Immunoglobulin secretion by mouse X human hybridomas: an approach for the production of anti-idiotype reagents useful in monitoring patients with B cell lymphoma.

Tumor cells were obtained from a patient with nodular lymphoma, a monoclonal B cell malignancy. These non-Ig-secreting lymphoma cells were hybridized to mouse myeloma cells. Hybridomas secreting human Ig were obtained in high frequency. One clone, which was a stable producer of human heavy and light chains, but which had lost production of mouse light chains, was chosen for study. It secreted a human IgM pentamer. The Ig produced by this clone was purified and used as an immunogen for the production of anti-idiotype antibodies. These antibodies recognized the specific cell surface Ig of the lymphoma cells and have been used to detect idiotype-bearing cells in the blood of the original patient, even at times when the disease was in clinical remission. Moreover, free idiotype could be detected in the patient's serum. Both the levels of Id+ cells and free idiotype correlated with disease activity, rising in relapse and falling in remission.