Sequencing analysis finally became feasible with the discovery of multiple myeloma, a cancer of antibody-producing plasma cells. The plasma cells in a normal individual are endstage cells that secrete a single molecular species of antibody for a limited period of time and then die. In contrast, a clone of plasma cells in an individual with multiple myeloma has escaped normal controls on their life span and proliferation and are not end-stage cells; rather, they divide over and over in an unregulated way without requiring any activation by antigen to induce proliferation. Although such a cancerous plasma cell, called a myeloma cell, has been transformed, its protein-synthesizing machinery and secretory functions are not altered; thus, the cell continues to secrete molecular ly homogeneous antibody. This antibody is indistinguishable from normal antibody molecules but is called myeloma protein to denote its source. In a patient afflicted with multiple myeloma, myeloma protein can account for 95% of the serum immunoglobulins. In most patients, the myeloma cells also secrete excessive amounts of light chains. These excess light chains were first discovered in the urine of myeloma patients and were named Bence-Jones proteins, for their discoverer.
Multiple myeloma also occurs in other animals. In mice it can arise spontaneously, as it does in humans, or conditions favoring myeloma induction can be created by injecting mineral oil into the peritoneal cavity. The clones of malignant plasma cells that develop are called plasmacytomas, and many of these are designated MOPCs, denoting the mineral-oil induction of plasmacytoma cells. A large number of mouse MOPC lines secreting different immunoglobulin classes are presently carried by the American Type-Culture Collection, a nonprofit repository of cell lines commonly used in research.
Was this article helpful?
This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.