PALO ALTO, Calif. – StemCells, Inc. (Nasdaq:STEM) announced today the launch of STEM24™ and STEM133™, two new antibody reagents that have utility for the isolation and detection of a range of different human cell types. These antibodies are the latest additions to the Company’s SC Proven® portfolio of innovative research products.

“We plan to continue to expand and diversify the SC Proven portfolio with a range of products for the burgeoning stem cell and general cell biology research markets,” said Stewart Craig, Senior Vice President, Development and Operations at StemCells, Inc. “Our pipeline contains a series of new products that, in combination with the existing portfolio, will provide the research community with a battery of reagents for the detection, isolation, expansion, differentiation and characterization of a variety of different human and animal cell types.”

STEM24 and its conjugated forms recognize human CD24, also known as Heat Stable Antigen (HSA), a glycoprotein expressed on the surface of many human cell types, including immature human hematopoietic cells,1 peripheral blood lymphocytes,2 erythrocytes,3 and many human carcinomas.4 CD24 is also a marker of human neural differentiation.5 STEM24 is available in the following forms:

STEM24 Unconjugated

STEM24 Allophycocyanin (APC)-conjugated

STEM24 Phycoerythrin (PE)-conjugated

STEM133 and its biotin-conjugated form recognize the human antigen CD133 (Prominin-1), a marker expressed on the surface of primitive cells, including hematopoietic stem and progenitor cells,6,7 neural stem cells,8 endothelial stem cells,9 cancer stem cells,10 as well as developing epithelium.11 STEM133 is available in the following forms:

STEM133 Unconjugated

STEM133 Biotin-conjugated

About SC Proven Products

The SC Proven product portfolio comprises a range of specialty cell culture products that enable the standardized and reproducible production and propagation of highly purified stem cells and their differentiated progeny, as well as antibody reagents for cell detection, isolation and characterization. The entire SC Proven product catalog and online ordering can be found at www.scproven.com.

References

(1)

Alterman LA, et al. Characterization of the murine heat-stable antigen: An hematolymphoid differentiation antigen defined by the J11d. M1/69 and B2A2 antibodies. Eur. J. Immunol. (1990) 20:1597-1602

(2)

Allman DM, et al. Peripheral B cell maturation. I. Immature peripheral B cells in adults are heat-stable antigen hi and exhibit unique signaling characteristics. J. Immunol. (1992) 149:2533-2540

(3) Nielsen PJ, et al. Altered erythrocytes and a leaky block in B-cell development in CD24/HAS-deficient mice. Blood (1997) 89:1058-1067

(4)

Baumann P, et al. CD24 Expression Causes the Acquisition of Multiple Cellular Properties Associated with Tumor Growth and Metastasis. Cancer Res. (2005) 65:10783-10793

(5) Pruszak J, et al. CD15, CD24, and CD29 Define a surface biomarker code for neural lineage differentiation of stem cells. Stem Cells (2009) 27:2928-2940

(6) Yin AH, et al. AC133, a novel marker for human hematopoietic stem and progenitor cells. Blood (1997) 90:5002-5012

(7) Buhring HJ, et al. Expression of novel surface antigens on early hematopoietic cells. Ann NY Acad. Sci. (1999) 872:25-39

(8) Uchida N, et al. Direct Isolation of human central nervous system stem cells. PNAS (2000) 97:14720-14725

(9)

Peichev M, et al. Expression of VEGFR-2 and AC133 by circulating human CD34(+) cells identifies a population of functional endothelial precursors. Blood (2000) 95: 952-958

(10) Singh SK, et al. Identification of human brain tumour initiating cells. Nature (2004) 432:396-401

(11)

Weigmann A, et al. Prominin, a novel microvilli-specific polytopic membrane protein of the apical surface of epithelial cells, is targeted to plasmalemmal protrusion of non-epithelial cells. PNAS (1997) 94:12425-12430

About StemCells, Inc.

StemCells, Inc. is engaged in the research, development, and commercialization of cell-based therapeutics and tools for use in stem cell-based research and drug discovery. In its therapeutic product development programs, StemCells is targeting disorders of the central nervous system and the liver. StemCells’ lead product candidate, HuCNS-SC® cells (purified human neural stem cells), is currently in clinical development for spinal cord injury and two fatal neurodegenerative disorders in children, and in preclinical development for retinal disorders such as age-related macular degeneration. StemCells also markets stem cell research products, including media and reagents, under the SC Proven® brand, and is developing stem cell-based assay platforms for use in pharmaceutical research, drug discovery and drug development. Further information about StemCells is available at www.stemcellsinc.com.