ABSTRACT
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-(alpha-D-glucopyranosyl)- 6'-O-acyl-alpha-D-glucopyranosyl]-1,2-di-O- acyl-sn-glycerol (GAGDG) using (1)H- and (13)C-NMR and GC-MS. The compositions of the major saturated fatty acids were nC (14) (17.8%), isoC(14) (10.7%) and nC (16) (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 isoC(14) acyl group was higher than those with nC(14) and nC(16) acyl groups. The binding to lymphoid cells reveals a novel biological activity of GAGDGs.
