Antibodies induced by antigen-containing liposomes as immunogens preferentially recognize their antigens present on lipid vesicles

We established a flow cytometry method to detect interactions between antibodies against glycosphingolipids (GSLs) and liposomes composed of phospholipids, cholesterol, and GSLs. Using this system, we found that antibodies induced by antigen-containing liposomes as immunogens bound preferentially to the antigens present on liposomes. Anti-GSL antibodies obtained using GSL-containing liposomes as immunogens exhibited greater sensitivity in detecting GSLs present on liposomes compared with antibodies obtained using cells or glycoproteins as immunogens. Further analyses using the breast cancer–associated glycolipid Globo-H showed that antibodies capable of detecting extracellular vesicles secreted by MCF-7 breast cancer cells could be induced by immunizing mice with Globo-H–containing liposomes. Our results indicate that antibodies obtained using antigen-containing liposomes as immunogens are suitable for detecting antigens present on liposomes, and such antibodies can be applied to the detection of specific antigens present on extracellular vesicles.