Immunohistochemical expression of CD68 antigen in human peripheral blood T cells

Hum Pathol. 1994 Sep;25(9):872-6. doi: 10.1016/0046-8177(94)90005-1.


CD68 antigen is expressed by tissue macrophages and cells of myeloid/mononuclear lineage. CD68 is recognized by many monoclonal antibodies (mAbs), including KP1, EMB11, Y1/82A, Y2/131, Ki-M6, and Ki-M7. Using the labeled strept-avidin-biotin (LSAB) immunoperoxidase technique, we examined CD68 antigen expression in human peripheral blood T cells. The anti-CD68 mAbs KP1 and EMB11 stained virtually all fresh isolated gamma/delta T cells and CD3-CD56+ natural killer (NK) cells in a granular cytoplasmic pattern. In contrast, fresh isolated CD4+ and CD8+ T lymphocytes showed no detectable reactivity with these two anti-CD68 mAbs. However, in vitro stimulation with T-cell mitogen or recombinant interleukin-2 (rIL-2) induced expression of CD68 antigen in activated CD4+ and CD8+ T lymphocytes. Similarly, the lymphokine-activated killer (LAK) cells generated after long-term (14 to 21 days) culture of peripheral blood mononuclear cells (PBMC) in rIL-2 also showed strong granular cytoplasmic staining by the anti-CD68 antibodies. This study shows that the CD68 antigen is constitutively expressed in NK cells and gamma/delta T cells and that its expression is strongly induced in activated CD4+ and CD8+ T lymphocytes as well as LAK cells.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies, Monoclonal
  • Antigens, CD / blood*
  • Antigens, Differentiation, Myelomonocytic / blood*
  • Flow Cytometry
  • Humans
  • Immunoenzyme Techniques
  • Killer Cells, Lymphokine-Activated / immunology
  • Killer Cells, Natural / immunology
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocytes / immunology*


  • Antibodies, Monoclonal
  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • CD68 antigen, human