Phenotypic and functional characteristics of activated CD8+ cells: a CD11b-CD28- subset mediates noncytolytic functional suppression

Clin Immunol Immunopathol. 1991 Aug;60(2):254-67. doi: 10.1016/0090-1229(91)90068-l.


Freshly isolated human CD8+ cells can be divided into mutually exclusive subsets bearing the phenotypes CD11b+(CD28-) or CD28+(CD11b-). We found that activation of CD8+ cells with anti-CD3 mAb and IL-2 preferentially expanded the CD11b-(CD28+) subset. This subset, when separated and activated independently, mediated both functional suppression and lectin-dependent cell cytotoxicity (LDCC). CD28- cells, prepared by elimination of the CD 28+ cells from expanded unfractionated CD8+ cell cultures, retained functional suppressor activity but demonstrated reduced LDCC compared to either the CD28+(CD11b-)-enriched fraction or the unfractionated CD8+ population. The majority of the CD28- cells were also CD11b-, reflecting the observation that initially CD11b+ cells lose CD11b expression following activation with anti-CD3 mAb and IL-2. Our results therefore indicate that CD8+ cells deriving from the CD11b+CD28- subset, but expressing neither CD11b nor CD28 after activation, represent the main noncytotoxic functional suppressor cell in the mitogen "activated" suppressor assay. The preferential expansion of CD8+CD28+ cells relative to CD8+CD28- cells, if occurring in vivo in the central nervous system (CNS) compartment, would be consistent with observed phenotypic analysis of cerebrospinal fluid-derived T cells and might contribute to the reduced functional suppressor activity previously found for CNS compared to peripheral blood-derived lymphocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal
  • Antigens, Differentiation / metabolism
  • Antigens, Differentiation, T-Lymphocyte / immunology*
  • Antigens, Differentiation, T-Lymphocyte / metabolism
  • CD28 Antigens
  • CD8 Antigens
  • Cytotoxicity, Immunologic / drug effects
  • Cytotoxicity, Immunologic / immunology
  • Humans
  • Immunophenotyping
  • Immunosuppression Therapy
  • In Vitro Techniques
  • Killer Cells, Natural / physiology
  • Lectins / pharmacology
  • Lymphocyte Activation / immunology*
  • Macrophage-1 Antigen / metabolism
  • Receptors, Fc / metabolism
  • Receptors, IgG
  • T-Lymphocyte Subsets / immunology*
  • T-Lymphocytes, Regulatory / physiology


  • Antibodies, Monoclonal
  • Antigens, Differentiation
  • Antigens, Differentiation, T-Lymphocyte
  • CD28 Antigens
  • CD8 Antigens
  • Lectins
  • Macrophage-1 Antigen
  • Receptors, Fc
  • Receptors, IgG