Effect of pure bovine brain-derived gangliosides on normal human B cell proliferation in vitro.
Pure gangliosides obtained from bovine brain including GM1, GD1b, GT1b and asialo-GM1 (GA1) did not induce normal human B cell proliferation in vitro. No B cell proliferation was observed either when GM1 was tested in the presence of interleukin-2 (IL-2), IL-4 or IL-6. Furthermore, the proliferative responses of human B cells induced by Staphylococcus aureus Cowan I (SAC), a T cell-independent B cell mitogen, were inhibited by these gangliosides. The degree of inhibition was influenced by ganglioside-bound sialic acid, although sialic acid per se was not inhibitory. Strongest inhibition was observed in the presence of GT1b (EC50 8.8 microM/10(5) B cells) and lowest in the presence of GA1 (EC50 129.5 microM/10(5) B cells) with intermediate values for GM1 and GD1b. GM1 inhibition of SAC-induced B cell proliferation did not represent cytotoxic effects and was still evident when GM1 was added 24-48 h after the beginning of the cultures. GM1 inhibition of SAC-induced proliferation was not reversed by the addition of IL-2, IL-4, IL-6 or their combination. In addition, GM1 inhibited the ILs-driven proliferative responses of SAC-induced B cell blasts. However, no inhibition of Epstein-Barr virus-induced B cell proliferative responses was observed. In conclusion, these results show that bovine brain-derived gangliosides do not induce proliferative responses of normal human B cells but, on the contrary, inhibit B cell responses induced by SAC.
Frugoni
P
P
Department of Immunology, Fidia Research Laboratories, Abano Terme, Italy.
Secchi
E F
EF
Chizzolini
C
C
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002417:Cattle; D002478:Cells, Cultured; D005732:Gangliosides / Q000494:pharmacology*; D006801:Humans; D007378:Interleukins / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects*; D019158:N-Acetylneuraminic Acid; D012794:Sialic Acids / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000276:immunology
D005732:Gangliosides; D007378:Interleukins; D012794:Sialic Acids; D019158:N-Acetylneuraminic Acid