This background paper focuses on the Federal role in supporting a national high-performance computing initiative. High-performance ‘‘supercomputers’ * are fast becoming tools of international competition and they play an important role in such areas as scientific research, weather forecasting, and popular entertainment. They may prove to be the key to maintaining America’s preeminence in science and engineering. The automotive, aerospace, electronic, and pharmaceutical industries are becoming more reliant on the use of high-performance computers in the analysis, engineering, design, and manufacture of high-technology products.

This background paper, which describes the state-of the- art of identifying substances that can harm the immune system, represents one response to the committee’s request. Chapter 2 provides basic information about the principal components of the immune system and the general consequences that stem from perturbations to it. Chapter 3 describes methods for evaluating chemical immunotoxicity and reports on some known or suspected immunotoxicants. Chapter 4 summarizes Federal research and regulatory activities related to immunotoxicity.