Superantigen presenting capacity of human astrocytes

We found that human fetal astrocytes (HFA) are able to support superantigen (SAG) staphylococcal enterotoxin B (SEB) and toxic shock syndrome toxin-l (TSST-1)-induced activation of immediately ex vivo allogenic human CD4 T ce lls. Using radiolabelled toxins, we demonstrate that both SEE and TSST-1 bi nd with high affinity to MHC class II antigen expressing astrocytes; bindin g is displaceable with excess cold toxin, Competition experiments further i ndicate that TSST-1 and SEE at least partially compete with each other for binding to astrocytes suggesting they bind to the same HLA-DR region on the se cells. Our study supports the hypothesis that SAG would be capable of st imulating immune responses within the human CNS and contribute to persisten ce or recurrence of inflammatory responses within this compartment. (C) 200 0 Elsevier Science B.V. All rights reserved.