Antigen-specific Effector CD8 T Cells Regulate Allergic Responses via IFN-y and Dendritic Cell Function

Abstract

In this study, we aim to investigate the potential of CD8 T cells to modulate the elicitation of allergic inflammation and investigate the underlying mechanisms. Effector CD8 T cells from OT-I and IFN-gamma-/-OT-I mice were transferred to OVA-sensitized mice one day before OVA challenges. The effect on lung dendritic cells (DCs) exerted by CD8 T cells was studied with ex vivo culture of sorted DCs from treatment mice with either naive or antigen-experienced CD4 T cells. We found that effector OT-I, but not IFN-gamma-/-OT-I CD8 T cells attenuated eosinophilia and mucus secretion in the lungs of sensitized mice in an antigen-specific manner. Effector IFN-gamma-/-OT-I CD8 T cells displayed a Tc2/Tc17-biased phenotype with weaker cytotoxicity and were able to both induce and exacerbate eosinophilia as well as neutrophilia. OT-I CD8 T cells increased the ability of lung CD11b+CD103- DCs to both prime the differentiation of naive CD4 T cells toward a Th1 phenotype and enhance IFN-gamma production by antigen-experienced lung CD4 T cells.