EBV-specific CD8⁺ cells express high telomerase activity during AIM.

CD8⁺ T cells were first isolated from a PBMC population from an AIM patient. B8-RAK tetramer–positive cells were then isolated from the CD8⁺ population using anti-PE MACS beads. Telomerase activity was determined using the TRAP assay autoradiography performed on CD8⁺, CD8⁻, and tetramer–enriched T-cell fractions from the patient during AIM and 12 months after follow-up (A). The TRAP-eze protocol, in which telomerase activity is amplified by PCR, gives rise to a ladder of products with 6-bp increments, starting at 50 nucleotides. Heat-inactivated (HI) cell extracts provided a telomerase negative control for each sample. The negative control (−CNT) contains the PCR mix without the cell extract. In addition, amplification of the internal control oligonucleotides together with the TS primer give rise to the internal PCR control (36 bp). Telomerase activity in acute and follow-up AIM patient activity was expressed as total product generated calculated according to manufacturer's instructions (B). Each unit of total product generated corresponds to the number of TS primers extended with at least 4 telomeric repeats by telomerase in the extract in a 10-minute incubation at 30°C. Telomerase activity in acute AIM patients, ▪; follow-up patient samples, ■. In a total of 4 patients studied, high telomerase activity was found in CD8⁺ T cells during AIM, which was substantially reduced in the follow-up samples taken after 12 months or longer after resolution of the acute infection.