Gammadelta T cells: an alternative type of professional APC.

A subtype of activated human gammadelta T cells, termed Vdelta2+ T cells, has antigen-presentation features similar in potency and efficacy to those seen in dendritic cells. Comparable treatment of alphabeta T cells does not result in 'professional' antigen presenting cells (APCs). What is so special about Vdelta2+ T cells? How do they acquire these unexpected properties? Under what physiological conditions would such a bridge between innate and adaptive immunity come into play? In addition to discussing these questions, we introduce a model that correlates the expression of lymph node homing receptors in Vdelta2+ T cells with the involvement of this alternative type of APC in anti-microbial alphabeta T cell responses.