Essential role of CD4 T cells for the activation of group 2 innate lymphoid cells during respiratory syncytial virus infection in mice.

Abstract

To investigate whether and how CD4T cells contribute to ILC2 activation during respiratory syncytial virus (RSV) infection.The methods of flow cytometry, quantitative PCR and ELISA were used in the present study.Depletion of CD4 T cells diminished the numbers of lung ILC2s as well as their ability to produce type 2 cytokines. CD4T cell-mediated ILC2 activation is related to IL-2. The main cellular source of IL-2 was CD4T cells. Depletion of CD4 T cells decreased IL-2 levels in the lungs of RSV-infected mice. IL-2 can directly stimulate ILC2 proliferation and promote ILC2s to produce cytokines. Treatment of mice with neutralizing anti-IL-2 monoclonal antibodies diminished ILC2 activation.These results suggest that CD4 T cells contribute to RSV-induced ILC2 activation partly via producing IL-2.