Exogenous microglia anter the brain and migrate into ichaemic hippocampal lesions. - Imai,F.; Sawada,M.; Suzuki,H.; Zlokovic,BV.; Kojima,J.; Kuno,S.; Nagatsu,T.; Nitatori,T.; Uchiyama,Y.; Kanno,T. (Neurosci Lett, 1999)