Interactions Between Antibody-Coated Iron Micro-Particles and Leukemic Cells as seen by Electron Microscopy

Abstract

An electron microscopy study was performed to visualize the interactions between monoclonal antibodies (MoAbs) coated to ferromagnetic microparticles and leukemic cells. The properties of this specific reagent used for the efficient purging of residual leukemic cells from autografts before autologuous bone marrow transplantation (ABMT) have been previously reported.

Incubation of a CD10+ NALM6- cell suspension with CD10 or CD8 MoAb conjugated particles was performed following a time-course schedule ranging from 0 to 90 min. at 4°C and 37°C. Transmission electron microscopy demonstrated that, although the CD10 MoAb-particles complex linked to the cell surface only at 4°C, they readily penetrated into cells at 37°C.

In contrast, after incubation with CD8 MoAb-particles, no iron particles were seen at the cell surface, or within the cells no matter what the temperature and duration of the incubation were.

This observation offers the unique opportunity to deliver a pharmaceutical agent crosslinked to the same magnetic carrier inside a cell, using an interesting site-specific drug delivery concept.

Key Words:

• Antibody-coated particles
• iron particles
• leukemic cells
• electron microscopy