Activation of murine T cells by bacterial superantigens requires B7-mediated costimulation

Cell Immunol. 1995 May;162(2):315-20. doi: 10.1006/cimm.1995.1084.


Staphylococcus enterotoxins bind class II MHC molecules on antigen-presenting cells (APC) and stimulate T cells expressing appropriate V beta gene products. Although the role of non-TcR-associated costimulatory receptors during antigen-specific T cell stimulation has been clearly established, the involvement of costimulatory activity in T cell activation by superantigens (SAgs) has been the matter of controversy. The aim of this study was to evaluate the role of the costimulatory-receptor ligand molecules CD28/B7 on bacterial SAg-mediated activation of naive murine T cells. We demonstrate in this report that a combination of monoclonal antibodies to murine B7.1 and B7.2 molecules inhibits the in vitro response of naive T cells to SAgs SEA, SEB, and TSST-1. The inhibition of T cell responses required simultaneous blocking of B7.1 and B7.2, suggesting that either B7.1 or B7.2 is sufficient to provide costimulatory signals to naive T cells in response to bacterial exotoxins. Inhibition of T cell activation by antibodies to B7-related molecules can be overcome by antibodies to CD28, a finding in agreement with the hypothesis that CD28-mediated signals participate in T cell activation by bacterial SAgs. These observations suggest that, as demonstrated for conventional antigen, T cell activation by SAgs requires the coordinated participation of TcR- and CD28-derived signals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B7-1 Antigen / physiology*
  • Bacterial Toxins / immunology
  • CD28 Antigens / physiology*
  • Female
  • In Vitro Techniques
  • Lymphocyte Activation*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred DBA
  • Receptors, Antigen, T-Cell / physiology*
  • Signal Transduction
  • Superantigens / immunology*
  • T-Lymphocytes / immunology*


  • B7-1 Antigen
  • Bacterial Toxins
  • CD28 Antigens
  • Receptors, Antigen, T-Cell
  • Superantigens