1. Laboratory of Parasitic Diseases, at the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20205.
2. Department of Immunology, Walter Reed Army Institute of Research, Washington, D.C. 20037.
3. Department of Entomology, Walter Reed Army Institute of Research, Washington, D.C. 20037.
4. Laboratory of Immunogenetics, at the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20205.
5. Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health.