CD11b expression as a marker to distinguish between recently activated effector CD8(+) T cells and memory cells

Int Immunol. 2001 Apr;13(4):593-600. doi: 10.1093/intimm/13.4.593.


CD8(+) T cells in different activation states have been difficult to identify phenotypically. In this study we have investigated whether Mac-1 (CD11b) expression can be used as a criterion to distinguish between recently activated effector cells and memory cells belonging to the CD8(+) T cell subset. Polyclonal virus-specific effector and memory CD8(+) T cells from lymphocytic choriomeningitis- and vesicular stomatitis virus-infected mice were visualized through staining for intracellular IFN-gamma or binding of MHC-peptide tetramers, and Mac-1 expression was evaluated. Naive T cells and most virus-specific memory CD8(+) T cells express little or no Mac-1 independent of the virus model employed. In contrast, the majority of CD8(+) T cells present during acute infection express a significant level of Mac-1 and, similarly, Mac-1 expression is found on secondary effectors generated in response to viral re-exposure. We therefore suggest that high Mac-1 expression defines a subset of circulating effector cells and that the presence of this marker on antigen-specific CD8(+) T cells signifies recent activation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Animals
  • Biomarkers / analysis
  • CD8-Positive T-Lymphocytes / immunology*
  • Female
  • Flow Cytometry
  • Immunologic Memory*
  • Lymphocyte Activation
  • Lymphocytic Choriomeningitis / immunology
  • Lymphocytic Choriomeningitis / virology
  • Lymphocytic choriomeningitis virus
  • Macrophage-1 Antigen / analysis*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Rhabdoviridae Infections / immunology
  • Rhabdoviridae Infections / virology
  • Vesicular stomatitis Indiana virus


  • Biomarkers
  • Macrophage-1 Antigen