Positive test controls include: HeLa, HepG2, Raji, Mouse thymus, Rat lung. Immunogen sequence: MSETAPAAPA AAPPAEKAPV KKKAAKKAGG TPRKASGPPV SELITKAVAA SKERSGVSLA ALKKALAAAG YDVEKNNSRI KLGLKSLVSK GTLVQTKGTG. Histones are basic nuclear proteins responsible