphoidPrecursor

proB preB B

CD4-CD8-

CD4+

GMP

MEP

CD8+

Thymus

Common Myeloid Progenitor

HematopoieticStem Cell

Granulocyte Macrophage

Erythrocyte Megakaryocyte

CD4+ CD8+

immature

Hematopoiesis

IgM IgD

CLP

FACS Resolution of CMP and GMP

Old

CD16/32

Young

CD16/32

CMP

GMP

CD

34

0.19

0.56

0.21

0.38

Gated on Lin-Sca-1-CD127-CD117+

HSC

CLP

CMP

MultipotentlLymphoidPrecursor

proB

GMP

MEP

Common Myeloid Progenitor

HematopoieticStem Cell

Granulocyte Macrophage

Erythrocyte Megakaryocyte

Common Lymphoid Progenitor

CD45RCD43

IgM

immature mature

IgD

Myelopoiesis

preB

ETP

CD4+

CD8+

Thymus

Granulocyte Macrophage Progenitor

Megakaryocyte Erythrocyte Progenitor

Adolfsson et al. Cell 121:295, 2005

Lin- Sca-1+ c-kit+ Flt3+ cells Have B, Granulocyte, and Macrophage Developmental

Potential

HSC

CMP

CommonLymphoidProgenitor

proB preB B

CD4-CD8-

CD4+

GMP

MEP

CD8+

Thymus

Common Myeloid Progenitor

HematopoieticStem Cell

Granulocyte Macrophage

Erythrocyte Megakaryocyte

CD4+ CD8+

immature

Hematopoiesis

IgM IgD

CLP

Adolfsson et al. Cell 121:295, 2005

Lin- Sca-1+ c-kit+ Flt3+ cells Have B, Granulocyte, and Macrophage Developmental

Potential

Adolfsson et al. Cell 121:295, 2005

Lin- Sca-1+ c-kit+ Flt3+ cells Lack Erythroid andMegakaryocyte Developmental Potential

Adolfsson J. et al. Cell 121:295, 2005

Alternative Models of Hematopoiesis

HSC

CMP

CommonLymphoidProgenitor

proB preB B

CD4-CD8-

CD4+

GMP

MEP

CD8+

Thymus

Common Myeloid Progenitor

HematopoieticStem Cell

Granulocyte Macrophage

Erythrocyte Megakaryocyte

CD4+ CD8+

immature

Hematopoiesis

IgM IgD

CLP

CD

117

Sca-1

Lin- CD127+

0.03 % CLP

CD

127

Lin

0.2 %

Identification of bone marrow CLP

Kondo et al. Cell 1999. 91:661-672.

Notch and T Cell Development

MacDonald H.R. 2001. Trends in Immunol. 22:155-160.

Radtke, F. et al. 1999. Immunity10:547-558.

Thymopoiesis

Thymus

TN3

HSC

44+25- 4+8+

44-25-44+25+

44-25+

4+

8+

TN4TN2

TN1

Myeloid ErythroidCMP

Common Myeloid Progenitor

CD3-CD4-CD8-

(TN, 3-5%)

CD4+CD8+

CD4+CD8+

Common LymphoidProgenitor

CLP

Lin

CD

44

0.012%

CD127(IL-7Ra)C

D11

7(c

-kit) 0.009%

Based on Allman et al., Nat. Immunol. 4:168, 2003

Isolation of ETP by FACS

Models of Early Thymopoiesis

Bhandoola et al. J. Immunol 171:5653, 2003

HSC

CMP

CommonLymphoidProgenitor

proB preB B

CD4-CD8-

CD4+

GMP

MEP

CD8+

Thymus

Common Myeloid Progenitor

HematopoieticStem Cell

Granulocyte Macrophage

Erythrocyte Megakaryocyte

CD4+ CD8+

immature

Hematopoiesis

IgM IgD

CLP

FETAL HEMATOPOIESIS

HSC

CMP

CommonLymphoidPrecursor

proB preB B

CD4-CD8-

CD4+

GMP

MEP

CD8+

Thymus

Common Myeloid Progenitor

HematopoieticStem Cell

Granulocyte Macrophage

Erythrocyte Megakaryocyte

CD4+ CD8+

immature

Adult Hematopoiesis

IgM IgD

CLP

HSC

CMP

GMP

MEP

Common Myeloid Progenitor

HematopoieticStem Cell

Granulocyte Macrophage

Erythrocyte Megakaryocyte

Fetal Hematopoiesis

B

IgM

Pro-B Pre-B

Macrophage

Fetal Hematopoiesis

Godin and Cumano Nat. Rev. Immunol. 2: 593, 2002

Quail

Chick

Fetal Hematopoiesis

Godin and Cumano Nat. Rev. Immunol. 2: 593, 2002

Dzierzak E. et al. 1998. Immunol. Today 19:228-236.

Gekas et al. Developmental Cell 8:365, 2005.

Identification of Hematopoietic Stem Cells in the Placenta

Fetal

Adult

Fetal RBCMyeloid Cells

T cellsB-1 B Cells

Adult RBCMyeloid Cells

B2 B Cells

Fetal Hematopoiesis

B1

B2

B1 and B2 B Cells

IgM

IgMhigh

CD5+/-

CD11b

CD45R

CD45R

IgDlow

IgDhigh

Serous Cavities (peritoneum); self-

renewing; function in innate immunity

Spleen and Lymph Nodes; Produced throughout life;

function in adaptive immunity

Fetal Liver

B-1 B Cells

B2 B Cells

Adult Bone Marrow

Adapted from Rothstein TL. J. Immunol. 168:4257, 2002

Models of B1 B Cell Development

Lineage Selection

B1 Progenitor

B1 Precursor

B2 Progenitor

B2 Precursor

B1 B1B2 B2

B2 Progenitor

B2 Precursor

BCR signals

I. B Cell Development: Recent History

Carvalho TL et al. J.Exp. Med. 194:1141, 2001

B Cell Development In IL-7-/- Mice

Carvalho TL et al. J.Exp. Med. 194:1141, 2001

B-1 B Cells Are Present In IL-7-/- Mice

AGM

Placenta

Melchers, F. Nature 277:219, 1979 d9-11

Paige et al.,J. Exp. Med. 150:548, 1979 d8

Owen, Cooper, & Raff. Nature 249:361, 1974 d12

Solvason et al. Int. Immunol. 3:543, 1991 d13

Velardi, A. and M. Cooper. J. Immunol. 133:672, 1984. d14

Appearance of B Lineage Cells During Embryogenesis

Godin, I. et al. PNAS. 92:773, 1995 d8

AGM

Placenta

Solvason et al. Int. Immunol. 3:543, 1991 d13

Appearance of B Lineage Cells During Embryogenesis

Milne CD et al. Immunol. Rev. 197:75, 2004

Regulation of B Lymphopoiesis By IL-7 and TSLP

IL-7TSLP

Giliani, S. et al. Immunol. Rev. 203:110, 2005

The IL-7 and TSLP Receptors

IL-7R TSLPR TSLPR

Vosshenrich et al. PNAS 101:11070, 2004

B1 B Cell Numbers Are Reduced In Mice That Fail to Express IL-7R

HSC

CMP

GMP

MEP

Common Myeloid Progenitor

HematopoieticStem Cell

Granulocyte Macrophage

Erythrocyte Megakaryocyte

Fetal Hematopoiesis

B

IgM

Pro-B Pre-B

Macrophage

Effects of Aging on Hematopoiesis

Embryogenesis Senescence

CD4+

CD8+

T cells

B CELLSMemory B cells

ActivationGerminal center reaction

MZ B cellsSkewed VH repertoire

T CELLSMemory T cells

Activation Oligoclonal dominance

Cytokine productionEffector generation

ThymusBone Marrow

IgM+

B cells

Aging Aging

Spleen

Primary and secondary folliclewith germinal center

Periarteriolar lymphoid sheath

MZ B Cells

Exit of IgM+ cellsT cell

productionAntibody-forming

cells

AgingAging