Enhancement of antigen-induced T-cell proliferation by soluble CD26/dipeptidyl peptidase IV

Toshiaki Tanaka, Jonathan S. Duke-Cohan, Junichi Kameoka, Arieh Yaron, Iris Lee, Stuart F. Schlossman, Chikao Morimoto

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129 Citations (Scopus)


The addition of a soluble recombinant CD26 (sCD26) enhanced proliferation of peripheral blood lymphocytes induced by the recall antigen tetanus toxoid. sCD26 itself did not provide a mitogenic signal and did not augment the proliferative response of T cells to other mitogenic stimuli such as phytohemagglutinin and anti-CD3. Dipeptidyl peptidase IV-negative sCD26 did not have this enhancement effect, implying a requirement for enzyme activity. It was found that there exists a large variation in the levels of human plasma sCD26/dipeptidyl peptidase IV in vivo which may regulate T-cell activity. Peripheral blood lymphocytes from individuals whose plasma sCD26 was high and responded strongly to tetanus toxoid stimulation were insensitive to the enhancing effects of exogenously added sCD26. This suggests that plasma sCD26 had modulated the responsiveness of T cells of these individuals in vivo and that the endogenous plasma sCD26 regulates immune responses by allowing antigen-specific T cells to exert a maximal response to their specific antigen.

Original languageEnglish
Pages (from-to)3082-3086
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number8
Publication statusPublished - 1994 Apr 12
Externally publishedYes


  • cell-mediated immunity
  • costimulation
  • memory T cells

ASJC Scopus subject areas

  • General


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