A novel pentapeptide originated from calf thymus named TIPP shows an inhibitory effect on lung allergic inflammation.

Thymic immunosuppressive pentapeptide (TIPP) is a novel pentapeptide originally obtained from calf thymic immunosuppressive extract. In this study we aimed to investigate the anti-inflammatory effect and mechanisms of TIPP in vivo with an ovalbumin-induced mouse allergic asthma model. We investigated the effects of TIPP on the infiltration of inflammation cells, immune cell subtypes, Th2 cytokines in BALF and IgE in serum, mRNA levels of IL-4, IL-10, TNF-α and eotaxin-1, expression of MCP-1, VCAM-1 and COX-2, and activation of MAP kinases and NF-κB. Our results showed that TIPP significantly inhibited the increase in Th2 cytokines and OVA-specific IgE production, mRNA levels of IL-4, TNF-α and eotaxin-1 and the expression of MCP-1, VCAM-1 and COX-2 in lung tissues, as well effectively resisting the balance changes of cells in BALF. In addition, it was found that the administration of TIPP attenuated the activation of MAP kinases and NF-κB in the lung tissues of the allergic mice. Our data suggest that TIPP effectively suppresses the allergic and inflammatory responses in allergic mice via blocking MAP kinases/NF-κB signalling pathway. The investigation indicated that TIPP may become an anti-allergic and anti-inflammatory drug.