CD8+ T activation attenuates CD4+ T proliferation through dendritic cells modification

•Activation of CD8+ T cells inhibited the proliferation of antigen specific CD4+ T cells in vivo and in vitro.•Activated CD8+ T derived soluble factors contributed to DCs modification.•IFN-γ neutralization partly reversed the immunosuppression of activated CD8+ T cells.•CD8+ T activation markedly alleviated OVA induced CD4+ T mediated asthma in mice.