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Biotech / Medical : XOMA. Bull or Bear? -- Ignore unavailable to you. Want to Upgrade?

To: opalapril who wrote (6491)	6/19/1998 10:30:00 AM
From: aknahow	Respond to of 17367

Opala, nice summary of XOMA the stock. Meanwhile, XOMA the company looks interesting. IMO the following article indicates a role for them here not only with their existing TIF patents but also in the most recent humanizing patent. 11:53 AM ET 06/18/98 Transplant drug may offer hope for AIDS -expert (Release at 4 p.m. EDT (2000 GMT) Thursday) By Maggie Fox, Health and Science Correspondent WASHINGTON8 (Reuters) - A drug used on organ transplant patients may offer a way of eliminating the AIDS virus from the body, a top researcher said Thursday. Dr. David Ho, one of the developers of the drug ''cocktail'' approach that has made HIV infection a controllable disease for many people, said the drug may be able to tease out bits of the virus that are known to lurk in the body for years. Ho, of the Aaron Diamond AIDS Research Center at Rockefeller University in New York, has considerably toned down his early enthusiasm for the cocktail approach. When he first announced it could beat the virus down below detectable levels in the blood, at the 11th International AIDS Conference in Vancouver in 1996, he thought HIV could be defeated with a year or two of combination drug therapy. But although patients taking the three and four drug combinations stayed well, and showed no sign of infection, careful tests showed that HIV lingered in their bodies. Experts like Ho think it hides in resting immune cells -- which are known to lie quiescent in the body for years until they are needed. The drugs that attack HIV work against the virus's replicative process -- so if the virus is quiet, and the cell it is hiding in is quiet, the drugs cannot work. Writing in a commentary in the journal Science, Ho said it is clear that the immune system must be tweaked to activate all of these cells and flush out the HIV. Unfortunately, the cells are probably specialized to recognize a wide array of invaders. ''Thus, administration of a limited set of antigens is unlikely to activate a sufficient number of these cells to replicate viruses and thereby facilitate their rapid death,'' Ho wrote. Antigens ''flag'' invaders such as viruses and bacteria so that antibodies, proteins produced by immune cells, can home in on them. ''What about cytokines?'' Ho asks. Cytokines are immune system signaling chemicals that can stimulate immune cells. Using single cytokines such as interleukin-2, or IL-2, would not work, but mixtures of several such as IL-2, IL-6 and tumor necrosis factor (TNF) work in test tubes. Other activators such as bacterial superantigens and a class of monoclonal antibodies -- proteins that can locate and attach to a specific cell -- might work, Ho added. He named specifically a mouse antibody known as OKT3 (muromonab-CD3), used to prevent the body from rejecting kidney transplants. ''In particular, a mouse CD3 monoclonal antibody, OKT3, is already a licensed clinical product,'' Ho wrote. ''Relatively high doses of OKT3 are routinely used to deplete T-cells (immune system cells) to prevent transplant rejection,'' he added. Low doses could stimulate T-cells. ''Thus, low-dose OKT3 should be judiciously tested not only to define its safety profile ... but also to determine the magnitude of T-cell activation achievable without prohibitive toxicity.'' He said many doses would be needed to flush out HIV-infected cells, and thus perhaps a human version of OKT3 could be genetically engineered. OKT3 is made by Ortho Biotech, a subsidiary of Johnson & Johnson . ^REUTERS@