Binding of glycoglycerolipid derived from membranes of Acholeplasma laidlawii PG8 and synthetic analogues to lymphoid cells

A component that binds to human lymphoid cells was isolated from the membranes of Acholeplasma laidlawii PG8. The component was extracted using the Bligh-Dyer method and purified using a silica-gel column and TLC. The active component was identified as 3-O-[2'-O- (α-D-glucopyranosyl)-6'-O-acyl-α-D-glucopyranosyl]-1, 2-di-O-acyl-sn-glycerol (GAGDG) using ¹H- and ¹³C-NMR and GC-MS. The compositions of the major saturated fatty acids were nC₁₄ (17·8%), isoC₁₄ (10·7%) and nC₁₆ (34·9%) as determined by GC-MS. The amounts of unsaturated species were less than 10% of those of the corresponding saturated acids. GAGDGs which have three tetradecanoyl groups were synthesized. These synthetic GAGDGs, as well as GAGDGs derived from A. laidlawii membranes, had a high binding affinity for MOLT-4 and HUT-78 (human T cell lines), Raji (a B cell line), HL-60 (a monoblastoid cell line) and primary cultured human T cells. The binding affinities of GAGDGs with an isoC₁₄ acyl group was higher than those with nC₁₄ and nC₁₆ acyl groups. The binding to lymphoid cells reveals a novel biological activity of GAGDGs.