The self peptide annexin II (208-223) presented by dendritic cells sensitizes autologous CD4+T lymphocytes to recognize melanoma cells

Annexin II is known to be over-expressed in different types of tumours. We show here that annexin II protein is expressed by melanoma cell lines in va rious amounts, consistent with previous findings that an annexin II (208-22 3) peptide could be eluted from isolated HLA-DR molecules of a constitutive ly MHC class II-positive melanoma line. T cells sensitized to annexin II (2 08-223) in vitro using peptide-pulsed autologous dendritic cells responded only to the lines which overexpressed annexin II, in a peptide-specific, HL A-DR-restricted fashion. These CD4+ T cells proliferated strongly and secre ted large amounts of type 1 cytokines in response to annexin II (208-223) p eptide or annexin II protein-positive melanoma cell lines. These results de monstrate that the annexin II (208-223) peptide, corresponding to a non-mut ated sequence of a normal protein, induces antigen-specific T cells which c an respond to melanoma cells over-expressing the annexin II molecule. This peptide may therefore be useful in immunotherapy for recruiting CD4+ type 1 helper cells active locally in the tumour environment.