1. Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
2. College of Veterinary Medicine, Jilin University, Changchun 130062, China.
3. Department of Medicine, University of California San Francisco, San Francisco, CA 94121, USA.
4. Departments of Microbiology & Immunology and Pediatrics, State University of New York Upstate Medical University, Syracuse, NY 13210, USA.
5. Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
6. Department of Veterans Affairs, Oklahoma City, OK 73104, USA.