Immune System and Blood Cells

Overview

The biology of the immune system and of blood cells is incredibly rich in detail. I prefer “rich in detail” as opposed to “complex.” “Rich” invites us to explore the intricacies; “complex” is forbidding. Yet I must admit that the immune system is complex, probably as complex as the central nervous system. The immune system, like the brain, has input, output, central processing, memory, and schooling. Our understanding is far from complete, but molecular medicine has given us a much deeper look into the details and has provided many new tools for modifying the immune system. We will see that the diversity of the immune system in terms of its ability to respond to millions of antigens is derived from rearrangement of the family of genes that encode for the immune proteins—a process that, insofar as we know, is unique to the immune system. We also have discovered many of the cytokines and growth factors that modulate the immune system. Finally, we find that the major organ of the immune system, the bone marrow, can be easily removed, manipulated, and reinfused. Thus, the bone marrow has become a prime modality for genetic engineering to introduce genes that can correct metabolic and immunologic diseases.