A NOVEL DISIALOGANGLIOSIDE IN RAT SPLEEN LYMPHOCYTES

A novel ganglioside has been identified as the predominant disialoganglioside of the lymphocytes prepared from rat spleen. The ganglioside was isolated from rat spleen and characterized by compositional analysis, methylation analysis, sialidase hydrolysis, proton NMR spectroscopy, and negative ion fast atom bombardment mass spectrometry. The structure was determined as follows. [GRAPHICS] This ganglioside is a unique derivative of N-acetyllactosaminyl-G(M1). The three monosialogangliosides containing N-acetyllactosaminyl-G(M1) structure, which had been originally isolated from rat spleen (Nohara, K., Suzuki, M., Inagaki, F., Ito, H., and Kaya, K. (1990) J. Biol. Chem. 265, 14335-14339), were also found in the lymphocytes and were hardly detected in the spleen remnant tissue depleted of single cells. On the other hand, G(D1C)(NeuGc,NeuGC) (IV3(NeuGc-alpha-2-8NeuGc)-Gg4Cer), the overwhelmingly predominant gangLioside of rat thymocytes (Nohara, K., Suzuki, M., Inagaki, F., and Kaya, K. (1991) J. Biochem. (Tokyo) 110, 274-278), was demonstrated to be only a minor component of the gangliosides of the spleen Lymphocytes. These results suggested that G(D1c) is characteristic for the immature T lineage lymphoid cells and the gangliosides having lactosaminyl-G(M1) structure are specific for other populations of the lymphocytes in rat.