Abstract
To elucidate the role of Bullous pemphigoid (BP) IgG subclasses in the transmembrane signal transduction of keratinocytes, we examined whether BP IgG2 or IgG4 inhibits the intracellular Ca2+ concentration ([Ca2+]i) increase induced by BP IgG1, IgG2 from one of five BP patients inhibited the increase of [Ca2+]i in human squamous cell carcinoma cell line; DJM-1 cells induced by BP IgG1. IgG4 from two of four BP patients inhibited the increase of [Ca2+]i induced by BP IgG1. In addition, a two fold quantity of IgG2 inhibited the increase of [Ca2+]i induced by BP IG1. A two fold quantity of IgG4 from two of five BP patients inhibited the increase of [Ca 2+]i induced by BP IgG1. These results indicate that BP IgG2 and IgG4 have a capability to inhibit the increase of [Ca2+]i induced by BP IgG1.