John Williams


Chief, Division of Pediatric Infectious Diseases, UPMC Children’s Hospital of Pittsburgh

Professor of Pediatrics, Microbiology & Molecular Genetics, University of Pittsburgh School of Medicine

Member, Program in Microbiology & Immunology Graduate Program

Education & Training

Fellowship, Vanderbilt University Medical Center

Residency, University of Pittsburgh School of Medicine

MD, Medical College of Virginia/Virginia Commonwealth University

BA in Biology, University of Virginia



The Williams laboratory studies the immunology and pathogenesis of human metapneumovirus (HMPV) and other respiratory viruses. HMPV, a pneumovirus discovered in 2001, is a leading cause of acute lower respiratory illness in infants, children, the elderly, and persons with underlying medical conditions. There are no licensed antivirals or vaccines for HMPV and little is known about protective immunity and viral pathogenesis. We have developed animal models for HMPV, purified prototype viral strains, generated recombinant viral proteins and identified a cellular receptor. Our group discovered that HMPV and other respiratory viruses lead to pulmonary CD8+ T cell impairment via signaling through Programmed Cell Death-1 (PD-1) and other inhibitory receptors. We seek to understand the immunobiology of this important human pathogen, to elucidate mechanisms of lung CD8+ T cell impairment, and to facilitate the development of preventive and therapeutic strategies.