( MENLO PARK Calif.--(BUSINESS WIRE)--Ju...)Research Indicates Geron's Human Embryonic Stem Cell-Based,Therapeutic for Spinal Cord Injury Evades Direct Attack by the,Human Immune System,Health

Presented by Geron scientist Ross Okamura at the Federation of Clinical Immunology Societies meeting in San Diego, the findings could mean that patients treated with GRNOPC1 would require significantly lower doses and/or shorter courses of immunosuppression than what are required for patients who undergo solid organ transplants.

"The results imply that our cell-based therapeutic, unlike traditional solid organ transplants, is minimally recognized by the human immune system," said Thomas B. Okarma, Ph.D, M.D., Geron's president and chief executive officer. "Because GRNOPC1 cells are allogenic, it was expected that they would be recognized and destroyed by multiple immune rejection modulators. This isn't the case. The benefit to patients is that a reduction in the requirement for immunosuppression decreases the potential for untoward side effects that are common with those types of drugs."

The data indicate that GRNOPC1 cells have low susceptibility to both direct cell and antibody-mediated immune responses. The data also show that GRNOPC1 cells do not widely express non-human antigens, such as Neu5GC, that might have originated from mouse feeder cells to which the original hESC cell line was exposed in its initial derivation. Expression of such non-human antigens would typically lead to lysis by antibodies present in the sera of normal individuals.

In the studies, GRNOPC1 cells were tested for susceptibility to both immune effector cells and sera from normal healthy individuals. GRNOPC1 cells stimulated very low levels of T cell proliferation. Allogenic T cell proliferation is a
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