The invention provides a composition comprising a population of isolated cells that comprise CD56 + , CD16 - placental intermediate natural killer cells obtainable by perfusion of a human placenta that has been drained of cord blood and flushed to remove residual blood to produce placental perfusate comprising nucleated placental cells and isolation of the nucleated placental cells from said placental perfusate, wherein said population comprises at least about 50% CD56 + , CD16 - placental intermediate natural killer cells. The composition may further comprise isolated CD56 + , CD16 + natural killer cells and/or isolated placental perfusate. The composition may further comprise natural killer cells isolated from umbilical cord blood, wherein said umbilical cord blood is isolated from the placenta from which the placental perfusate was obtained
