Studies in the immunology program focus on investigating whether atomic-bomb radiation exposure caused changes in the immune function of survivors. The immune system protects the body from the intrusion of alien substances, such as bacteria and parasites, and in some cases from the continued proliferation of malignant (cancerous) cells. Through repeated division, a pool of blood stem (precursor) cells produces cells that, in turn, differentiate (mature and specialize) into the heterogeneous cell subpopulations that make up the immune system. These subpopulations closely interact with and regulate one another to effectively eliminate foreign or intruding substances.

Immunology program studies investigate radiation-induced changes in the immune system and their relationship to disease development in A-bomb survivors. In addition, radiation-induced mutations in blood cells have been studied using immunological methods; these techniques are useful as a means of assessing radiation dose (so-called biological dosimetry) as well as an approach for analyzing in vivo behaivor of various blood cells using mutations as cell markers.

The immunology program is described schematically here.