γδ T cells:: an alternative type of professional APC

A subtype of activated human gamma delta T cells, termed V delta 2(+) T cells, has antigen-presentation features similar in potency and efficacy to those seen in dendritic cells. Comparable treatment of alpha beta T cells does not result in 'professional' antigen presenting cells (APCs). What is so special about V delta 2(+) 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 V delta 2(+) T cells with the involvement of this alternative type of APC in anti-microbial alpha beta T cell responses.