Virus-specific CD4+ T cells:: ready for direct attack

CD4(+) T cells are classically thought to orchestrate adaptive immune responses. But recent studies demonstrate that they can also kill infected cells directly. A new paper shows that highly efficient processing of Epstein Barr virus (EBV) glycoproteins for presentation on MHC class II makes virus-transformed B cells susceptible to lysis by CD4(+) T cells. Thus, antiviral vaccines should aim to stimulate both helper and cytolytic CD4(+) T cells.