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The Scientist 15[21]:21, Oct. 29, 2001
TOOLS AND TECHNOLOGY
Improving Cell Death
Upstate Biotechnology's membranous FasL packs
more potency for less money
The process of apoptosis removes infected, mutated, and aging cells from
the body. Gene-directed apoptosis, or programmed cell death, occurs
normally during development and in many pathological conditions. In 1989
the cell surface receptor, Fas (CD95), was identified as the antigen
recognized by antibodies that initiate cell death. Normally, Fas
initiates cell death by binding the Fas ligand (FasL). Understanding and
manipulating the interactions between these two proteins plays a
critical role in the study and treatment of cancer, autoimmune diseases,
and viral infections.
Traditionally researchers have studied the interactions between Fas and
FasL using soluble FasL (sFasL) or anti-Fas monoclonal antibodies (mAbs).
Now Lake Placid, N.Y.-based Upstate Biotechnology Inc.
offers a less expensive and more potent research tool-a bioactive,
lyophilized form of FasL on membranous vesicles.
FasL, a TNF superfamily member, is a mediator of immune responses, and
the Fas/FasL system plays a pivotal role in T-cell development and clonal
deletion of self-reactive T cells. Binding of FasL to its receptor
activates death domain proteins, which in turn activate various caspase
family members.1 The caspases, which are cysteine-dependent,
aspartate-specific proteases, target specific enzymes involved in cell
function, leading to cell death.
Upstate Biotechnology's preparation of FasL-expressing membranous
vesicles, developed from recombinant human full-length FasL, exerts a much
higher cytotoxic and apoptotic activity than that of other FasL tools.2
According to Upstate Biotechnology's John Ficele,
this makes membrane-bound FasL more cost-effective than other FasL
reagents. Indeed, the company's membranous FasL yields approximately 25
percent more assays for half the price of sFasL. Another advantage of
these vesicles is that they can attack sFasL- and anti-Fas mAb-resistant
cells.2 Researchers can further enhance the cytotoxicity of
membranous FasL with either Polybrene or poly-L-lysine.2
References
1. J. Cortese, "Death watch II: Caspases and apoptosis,"
The
Scientist, 15[13]:24, June 25, 2001.
2. S. Jodo et al., "Bioactivities of Fas ligand-expressing
retroviral particles," Journal of Immunology, 164:5062-9,
2000.
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