Cutting edge: adenovirus E19 has two mechanisms for affecting class I MHC expression.
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Bennett EM, Bennink JR, Yewdell JW, Brodsky FM
Cutting edge: adenovirus E19 has two mechanisms for affecting class I MHC expression.
J Immunol. 1999 May 1;162(9):5049-52.
- PubMed ID
- 10227971 [ View in PubMed]
- Abstract
Viral strategies for immune evasion include inhibition of various steps in the class I MHC assembly pathway. Here, we demonstrate that adenovirus produces one gene product with a dual function in this regard. It is well established that adenovirus E19 binds class I molecules and retains them in the endoplasmic reticulum (ER). However, E19 also delays the expression of class I alleles to which it cannot tightly bind. Here, we show that E19 binds TAP and acts as a tapasin inhibitor, preventing class I/TAP association. DeltaE19, an E19 mutant lacking the ER-retention signal, delays maturation of class I molecules, indicating that E19's inhibition of class I/TAP interaction is sufficient to delay class I expression. These data identify tapasin inhibition as a novel mechanism of viral immune evasion and suggest that, through this secondary mechanism, adenovirus can affect Ag presentation by MHC alleles that it can only weakly affect by direct retention.