PD-1 Is a Negative Costimulatory Signal Expressed by Tumor Cells

question 33

Multiple Choice

PD-1 is a negative costimulatory signal expressed by tumor cells.What advantage would the expression of PD-1 have in a tumor cell avoiding the immune response?

• A)Tumor cells can avoid being killed by activated T_C cells.
• B)Tumor cells can avoid apoptosis triggered by T_H cells.
• C)Tumor cells avoid phagocytosis by dendritic cells.
• D)Tumor cells are stimulated to reproduce faster than tumor cells that do not express PD-1.
• E)None.Tumor cells are recognized as self and, therefore, do not pose a health threat.