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CD8+ T cell recognition of peptides presented by major histocompatibility complex class I molecules is essential for effective antiviral and antitumor immune responses. How the repertoire of peptides is selected, shaped and presented is becoming increasingly clear.
How regulatory T cells dampen T cell responses in vivo remains unclear. Direct visualization of regulatory T cell activity in an autoimmune setting provides exciting new insights into regulatory T cell–mediated suppression.
The thymus is considered the source of mature lymphocytes and is not thought to produce progenitors with the capacity to develop into unconventional T cells in the periphery. That view requires revision.
Discrimination between self and bacterial DNA has been attributed in part to differential modification of prokaryotic and eukaryotic DNA. However, cellular localization of innate DNA receptors may be even more important.
The function of TRAF3, a member of the family of tumor necrosis factor receptor–associated factors, has remained an enigma. Two recent Nature papers now show that TRAF3 regulates interferon and interleukin 10 production.