Molecular Basis of Human Phagocyte Interactions With Bacterial Pathogens

NCT00339287 | Recruiting

• 2 other identifiers: 99990105501-I-N055
• Study Type: observational
• Target: 200
• Locations: 1 country
• Sites: 1

Brief Summary

Human phagocytic cells such as polymorphonuclear leukocytes (PMNs) are readily mobilized to sites of infection and ingest microorganisms by a process known as phagocytosis. The combined effects of reactive oxygen species (ROS) and proteolytic peptides and enzymes released into forming bacterial phagosomes kill most ingested bacteria. However, many human bacterial pathogens have devised means to subvert normal phagocyte responses and the innate immune response and cause severe disease. The overall objective of this study is to elucidate specific features of pathogen-phagocyte interactions that underlie evasion of the innate immune response or contribute to the pathophysiology of disease or inflammatory disorders. Therefore, specific projects will:

1. 1.Identify and characterize specific mechanisms used by pathogenic microorganisms to evade or subvert normal phagocyte responses and therefore cause disease.
2. 2.Investigate phagocyte response mechanisms to specific pathogenic microorganisms.
3. 3.Identify specific bacterial structures and/or (gene) products that dictate differences in phagocyte responses among a range of pathogens so that generalized statements can be made about the pathophysiology of disease states.

Conditions

Host Defense Mechanisms

Keywords

Virulence; PHAGOCYTOSIS; Neutrophil; Pathogenesis; Natural History

Outcome Measures

Primary Outcomes (1)

• identify and characterize specific mechanisms used by pathogenic microorganisms to evade or subvert normal phagocyte responses and therefore cause disease.

  The study involves the use of human subjects as a source of blood for in vitro assays with bacteria, the isolation of hematopoietic cells (polymorphonuclear leukocytes, mononuclear phagocytes, erythrocytes, and lymphocytes), and serum as a source of complement, antibody, and matrix-binding proteins.

  Ongoing

Study Arms (1)

Healthy volunteers

Healthy adult volunteers at least 18 years of age.

Eligibility Criteria

• Age: 18 Years - 120 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Volunteers will be selected from a healthy adult population, 21-65 years of age, with no known medical problems and will generally be NIH employees working at Rocky Mountain Laboratories (RML) or within the community of Hamilton, MT. No race or gender is excluded from the donor pool and reflects the diversity of the community and that of the employees at RML.

You may not qualify if:

• Volunteers will be selected from a healthy adult population, 18 years of age or older, with no known medical problems and will generally be NIH employees working at Rocky Mountain Laboratories (RML) or within the community of Hamilton, MT.
• No race or gender is excluded from the donor pool and reflects the diversity of the community and that of the employees at RML.
• The specific criteria for eligibility are as follows:
• Subjects must fit the definition of "healthy adults" as assessed by the medical/health screening evaluations, and willing to have blood and/or tissue samples stored for future use.
• Inasmuch as all subjects are RML employees, they will be 18 years of age or older.
• Children are excluded.
• Pregnant women will be identified by verbal history and are not eligible to donate blood for this protocol.
• The study population will be all-inclusive except in certain instances where individuals possess genetic defects that impair phagocyte function (e.g., myeloperoxidase-deficiency) or have altered phagocyte function due to outside influences such as recent bacterial or viral infection.
• Individuals below the normal hematocrit and hemoglobin ranges will be excluded from the protocol.

Sponsors & Collaborators

• National Institute of Allergy and Infectious Diseases (NIAID): lead

Study Sites (1)

NIAID, Rocky Mountain Laboratories

Hamilton, Montana, 59840, United States

RECRUITING

Related Publications (2)

• Rungelrath V, DeLeo FR. Staphylococcus aureus, Antibiotic Resistance, and the Interaction with Human Neutrophils. Antioxid Redox Signal. 2021 Feb 20;34(6):452-470. doi: 10.1089/ars.2020.8127. Epub 2020 Jun 23.

  PMID: 32460514 BACKGROUND

• Kobayashi SD, Malachowa N, DeLeo FR. Neutrophils and Bacterial Immune Evasion. J Innate Immun. 2018;10(5-6):432-441. doi: 10.1159/000487756. Epub 2018 Apr 11.

  PMID: 29642066 BACKGROUND

Study Officials

• Frank R De Leo, Ph.D.

  National Institute of Allergy and Infectious Diseases (NIAID)

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Frank R De Leo, Ph.D.

CONTACT

(406) 363-9448; fdeleo@niaid.nih.gov

Study Design

• Study Type: observational
• Observational Model: OTHER
• Time Perspective: OTHER
• Sponsor Type: NIH
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 19, 2006
• First Posted: June 21, 2006
• Study Start: February 12, 2001
• Last Updated: March 31, 2026

Record last verified: 2025-07-08

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)