HTLV-1-ASSOCIATED MYELOPATHY TROPICAL SPASTIC PARAPARESIS-LIKE RATS BY INTRAVENOUS-INJECTION OF HTLV-1-PRODUCING RABBIT OR HUMAN T-CELL LINE INTO ADULT WKA RATS

We intravenously injected Ra-1 cells or MT-2 cells into female adult W KA rats. Spastic paraparesis mainly in the hind-limbs was observed in 1 out of 2 Ra-1 cell-injected WKA rats and in 3 out of 8 MT-2 cell-inj ected WKA rats 20 27 months after injection. The main neuropathologica l finding was symmetrical white matter degeneration with mononuclear c ell infiltration of the spinal cord, similar to that of HTLV-1-associa ted myelopathy/tropical spastic paraparesis (HAM/TSP) patients, and de generation of nerve roots and peripheral nerves. Antibodies against HT LV-1 antigens were detected in plasma and cerebrospinal fluid from the se HAM/TSP-like rats. HTLV-1 provirus was detected from the peripheral blood mononuclear cells of one of these rats 20 months after injectio n. Interestingly, spastic paraparesis was not observed in F344 rats.