Key To Immune System Found

Scientists at a biotechnology company set up to examine the entire human gene collection say they have discovered the protein that triggers production of immune-system cells that fight disease.

Human Genome Sciences Inc., reporting its findings in the journal Science, says the newly identified protein B lymphocyte stimulant, or BLyS, could have many uses. These include boosting immune systems weakened by chemotherapy, organ transplant drugs or diseases such as AIDS, leukemia and lymphomas.

BLyS spurs immune cells known as B cells to produce antibodies, which mark invaders such as viruses or bacteria for other cells to attack and kill.

William Haseltine, chairman and chief executive of Human Genome Sciences Inc., said he hopes to produce the protein to use as an immune system stimulant and to fight a range of diseases.

"I think it's a major discovery for how the immune system works," Haseltine said.

B lymphocytes are white blood cells whose main job is to secrete antibodies. Each cell produces one specific antibody in response to a specific antigen or foreign invader.

"For instance, one B lymphocyte will make an antibody to block a virus that causes the common cold, while another produces an antibody that attacks a bacterium that causes pneumonia," the company said in a statement.

"You have about 10 million different kinds of B cells, each one decorated with a different antibody. When an antigen comes in and is presented to a B cell in the right context, that particular B cell expands -- it grows like a weed," Haseltine added.

The antibody is spread through the body, attracting other immune cells to seek out and kill the flagged invader.

"Nobody's ever found the signal that lets the B cells grow and release the antibodies. So we have just found it," Haseltine said. "We believe that this protein can be manufactured, which we are now doing, for use as a drug."

Some possible uses could be to treat AIDS patients, whose immune systems are under attack from the HIV virus; people whose immune systems are deliberately suppressed after getting an organ transplant; and as a treatment for cancers such as leukemias and lymphomas that arise from the abnormal proliferation of B cells.

"We hope to have this drug in clinical trials during the first half of the next year," said Haseltine, whose Maryland-based company has filed several patents on the protein.

Human Genome Sciences was set up to discover just such proteins by plowing through the collection of human genes known as the genome. At least a dozen companies are trying to decipher information about the body's 80,000 to 100,000 genes in an effort to prevent diseases.

Haseltine claims to have mapped 95 percent of the useful genes in the human body. His company has programmed computers to sort through the code in an attempt to find proteins that can be turned around and used as drugs.