Antibodies

June 1996

   Modern medicine can cure Hodgkin's and non-Hodgkin's lymphoma in many cases with advances evolving in the classification and staging of lymphomas. Physicians must asses the histologic type and grade and the disease stage to customize the most effective treatment plan (This is stuff ya'll knew, but, we ARE getting to it..). Traditional treatment options include radiotherapy, chemotherapy, or combination of the two methods. Relapses of lymphoma cases are usually treated with combination chemotherapy at standard doses.

   NOW.... Biologic therapy techniques are currently being evaluated. Hematopoietic growth factors normally help regulate blood cell growth and can accelerate the recovery of blood cells. Interfereons are proteins that inhibit the growth of viruses and appear to be toxic to cancer cells. Specially conjugated toxins, radioactive material, chemotherapy, or substances that enhance the body's antitumor rewponse can be targeted more precisely with monoclonal antibodies w3hich react with certain protein or carbohydrate antigens on the surface of the lymphoma cell. A vaccine which provides a unique cell surface protein attachment on lymphoma cells can trigger the body's immune system to attack the cell surface as a foreign body.

March 1996

   Monoclonial antibodies (MAbs) are showing great promise .. An MAb is an antibody shaped like a Y. At each end of the tow arms of the Y, the antibody forms a receptor site in a specific shape. The MAbs will bind only to cells that have this specific shape on their exterior. MAbs are used to seek out cancerous sites, many of which are too small to be detected by any other means. Researchers are making genetic changes to MAbs to enable them to more effectively seek out and destroy cancerous cells. About 200 new types of MAbs have been created.

   MAbs were commonly derived from mice. This limited their effectiveness in cancer treatment, because the human body would identify such foreign MAbs as invaders and destroy them. Two new versions of MAbs have been engineered to make them more amenable to the human immune system. One type is called chimeric antibodies, which are part human and part mouse. Another type of MAb is called human-gybrid antibodies, which are predominantly human. Since no cancer treatment can be achieved on one dose, multiple doses of these antibodies can usually be given without invoking an immune response.

   Early MAbs were also limited by their lack of toxic effect on the target cancer cell. Human-hybrid MAbs are more effective in calling other destroyer cells to the site once it is identified. To make human-hybrid MAbs even more effective, scientists have engineered them to carry radioactive isotopes or toxins to kill the target cell. In two seperate clinical trials, patients with nhl were treated with radiolabeled MAbs with good success rates. Physicians have also used human-hybrid MAbs in successful treatments of persistent lymphoma, acute promyelocytic leukemia, and colon cancer. Such engineered MAbs do a good job of targeting only cancerous cells without destroying normal tissue. Often, in the short-term, radiolabeled MAbs eradicate all traces of the cancer. The long-term effects are not known.

   Researchers are attempting to designb MAbs that targe the growth factors of cancer cells, preventing their spread. Another target is the supporting cells that surround cancer cells. The cells, called stromal antigens, are highly accessible to MAbs and are uniformly present on target cells. Another research goal is to manufacture MAbs that will bind to both an immune cell and a cancer cell, such MAbs will carry the cancer cell's destroyer right to the site.