In these cells , the expression of MHC-class I antigens is repressed and might allow them to escape from recognition by cytotoxic T lymphocytes ( CTL ) and to develop in tumor .
in these cells , the expression of mhc-class i antigens is repressed and might allow them to escape from recognition by cytotoxic t lymphocytes ( ctl ) and to develop in tumor .
O O O O O O O B-protein_family_or_group I-protein_family_or_group I-protein_family_or_group O O O O O O O O O O O B-cell_type I-cell_type I-cell_type O B-cell_type O O O O O B-tissue O