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                                                                    Sangamo BioSciences, Inc.
                                                                       Point Richmond Tech Center
                                                                               501 Canal Boulevard
                                                                              Richmond, CA 94804
                                                                 510-970-6000 510-236-8951(Fax)


                                                                                       MaxCyte, Inc.
                                                                        22 Firstfield Road, Suite 250
                                                                           Gaithersburg, MD 20878

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        SANGAMO BIOSCIENCES LICENSES MAXCYTE CELL LOADING
       TECHNOLOGY FOR ZFP THERAPEUTIC PROGRAM FOR HIV/AIDS

Gaithersburg, MD and Richmond, CA ­ March [2], 2006 ­ MaxCyte, Inc. and Sangamo
BioSciences, Inc. (Nasdaq: SGMO) announced today a license, option, development, and supply
agreement to utilize MaxCyte's proprietary cell loading system for use in Sangamo's HIV/CCR5 ZFP
TherapeuticTM program. The two companies have initiated a research and development plan to
evaluate and further develop the GMP-compliant MaxCyte system to load zinc finger DNA-binding
protein (ZFP)-based therapeutics into cells. Sangamo also has the option to utilize MaxCyte's system
for ZFP Therapeutics in oncology.

The agreement provides Sangamo an option for a commercial license to MaxCyte's technology that
includes a supply contract and clinical and commercial milestones to MaxCyte for products
developed under the agreement. Under the license, Sangamo has the right to reference MaxCyte's
FDA Master File in its regulatory submissions. Financial terms of the agreement were not disclosed.

"We believe MaxCyte's cell loading technology can be an important component of an ex vivo
delivery system for our HIV T-cell program that uses ZFP nucleases (ZFN) to modify the gene for the
CCR5 protein. A key part of our business model is to identify partners such as MaxCyte that have
complementary delivery methods that can accelerate the clinical success of our programs and support
their ultimate commercialization," said Edward Lanphier, President and CEO, Sangamo BioSciences,
Inc.

"Preclinical data employing Sangamo's ZFN approach are encouraging, and we are excited about
working with Sangamo to help move its HIV product into clinical trials. We're confident that the
unmatched efficiency and scalability of our cell loading technology can have a positive impact on the
clinical and commercial production of promising therapeutics such as Sangamo's," said Douglas
Doerfler, President and CEO, MaxCyte Inc.

About MaxCyte
MaxCyte is a clinical-stage cell therapeutics company with a rapidly growing pipeline of partnered
and internally developed therapeutic candidates. The Company's proprietary ex vivo cell loading
technology overcomes critical obstacles, such as safety, scalability, and reproducibility, which are
fundamental to successful cell-based therapies. MaxCyte has demonstrated the value of its versatile
technology by building a pipeline of six partnered therapeutic programs in oncology, pulmonary,
metabolic and infectious diseases as well as developing three drug candidates in collaboration with
leading researchers: one in Phase I/II clinical trials for treatment of chronic lymphocytic leukemia and
two preclinical solid tumor programs. The MaxCyte system has a FDA Master File in place at CBER.
For more information, visit www.maxcyte.com.

About Sangamo
Sangamo BioSciences, Inc. is focused on the research and development of novel DNA-binding
proteins for therapeutic gene regulation and modification. The most advanced ZFP TherapeuticTM
development programs are currently in Phase 1 clinical trials for evaluation of safety in patients with
diabetic neuropathy and peripheral artery disease. Other therapeutic development programs are
focused on macular degeneration, ischemic heart disease, congestive heart failure, neuropathic pain,
and infectious and monogenic diseases. Sangamo's core competencies enable the engineering of a
class of DNA-binding proteins known as zinc finger DNA-binding proteins (ZFPs). By engineering
ZFPs that recognize a specific DNA sequence Sangamo has created ZFP transcription factors (ZFP
TFTM) that can control gene expression and, consequently, cell function. Sangamo is also developing
sequence-specific ZFP Nucleases (ZFNTM) for therapeutic gene modification as a treatment for a
variety of monogenic diseases, such as sickle cell anemia, and for infectious diseases, such as HIV.
Sangamo has established several Enabling Technology Agreements with companies to apply its ZFP
Technology to enhance the production of protein pharmaceuticals. Research at Sangamo is partially
funded by an Advanced Technology Program (ATP) grant awarded by the National Institute of
Standards and Technology (NIST). For more information about Sangamo, visit the company's web
site at www.sangamo.com .

This press release may contain forward-looking statements based on Sangamo's current expectations.
These forward-looking statements include, without limitation, references to the development of the
MaxCyte system to load ZFP Therapeutics into cells and the acceleration of the success of our
clinical programs. Actual results may differ materially from these forward-looking statements due to
a number of factors, including uncertainties relating to the further study and development of our ZFP
technology, initiation of clinical trials of ZFP Therapeutics, whether such clinical trials will validate
and support tolerability and efficacy of ZFP Therapeutics, the effectiveness of our research and
development of novel ZFP TFs and ZFNs and therapeutic applications of Sangamo's ZFP technology
platform, technological challenges, Sangamo's ability to develop commercially viable products and
technological developments by its competitors. See the company's SEC filings, and in particular, the
risk factors described in the company's Annual Report on Form 10-K and its most recent 10-Q.
Sangamo BioSciences, Inc. assumes no obligation to update the forward-looking information
contained in this press release.

Contacts:
MaxCyte, Inc.                                                      Sangamo BioSciences, Inc.
Ron Holtz                                                          Elizabeth Wolffe, Ph.D.
Chief Financial Officer                                            ewolffe@sangamo.com

301-944-1624                                                       510-970-6000 X271


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