EXPRESSION OF NEUTRAL GLYCOSPHINGOLIPIDS AND GANGLIOSIDES IN HUMAN SKELETAL AND HEART-MUSCLE DETERMINED BY INDIRECT IMMUNOFLUORESCENCE STAINING

The expression of neutral glycosphingolipids and gangliosides has been studied in human skeletal and heart muscle using indirect immunofluor escence microscopy. Transversal and longitudinal cryosections were imm unostained with specific monoclonal and polyclonal antibodies against the neutral glycosphingolipids lactosylceramide, globoside, Forssman g lycosphingolipid, gangliotetraosylceramide, lacto-N-neotetraosylcerami de and against the gangliosides G(M3)(Neu5Ac) and G(M1)(Neu5Ac). To co nfirm the lipid nature of positive staining, control sections were tre ated with methanol and chloroform:methanol (1:1) before immunostaining . These controls were found to be either negative or strongly reduced in fluorescence intensity, suggesting that lipid bound oligosaccharide s were detected. In human skeletal muscle, lactosylceramide was found to be the main neutral glycosphinogolipid. Globoside was moderately ex pressed, lacto-N-neotetraosylceramide and gangliotetraosylceramide wer e minimally expressed and Forssman glycosphingolipid was not detected in human skeletal muscle. The intensities of the immunohistological st ains of GM(3) and GM(1) correlated to the fact that GM(3) is the major ganglioside in skeletal muscle whereas GM(1) is expressed only weakly . In human heart muscle globoside was the major neutral glycosphingoli pid. Lactosylceramide and lacto-N-neotetraosylceramide were moderately expressed, gangliotetraosylceramide was weakly expressed and the Fors sman glycosphingolipid was not expressed at all in cardiac muscle. GM( 3) and GM(1) were detected with almost identical intensity. All glycos phingolipids were present in plasma membranes as well as at the intrac ellular level.