1. Immunobiology Section1and
2. Schistosomiasis Immunology and Pathology Unit,2 Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892-0425;
3. Animal Health Diagnostic Laboratory, Laboratory Animal Sciences Program, National Cancer Institute-Frederick Cancer Research and Development Center, Science Applications International Corporation, Frederick, Maryland 21702-12013; and
4. The Biomedical Research Institute, Rockville, Maryland 208524