SV40 LARGE-T IMMORTALIZED CELL-LINES OF THE RAT BLOOD-BRAIN AND BLOOD-RETINAL BARRIERS RETAIN THEIR PHENOTYPIC AND IMMUNOLOGICAL CHARACTERISTICS

In the central nervous system the blood-brain and blood-retinal barrie rs (BBB and BRB respectively) are instrumental in maintaining homeosta sis of the neural parenchyma and controlling leucocyte traffic. These cellular barriers are formed primarily by the vascular endothelium of the brain and retina although in the latter the pigmented epithelial c ells also form part of the barrier. From primary cultures of rat brain endothelium, retinal endothelium and retinal pigment epithelium (RPE) we have generated temperature sensitive SV40 large T immortalised cel l lines. Clones of brain (GP8.3) and retinal (JG2.1) endothelia and RP E (LD7.4) have been derived from parent lines that express the large T antigen at the permissive temperature. The endothelial cell (EC) line s expressed P-glycoprotein, GLUT-1, the transferrin receptor, von Will ebrand factor and the RECA-1 antigen and exhibited high affinity uptak e of acetylated LDL and stained positive with the lectin Griffonia sim plicifolia. The RPE cell line was positive for cytokeratins and for th e rat RPE antigen RET-PE2. All the cell lines expressed major histocom patibility complex (MHC) class I and intercellular adhesion molecule ( VCAM)-1 constitutively and could be induced to express MHC class II an d vascular cell adhesion molecule (VCAM)-1 following cytokine activati on. The EC also expressed platelet endothelial cell adhesion molecule (PECAM)-1. Monolayers of these cells could support the migration of an tigen specific T cell lines. The generation of immortalised cell lines derived from the rat BBB and BRB should prove to be useful tools for the study of these specialised cellular barriers.