1. Mycobacteria Research Laboratories, Department of Microbiology,1 and
2. Department of Pathology,2 Colorado State University, Fort Collins, Colorado 80523;
3. Department of Virus and Cell Biology, Merck Research Laboratories, West Point, Pennsylvania 194863;
4. Department of Virology, Pasteur Institute, B-1180 Brussels, Belgium4; and
5. Department of Medical Microbiology and Immunology, Texas A&M University, College Station, Texas 778435