B cell chronic lymphocytic leukaemia cells have reduced capacity to upregulate expression of MHC class I in response to interferon-
Source: Pathology, 1 February 2004, vol. 36, no. 1, pp. 69-76(8)
Abstract:Aims: An important consideration in the design of a tumour vaccine is the ability of tumour-specific cytotoxic T lymphocytes (CTL) to recognise unmanipulated tumour cells in vivo. To determine whether B-CLL might use an escape strategy, the current studies compared B-CLL and normal B cell MHC class I expression.
Methods: Flow cytometry, TAP allele PCR and MHC class I PCR were used.
Results: While baseline expression of MHC class I did not differ, upregulation of MHC class I expression by B-CLL cells in response to IFN- was reduced. No deletions or mutations of TAP 1 or 2 genes were detected. B-CLL cells upregulated TAP protein expression in response to IFN-. Responsiveness of B-CLL MHC class I mRNA to IFN- was not impaired.
Conclusions: The data suggest that MHC class I molecules might be less stable at the cell surface in B-CLL than normal B cells, as a result of the described release of 2m and 2m-free class I heavy chains from the membrane. This relative MHC class I expression defect of B-CLL cells may reduce their susceptibility to CTL lysis in response to immunotherapeutic approaches.
Document Type: Research Article