Steady-State Production of IL-4 Modulates Immunity in Mouse Stains, and is Determined by Lineage Diversity of iNKT Cells

Invariant natural killer (iNKT) cells are a population of T cells with limited TCR diversity which are able to respond to certain glycolipids presented in the MHC Class I-like molecule CDId, releasing a numbers of pro-inflammatory cytokines within hours of activation. iNKT cells may also be activated indirectly by certain cytokines released by dendritic cells after innate immune recognition (1). The role of iNKT cells in transplantation is not fully clucidated, however there is evidence that they are activated by IL-2 released by alloreactive T Cells via bystander activation (2) and that they may also contribute to rejection after activation in post-surgical inflammatory environments. Conversely, there are data that demonstrate a rule of iNKT cells in the induction of tolerance in transplantation (1). It is unclear whether such opposing roles of iNKT cells are secondary to the presence of heterogeneous population of iNKT or whether iNKT cells release distinct cytokines under the influence of particular environments.