The purpose of this study is to understand the effect of chitin on macrophage mediated immunity, which is a significant factor to wound healing and tissue regeneration. In this work, water soluble chitin (WSC) was prepared by re-acetylation of chitosan and was treated with the murine RAW 264.7 macrophage cell lines (ATCC TIB-71). WSC induced classical activation in the RAW 264.7 cells, accompanied by the induction of associated genes. The results suggest that WSC is one of the functional chitin molecules that are responsible for the immune response, especially present in macrophage classical activation. (c) 2012 Elsevier B.V. All rights reserved.