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The phagocytosis of gas-filled microbubbles by human and murine antigen-presenting cells

Gilles Bioley1, Philippe Bussat, Anne Lassus

  • 1R&D Laboratory, Immunology and Allergy, University State Hospital, Rue du Bugnon 46, 1011 Lausanne, Switzerland.

Biomaterials
|October 11, 2011
PubMed

Insights

Gas-filled microbubbles (MB) are readily internalized by antigen-presenting cells (APC), including monocytes and dendritic cells (DC). This natural uptake mechanism shows potential for antigen delivery without needing ultrasound sonoporation.

Area of Science:

  • Biomedical Engineering
  • Immunology
  • Nanotechnology

Background:

  • Antigen-presenting cells (APCs) are crucial for initiating adaptive immune responses.
  • Microbubbles (MBs) are established contrast agents for diagnostic imaging.
  • Targeted delivery of antigens to APCs is a key strategy for vaccine development and immunotherapy.

Purpose of the Study:

  • To investigate the potential of gas-filled microbubbles (MB) for direct internalization by antigen-presenting cells (APCs).
  • To determine if MBs can serve as an antigen delivery system to APCs without ultrasound assistance.

Main Methods:

  • Preparation of fluorescently labeled MBs for tracking.
  • In vitro studies using human and mouse APCs (monocytes, dendritic cells).
  • Confocal laser scanning microscopy to visualize MB uptake.
  • In vivo studies involving subcutaneous injection of MBs in mice and analysis of lymph nodes.

Main Results:

  • APCs (monocytes, dendritic cells) demonstrated phagocytosis of MBs in vitro.
  • MBs were rapidly internalized into cellular compartments and cytoplasm of APCs.
  • MBs were targeted to phagolysosomes within APCs, confirmed by lysosomal markers and inhibitors.
  • In vivo, fluorescent MBs were found associated with CD11c(+) dendritic cells in draining lymph nodes 24 hours post-injection.

Conclusions:

  • Gas-filled microbubbles are efficiently internalized by antigen-presenting cells via phagocytosis both in vitro and in vivo.
  • MBs can act as a potent antigen delivery system to APCs without the need for ultrasound sonoporation.
  • This finding expands the application potential of microbubbles beyond diagnostic imaging, particularly for immunotherapy and vaccine development.

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