Expression of glycosphingolipids in lymph nodes of mice lacking TNF receptor 1: biochemical and flow cytometry analysis

Abstract

The expression of gangliosides and neutral glycosphingolipids (GSLs) in the lymph nodes of mice lacking the gene for the tumour necrosis factor-α receptor p55 (TNFR1) has been investigated. GSL expression in the tissues of mice homozygous (TNFR1−/−) or heterozygous (TNFR1+/−) for the gene deletion was analysed by flow cytometry and high-performance thin-layer chromatography (HPTLC) followed by immunostaining with specific antibodies. HPTLC immunostaining revealed that lymph nodes from TNFR1−/− mice had reduced expression of ganglioside GM1b and GalNAc–GM1b, neolacto-series gangliosides, as well as the globo- (Gb3, Gb4 and Gb5) and ganglio-series (Gg3 and Gg4) neutral GSLs. Flow cytometry of freshly isolated lymph node cells showed no significant differences in GSL expression, except for the GalNAc–GM1b ganglioside, which was less abundant on T lymphocytes from TNFR1−/− lymph nodes. In TNFR1−/− mice, GalNAc–GM1b +/CD4 + T cells were twofold less abundant (3.8% vs 7.6% in the control mice), whereas GalNAc–GM1b +/CD8 + T cells were fourfold less abundant (5.0% vs 20.2% in the control mice). This study provides in vivo evidence that TNF signalling via the TNFR1 is important for the activation of GM1b-type ganglioside biosynthetic pathway in CD8 T lymphocytes, suggesting its possible role in the effector T lymphocyte function.