HIGH ACTIVATED AND MEMORY CYTOTOXIC T-CELL RESPONSES TO HTLV-1 IN HEALTHY CARRIERS AND PATIENTS WITH TROPICAL SPASTIC PARAPARESIS

The cytotoxic T-lymphocyte (CTL) response to HTLV-1 is directed mainly against the Tax protein. Circulating, activated Tax-specific CTL can be found in a majority of healthy carriers and patients with the HTLV- 1-associated disease tropical spastic paraparesis (HAM/TSP). In this s tudy we present data on the Tax-specific CTL response of 26 HTLV-1 car riers, including 10 newly recruited subjects. Rex-specific CTL were no t found in any subjects investigated. Activated and memory CTL respons es were determined separately in 4 healthy carriers, 3 HAM/TSP patient s, and 1 ''seronegative HAM/TSP.'' In all subjects, the mean frequency of peptide-specific memory cells per epitope (1/1307) was high. There was no significant difference in mean memory CTL frequency per epitop e or in the proportion of subjects with activated CTL between healthy carriers and HAM/TSP patients. One individual with HAM/TSP had an unus ually high frequency response to two peptides, suggesting immunodomina nce of epitope recognition in this individual. We conclude that the ma gnitude and components of the HTLV-1-specific CTL response do not diff er between healthy carriers and HAM/TSP patients. These data do not su pport a specific CTL-mediated component in the pathogenesis of HAM/TSP . (C) 1995 Academic Press, Inc.