On Mon, 11 Apr 2011 16:36:28 +0000, FrancisFurtado wrote:

My 2 Parthenocissus quinquefolia that i bought last November are full of
them, and i don't know what to do...

They appear to be "pearl glands" -- just outgrowths of the epidermis.
Nothing to do... completely normal. More obvious in high humidity growing
conditions.