FIG. 8.

CD4⁺CD56⁺ NKT cells activated by tetanus toxoid-derived peptide. The CD4⁺CD56⁺ NKT cell clone G5 was generated from purified CD3⁺CD56⁺ NKT cells of human PBMC stimulated with tetanus toxin ex vivo. CD4⁺CD56⁺ NKT cells were activated by peptide derived from tetanus toxoid. The G5 clone was cultured with autologous irradiated PBMC (2 × 10⁵) and peptide (LYNGLKFIIKRY) derived from the C fragment of tetanus toxin for 6 days. Cells were pulsed for an additional 10 h with [³H]thymidine (1 μCi/well), and cellular proliferation was measured by incorporation of radioactivity. The T-cell proliferation of the control culture (T cells + APC without peptide) was <1,000 cpm. The data are presented as mean counts per minute ± standard errors of the means of triplicate wells. Results shown in the figure were from one representative experiment of three.