dosSantos, Washington Luis Conrado “Documento produzido em parceria ou por autor vinculado à Fiocruz, mas não consta à informação no documento”.In the central nervous system the blood–brain and blood–retinal barriers (BBBand BRBrespectively)are instrumentalin maintaining homeostasisof the neural parenchymaand controllingleucocytetraffic. These cellular barriers are formed primarilyby the vascular endotheliumof the brain and retina althoughin the latter the pigmentedepithelial cells also form part of the barrier. From primary culturesof rat brain endothelium,retinal endotheliumand retinal pigmentepitheiium(RPE) we have generatedtemperaturesensitive SV40largeT immortalisedcell lines. Clonesof brain (GP8.3)and retinal(JG2.1)endotheliaand RPE (LD7.4)have been derivedfrom parent lines that expressthe large T antigen at the permissivetemperature.The endothelialcell (EC) lines expressedP-glycoprotein, GLUT-1,the transfernnreceptor,von Willebrandfactor and the RECA-1antigenand exhibitedhigh affinityuptakeof acetylatedLDL and stainedpositivewith the lectin Griffoniasimplicifolia.The RPE cell line was positivefor cytokeratinsand for the rat RPE antigen RET-PE2.All the cell lines expressedmajor histocompatibilitycomplex(MHC)class 1 and intercellularadhesionmolecule(ICAM)-1 constitutivelyand could be induced to expressMHC class II and vascular cell adhesion molecule (VCAM)-1following cytokine activation.The EC also expressedplatelet endothelialcelI adhesionmolecule(PECAM)-I.Monolayer of these cells could supportthe migrationof antigen-specificT cell lines.Thegenerationof immortalisedcell linesderivedfromthe rat BBBandBRBshouldproveto be usefultools for the studyof these specialisedcellularbarriers.