Antibody-directed superantigen-mediated T-cell killing of myeloid leukaemic cell line cells

Eur J Haematol. 1998 Apr;60(4):233-9. doi: 10.1111/j.1600-0609.1998.tb01029.x.


Bacterial superantigens (SAgs) bound to MHC class II molecules on target cells are efficient activators of cytotoxic T cells expressing certain T cell receptor (TCR) Vbeta regions We described earlier that the specificity of the SAg Staphylococcus enterotoxin A (SEA) can be changed by introducing a D227A point mutation in the major MHC class II binding site and by genetically fusing the SEA mutant (SEAm) to protein A (PA). This SEAm-PA fusion protein can then be used to direct cytotoxic T cells to tumour cells coated with monoclonal antibodies (mAbs). In this communication, we tested the PA-SEAm fusion protein together with mAbs against the myeloid cell surface antigens CD13, CD15 and CD33. A SEA-reactive T cell line was used as effector cells against 10 different myeloid leukaemic cell lines. Optimal lysis of antigen positive leukaemic cells was obtained at a PA-SEAm concentration of 1 ng/ml and effector : target cell ratios of 15 : 1. No correlation between target cell sensitivity and the level of surface antigen expression could be seen. The 6 acute myeloid leukaemia (AML) cell lines tested appeared to be more sensitive than the 4 chronic myeloid leukaemia (CML) cell lines. The sensitivity of the AML cell line HL-60 could be improved further by stimulation with TNFalpha. This was accompanied by increased surface ICAM-1 expression whereas specific target molecule expression (CD13, CD33) was unchanged. This suggests that sensitivity to lysis is related to the leukaemic subtype and ICAM-1 expression but not to the tumour antigen density. Our results show that it is possible to direct cytotoxic T cells to myeloid leukaemia cells by using SAgs linked to mAbs, and encourage the construction and testing of a recombinant direct SAg-mAb fusion protein as a candidate drug for therapy of myeloid leukaemias.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / immunology*
  • Antibody-Dependent Cell Cytotoxicity*
  • Antigens, CD / immunology
  • Antigens, Differentiation, Myelomonocytic / immunology
  • Cell Line
  • HL-60 Cells
  • Humans
  • Leukemia, Myeloid / immunology*
  • Leukemia, Myeloid / pathology
  • Phenotype
  • Sialic Acid Binding Ig-like Lectin 3
  • Stimulation, Chemical
  • Superantigens / immunology*
  • T-Lymphocytes / immunology*
  • T-Lymphocytes, Cytotoxic / immunology*
  • Tumor Necrosis Factor-alpha / pharmacology


  • Antibodies, Monoclonal
  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • CD33 protein, human
  • Sialic Acid Binding Ig-like Lectin 3
  • Superantigens
  • Tumor Necrosis Factor-alpha