Cytotoxic T-cells

There are no cytotoxic B cells, only cytotoxic T cells.

The cytotoxic T cell, when it finds cells displaying the wrong antigens, ruptures the cell membrane of the offending cell killing it. Cytotoxic T cells are effective against virus infected cells and cancer cells.

cytotoxic t cell and helper t cell

A cytotoxic T cell kills cells that have been infected by a virus or bacterium. It does this by puncturing the cell's membrane and by emitting a toxin that kills cells.