THE INFLAMMATORY LESION OF T-CELL LINE TRANSFERRED EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS OF THE LEWIS RAT - DISTINCT NATURE OF PARENCHYMAL AND PERIVASCULAR INFILTRATES

We have investigated the T cell receptor (TCR) repertoire in the infla mmatory infiltrates of T line-transferred experimental autoimmune ence phalomyelitis (EAE) of the Lewis rats. Using a panel of TCR V beta-spe cific monoclonal antibodies (mAbs) and immunocytochemistry, we studied the nature of the T cells entering the central nervous system (CNS) a fter transfer of either myelin basic protein (MBP)-reactive, or MBP-re active but non-encephalitogenic T cell lines. All the MBP-specific T c ell lines predominantely used the V beta 8.2 TCR chain. T cell lines s pecific for the tuberculin purified protein derivative (PPD), using TC R V genes different from V beta 8.2, served as controls. We first stud ied the time course of T cells entering the CNS. In all recipient rats , small, but significant numbers of alpha beta-TCR-expressing infiltra te cells appeared in the CNS within the first 24 h after T cell transf er. In animals injected with either type of MBP-reactive T cells, the early infiltrate cells were preferentially located within the parenchy ma of the spinal cord, while in PPD T line-injected rats, the lymphocy tes were mostly found in the meninges. TCR V beta gene usage was exami ned on the peak of clinical disease. Six days after T cell transfer, t he TCR repertoire used by infiltrating lymphocytes in general seemed t o be highly diverse. None of the V beta isotypes examined (i. e. V bet a 8.2, V beta 8.5 or V beta 10) was used by a major population of the alpha beta-TCR-positive T cells. A more detailed, quantitative analysi s of individual infiltrate compartments revealed, however, a preferent ial accumulation of V beta 8.2-positive T cells within the parenchyma. In contrast, perivascular infiltrating cells used V beta genes random ly. Our results confirm first that activated Tlymphocytes enter the br ain rapidly irrespective. of their antigen specificity. Second, the da ta show that most of the perivascular infiltrate T cells in the acute EAE lesion are host-derived, recruited presumably from the recirculati ng T cell pool, while the encephalitogenic, V beta 8.2-positive T cell s preferentially persist within the parenchyma.