T Cell Sciences Inc. announced Tuesday that it has received anotice of allowance from the U.S. Patent and Trademark Office(PTO) on one of a series of patents on the T cell antigenreceptor (TCAR) and its components. The claims on thisparticular patent cover nucleic acid sequences that encodefragments of the TCAR's beta chain.
This is a critical element in T Cell's expanding portfolio of 15U.S. patents based on pioneering work by researchers at, andlicensed from, various universities, including Stanford, MIT andCalTech, covering the various aspects of TCARs: the nucleicacids, proteins and antibodies relating to all four chains (alpha,beta, gamma and delta) of the receptor molecule.
It gives the Cambridge, Mass., company a "very strong position"in a "very hot field," commented Patrick Kung, the company'schief scientific officer.
It turns out that T cell antigen receptors are "the focus forautoimmune disease," explained Kung. They play a major rolein the immune system's ability to discriminate self from non-self. Normally, there are two types of TCARs in the humanbody, said Kung. Ninety percent of those receptors expressalpha and beta chains as a heterodimer (the other 10 percentexpress gamma and delta chains instead). And there are about20 alpha-beta receptor subtypes, which researchers identify bydifferences in the variable regions of the beta chains, thuscalling the variants "V beta" for short.
Researchers have found that there are relative changes in theV beta T cell receptor population in a number of majorautoimmune diseases, Kung told BioWorld, includingrheumatoid arthritis and multiple sclerosis (MS). Researchersreported in March that they have identified the particular T-lymphocytes that in MS attack the basic protein of the myelinsheath that surrounds nerve fibers.
In patients, there is an "enormous increase" in selective V betasubpopulations, said Kung. And other autoimmune disorders,such as Chron's disease, sarcoidosis and myasthenia gravis (andpossibly Type I diabetes), also show selectively elevatedpopulations of V beta TCARs, he added. There's even a subsetof rheumatoid arthritis patients in which there is selectiveenrichment of gamma-delta chain TCARs, Kung said.
"These are the targets whose action T Cell Sciences is trying tomodulate to produce a therapeutic effect," Kung told BioWorld.In fact, T Cell reached an agreement with multinationalpharmaceutical company AB Astra in January 1992 to developtherapeutic products for autoimmune diseases based on TCARtechnology.
The collaborators have already identified product candidatesfor treating MS and Chron's disease. "We've developed twoantibodies, one against MS and the other against Crohn's, aswell as a peptide directed at MS," explained Jacquie Arthur, TCell's chief financial officer.
Under the terms of the agreement, T Cell has the exclusivemarketing rights to products for treating rheumatoid arthritisin the U.S. and Canada, as well as manufacturing rights forthese and all other products worldwide. Astra has exclusiveworldwide marketing rights to all other products.
T Cell's stock (NASDAQ:TCEL) closed at $5.13 a share onTuesday, up 25 cents.
-- Jennifer Van Brunt Senior Editor
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