Expression of asialo GM1 by both Thy-1-positive and Thy-1-negative lymphocytes: evidence for modification of asialo GM1 by sialic acid.
In order to determine the extent to which Thy-1-positive and Thy-1-negative lymphocytes express the asialo GM1 antigen, lymphocytes in normal spleen and lymph node were examined for simultaneous expression of the asialo GM1 and Thy-1.2 determinants. The results presented herein demonstrate that 55-57% of Thy-1.2-positive cells in spleen and 61-70% of Thy-1.2-positive cells in lymph node express asialo GM1. Furthermore, a significant frequency of Thy-1-negative cells in spleen (12-19%) and in  lymph node (28-32%) also express asialo GM1. Since asialo GM1 has previously been shown to be absent on Ig-positive lymphocytes [9], these results establish that asialo GM1 is a marker shared by lymphocytes belonging to the T-cell lineage and lymphocytes apparently not committed to the T-cell to the T-cell lineage, most probably including natural killer (NK) cells. The implication of this finding as to the controversy regarding the possible relation of NK cells to T cells is discussed. Pretreatment of lymphocytes from spleen, thymus and lymph node with neuraminidase resulted in subsequent reactivity of 80-90% of these cells with anti-asialo GM1 anti-bodies. A smaller increase in asialo GM1 detection after neuraminidase treatment was seen with bone-marrow cells (65%). Protease treatment did not affect the subsequent reactivity of lymphocytes with anti-asialo GM1 antibodies. It is concluded that in situ enzymatic modification of asialo GM1 by the addition of sialic acid may be an important regulatory event in lymphocyte differentiation.
D000818:Animals; D002454:Cell Differentiation; D000939:Epitopes / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D005677:G(M1) Ganglioside; D006028:Glycosphingolipids / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology; D008198:Lymph Nodes / Q000166:cytology; D008214:Lymphocytes / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009439:Neuraminidase / Q000494:pharmacology; D012794:Sialic Acids / Q000494:pharmacology*; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology
D000939:Epitopes; D006028:Glycosphingolipids; D012794:Sialic Acids; D005677:G(M1) Ganglioside; C018835:asialo GM1 ganglioside; D009439:Neuraminidase