1. Women’s Reproductive Health Research Center, Department of Obstetrics and Gynecology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
2. Department of Microbiology, Immunology and Physiology, Meharry Medical College, Nashville, TN 37208, USA
3. Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
4. VA Tennessee Valley Healthcare System, Nashville, TN 37232, USA