Direct comparison between in vivo and in vitro microsized particle phagocytosis assays in Drosophila melanogaster

Area of Science:

• Immunology
• Cell Biology
• Biomaterials Science

Background:

• * In vivo and in vitro assays for micro and nanoparticles' effects on the innate immune system show discrepancies.
• * Understanding these differences is crucial for accurate nanomaterial safety and efficacy assessment.

Purpose of the Study:

• * To investigate the reasons for discrepancies between in vivo and in vitro phagocytosis assays.
• * To compare phagocytosis of polystyrene microspheres by immune cells in Drosophila melanogaster in vivo versus in vitro.

Main Methods:

• * Establishment of an in vivo phagocytosis assay using polystyrene microspheres in Drosophila melanogaster.
• * Comparison with an in vitro phagocytosis assay using the same immune cells and particles.
• * Analysis of the distribution of phagocytized beads per cell.

Main Results:

• * The in vitro assay showed a shift towards lower numbers of phagocytized beads per cell compared to the in vivo assay.
• * This difference suggests reduced membrane availability in cultured immune cells may impact phagocytosis.

Conclusions:

• * In vitro phagocytosis assays may underestimate particle uptake compared to in vivo conditions.
• * Reduced cell membrane availability in cultured cells is a potential factor contributing to assay discrepancies.
• * Further research is needed to reconcile in vivo and in vitro findings for accurate nanomaterial assessment.