idioheterolysin id·i·o·het·er·ol·y·sin (ĭd'ē-ō-hět'ə-rŏl'ĭ-sĭn, -rō-lī'sĭn)
n.
An idiolysin occurring in the blood of one species, but capable of combining with the red blood cells of another species, thereby causing hemolysis when complement is present.