Molecular basis of B-cell activation. I. Mitogenicity of native and substituted dextrans.

摘要: The present experiments were performed in an attempt to investigate the nature of surface receptor on B lymphocytes responsible for triggering these cells. B-cell mitogenicity unsubstituted dextrans, quantitated by activation DNA and antibody synthesis was detected only if ligand had a MVC higher than 7 × 104. Above this threshold increased linearly with log MW Substitution polymeric structure lipid residues did not result conjugate. However, sulphate substitution sugar units greatly enhanced ability conjugates activate and. much smaller extent, synthesis. Mitogenicity derivatives independent their MW. Another polyanionic derivative (carboxymethyl) show mitogenicity. whereas low-MW compound very similar dextran (pentosan sulphate) highly active. induced dextrans immunologically nonspecific caused induction polyclonal activated cells presumably belong subset at rather premature stage differentiation. These findings suggest that mitogenic signal is delivered single sites membrane. appear have capacity interact polysaccharide structures or releated conformations active ligands necessary requirement seems accessory function providing multipoint binding low-affinity receptors.