INTERLEUKIN-12-DEPENDENT ACTIVATION OF HUMAN LYMPHOCYTE SUBSETS

Recently, we reported that IL-12 increased expression and function of CD26/DPPIV, this may be a new cellular pathway of the Th1-like immune responses. Here, we looked for a specific subset which would respond t o CD26 upregulation by IL-12. Contrary to previously described results , under our culture conditions (1 mu g/ml of PHA), IL-12 enhanced pref erentially the CD8 cell proliferation. By using dual fluorescence anal ysis, IL-12-dependent CD26 expression was found in both CD4 and CD8 (p reviously CD26(+) or CD26(-)) activated T cells and, moreover, the CD4 5RO percentage was unaffected. However, the density of CD45RO Ag (whic h was reported to coexpress with CD26) was impaired. These effects can be implicated in the biological functions of IL-12 and provide some c linical possibilities. (C) 1998 Elsevier Science B.V. All rights reser ved.