Alzheimer disease (AD) is characterized as neurodegenerative disease showing impairment of cognitivefunction, death of neuronal cells, numerous numbers of senile plaques and tangle of neurofilaments.Humanin, HN, is novel 24- residue peptide which protects neuronal cell death . HN shows neuroprotectiveactivity to the cell damage not only with known three familial AD gene such as APP, PS1, and PS2 but alsowith Abeta peptide. HN is a secretary peptide and exerts its protective function from the outside of the cell.This antibody is useful not only to the study of identify the mechanism AD but also to the research fornovel therapeutic approach.