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Åke Lernmark

Principal investigator

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Activated human epitope-specific T cells identified by class II tetramers reside within a CD4high, proliferating subset


  • Erik J. Novak
  • Susan A. Masewicz
  • Andrew W. Liu
  • Åke Lernmark
  • William W. Kwok
  • Gerald T Nepom

Summary, in English

Antigen-specific T cells acquire a distinctive phenotype during activation, with characteristic acquisition of surface markers and patterns of gene expression. Early after antigen stimulation, CD4+ T lymphocytes increase their surface density of the CD4 marker, a trait which has been used to identify antigen-activated cells. The recent development of MHC tetramer technologies has greatly improved the ability to detect HLA class I-restricted T cells specific for known antigen epitopes. We have recently extended these studies to human class II-restricted CD4+ T cell responses and now describe antigen-specific T cell responses from human peripheral blood in which elevated CD4 expression levels in human T cells following antigen stimulation identify the activated and proliferating subset of cells. The CD4high population is substantially enriched in epitope-specific cells identified by class II tetramer staining and almost all tetramer-positive cells are contained within the CD4high population. T cell clones derived from the tetramer-positive, CD4high population demonstrate antigen specificity and maintain tetramer staining, while the substantial number of CD4high cells which fail to stain with tetramer appear to proliferate as a result of bystander activation. Epitope-specific components of a polyclonal immune response are directly visualized and quantitated by tetramer detection, providing a direct measure of the heterogeneity of the human immune response.

Publishing year







International Immunology





Document type

Journal article


Oxford University Press


  • Cellular activation
  • FACS
  • HLA
  • MHC
  • T Lymphocytes




  • ISSN: 0953-8178