Immune Response Corp. has discovered specific T cells in thejoint tissue of rheumatoid arthritis patients that appear to beone of the earliest triggers of the disease.

Three closely related populations of T cells -- VB17, VB14 andVB3 -- are activated and attack the joints of rheumatoidarthritis sufferers for unknown reasons. In the process, theyrelease a variety of cytokines, which then recruit macrophages,B cells and other destructive cells.

The report this week in The Proceedings of the NationalAcademy of Sciences details the science supporting ImmuneResponse's therapeutic vaccine. The company plans to file thismonth an investigational new drug application for one of the Tcells, VB17, and hopes to begin Phase I/II trials in early 1992.

The vaccine would be Immune Response's second product toenter clinical trials. The San Diego company's therapeutic HIVvaccine is in Phase II/III trials.

Immune Response shares (NASDAQ:IMNR) rose $5.75 onMonday, closing at $40.

The three T cell families were found in three of five patientsamples analyzed. VB17 cells were found in all five samples. Invitro tests of VB17 show that it kills synovial cells, the cellsfrom the lining of joints.

Immune Response's vaccine is based on synthetic peptidescomprising a portion of the T cell receptors. Although the Tcells are already present in patients, combining the peptideswith an adjuvant and injecting them enables the body torecognize them as a foreign substance.

Immune Response said it will begin preclinical studies of theother T cell types next year and eventually conduct separatesafety trials of each in humans. If all goes well, all three T celltypes will be combined in a single vaccine in more advancedclinical trials.

The vaccine has three advantages over other approaches totreating rheumatoid arthritis, said spokesman Steven Basta. Itis targeted against specific T cells and won't compromise theimmune system; it is directed against the earliest stages of theprocess; and it is expected to be long-lasting, perhaps requiringno more than an annual booster. -- KB

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