How are cytotoxic T cells (Tc cells) and natural killer (NK) cells similar?

Cytotoxic T cells (Tc cells) and natural killer (NK) cells share the characteristic of being effective against virally infected cells. Both types of cells play crucial roles in the immune response by identifying and destroying cells that have been compromised by infections, particularly those caused by viruses. Tc cells recognize specific viral antigens presented by infected cells on HLA class I molecules, while NK cells detect stressed, infected, or transformed cells through a variety of activating and inhibitory receptors without the need for antigen presentation. This allows both types of cells to efficiently target and eliminate virally infected cells, contributing to the body's defense mechanisms against viral pathogens.

The other options do not apply to the shared functions of these cell types. For example, cytotoxic T cells require specific antigen recognition, unlike NK cells which can act independently of antibodies. Additionally, while Tc cells recognize antigens presented on HLA class I molecules, NK cells do not require HLA class II markers for their activation. Lastly, it is inaccurate to say that both types of cells do not bind to infected cells, as binding is essential for their cytotoxic functions.