Both alpha-helices along the major histocompatibility complex binding cleft are required for staphylococcal enterotoxin A function.
Proc Natl Acad Sci U S A
; 88(16): 7228-32, 1991 Aug 15.
Article
en En
| MEDLINE
| ID: mdl-1871129
ABSTRACT
The superantigen staphylococcal enterotoxin A (SEA) requires interaction with class II major histocompatibility complex (MHC) molecules to activate T cells. We have previously used the synthetic peptide approach to establish one side of the hypothetical class II foreign-antigen binding cleft, alpha-helical region 65-85 of the beta chain, as a binding site involved in accessory cell presentation of SEA to T cells. To further characterize the structural basis for MHC-SEA interaction we have examined the role of the alpha-helical regions of the class II alpha and beta chains in SEA function. Using the synthetic peptide approach, we have found that both alpha-helical regions are required for SEA-induced proliferation. Their corresponding peptides directly bound SEA. Although the beta-chain peptides were able to inhibit SEA binding to human and mouse cells, the alpha-chain peptides were not. The data suggest that the alpha-helices along both sides of the hypothetical class II MHC molecule binding cleft are required for SEA-induced function, whereas the beta-chain alpha-helix is sufficient for SEA binding. A model of superantigen presentation is proposed wherein the MHC beta chain, possibly region 70-80, interacts with SEA region 1-45, whereas another region of SEA binds region 51-80 of the alpha chain.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Staphylococcus aureus
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Activación de Linfocitos
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Linfocitos T
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Antígenos HLA-D
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Enterotoxinas
Límite:
Humans
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
1991
Tipo del documento:
Article