Methods for determining concentrations of antimicrobial agents in human monocytes

Area of Science:

• Pharmacology
• Cell Biology
• Microbiology

Background:

• Human monocytes are crucial immune cells, often sourced from blood donations.
• Detecting antimicrobial agents within monocytes is vital for drug efficacy studies.
• Traditional methods may involve radiolabeled drugs or cell washing, risking drug loss.

Purpose of the Study:

• To establish a reliable bioassay for quantifying antimicrobial agents in human monocytes.
• To optimize drug detection without radiolabeling or cell washing steps.
• To assess the method's reproducibility and consistency.

Main Methods:

• Monocytes were isolated from leukocyte-rich blood by-products post-platelet separation.
• Cells were exposed to antimicrobial agents (rifamycins) without a washing step.
• Velocity gradient centrifugation separated monocytes from the extracellular medium.
• Bioassays using Micrococcus luteus detected rifamycins in cell pellets and extracellular fluid.

Main Results:

• The developed bioassay effectively detected antimicrobial agents within monocytes.
• Exclusion of the washing step prevented potential drug extraction.
• The method demonstrated good reproducibility and consistent results.
• High concentrations of antimicrobial agents were detectable.

Conclusions:

• This novel bioassay offers a non-radiolabeled, efficient method for drug detection in monocytes.
• The technique minimizes drug loss by omitting the cell washing step.
• The method is suitable for high-throughput screening and drug development studies.