VSTM2L, also known as V-set and transmembrane domain containing 2, is a new modulator of HN neuroprotective activity. It colocalizes with HN in distinct brain areas as well as in primary cultured neurons, where it plays a role in the modulation of neuronal viability. When tested in HN neuroprotection bioassays, it acts as a strong antagonist of HN neuroprotective activity. This protein is the first example of a secreted antagonist of HN and may play a role in the modulation of HN biological functions. Recombinant human VSTM2L protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography.