Calreticulin maintains the low threshold of peptide required for efficient antigen presentation.
نویسندگان
چکیده
Calreticulin (CRT) plays a critical role in MHC class I antigen processing and elicits peptide-specific CD8(+) T cell responses against tumours when administered with peptides. However, how CRT contributes to class I antigen processing and the mechanism of its adjuvant effect in anti-tumour responses, remain to be elucidated. Here we show that reduced class I expression in CRT deficient cells can be restored by the direct delivery of peptides into the ER or by incubation at low temperature. CRT deficient cells exhibited a TAP-deficient phenotype in terms of class I assembly, without loss of TAP expression or functionality. Furthermore, a higher concentration of antigen in the cytosol is required for specific T cell stimulation, suggesting that CRT has a functional role in the maintenance of the low peptide concentration threshold required in the ER for efficient antigen presentation. In the absence of CRT, ERp57 is up-regulated, which indicates that they collaborate with each other in class I antigen processing.
منابع مشابه
Assessment of Roles for Calreticulin in the Cross-Presentation of Soluble and Bead-Associated Antigens
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ورودعنوان ژورنال:
- Molecular immunology
دوره 46 16 شماره
صفحات -
تاریخ انتشار 2009