Volume 16 Issue 2, February 2015

Type 2 cytokine–producing innate lymphoid cells (ILC2 cells) can respond to interleukins IL-25 and IL-33. Distinct subsets are now recognized as inflammatory ILC2 cells and natural ILC2 cells that differ in their responses to these cytokines.

The identification of a new class of cross-reactive monoclonal antibodies that strongly neutralize all four serotypes of dengue virus has important implications for vaccine design as well as for the evaluation of vaccines and of natural infection with dengue virus.

The chemoattractant receptor GPR15 directs the homing of T cells to the colon; however, GRP15 expression differs in the effector and regulatory T cell subsets of humans versus those of mice. These findings have profound implications for the potential targeting of GRP15 for therapeutic intervention.

Regulatory T cells require the phosphatase PTEN to maintain suppressive function in homeostatic conditions through preserved expression of CD25 and the transcription factor Foxp3.

In this Review, Ueno, Vinuesa and Banchereau discuss the similarities and differences between mouse and human follicular helper T cells (T_FH cells) and discuss their role in response to vaccines and in disease pathogenesis.

Innate lymphoid cells (ILCs) contribute to lymphoid tissue development and influence immune responses. Locksley and colleagues identify arginase 1–expressing fetal ILC precursors that give rise to multiple ILC subsets and lymphoid tissue–inducer cells.

Type 2 innate lymphoid cells (ILC2 cells) contribute to early immune responses directed against helminths and fungi. Paul and colleagues identify distinct inflammatory IL-25-responsive and natural IL-33-responsive ILC2 cells in lung tissues.

Dengue virus is an important emerging pathogen, but so far there is no vaccine effective for all serotypes. Screaton and colleagues identify a class of broadly reactive human antibodies focused on an epitope that bridges two virion subunits.

T_reg cells control effector cells such as T_H1 and T_FH cells. Chi and colleagues demonstrate that PTEN is cell-intrinsically required for T_reg cell lineage stability and regulation of effector T cell responses.

Regulatory T cells normally maintain high expression of the phosphatase PTEN. Turka and colleagues use conditional deletion of PTEN in regulatory T cells to show that it is critical for their function and stability.

Regulatory T cells can express the classic effector T cell transcription factors T-bet and GATA-3. Zhu and colleagues demonstrate that T-bet and GATA-3 are dynamically expressed in regulatory T cells and are redundantly essential for stabilizing the identity and function of these cells.

The chemoattractant receptor GPR15 can direct CD4⁺ T cells to the colon. Habtezion and colleagues show that GATA-3 and Foxp3 exhibit species-specific differences in promoting GPR15 expression and thereby influences homing of CD4⁺ effector and regulatory T cells.