Macrophage depletion kits are composed of two vials; one vial of Clodrosome® (Clodronate liposomes) and one vial of Encapsome® (control liposomes containing no drug). The volume of the macrophage depletion kit represents the volume of each reagent individually. For example, the 5-ml macrophage depletion kit means 5 ml of Clodrosome® and 5 ml of Encapsome®. Each reagent in the kit can also be purchased individually.

Clodrosome® is a multilamellar liposome suspension in which clodronate is encapsulated in the aqueous compartments of the liposomes. Encapsome® is formulated and prepared identically to Clodrosome® except that clodronate is not added to the liposomes. The liposomes are filtered through 2 μm polycarbonate membranes to ensure that the larger particles, which may be toxic to animals, are removed from the suspension. Both are prepared and packaged under sterile conditions. When animals or cells are treated with Clodrosome®, phagocytic cells recognize the liposomes as invading foreign particles and proceed to remove the liposomes from the local tissue or serum via phagocytosis. The liposomes then release clodronate into the cytosol, resulting in cell death. Non-encapsulated clodronate cannot cross the cell membrane to initiate cell death.

Control liposomes (Encapsome®) are recognized and phagocytosed by the same mechanism as Clodrosome®. Since the control liposomes do not contain clodronate, the phagocytic cells are not killed. However, phagocytes do respond to the ingestion of control liposomes by cytokine secretion, temporary suspension of phagocytic activity and other responses described in the literature.

m-Clodrosome® and m-Encapsome® are mannosylated reagents that are specifically formulated to efficiently target the macrophages in central nervous systems and macrophages that contain more mannose receptors. For more information about these reagent see here.

Fluorescent liposomes (Fluoroliposome®) suitable for macrophage targeting and tracking are available. They can contain five different fluorescent dyes (DiA, DiD, DiI, DiO and DiR), which covers the entire spectrum. Fluorescent liposomes come in standard and mannosylated form. For more information see here.