Altered influenza virus haemagglutinin (HA)-derived peptide is potent therapy for CIA by inducing Th1 to Th2 shift.

There has been an increase in interest in the use of altered peptides as antigen-specific therapeutic agents in autoimmune diseases. Here we investigated the inhibitory effect and possible mechanism of an altered influenza virus haemagglutinin (HA)-derived peptide in collagen-induced arthritis (CIA). CIA was induced in DBA/1 mice by immunisation with type II collagen (CII). Altered HA308-317, wild-type HA308-317 or irrelevant peptide was administered intranasally beginning from arthritis onset. Clinical and histological scores were assessed, and cytokine levels in the serum or supernatants from splenocytes were determined. The percentages of Th1 and Th2 cells in response to different peptides were analysed by FACS both in vivo and in vitro. Our results showed that intranasal administration of altered HA308-317 peptide significantly ameliorated CIA. The therapeutic effect of altered HA308-317 peptide was associated with a substantial decrease in production of interferon (IFN)-γ, interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, anti-CII IgG, IgG1 and IgG2a antibodies, and an markedly increase in production of IL-10 and IL-4 in serum or supernatants from splenocytes treated with altered HA308-317 peptide. The percentage of Th2 (CD4(+)IL-4(+)) cells was upregulated significantly by altered HA308-317 peptide with a decreased percentage of Th1 (T helper 1; CD4(+)INF-γ(+)) cells both in vivo and in vitro. These findings suggest that altered HA308-317 peptide might be a promising candidate for rheumatoid arthritis (RA) treatment.