Frank R. DeLeo, Ph.D.

Frank R. DeLeo, Ph.D.

Chief, Laboratory of Bacteriology
Chief, Pathogen-Host Cell Biology Section

Major Areas of Research

  • Neutrophil biology and function
  • Evasion of innate immunity by bacterial pathogens  
  • Host interactions with antibiotic-resistant bacteria

Program Description

Phagocytosis of MRSA by a human neutrophil.

Bacterial infection and host response.

Although most bacteria are killed readily by neutrophils, pathogens such asStaphylococcus aureus have evolved mechanisms to circumvent destruction by these key innate immune cells and thereby cause human infections. A better understanding of the bacteria-neutrophil interface at the cell and molecular levels will provide information critical to our understanding, treatment, and control of disease caused by bacterial pathogens.

Interaction of Klebsiella pneumoniae with a human neutrophil.

Interaction of Klebsiella pneumoniae with a human neutrophil.


Interaction of Klebsiella pneumoniae with a human neutrophil.


Formation of a neutrophil extracellular trap.

Formation of a neutrophil extracellular trap.


Formation of a neutrophil extracellular trap.



The long-term objective of our research is to promote development of enhanced diagnostics, better prophylactic agents, and new treatments for emerging bacterial pathogens such as community-associated methicillin-resistant S. aureus(CA-MRSA) and carbapenem-resistant Klebsiella pneumoniae. To achieve that objective, the Pathogen-Host Cell Biology Section does the following:

  • Conducts a systematic molecular dissection of steps involved in the pathogen-host interaction, with emphasis on the interaction of bacterial pathogens with human neutrophils
  • Investigates mechanisms mediating evasion of innate immunity by bacterial pathogens
  • Identifies new virulence genes involved in the pathogenesis of infections caused by pathogens of special interest
  • Uses animal infection models and (if possible) human specimens to test hypotheses developed from in vitro analyses


Dr. DeLeo received his Ph.D. in microbiology from Montana State University in 1996, studying the molecular basis of superoxide generation by human neutrophils. He did his postdoctoral training in the area of innate immunity and infectious diseases in the Department of Medicine at the University of Iowa (1996–2000). Dr. DeLeo joined the staff at the NIAID Rocky Mountain Laboratories in 2000 as a tenure-track investigator. He served previously as Acting Chief (2007-2013) and Chief (2013-2015) of the Laboratory of Human Bacterial Pathogenesis. Dr. DeLeo was appointed to the NIH Senior Biomedical Research Service (2011-2017) and elected as an American Academy of Microbiology Fellow in 2017. He is currently Chief of the Laboratory of Bacteriology.

Editorial Boards

  • Infection and Immunity
  • Journal of Innate Immunity

Research Group

Scott Kobayashi, Ph.D. (Associate Scientist)
Natalia Malachowa, Ph.D. (Staff Scientist)
Adeline Porter, B.A. (Microbiologist)
Brett Freedman, M.S. (Biologist)
Viktoria Rungelrath, Ph.D. (Postdoctoral Visiting Fellow)

Selected Publications

Neutrophils and Bacterial Immune Evasion.

Kobayashi SD, Malachowa N, DeLeo FR.

J Innate Immun. 2018 Apr 11. doi: 10.1159/000487756. [Epub ahead of print]


Antibody-Mediated Killing of Carbapenem-Resistant ST258 Klebsiella pneumoniae by Human Neutrophils.

Kobayashi SD, Porter AR, Freedman B, Pandey R, Chen L, Kreiswirth BN, DeLeo FR.

MBio. 2018 Mar 13;9(2). pii: e00297-18. doi: 10.1128/mBio.00297-18.

PMID: 29535199

Differential Ability of Pandemic and Seasonal H1N1 Influenza A Viruses To Alter the Function of Human Neutrophils.

Malachowa N, Freedman B, Sturdevant DE, Kobayashi SD, Nair V, Feldmann F, Starr T, Steele-Mortimer O, Kash JC, Taubenberger JK, Feldmann H, DeLeo FR.

mSphere. 2018 Jan 3;3(1). pii: e00567-17. doi: 10.1128/mSphereDirect.00567-17. eCollection 2018 Jan-Feb.

PMID: 29299535

Visit PubMed for a complete publication list.



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