Division of Computational Bioscience, Center for Information Technology, NIH, 12 South Drive, Bethesda, MD, 20892, USA. druss@mail.nih.gov.|Division of Computational Bioscience, Center for Information Technology, NIH, 12 South Drive, Bethesda, MD, 20892, USA. hok@mail.nih.gov.|Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, 40 Convent Drive, Bethesda, MD, 20892, USA. longon@mail.nih.gov.