Unusual cytotoxic activities of thymus-independent, self-antigen-specific CD8+ T cells

Hisakata Yamada, Goro Matsuzaki, Yukihide Iwamoto, Kikuo Nomoto

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We compared the cytotoxic activities of thymus-dependent and thymus-independent CD8+ T cells. Thymus-dependent CD8+ T cells, which are foreign antigen specific, acquired cytotoxic activity to tumor cells with a basal dose of the antigen peptides and to hybridoma cells expressing anti-TCR mAb only after differentiation into effector cytotoxic T lymphocytes (CTL). In contrast, thymus-independent CD8+ T cells, which have been shown to be self-antigen specific, never showed cytotoxic activity to the target cells with a basal dose of the self-antigen peptide, while they could lyse hybridoma cells expressing anti-TCR mAb even without prior antigenic stimulation. Furthermore, the ex vivo cytotoxic activity of thymus-independent CD8+ T cells was also observed against the target cells with high doses of the antigen peptides, which were not lysed by freshly isolated thymus-dependent CD8+ T cells. Thus it is revealed that thymus-independent, self-antigen-specific CD8+ T cells already acquire mature CTL functions in situ but have an increased threshold of TCR-mediated signaling for activation. These differences in cytotoxic activities between thymus-dependent and thymus-independent CD8+ T cells suggest distinct roles of the two subsets of CD8+ T cells in vivo.

Original languageEnglish
Pages (from-to)1677-1683
Number of pages7
JournalInternational Immunology
Volume12
Issue number12
DOIs
Publication statusPublished - Jan 1 2000

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology

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