The present invention relates to a microvesicle that is derived from nucleated mammalian cells, which are smaller than the nucleated cells. The microvesicles of the present invention can be used in the delivery of a therapeutic or diagnostic substance to specific tissues or cells, and more particularly, relates to microvesicles derived from monocytes, macrophages, dendritic cells, stem cells or the like, which can be used to deliver specific therapeutic or diagnostic substances for treating and/or diagnosing tissue associated with cancer, diseased blood vessels, inflammation, or the like.【課題】哺乳類の有核細胞に由来し、前記細胞より小さいマイクロベシクルを提供する。【解決手段】本発明のマイクロベシクルを用いて治療又は診断用物質を特定の組織又は細胞へ伝達することができ、具体的には、単核球、マクロファージ、樹枝状細胞、幹細胞などに由来するマイクロベシクルを用いて、癌組織、血管又は炎症組織などへ前記治療及び／又は診断用物質を特異的に伝達することができる。【選択図】図１
