CD20 (pan-B cell) antigen is expressed at a low level on a subpopulation of human T lymphocytes

Cytometry. 1993;14(2):196-204. doi: 10.1002/cyto.990140212.


Despite the previous description of the leukocyte differentiation antigen CD20 as B cell restricted, the findings reported here indicate that a small subset of human T cells expresses low levels of CD20 or a cross-reacting antigen. Three different CD20 monoclonal antibodies (mAb), Leu16, B1, and 1F5, reacted with the T cell subset. B cells that expressed CD20 were CD20bright and constituted an average of 9.2 +/- 3.3% of adult PBL. Meanwhile, T cells that expressed CD20 were CD20dim and represented 2.4 +/- 1.5% of the PBL. This population may have been overlooked in previous studies due to the low level of CD20 expression per T cell and the small size of the subset in most individuals. Blocking studies indicated that CD20 mAb binding to CD3+ cells was due to the antigen-reactive regions of the CD20 antibodies and was not a result of Fc receptor binding, or non-specific fluorochrome or protein binding. The T cell nature of the CD20dim CD3+ cells was confirmed by the rapid rise in the intracellular calcium concentration ([Ca2+]i) of CD20dim cells observed following treatment with CD3 mAb but not following treatment with anti-human immunoglobulin (Ig). Extensive three-color immunophenotypic analyses indicated that CD20dim T cells were phenotypically heterogeneous and displayed a leukocyte differentiation profile that was slightly different than that of CD20- T cells. Thus, the CD20dim T cells were more likely than CD20- T cells to be gamma/delta T cell antigen receptor positive (14% vs. 3.4%), CD8+ (57% vs. 33%), and CD45RO+ (82% vs. 51%); fewer were CD38+ (5% vs. 24%) or CD4+ (35% vs. 61%).(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

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

MeSH terms

  • Antibodies, Monoclonal / pharmacology*
  • Antigens, CD / analysis*
  • Antigens, CD20
  • Antigens, Differentiation, B-Lymphocyte / analysis*
  • CD3 Complex / immunology
  • Calcium / metabolism
  • Cell Separation
  • Female
  • Flow Cytometry
  • Humans
  • Immunohistochemistry
  • Immunophenotyping
  • Male
  • T-Lymphocyte Subsets / drug effects
  • T-Lymphocyte Subsets / immunology*


  • Antibodies, Monoclonal
  • Antigens, CD
  • Antigens, CD20
  • Antigens, Differentiation, B-Lymphocyte
  • CD3 Complex
  • Calcium