Which Statement About the Cellular Immune Response Is True

Which statement about the cellular immune response is true?

A) During the activation phase, cytotoxic T cells recognize and bind to antigen-class II MHC complexes.
B) Cytotoxic T cells release interleukin-1 when bound to an antigen-presenting macrophage.
C) Class I MHC proteins display antigenic fragments on virus-infected cells during both the activation and effector phases.
D) Binding by a T cell to the CD4 receptor on the target cell initiates programmed cell death during the effector phase.
E) Perforin is a cytokine that stimulates proliferation of cytotoxic T cells in the effector phase.