Stem Cells, the Source of Life
Stem cells are the cells that have a capacity for self-renewal (producing more of the same cell type) and differentiation into other cell types. Two major stem cell types are present in mammals, embryonic stem cells and adult stem cells.
Embryonic Stem Cells
Embryonic stem cells are found early in the development in the inner mass of blastocyst, and possess properties of both self-renewal and potency. The embryonic stem cells are pluripotent cells, meaning they can give rise to unlimited number of other cell types.
Pluripotent embryonic stem cells are identified by expression of several pluripotency markers, including OCT4, SOX2 and NANOG. These transcription factors suppress the genes that lead to differentiation and thus maintain the pluripotency of the cells.

Figure 1: NANOG protein normally is expressed during early embryonal development, and is absent in normal adult tissues. Overexpression is observed in testicular embryonal carcinoma, shown by IHC staining using monoclonal Anti-NANOG (AMAb91393). Anti-NANOG antibody AMAb91393 also shows nuclear positivity in NTERA-2 cells and band of expected size in the WB assay. NTERA-2 cells are pluripotent human embryonal carcinoma cell line, exhibiting biochemical and developmental properties similar to the cells of the early embryo.
During embryonal development, the embryonic stem cells differentiate and give rise to the three germ layers, including ectoderm, endoderm and mesoderm, from which all the tissues and organs are ultimately formed. For instance, the dorsal part of ectoderm will specialize into neuroectoderm, which later will undergo neurulation and encephalization and will finally develop into the central nervous system.

Figure 2: SOX2 is persistently expressed during embryonal development, first in the epiblast of preimplantation embryos, then more predominantly in the central nervous system after gastrulation. Immunohistochemical staining using monoclonal Anti-SOX2 (AMAb91307) shows nuclear positivity in the developing brain and eye (A) and neural tube (B) of mouse embryo.
The neural stem cells are multipotent cells, and generate various types of neural cells in a process of neurogenesis, including neurons, astrocytes and oligodendrocytes.
Adult Stem Cells
Adult (or somatic) stem cells are found in varioustissuesoftheorganismafterbirth. Adult stem cells are lineage-restricted (multipotent), and produce only the cells representing the tissue of origin. Together with progenitor cells, they contribute to normal turnover of cells in adult tissues or may act as a repair system.

Figure 3: PAX6 is an essential transcription factor for overall eye development. Immunohistochemical staining using monoclonal Anti-PAX6 (AMAb91372) shows positivity in the developing eye of mouse embryo (A) and adult rat retina (B). ICC-IF staining in HEK-293 cells shows nuclear immunoreactivity (C).
Cell Surface Pluripotency Markers

HPA062245
- Target: NACC1
- Clonality: Polyclonal
- Validated Applications: IHC, WB*, ICC-IF
- Sequence Identity Mouse/Rat: 71/73%

AMAb91393
- Target: NANOG
- Clonality: Monoclonal
- Validated Applications: IHC, WB, ICC-IF
- Sequence Identity Mouse/Rat: -

AMAb90556
- Target: NES
- Clonality: Monoclonal
- Validated Applications: IHC, WB*, ICC-IF
- Sequence Identity Mouse/Rat: 47/42%

HPA058267
- Target: OCT4/POU5F1
- Clonality: Polyclonal
- Validated Application: ICC-IF
- Sequence Identity Mouse/Rat: 76/76%

HPA015791
- Target: SALL4
- Clonality: Polyclonal
- Validated Applications: IHC*, ICC-IF
- Sequence Identity Mouse/Rat: 74/74%

AMAb91307
- Target: SOX2
- Clonality: Monoclonal
- Validated Applications: IHC, WB*, ICC-IF
- Sequence Identity Mouse/Rat: 99/99%

HPA016604
- Target: TZL1
- Clonality: Monoclonal
- Validated Applications: IHC*, WB
- Sequence Identity Mouse/Rat: 52/53%

AMAB91414
- Target: FUT4/SSEA4/CD15
- Clonality: Monoclonal
- Validated Applications: WB
- Sequence Identity Mouse/Rat: -

AMAb91312
- Target: SOX3
- Clonality: Monoclonal
- Validated Applications: WB
- Sequence Identity Mouse/Rat: 82/31%
* Products with enhanced validation for indicated application

Figure 4: Representative examples of Orthogonal Antibody Validation. Immunohistochemical staining using polyclonal Anti-KLF (HPA002926) (A), Anti-IFITM1 (HPA004810) (B) and Anti-KIT/CD-117 (HPA004471) (C) antibodies. Note the specific expression in tissues with high RNA levels and absence of positivity in tissues with no/low RNA levels.
Transcription Factor Markers

HPA055893
- Target: c-MYC
- Clonality: Polyclonal
- Validated Application: IHC, ICC-IF
- Sequence Identity Mouse/Rat: 92/89%

HPA055964
- Target: KLF2
- Clonality: Polyclonal
- Validated Application: IHC, ICC-IF
- Sequence Identity Mouse/Rat: 87/91%

AMAb91389
- Target: KLF4
- Clonality: Monoclonal
- Validated Applications: IHC, WB, ICC-IF
- Sequence Identity Mouse/Rat: -

HPA040398
- Target: KLF5
- Clonality: Poloclonal
- Validated Applications: IHC, WB, ICC-IF
- Sequence Identity Mouse/Rat: 93/96%

AMAb91393
- Target: NANOG
- Clonality: Monoclonal
- Validated Applications: IHC, WB, ICC-IF
- Sequence Identity Mouse/Rat: -

HPA058267
- Target: OCT4/POU5F1
- Clonality: Polyclonal
- Validated Application: ICC-IF
- Sequence Identity Mouse/Rat: 76/76%

HPA015791
- Target: SALL4
- Clonality: Polyclonal
- Validated Applications: IHC*, ICC-IF
- Sequence Identity Mouse/Rat: 74/74%

HPA067196
- Target: SOX15
- Clonality: Polyclonal
- Validated Applications: IHC*, ICC-IF
- Sequence Identity Mouse/Rat: 52/52%

AMAb91307
- Target: SOX2
- Clonality: Monoclonal
- Validated Applications: IHC, WB*, ICC-IF
- Sequence Identity Mouse/Rat: 99/99%

AMAb91312
- Target: SOX3
- Clonality: Monoclonal
- Validated Applications: WB
- Sequence Identity Mouse/Rat: 82/31%

HPA062476
- Target: TCF3
- Clonality: Polyclonal
- Validated Application: IHC, WB*
- Sequence Identity Mouse/Rat: 75/73%

HPA016604
- Target: TZL1
- Clonality: Monoclonal
- Validated Applications: IHC*, WB
- Sequence Identity Mouse/Rat: 52/53%
* Products with enhanced validation for indicated application
Induced PSCs Markers

HPA004625
- Target: ANPEP/CD13
- Clonality: Polyclonal
- Validated Application: IHC*, WB, ICCC-IF
- Sequence Identity Mouse/Rat: 78/78%

AMAB91414
- Target: FUT4/SSEA4/CD15
- Clonality: Monoclonal
- Validated Applications: WB
- Sequence Identity Mouse/Rat: -

AMAb91393
- Target: NANOG
- Clonality: Monoclonal
- Validated Application: IHC, WB, ICC-IF
- Sequence Identity Mouse/Rat: -
* Products with enhanced validation for indicated application
Germ Cell Markers
(during specification)

HPA019777
- Target: DAZL
- Clonality: Polyclonal
- Validated Application: IHC*, WB*
- Sequence Identity Mouse/Rat: 92/92%

HPA037764
- Target: DDX4/MVH
- Clonality: Polyclonal
- Validated Applicatio: IHC*
- Sequence Identity Mouse/Rat: 99/99%

HPA069146
- Target: GDF9
- Clonality: Polyclonal
- Validated Application: IHC
- Sequence Identity Mouse/Rat: 59/58%

HPA004810
- Target: IFITM1
- Clonality: Polyclonal
- Validated Application: IHC*, WB, ICC-IF
- Sequence Identity Mouse/Rat: 56/56%

HPA058267
- Target: OCT4/POU5Fq
- Clonality: Polyclonal
- Validated Application: ICC-IF
- Sequence Identity Mouse/Rat: 76/76%

HPA062285
- Target: TEKT1
- Clonality: Polyclonal
- Validated Application: IHC
- Sequence Identity Mouse/Rat: 80/55%
* Products with enhanced validation for indicated application
Ectoderm and Endoderm Markers

HPA035827
- Target: CHRD
- Clonality: Polyclonal
- Validated Application: IHC
- Sequence Identity Mouse/Rat: 90/91%

HPA067284
- Target: FOXJ3
- Clonality: Polyclonal
- Validated Applications: ICC-IF
- Sequence Identity Mouse/Rat: 90/91%

HPA067809
- Target: GBX2
- Clonality: Polyclonal
- Validated Applications: WB, ICC-IF
- Sequence Identity Mouse/Rat: 96/96%

AMAb90556
- Target: NES
- Clonality: Monoclonal
- Validated Applications: IHC, WB*, ICC-IF
- Sequence Identity Mouse/Rat: 47/42%

HPA061318
- Target: NOG
- Clonality: Polyclonal
- Validated Application: IHC
- Sequence Identity Mouse/Rat: 100/100%

AMAb91224
- Target: P63/TP73L
- Clonality: Monoclonal
- Validated Application: IHC, WB
- Sequence Identity Mouse/Rat: 99/94%

HPA070751
- Target: PAX2
- Clonality: Polyclonal
- Validated Applications: IHC*, ICC-IF
- Sequence Identity Mouse/Rat: 100/100%

AMAb91372
- Target: PAX6
- Clonality: Monoclonal
- Validated Application: IHC, ICC-IF
- Sequence Identity Mouse/Rat: 100/100%

AMAb91395
- Target: TUBB3
- Clonality: Monoclonal
- Validated Application: IHC, WB, ICC-IF
- Sequence Identity Mouse/Rat:
* Products with enhanced validation for indicated application