A recombinant C-terminal fragment of staphylococcal enterotoxin A binds to human MHC class II products but does not activate T cells. |
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Authors: | G Hedlund M Dohlsten T Herrmann G Buell P A Lando S Segrén J Schrimsher H R MacDonald H O Sj?gren T Kalland |
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Institution: | Kabi Pharmacia Therapeutics AB, Lund, Sweden. |
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Abstract: | Binding of staphylococcal enterotoxin A (SEA) to MHC class II encoded proteins is a prerequisite for its subsequent activation of a large fraction of T lymphocytes through interaction with variable segments of the TCR-beta chain. We cloned SEA in Escherichia coli and produced four recombinant fragments covering both the N- and C-terminal regions. These fragments were used to analyze the interaction between SEA and the human MHC class II products. A C-terminal fragment of SEA, representing amino acids 107-233 bound to HLA-DR and HLA-DP but did not activate T cells. The three other fragments (amino acids 1-125, 1-179 and 126-233) neither bound to MHC class II Ag nor activated T cells. SEA apparently bind to HLA-DR and HLA-DP through its C-terminal part, whereas T cell activation is dependent on additional parts of the protein. |
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