γδ T cells as regulators of airway hyperresponsiveness

Airway responsiveness (AR) is determined by complex mechanisms reflecting lung responses to airborne stimuli. Murine studies have identified a number of potential factors modulating AR and thus have contributed to the current understanding of these mechanisms. In allergic inflammation, immune cells, in particularαβ T cells, have emerged as important contributors to increased AR. We have found that in contrast to αβ T cells, γδ T cells can have a negative regulatory effect on AR. Here, we review the current studies on γδ T cells in allergic inflammation and discuss their role in modulating AR. We propose that γδ T cells exhibit different immune properties depending on the type of stimulus and inflammation. These differential immune properties appear to be associated with specific γδ T cell subsets, which control AR to airborne stimuli. In particular, our recent data indicate that the Vγ4⁺T cell subset acts as an important negative regulator of AR and contributes to maintaining normal lung function in mice.