Endocytic trafficking and intracellular fate of a high-affinity monoclonal antibody to ganglioside GD1a

RUGGIERO F.M.; VILCAES A.; TORRES DEMICHELIS V.A.; DANIOTTI J.L.

Buenos Aires

Simposio; First Argentinian Symposium of Glycobiology GlycoAR 2014; 2014

Local Organizing committee

Gangliosides are glycolipids mainly located at the plasma membrane (PM). Antibodies to gangliosides (AGAbs) have been associated with a wide range of clinically identifiable acute and chronic neuropathy syndromes. Particularly, antibodies to GM1 (Ab-GM1) and to GD1a gangliosides are present in patients with Guillain-Barre syndrome. Previous findings demonstrated that Ab-GM1 is internalized via caveolae, accumulated in recycling endosomes and recycled back to PM and culture medium. In this work, we investigated the binding and intracellular fate of a high-affinity purified mouse IgG1 antibody to GD1a (Ab-GD1a) in CHO-K1(GD1a+) cells. Confocal microscopy analysis showed that an Ab-GD1a fraction was rapidly internalized at 37°C, mainly colocalizing with recycling endosomes markers. In addition, the endocytic mechanism of Ab-GD1a uptake occurred by a dynamin-2 independent and ARF-6 dependent mechanism. In contrast to Ab-GM1, Ab-GD1a was slightly internalized at 37°C, and remained mostly localized at the PM in experiments performed at 16°C, widely used to accumulate the endocytic cargo in sorting endosomes. Taken together, these results provide additional evidences about the mechanisms that operate in the intracellular trafficking of antibodies binding to glycolipids and the possible pathological implications of differential endocytic processing of neuropathy associated AGAbs.